On-block mechanistic determinants of start performance in high performance swimmers

This study aimed to 1) identify what starting block outcome kinetics have the greatest relationship to 15 m start time; 2) investigate key mechanistic determinants of the block phase and how these forces are sequenced. One hundred and fifty-two high-level competitive swimmers were included in the study. Linear mixed modelling identified four on-block outcome kinetic variables (work, average power, horizontal take-off velocity (HTOV), and average acceleration) as having a very large relationship (R2 = 0.79-0.83) to 15 m start time, with average power having the most substantial impact. On-block force sequencing started with the rear leg, followed by upper limb grab forces and the front leg. Further exploration of underlying determinants was performed for average power and HTOV of the centre of mass. Multiple linear regression identified grab resultant peak force, rear resultant average force, front horizontal peak force, and resultant peak force as significant predictors of average power (R2 = 0.88). HTOV was predicted using the same variables, apart from the inclusion of rear horizontal peak force instead of rear resultant average force (R2 = 0.73). These findings may influence how strength and conditioning and skill acquisition interventions are designed to improve swim start performance.

Prioritising restorative care programs in light of current age care reform

BACKGROUND

Short-term restorative care (STRC) aims to reduce the demand for long-term aged care services through 8 weeks of intensive, multidisciplinary services designed to enhance the independence of community-dwelling older Australians at risk of functional decline. Evidence surrounding the effectiveness and feasibility of STRC is limited.

OBJECTIVE

This study aimed to examine the effectiveness of an existing exercise-based STRC model and help inform successful service delivery to maximise participant outcomes nationally.

METHODS

An observational cohort study was conducted to evaluate the potential benefits accrued by community-dwelling older adults accessing Southern Cross Care's current exercise-based STRC model in Adelaide, South Australia. Program effectiveness was determined via improvements in outcome measures specific to functional decline risk factors from baseline (Week 0) to discharge (Week 8).

RESULTS

Results demonstrated significant improvements (p < 0.001) in participants' (n = 62) lower extremity function (44.9%), depressive symptoms (52.4%), anxiety (45.8%), frailty stage (57.9%), independence in activities of daily living (17.3%) and health-related quality of life (24.0%). No significant change was found for grip strength or BMI post-intervention. The most frequent services were exercise-based (54.3% of total services), with participants receiving an average of two to three exercise services per week.

CONCLUSIONS

An exercise-based STRC model is an effective mechanism to reverse functional decline and associated risk factors among community-dwelling older Australians. Adoption of multidisciplinary intervention as a standardised STRC service model could help improve client outcomes nationally and offset expected increases in community and long-term aged care demand.

The Training and Tapering Practices of Highland Games Heavy Event Athletes

ABSTRACT

Winwood, PW, Keogh, JW, Travis, SK, Grieve, I, and Pritchard, HJ. The training and tapering practices of Highland Games heavy event athletes. J Strength Cond Res 38(3): e116-e124, 2024-This study provides the first empirical evidence of how Highland Games heavy event athletes train and taper for Highland Games competitions. Athletes (n = 169) (mean ± SD: age 40.8 ± 10.7 years, height 181.2 ± 9.5 cm, weight 107.2 ± 23.0 kg, 18.8 ± 10.3 years of general resistance training, and 8.1 ± 6.9 years of competitive Highland Games experience) completed a self-reported 4-page online survey on training and tapering practices. Analysis by sex (male and female) and competitive standard (local or regional, national, and international) was conducted. Seventy-eight percent (n = 132) of athletes reported that they used a taper. Athletes stated that their taper length was 5.2 ± 3.5 days, with the step (36%) and linear tapers (33%) being the most performed. Athletes reported that their highest training volume and intensity were 5.5 and 3.8 weeks out (respectively) from competition, and all training ceased 2.4 ± 1.4 days before competition. Training volume decreased during the taper by 34%. Athletes typically stated that, tapering was performed to achieve recovery, peak performance, and injury prevention; training intensity, frequency, and duration stayed the same or decreased; game-specific training increased with reductions in traditional exercises; the caber toss, weight for height, and heavy weight throw were performed further out from competition than other events; muscular power and strength were the most common types of training performed; static stretching, foam rolling, and massage were strategies used in the taper; and poor tapering occurred because of life/work circumstances, lack of sleep/rest, or training too heavy/hard. These results may aid Highland Games athletes to optimize training and tapering variables leading to improved performances.

Relationships between physical fitness characteristics, technical skill attributes, and sports injury in female Australian football players

OBJECTIVES

To explore the relationships between physical fitness and i) technical skills and ii) time-loss from Australian football injury in female players across the talent and participation pathways.

METHODS

This study uses a subset of data from two cross-sectional and one prospective cohort studies. A total of 223 female Australian football players across five competition levels (elite/non-elite senior, high-level junior, and non-elite junior (14-17 years)/(10-13 years)) were included in this study. Comprehensive physical fitness assessments and modified Australian football kicking and handballing tests were conducted in the 2018/19 pre-seasons. During the respective competitive in-season, time-loss injuries were recorded by team personnel. Stepwise multiple linear regressions were performed to determine the relationship between physical fitness and kicking and handballing scores. Cox proportional regressions were conducted to identify physical fitness factors associated with injury.

RESULTS

Increased running vertical jump height, greater hip abduction strength, and faster timed 6 m hop speed demonstrated a relationship with kicking accuracy when adjusted for years of Australian football playing experience (adjusted R2 = 0.522, p < 0.001). Faster agility time and increased lean mass were associated with better handballing accuracy (adjusted R2 = 0.221, p < 0.001). Multivariate Cox regression revealed an increased risk for sustaining a time-loss injury in less agile players (adjusted HR 2.41, 95% CI 1.23, 4.73, p = 0.010). However, this relationship no longer remained when adjusted for age and years of Australian football experience (adjusted HR 1.68, 95% CI 0.81, 3.50, p = 0.166).

CONCLUSIONS

Physical fitness may be a significant factor contributing to development of Australian football technical skills in female players. However, its role is unclear in protecting against injury risk in this athlete population. Further research is needed to explore the multifactorial and complex phenomenon of talent development and injury risk reduction in female Australian football players.

Effects of 56-Kilogram Kettlebell Swing Endpoint on Total Body Mechanics

ABSTRACT

Ross, JA, Keogh, JWL, Lorenzen, C, and Lake, J. Effects of 56-kilogram kettlebell swing endpoint on total body mechanics. J Strength Cond Res 37(12): 2333-2338, 2023-In the past 2 decades, kettlebell training popularity has increased and the range of kettlebells has expanded to 2-92 kg. However, commercially available kettlebells above 56 kg have 12 kg increments, so alternatives to load are required to provide a suitable way of increasing training stimulus until the athlete is strong enough for a load increase. This study aimed to determine the differences in the force plate-derived biomechanical characteristics of heavy kettlebell swings to 3 different heights, as altering the height of the kettlebell swing may be one way to alter the mechanical demands with the same kettlebell mass. Fifteen resistance-trained men performed the kettlebell swing to acromion process height (AH), acromion process height + 20% (AH+20), and acromion process height-20% (AH-20). Swing height significantly affected vertical braking and propulsion phase net impulse and displacement, vertical braking velocity, and braking and propulsion work but not braking and propulsion duration. Altering kettlebell swing trajectory endpoint is a method to regress/progress the demands of kettlebell training. Coaches may be able to alter the acute demands and likely chronic adaptations of kettlebell training by prescribing different swing heights and kettlebell masses to their athletes.

The Tapering Practices of Competitive Weightlifters

ABSTRACT

Winwood, PW, Keogh, JW, Travis, SK, and Pritchard, HJ. The tapering practices of competitive weightlifters. J Strength Cond Res 37(4): 829-839, 2023-This study explored the tapering strategies of weightlifting athletes. Weightlifting athletes ( n = 146) (mean ± SD ; age: 29.2 ± 8.7 years, height: 172.5 ± 10.1 cm, body mass: 84.0 ± 17.2 kg, 4.7 ± 3.4 years of weightlifting training experience, and 3.9 ± 3.3 years of competitive weightlifting experience) completed a self-reported 4-page, 39-item internet survey on tapering practices. Subgroup analysis by sex (male and female) and competitive standard (local or regional, national and international level) was conducted. Ninety-nine percent ( n = 144) of weightlifting athletes reported they used a taper. Athletes stated that their typical taper length was 8.0 ± 4.4 days, with the linear (36%) and step tapers (33%) being the most performed. Training volume decreased during the taper by 43.1 ± 14.6%, and athletes ceased all training 1.5 ± 0.6 days out from competition. Muscular strength, light technique work, and aerobic conditioning were the most common types of training performed in the taper. Athletes typically stated that tapering was performed to achieve rest and recovery, physical preparation for peak performance and mental preparation; training intensity and training duration decreased whereas training frequency remained the same or decreased; traditional exercises were performed further out from competition than weightlifting exercises; assistance exercises and some strength work were reduced; nutritional changes, foam rolling, static stretching, and massage were strategies used in the taper; and poor tapering occurred because of training too heavy, too hard, or too light and life-work circumstances. These results may aid athletes and coaches in strength sports to optimize tapering variables leading to improved performances.

The Relationship Between Undulatory Underwater Kick Performance Determinants and Underwater Velocity in Competitive Swimmers: A Systematic Review

Background

Undulatory underwater swimming (UUS) has become an integral component of the start and turn phases in competitive swimming allowing higher velocities than can be achieved swimming at the surface. An understanding of the most important determinants for UUS performance and how these can be optimised to different swimmers is poorly understood.

Objective

The aim of this systematic review was to systematically assess the current peer-reviewed literature on the relationship between UUS performance determinants and underwater velocity in competitive swimmers.

Methods

An electronic search using AusSportMed, Embase, PubMed, SPORTDiscus and Biomechanics and Medicine in Swimming was performed. The methodological quality of the studies was evaluated using a biomechanics-specific checklist developed by Hindle and colleagues (Sports Med Open. 5(1):49, 2019. 10.1186/s40798-019-0222-z).

Results

Twenty-five studies met the eligibility criteria. While UUS velocity was nearly perfectly related (r > 0.90) to foot resultant acceleration and kick frequency, several other biomechanical factors were also significant correlates. UUS velocity and frequency were typically higher in high-performance swimmers and during prone versus dorsal positions. UUS velocity, kick frequency and kick amplitude were also significantly correlated with high angular velocities of the hip, knee and ankle joints and knee range of motion.

Conclusion

While there appears to be evidence supporting some performance variables to be related to UUS, future research should examine how to optimise the kinematic and kinetic characteristics with respect to the imposed task constraints and organism constraints between swimmers. Additional research should also investigate the effect of biomechanically informed interventions to improve UUS performance.

Registration

Open Science Framework.

Reliability of kettlebell swing one and five repetition maximum

Background

Research into the kettlebell swing has increased in the last decade. There has been a paucity of literature assessing an individual's ability to perform the kettlebell swing exercise. The purpose of this study was to determine the test-retest reliability of the one and five repetition maximum (1RM and 5RM) kettlebell swing.

Materials & Methods

Twenty four recreational resistance-trained participants performed an isometric mid-thigh pull (IMTP) and two familiarization sessions followed by three test sessions for each RM load approximately one week apart, using a custom-built plate-loaded kettlebell. On each test occasion, subjects completed a series of warm-up sets followed by 3-4 progressively heavier kettlebell swings to a standardized height until 1RM or 5RM was reached. Test-retest reliability was calculated using the intra-class correlation (ICC) and typical error was represented as the coefficient of variation (CV%) with 90% confidence limits (90% CL). The smallest worthwhile change (SWC%) representing the smallest change of practical importance, was calculated as 0.2 × between-subject standard deviation. The relationship of kettlebell swing performance and maximum strength was determined by Pearson correlation with ±90% CL between the absolute peak force recorded during IMTP and 1RM or 5RM.

Results

Results demonstrated a high test-retest reliability for both the 1RM (ICC = 0.97, 90% CL [0.95-0.99]; CV = 2.7%, 90% CL [2.2-3.7%]) and 5RM (ICC = 0.98, 90% CL [0.96-0.99]; CV = 2.4%, 90% CL [1.9-3.3%]), respectively. The CV% was lower than the SWC for both the 1RM (SWC = 2.8%, 90% CL [1.9-3.5]) and 5RM (SWC = 2.9%, 90% CL [1.9-3.6]) kettlebell swing. The correlation between IMTP absolute peak force and the 1RM (r = 0.69, 90% CL 0.43-0.83) was large and very large for the 5RM (r = 0.75, 90% CL [0.55-0.87]).

Conclusions

These results demonstrate the stability of 1RM and 5RM kettlebell swing performance after two familiarization sessions. Practitioners can be confident that changes in kettlebell swing 1RM and 5RM performance of >3.6 kg represent a practically important difference, which is the upper limit of the 90% CL.

Motives for Physical Activity in Prostate Cancer Survivors: A Qualitative Exploration

Physical activity (PA) is beneficial for both the physical and psychological health of prostate cancer (PCa) survivors. This study identified and examined motives for PA in a cross-section of PCa survivors, including both men in remission and those receiving treatment in the form of androgen deprivation therapy (ADT). Sixteen PCa survivors from Auckland, New Zealand were individually interviewed. Data were analyzed using an inductive thematic approach. Both groups of men were motivated to engage in PA post-diagnosis to obtain and experience the physical, mental, and cognitive health-related benefits associated with regular PA engagement. Past history of PA was also identified as a motive for current PA for men in remission. These findings provide important insight into how PCa survivors perceive the benefits of PA as a part of their cancer survivorship. Healthcare practitioners, exercise physiologists, and cancer support organizations can use this information to further improve PCa survivors’ quality of life and overall cancer survivorship by better promoting PA to these individuals.

"If somebody had told me I'd feel like I do now, I wouldn't have believed them…" older adults' experiences of the BELL trial: a qualitative study

Objectives

This study examined older adults’ experiences of participating in the Ballistic Exercise of the Lower Limb (BELL) trial, involving 12-weeks of group-based hardstyle kettlebell training.

Methods

In the BELL trial, 28 insufficiently active older adults (15 women, 13 men, 59–79 years) completed six weeks of face-to-face group training, and six weeks of home-based training. In-depth semi-structured interviews were audio recorded, transcribed, and inductively coded, with themes constructed from patterns of shared meaning.

Results

Four higher-order themes were developed that reflect older adults’ experiences participating in a group-exercise program of hardstyle kettlebell training. These included: (1) “It’s one of the best things we’ve done”—enjoying the physical and psychosocial benefits, (2) “It’s improved it tremendously!”—change in a long-term health condition, (3) “It put me on a better course”—overcoming challenges, and (4) “I wasn’t just a number”—feeling part of a group/community.

Discussion

Findings highlight the perceived physical and psychological benefits of older adults participating in hardstyle group kettlebell training, and the value attributed to being part of an age-matched community of like-minded people engaged in group exercise. Implications for program design and delivery, and future research, are discussed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03174-5.

Effects of supervised high-intensity hardstyle kettlebell training on grip strength and health-related physical fitness in insufficiently active older adults: the BELL pragmatic controlled trial

The Ballistic Exercise of the Lower Limb (BELL) trial examined the efficacy and safety of a pragmatic hardstyle kettlebell training program in older adults. Insufficiently active men and women aged 59–79 years, were recruited to a 6-month repeated measures study, involving 3-months usual activity and 3-months progressive hardstyle kettlebell training. Health-related physical fitness outcomes included: grip strength [GS], 6-min walk distance [6MWD], resting heart rate [HR], stair-climb [SC], leg extensor strength [LES], hip extensor strength [HES], Sit-To-Stand [STS], vertical jump [CMVJ], five-times floor transfer [5xFT], 1RM deadlift, body composition (DXA), attendance, and adverse events. Sixteen males (68.8 ± 4.6 yrs, 176.2 ± 7.8 cm, 90.7 ± 11.0 kg, 29.2 ± 2.6 kg/m²) and sixteen females (68.6 ± 4.7 yrs, 163.9 ± 5.4 cm, 70.4 ± 12.7 kg, 26.3 ± 4.9 kg/m²) were recruited. Compliance with the supervised exercise program was very high (91.5%). Kettlebell training increased GS (R: MD = 7.1 kg 95% CI [4.9, 9.3], L: MD = 6.3 kg 95% CI [4.1, 8.4]), 6MWD (41.7 m, 95% CI [17.9, 65.5]), 1RM (16.2 kg, 95% CI [2.4, 30.0]), 30 s STS (3.3 reps, 95% CI [0.9, 5.7]), LES (R: MD = 61.6 N, 95% CI [4.4, 118.8]), HES (L: MD = 21.0 N,95% CI [4.2,37.8]), appendicular skeletal lean mass (MD = 0.65 kg, 95% CI [0.08, 1.22]), self-reported health change (17.1%, 95% CI [4.4, 29.8]) and decreased SC time (2.7 s, 95% CI [0.2, 5.2]), 5xFT time (6.0 s, 95% CI [2.2, 9.8]) and resting HR (7.4 bpm, 95% CI [0.7, 14.1]). There were four non-serious adverse events. Mean individual training load for group training sessions during the trial was 100,977 ± 9,050 kg. High-intensity hardstyle kettlebell training was well tolerated and improved grip strength and measures of health-related physical fitness in insufficiently active older adults.

Trial registration: Prospectively registered: 20/08/2019, Australian New Zealand Clinical Trials Registry (ACTRN12619001177145).

Physical fitness profiles of female Australian football players across five competition levels

OBJECTIVES

To examine physical fitness profiles of female Australian football players and investigate differences according to competition level.

METHODS

A testing battery of 28 physical fitness assessments was undertaken with 240 players across five competition levels: elite senior (≥18 years), non-elite senior (≥18 years), high-level junior (<18 years), non-elite junior (14-17 years), and non-elite junior (10-13 years). Physical fitness profiles were examined and competition level differences were investigated using multivariate analyses of variance.

RESULTS

Significant differences (p<0.001) were observed between competition levels in body composition (η²_p=0.225), flexibility (η²_p=0.071), muscular strength and endurance (η²_p=0.238), balance (η²_p=0.093), reaction time (η²_p=0.103), and whole-body locomotor performance (η²_p=0.200). Elite seniors and high-level juniors were stronger (p<0.001-0.043), faster (p=0.001-0.022), more responsive (p<0.001-0.048), and had better cardiorespiratory fitness (p<0.001) compared to the non-elite groups. Additionally, body composition and muscular strength and endurance differences were common between the senior and non-elite junior groups.

CONCLUSIONS

This is the first study to comprehensively profile physical characteristics of female Australian footballers across a broader development pathway. These preliminary findings may assist sport practitioners to better understand athlete development, provide insight on talent identification and development programs, and injury management in this population.

Profiling the kicking and handballing accuracy of female Australian football players across five competition levels

OBJECTIVES

To profile the kicking and handballing accuracy of female Australian football (AF) players and investigate potential differences across five competition levels.

METHODS

Female AF players were classified into five competition levels: elite senior (≥18 years) (n=35), non-elite senior (≥18 years) (n=58), high-level junior (<18 years) (n=32), non-elite junior (14-17 years) (n=38), and non-elite junior (10-13 years) (n=42). Modified AF kicking and handballing tests examined accuracy outcomes. Competition level differences in accuracy were modelled using multivariate analysis of variance.

RESULTS

A large, significant difference between the competition levels was noted (F=11.508, p<0.001, Wilk's Λ=0.462, η²_p=0.227), with significant differences (p<0.001) observed in the modified AF kicking (ω²=0.514) and handballing (η²_p=0.150-0.250) tests. Elite seniors and high-level juniors performed the modified AF kicking test more accurately than all non-elite competition levels (p≤0.001). Elite seniors were also more accurate in the modified AF handballing test (dominant hand) compared to all non-elite competition levels (p≤0.001).

CONCLUSIONS

This study is the first to report technical skill characteristics in female AF across a broader participation pathway. These exploratory findings could be used as reference data for player development and inform training designs, namely by incorporating non-dominant handballing competitive play situations to develop this skill in female AF players.

Predicting the progressive resistance and balance training response of community-dwelling older adults accessing aged care support services: A stepped-wedge randomised controlled trial

OBJECTIVE

To quantify the variation in body composition, physical function and cognitive health changes resulting from the Muscling Up Against Disability (MUAD) resistance and balance training program and the potential for baseline characteristics to predict the magnitude of training-related response.

METHODS

The study represented a secondary analysis of a stepped-wedge randomised controlled trial involving 245 community-dwelling adults receiving Australian Government-funded aged care services who performed 26 weeks of supervised progressive resistance and balance training (PRBT). The primary outcome was the proportion of response that described the number of individuals expected to make any positive change due to the intervention and not external factors.

RESULTS

For all outcomes, the observed average change in the PRBT group was more favourable than the control. Analyses identified that most participants completing the PRBT program would be expected to respond positively to the intervention (86%-99%) with respect to their physical performance (SPPB summary, grip strength, chair stand and isometric knee strength). A smaller proportion completing the PRBT program group would be expected to respond positively in aspects of body composition (45%-60%) or cognitive function (44%-84%). The strongest predictors of positive change were baseline physical function, whereby those with the poorest baseline function experienced the greatest benefits.

CONCLUSIONS

This study strongly supports the promotion of PRBT as a standard component of any care plan for community-dwelling older adults, especially those with low levels of physical function.

Eccentric Exercise: Adaptations and Applications for Health and Performance

The goals of this narrative review are to provide a brief overview of the muscle and tendon adaptations to eccentric resistance exercise and address the applications of this form of training to aid rehabilitative interventions and enhance sports performance. This work is centered on the author contributions to the Special Issue entitled "Eccentric Exercise: Adaptations and Applications for Health and Performance". The major themes from the contributing authors include the need to place greater attention on eccentric exercise mode selection based on training goals and individual fitness level, optimal approaches to implementing eccentric resistance exercise for therapeutic purposes, factors that affect the use of eccentric exercise across the lifespan, and general recommendations to integrate eccentric exercise in athletic training regimens. The authors propose that movement velocity and the absorption or recovery of kinetic energy are critical components of eccentric exercise programming. Regarding the therapeutic use of eccentric resistance training, patient-level factors regarding condition severity, fitness level, and stage of rehabilitation should govern the plan of care. In athletic populations, use of eccentric exercise may improve movement competency and promote improved safety and performance of sport-specific tasks. Eccentric resistance training is a viable option for youth, young adults, and older adults when the exercise prescription appropriately addresses program goals, exercise tolerability, and compliance. Despite the benefits of eccentric exercise, several key questions remain unanswered regarding its application underscoring the need for further investigation.

Isokinetic force-power profile of the shoulder joint in males participating in CrossFit training and competing at different levels

Background

As participants who engage in CrossFit training and competition perform a large volume of high intensity overhead activities, injuries to the shoulder are one of the most common in this sport. Previous research in other sports has indicated that the isokinetic force power profile of the shoulder joint (IPSJ) rotator muscles may assist in the prediction of shoulder injury.

Aim

Therefore, the objective of this study was to determine the IPSJ in males engaged in CrossFit training at different competitive levels.

Methods

In a cross-sectional study design, participants (age, 24.1 ± 2.7 years) classified as ‘beginner’ (n = 6), ‘intermediate’ (n = 7) or ‘advanced’ (n = 9) provided informed consent to participate in this study. The IPSJ assessment involved rotational and diagonal movements, including internal and external shoulder rotator muscles, at both 180°.s⁻¹ and 300°.s⁻¹. The variables analysed were peak torque/body mass (%), mean power (W) and the external/internal peak torque/body mass ratio (%). A Kruskal–Wallis test was used to compare the IPSJ of the three groups, with Dunn’s test used for post-hoc analysis. The alpha level was set at p < 0.05.

Results

The IPSJ showed greater torque and power values in those who competed at the advanced level as compared to those at a lower competitive level (i.e. intermediate, beginner). This was observed mainly for the internal rotation and internal diagonal movements at both 180°.s⁻¹ and 300°.s⁻¹. However, such differences between competitive levels were, in general, absent for the external rotation and external diagonal movements. Moreover, the participants from the advanced competitive level exhibited an imbalance of peak torque between the muscles responsible for the external–internal rotational and external-internal diagonal movements of the shoulder (i.e. peak torque external/internal ratio <66%), particularly in the dominant shoulder.

Conclusion

These findings suggest greater development of the shoulder internal rotators and a higher probability of shoulder injury in CrossFit athletes at the advanced competitive level. Based on these results, participants engaged in CrossFit training and competition may wish to increase the volume of training for the shoulder external rotator muscles to complement the large increases in shoulder internal rotator strength that occur as a part of their regular training regimes.

Sex Differences in Adaptations in Muscle Strength and Size Following Resistance Training in Older Adults: A Systematic Review and Meta-analysis

BACKGROUND

Reductions in muscle size and strength occur with aging. These changes can be mitigated by participation in resistance training. At present, it is unknown if sex contributes to differences in adaptation to resistance training in older adults.

OBJECTIVE

The aim of this systematic review was to determine if sex differences are apparent in adaptations to resistance training in older adults.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Web of Science; Science Direct; SPORTDiscus; CINAHL; and MEDLINE were searched from inception to June 2020.

ELIGIBILITY CRITERIA

Studies where males and females older than 50 years of age performed identical resistance training interventions and had outcome measures of muscle strength or size.

RESULTS

We initially screened 5337 studies. 30 studies (with 41 comparison groups) were included in our review (1410 participants; 651 males, 759 females). Mean study quality was 14.7/29 on a modified Downs and Black checklist, considered moderate quality. Females gained more relative lower-body strength than males (g = - 0.21 [95% CI - 0.33, - 0.10], p = 0.0003) but there were no differences in relative change for upper-body strength (g = - 0.29 [95% CI - 0.62, 0.04], p = 0.08) or relative muscle size (g = 0.10 [95% CI - 0.04, 0.23], p = 0.16). Males gained more absolute upper-body strength (g = 0.48 [95% CI 0.09, 0.88], p = 0.016), absolute lower-body strength (g = 0.33 [95% CI 0.19, 0.47], p < 0.0001), and absolute muscle size (g = 0.45 [95% CI 0.23, 0.66], p < 0.0001).

CONCLUSION

Our results indicate that sex differences in adaptations to resistance training are apparent in older adults. However, it is evident that the interpretation of sex-dependent adaptations to resistance training is heavily influenced by the presentation of the results in either an absolute or relative context.

STUDY REGISTRATION

Open Science Framework (osf.io/afn3y/).

The Biomechanical Characteristics of the Strongman Yoke Walk

The yoke walk is a popular strongman exercise where athletes carry a heavily loaded frame balanced across the back of their shoulders over a set distance as quickly as possible. The aim of this study was to use ecologically realistic training loads and carry distances to (1) establish the preliminary biomechanical characteristics of the yoke walk; (2) identify any biomechanical differences between male and female athletes performing the yoke walk; and (3) determine spatiotemporal and kinematic differences between stages (intervals) of the yoke walk. Kinematic and spatiotemporal measures of hip and knee joint angle, and mean velocity, stride length, stride rate and stance duration of each 5 m interval were taken whilst 19 strongman athletes performed three sets of a 20 m yoke walk at 85% of their pre-determined 20 m yoke walk one repetition maximum. The yoke walk was characterised by flexion of the hip and slight to neutral flexion of the knee at heel strike, slight to neutral extension of the hip and flexion of the knee at toe-off and moderate hip and knee range of motion (ROM), with high stride rate and stance duration, and short stride length. Between-interval comparisons revealed increased stride length, stride rate and lower limb ROM, and decreased stance duration at greater velocity. Although no main between-sex differences were observed, two-way interactions revealed female athletes exhibited greater knee extension at toe-off and reduced hip ROM during the initial (0–5 m) when compared with the final three intervals (5–20 m), and covered a greater distance before reaching maximal normalised stride length than males. The findings from this study may better inform strongman coaches, athletes and strength and conditioning coaches with the biomechanical knowledge to: provide athletes with recommendation on how to perform the yoke walk based on the technique used by experienced strongman athletes; better prescribe exercises to target training adaptations required for improved yoke walk performance; and better coach the yoke walk as a training tool for non-strongman athletes.

Posterior-Chain Resistance Training Compared to General Exercise and Walking Programmes for the Treatment of Chronic Low Back Pain in the General Population: A Systematic Review and Meta-Analysis

BACKGROUND

While chronic exercise training has been demonstrated to be an effective non-pharmacological treatment for chronic low back pain (CLBP), there has been a relative lack of evidence or clinical guidelines for whether a posterior chain resistance training programme provides any benefits over general exercise (GE).

OBJECTIVES

To determine if chronic posterior chain resistance training (PCRT), defined as exercise programmes of ≥6 weeks duration focused on the thoracic, lumbar and hip extensor musculature, is more effective than GE in improving pain, level of disability, muscular strength and the number of adverse events in recreationally active and sedentary individuals with CLBP.

METHODS

Four electronic databases were systematically searched from 25 September 2019 until 30 August 2020. Using the Joanna Briggs Institute (JBI) Critical Appraisal Tools checklist for randomized controlled trials (RCTs), articles were critically appraised and compared against the inclusion/exclusion criteria. Standardized mean difference (SMD), risk difference (RD) and confidence interval (CI) were calculated using Review Manager 5.3.

RESULTS

Eight articles were included, with a total of 408 participants (203 PCRT, 205 GE). Both PCRT and GE were effective in improving a number of CLBP-related outcomes, but these effects were often significantly greater in PCRT than GE, especially with greater training durations (i.e. 12-16 weeks compared to 6-8 weeks). Specifically, when compared to GE, PCRT demonstrated a greater reduction in pain (SMD = - 0.61 (95% CI - 1.21 to 0.00), p = 0.05; I2 = 74%) and level of disability (SMD = - 0.53 (95% CI - 0.97 to - 0.09), p = 0.02; I2 = 52%), as well as a greater increase in muscle strength (SMD = 0.67 (95% CI 0.21 to 1.13), p = 0.004; I2 = 0%). No differences in the number of adverse events were reported between PCRT and GE (RD = - 0.02 (95% CI - 0.10 to 0.05), p = 0.57; I2 = 72%).

CONCLUSION

Results of the meta-analysis indicated that 12-16 weeks of PCRT had a statistically significantly greater effect than GE on pain, level of disability and muscular strength, with no significant difference in the number of adverse events for recreationally active and sedentary patients with CLBP. Clinicians should strongly consider utilizing PCRT interventions for 12-16 weeks with patients with CLBP to maximize their improvements in pain, disability and muscle strength. Future research should focus on comparing the efficacy and adverse events associated with specific PCRT exercise training and movement patterns (i.e. deadlift, hip lift) in treating this population.

TRIAL REGISTRATION

PROSPERO CRD42020155700 .

Pushing up or pushing out-an initial investigation into horizontal- versus vertical-force training on swimming start performance: a pilot study

Background

The block phase in the swimming start requires a quick reaction to the starting signal and a large take-off velocity that is primarily horizontal in direction. Due to the principle of specificity of training, there is a potential benefit of performing a greater proportion of horizontal force production exercises in a swimmers' dry-land resistance training sessions. Therefore, the purpose of this pilot study was to provide an insight into the effects of a horizontal- (HF) vs vertical-force (VF) training intervention on swim start performance.

Methods

Eleven competitive swimmers (six males (age 20.9 ± 1.8 years, body mass 77.3 ± 9.7 kg, height 1.78 ± 0.05 m) and five females (age 21.4 ± 2.0 years, body mass 67.5 ± 7.4 kg, height 1.69 ± 0.05 m)) completed 2 weekly sessions of either a horizontal- or vertical-force focused resistance training programme for 8 weeks. Squat jump force-time characteristics and swim start kinetic and kinematic parameters were collected pre- and post-intervention.

Results

Across the study duration, the swimmers completed an average of nine swimming sessions per week with an average weekly swim volume of 45.5 ± 17.7 km (HF group) and 53 ± 20.0 km (VF group), but little practice of the swim start per week (n = 9). Within-group analyses indicated a significant increase in predicted one repetition maximum (1RM) hip thrust strength in the HF group, as well as significant increases in grab resultant peak force but reductions in resultant peak force of the block phase for the VF group. No significant between-group differences in predicted 1RM hip thrust and back squat strength, squat jump force-time and swim start performance measures were observed after 8 weeks of training. Significant correlations in the change scores of five block kinetic variables to time to 5 m were observed, whereby increased block kinetic outputs were associated with a reduced time to 5 m. This may be indicative of individual responses to the different training programmes.

Discussion

The results of this current study have been unable to determine whether a horizontal- or vertical-force training programme enhances swim start performance after an 8-week training intervention. Some reasons for the lack of within and between group effects may reflect the large volume of concurrent training and the relative lack of any deliberate practice of the swim start. Larger samples and longer training duration may be required to determine whether significant differences occur between these training approaches. Such research should also look to investigate how a reduction in the concurrent training loads and/or an increase in the deliberate practice of the swim start may influence the potential changes in swim start performance.

The Effect of High Volume Power Training on Repeated High-Intensity Performance and the Assessment of Repeat Power Ability: A Systematic Review

BACKGROUND

High volume power training (HVPT) involves high volumes of high-velocity resistance training, with the aim to improve repeated high-intensity efforts (RHIEs). Repeat power ability (RPA) is the ability to repeatedly produce maximal or near maximal efforts. Assessments of RPA using external loading may determine the ability to perform repeat RHIEs typical of many sports and, therefore, provide useful information on the effectiveness of training.

OBJECTIVES

(1) Identify the different HVPT protocols; (2) examine the acute responses and chronic adaptations to different HVPT protocols; (3) identify different lower body RPA assessment protocols and highlight similarities, differences and potential limitations between each protocol, and; (4) describe the reliability and validity of RPA assessments.

METHODS

An electronic search was performed using SPORTDiscus, PubMed, CINAHL and Embase for studies utilising HVPT protocols and assessments of RPA. Eligible studies included peer-reviewed journal articles published in English.

RESULTS

Twenty studies met the inclusion criteria of the final review. Of the eight longitudinal studies, three were rated as fair and five were rated as poor methodological quality, respectively. In contrast, all 12 cross-sectional studies were considered to have a low risk of bias. Preliminary evidence suggests that HVPT can enhance RHIE, RPA, anaerobic capacity, anaerobic power and aerobic performance. HVPT generally consists of 2-3 sessions per week, utilising loads of 30-40% 1 repetition maximum (RM), for 3-5 sets of 10-20 repetitions, with inter-set rest periods of 2-3 min. RPA assessments can be valid and reliable and may provide useful information on an athlete's ability to perform RHIE and the success of HVPT programmes.

CONCLUSIONS

HVPT can be used to improve a number of physical qualities including RPA and RHIE; while a variety of RPA assessments provide valid and reliable information regarding the athlete's ability to perform RHIEs. Considering the heterogeneity in the HVPT protocols currently used and the relatively low volume and quality of longitudinal publications in this area, further studies are needed to identify the effects of a variety of HVPT methods on RPA, RHIE and other performance outcomes and to identify the most valid and reliable RPA outcomes to use in such studies.

Long-term effects of school barefoot running program on sprinting biomechanics in children: A case-control study

BACKGROUND

The acute changes of running biomechanics in habitually shod children when running barefoot have been demonstrated. However, the long-term effects of barefoot running on sprinting biomechanics in children is not well understood.

RESEARCH QUESTION

How does four years of participation in a daily school barefoot running program influence sprint biomechanics and stretch-shortening cycle jump ability in children?

METHODS

One hundred and one children from barefoot education school (age, 11.2 ± 0.7 years-old) and 93 children from a control school (age, 11.1 ± 0.7 years-old) performed 50 m maximal shod and barefoot sprints and counter movement jump and five repeated-rebound jumping. To analyse sprint kinematics, a high-speed camera (240 fps) was used. In addition, foot strike patterns were evaluated by using three high-speed cameras (300 fps). Jump heights for both jump types and the contact times for the rebound jump were measured using a contact mat system. Two-way mixed ANOVA was used to examine the effect of school factor (barefoot education school vs control school) and footwear factor (barefoot vs shod) on the sprinting biomechanics.

RESULTS

Sprinting biomechanics in barefoot education school children was characterised by significantly shorter contact times (p = 0.003) and longer flight times (p = 0.005) compared to control school children regardless of footwear condition. In shod sprinting, a greater proportion of barefoot education school children sprinted with a fore-foot or mid-foot strike compared to control school children (p < 0.001). Barefoot education school children also had a significantly higher rebound jump height (p = 0.002) and shorter contact time than control school children (p = 0.001).

SIGNIFICANCE

The results suggest that school-based barefoot running programs may improve aspects of sprint biomechanics and develop the fast stretch-shortening cycle ability in children. In order to confirm this viewpoint, adequately powered randomised controlled trials should be conducted.

Hamstring Myoelectrical Activity During Three Different Kettlebell Swing Exercises

Del Monte, MJ, Opar, DA, Timmins, RG, Ross, JA, Keogh, JWL, and Lorenzen, C. Hamstring myoelectrical activity during three different kettlebell swing exercises. J Strength Cond Res 34(7): 1953-1958, 2020-Kettlebell exercises have become an increasingly popular form of resistance training and component of lower-body rehabilitative training programs, despite a lack of scientific literature illustrating internal mechanisms and effectiveness of these approaches. Participants (n = 14) performed 3 different styles of kettlebell swings (hip hinge, squat, and double knee extension) and were assessed for medial hamstrings (MHs) and biceps femoris (BF) myoelectrical activity through surface electromyography (sEMG). Bipolar pregelled Ag/AgCl sEMG electrodes (10 mm diameter, 20 mm interelectrode distance) were placed on the participant's dominant limb after correct skin preparation. There was a main effect for swing type (p = 0.004), where the hip hinge swing elicited a greater overall MH and BF sEMG in comparison with the squat swing (mean difference = 3.92; 95% confidence interval [CI] = 1.53-6.32; p = 0.002) and the double knee extension swing (mean difference = 5.32; 95% CI = 0.80-9.83; p = 0.020). Across all swing types, normalized percentage of MH sEMG was significantly higher compared with the BF (mean difference = 9.93; 95% CI = 1.67-18.19; p = 0.022). The hip hinge kettlebell swing produced the greatest amount of hamstring sEMG for the 3 styles of kettlebell swings assessed. These findings have implications for the application of kettlebell swing exercises in strength and conditioning, injury prevention, and rehabilitation programs.

Utilising one minute and four minute recovery when employing the resistance training contrast method does not negatively affect subsequent jump performance in the presence of concurrent training

Background

Little is known about contrast training and post-activation performance enhancement (PAPE) in a same day concurrent training model. The aim of the current study was to examine the use of two short duration (1-min and 4-min) recovery periods on drop jump performance in same day concurrently trained athletes.

Methods

Ten professional Australian Rules footballers (age, 20.6 ± 1.9 yr; height, 184.8 ± 6.9 cm; body mass, 85.8 ± 8.4 kg) completed two resistance training sessions with different PAPE recovery durations; 1-min and 4-min, 1 h following a field-based endurance session. Baseline (pre) drop jumps were compared to post-test maximal drop jumps, performed after each set of three squats (where each participant was encouraged to lift as heavy as they could), to determine changes between 1-min and 4-min recovery periods. Data were analysed by fitting a mixed model (significance was set at P ≤ 0.05). Corrected Hedges' g standardised effect sizes ±95% confidence limits were calculated using group means ± SDs.

Results

There were no significant differences between baseline and experimental sets 1, 2 and 3 for reactive strength index (RSI), flight time, and total and relative impulse for either recovery duration. However, for contact time, 1-min baseline was significantly different from set 2 (mean difference; 95% CI [0.029; 0.000-0.057 s], P = 0.047, ES; 95% CI [-0.27; -1.20 to 0.66]). For RSI and flight time, 1-min was significantly higher than 4-min (RSI: 0.367; 0.091 to 0.642, P = 0.010, ES; 95% CI [0.52; -0.37 to 1.42]; flight time: 0.033; 0.003 to 0.063 s, P = 0.027, ES; 95% CI [0.86; -0.06 to 1.78]).

Discussion

Short recovery periods of 1-min may be a time-efficient form of prescribing strength-power exercise in contrast loading schemes. Longer recovery periods do not appear to benefit immediate, subsequent performance.

The relationship between physical fitness attributes and sports injury in female, team ball sport players: a systematic review

BACKGROUND

Understanding the relationships between physical fitness characteristics and sports injury may assist with the development of injury minimisation programs. The purpose of this systematic review was to investigate the association between physical fitness attributes and sports injury in female, team ball sport players.

METHODS

Four scientific databases (MEDLINE, EMBASE, SPORTDiscus, Scopus) and reference lists of relevant research were searched for eligible studies up to September 2, 2019. Full-text articles examining the relationship between physical fitness and sports injury in female, team ball sport players were included. A modified Downs and Black checklist was used to assess methodological quality. Data synthesis determined summary conclusions based on the number of significant relationships divided by the total relationships investigated and reported as a percentage. Level of certainty was identified for summary conclusions based on level of evidence. Sub-analyses regarding competition level, age, and single injury types were also conducted.

RESULTS

A total of 44 studies were included. Data synthesis revealed no associations (low to moderate certainty) between body composition (1/9; 11%), flexibility (18-20%), and balance (2/8; 25%) and 'any injury' classification. No associations (mostly of moderate certainty) were found between flexibility (0-27%), muscular strength (0-27%), and body composition (14-33%) and various body region injury classifications, whereas mixed summary conclusions were shown for balance (0-48%). Many associations between physical fitness and sports injury were deemed 'unknown' or with an insufficient level of certainty. Sub-analyses revealed no association between strength and noncontact ACL injuries (0/5; 0%) or ankle sprains (0/12; 0%), and between flexibility and ankle sprains (1/5; 20%); however, insufficient certainty of these results exists. Clear associations were concluded between balance and lower body injuries in female, non-elite (10/16; 63%) and junior (9/12; 75%) team ball sport players, with moderate and insufficient certainty of these results, respectively.

CONCLUSION

Limited evidence is available to demonstrate relationships between physical fitness and sports injury in female, team ball sport players. High-quality evidence investigating the multifactorial nature of sports injury, including the interactions physical fitness qualities have with other injury determinants, is needed to better understand the role of physical fitness in minimising sports injuries in female, team ball sport players.

TRIAL REGISTRATION

CRD42017077374 (PROSPERO on September 14, 2017).

The prediction of swim start performance based on squat jump force-time characteristics

Background

Depending on the stroke and distances of the events, swim starts have been estimated to account for 0.8% to 26.1% of the overall race time, with the latter representing the percentage in a 50 m sprint front crawl event (Cossor & Mason, 2001). However, it is still somewhat unclear what are the key physiological characteristics underpinning swim start performance. The primary aim of this study was to develop a multiple regression model to determine key lower body force-time predictors using the squat jump for swim start performance as assessed by time to 5 m and 15 m in national and international level swimmers. A secondary aim was to determine if any differences exist between males and females in jump performance predictors for swim start performance.

Methods

A total of 38 males (age 21 ±  3.1 years, height 1.83 ±  0.08 m, body mass 76.7 ±  10.2 kg) and 34 females (age 20.1 ±  3.2 years, height 1.73 ±  0.06 m, body mass 64.8 ±  8.4 kg) who had competed at either an elite (n = 31) or national level (n = 41) participated in this study. All tests were performed on the same day, with participants performing three bodyweight squat jumps on a force platform, followed by three swim starts using their main swimming stroke. Swim start performance was quantified via time to 5 m and 15 m using an instrumented starting block.

Results

Stepwise multiple linear regression with quadratic fitting identified concentric impulse and concentric impulse² as statistically significant predictors for time to 5 m (R² = 0.659) in males. With time to 15 m, concentric impulse, age and concentric impulse² were statistically significant predictors for males (R² = 0.807). A minimum concentric impulse of 200–230 N.s appears required for faster times to 5 m and 15 m, with any additional impulse production not being associated with a reduction in swim start times for most male swimmers. Concentric impulse, Reactive strength index modified and concentric mean power were identified as statistically significant predictors for female swimmers to time to 5 m (R² = 0.689). Variables that were statistically significant predictors of time to 15 m in females were concentric impulse, body mass, concentric rate of power development and Reactive strength index modified (R² = 0.841).

Discussion

The results of this study highlight the importance of lower body power and strength for swim start performance, although being able to produce greater than 200 or 230 N.s concentric impulse in squat jump did not necessarily increase swim start performance over 5 m and 15 m, respectively. Swimmers who can already generate greater levels of concentric impulse may benefit more from improving their rate of force development and/or technical aspects of the swim start performance. The sex-related differences in key force-time predictors suggest that male and female swimmers may require individualised strength and conditioning programs and regular monitoring of performance.

Effects of 4 Weeks of Active Exergames Training on Muscular Fitness in Elderly Women

Gallardo-Meza, C, Simon, K, Bustamante-Ara, N, Ramirez-Campillo, R, García-Pinillos, F, Keogh, JWL, and Izquierdo, M. Effects of 4 weeks of active exergames training on muscular fitness in elderly women. J Strength Cond Res XX(X): 000-000, 2020-To analyze the effects of 4 weeks of an active exergames training program on muscular fitness in older women, 2 groups of community dwelling physically active subjects were formed by block-design randomization. One was deemed the control group (CG, n = 37; age 68.1 ± 3.3 years), and a second group completed 4 weeks of an active exergames training program (ExG, n = 35; age, 69.2 ± 3.7 years). Training included active exergames (Wii Fit Plus) performed on the Wii Balanceboard, 2 sessions per week. The exergames required mainly balance-related movements, such as leaning forward, leftward, and rightward, also requiring isometric squat positions and explosive leg extension. A supervisor-to-subject ratio method of 2:1 was used. An intensity-based individual progressive overload was applied. There were no significant (all p > 0.05, d = 0.01-0.07) baseline differences between-groups for all dependent variables. For the ExG, significant improvements were observed in static balance right leg test (Δ75.5%, d = 0.89), static balance left leg (Δ33.7%, d = 0.57), timed up-and-go test (Δ14.8%, d = 0.85) and sit-to-stand velocity test (Δ83.8%, d = 1.62). For the control group, trivial to small decrements in performance were observed across all tests (Δ -2.1 to -8.4%, d = -0.08 to 0.32). Group × time interactions were observed for the static balance right and left leg, timed up-and-go test, and the mean velocity achieved in the 5-repetition sit-to-stand test (all p < 0.001; d = 0.33-0.60). In conclusion, exergames training improves muscular fitness in older women. These results should be considered when designing appropriate and better exercise training programs for older women.

Can Resistance Training Improve Upper Limb Postural Tremor, Force Steadiness and Dexterity in Older Adults? A Systematic Review

BACKGROUND

The ageing process and several health conditions may increase tremor and reduce force steadiness and dexterity, which can severely impact on function and quality of life. Resistance training can evoke a range of neuromuscular adaptions that may significantly reduce tremor and/or increase force steadiness and/or dexterity in older adults, irrespective of their health condition.

OBJECTIVES

The objective of this study was to systematically review the literature to determine if a minimum of 4 weeks' resistance training can reduce postural tremor and improve force steadiness and/or dexterity in older adults, defined as aged 65 years and over.

METHODS

An electronic search using Ovid, CINAHL, SPORTDiscus and EMBASE was performed. Risk of bias was assessed using the Cochrane Risk of Bias Tool.

RESULTS

Fourteen studies met the eligibility criteria, including six randomised controlled trials and two quasi-randomised controlled trials. All eight studies that recruited healthy older adults reported significant reductions in postural tremor and/or improvements in force steadiness and dexterity. Five out of seven studies that examined older adults with a particular health condition reported some improvements in force steadiness and/or dexterity. Specifically, significant benefits were observed for older adults with chronic obstructive pulmonary disease and essential tremor; however, small or no changes were observed for individuals with osteoarthritis or stroke.

CONCLUSIONS

Resistance training is a non-pharmacological treatment that can reduce tremor and improve force steadiness and dexterity in a variety of older adult populations. Future research should employ randomised controlled trials with larger sample sizes, better describe training programme methods, and align exercise prescription to current recommendations for older adults.

The Relationship Between Physical Fitness Qualities and Sport-Specific Technical Skills in Female, Team-Based Ball Players: A Systematic Review

Background

Understanding the relationships between physical fitness attributes and sport-specific technical skills may assist with the establishment of beneficial training interventions. The aim of this systematic review was to determine if physical fitness qualities were associated with performance of sport-specific technical skills in female, team-based ball players.

Methods

Five databases (MEDLINE, EMBASE, SPORTDiscus, ProQuest, and Scopus) were searched for relevant studies up to April 15, 2019. Full-text articles investigating relationships between physical fitness and sport-specific technical skills in female, team-based ball players were included. Methodological quality of included studies was appraised using a modified Downs and Black checklist. Data synthesis was conducted to determine the summary of evidence based on the number of significantly associated relationships divided by the total relationships assessed. An individual relationship was defined as a reported result examining the association between a single physical fitness variable and a single sport-specific technical skill.

Results

Data synthesis of grouped female ball players from 41 included studies revealed three clear associations: (i) body composition and defensive technical skills (19/29; 66%), (ii) agility and movement with a ball (4/6; 67%), and (iii) coordination and movement with a ball (3/5; 60%). An uncertain association exists between cardiorespiratory fitness and defensive technical skills (2/5; 40%). No association or an unknown conclusion (< 5 relationships reported) exists between all remaining physical fitness attributes and sport-specific technical skills. Sub-analyses revealed clear associations between body composition and throwing/shooting (using hands) in junior ball players (15/15; 100%) and with movement with a ball in elite (6/9; 67%) and senior (6/6; 100%) ball players. Three uncertain associations were found between offensive technical skills and agility in elite ball players (3/8; 38%), and with speed in elite (6/14; 43%) and junior (7/18; 39%) female ball players.

Conclusion

There is limited evidence available to demonstrate relationships between physical fitness qualities and sport-specific technical skills in female, team-based ball players. This lack of association is possibly due to reductionist methods in available literature and a lack of research in female ball players globally.

Registration

CRD42017065339 (PROSPERO on 12 May 2017).

Older adults' evaluations of the standard and modified pedometer-based Green Prescription

INTRODUCTION The Green Prescription is a primary care programme designed to increase physical activity in individuals with low activity levels. Older adults tend to engage in insufficient physical activity to obtain health-related gain. AIM To examine participants' ratings of the Healthy Steps intervention and to assess how participants rated the use of a pedometer-based Green Prescription in aiding their physical activity. METHODS In total, 330 community-dwelling older adults who have low levels of activity were randomised to receive either a standard time-based Green Prescription or a modified pedometer-based Green Prescription. Post-intervention, 259 participants completed the participant evaluation questionnaire via postal survey. Data were analysed using descriptive statistics and Chi-squared analyses. RESULTS The standard components of the Green Prescription (general practitioner consultations and telephone counselling) received similar and higher ratings across both allocation groups than the use of print materials. A pedometer-based Green Prescription was rated as being helpful in aiding physical activity. DISCUSSION This study supports the importance of general practitioners' initial role in prescribing physical activity for older adults and of ongoing telephone support for longer-term adherence. Incorporating a pedometer can be effective in helping low-active older adults initiate and maintain regular physical activity.

Reliability of the velocity achieved during the last repetition of sets to failure and its association with the velocity of the 1-repetition maximum

Background

This study aimed to determine the reliability of the velocity achieved during the last repetition of sets to failure (V_last) and the association of V_last with the velocity of the 1-repetition maximum (V_1RM) during the paused and touch-and-go bench press (BP) exercises performed in a Smith machine.

Methods

A total of 96 healthy men participated in this study that consisted of two testing sessions. A single BP variant (paused BP or touch-and-go BP) was evaluated on each session in a randomized order. Each session consisted of an incremental loading test until reaching the 1RM, followed by two sets of repetitions to failure against a load ranging from 75% to 90% of 1RM.

Results

The reliability of V_last was unacceptable for both BP variants (CV > 18.3%, ICC < 0.60). The correlations between V_1RM and V_last were small for the paused BP (r = 0.18) and moderate for the touch-and-go BP (r = 0.37).

Conclusions

Although these results suggest that V_last could be a better indicator of the minimal velocity threshold than V_1RM, the low reliability of V_last and the similar values of V_last for both BP variants suggest that a standard V_1RM should be used to estimate the 1RM from the individualized load-velocity relationship.

Sarcopenia in male patients with head and neck cancer receiving chemoradiotherapy: a longitudinal pilot study

Introduction

Muscle wasting conditions such as sarcopenia may be highly prevalent in advanced head and neck cancer (HNC) patients (16-71%), with these prevalence rates substantially greater in those who have received chemo-radiotherapy (CRT). According to the updated European Working Group on Sarcopenia in Older People consensus statement, sarcopenia is defined as the age-related loss of muscle strength, muscle mass and physical performance. The high prevalence of sarcopenia in HNC patients is concerning as it has been associated with substantially increased risk of CRT toxicity, respiratory complications and early mortality. With the high prevalence of HNC and sarcopenia in India and the strong link between sarcopenia and poor HNC patient outcomes, it is important to screen for the presence of sarcopenia in Indian patients receiving CRT for HNC.

Methods

This longitudinal pilot study aimed to routinely monitor 19 men receiving CRT for their HNC for a variety of sarcopenic-related outcomes over three time points during their 7 weeks of CRT. Participants were required to be male, with a minimum age of 30 years, with a Stage III, IVa or IVb diagnosis of HNC and be currently undergoing a 7 weeks course of CRT in an oncology department. Outcomes included probable sarcopenic diagnosis were estimated by the SARC-F, handgrip strength, skeletal muscle mass was estimated by bioelectrical impedance and physical performance was assessed by the Timed Up and Go. Repeated measures ANOVA and Bonferroni post-hoc tests were used to identify significant differences at the three time points with a p < 0.05.

Results

The 19 participants in this trial at a mean age of 56.5 ± 10.2 years (range = 39-75 years), with most (n = 13, 68.4%) employed in laboring occupations. At baseline, 31.5% (n = 6) of the participants already had probable sarcopenia based on their total SARC-F score, with this increasing to 89.4% (n = 17) at the end of 7 weeks CRT. In addition, significant decreases in strength, skeletal muscle mass and Timed Up and Go performance were observed, with these declines significantly greater at 7 weeks than 3 weeks after commencing CRT.

Conclusions

Patients with HNC undergoing 7 weeks of CRT showed clinically significant increases in the incidence of probable sarcopenia based on their total SARC-F score as well as clinically significant declines in handgrip strength, skeletal muscle mass and Timed Up and Go performance. Due to the relationship between sarcopenia and a host of adverse events related to CRT in HNC patients, these results suggest that oncologists and their allied health teams should routinely monitor these patients during CRT and provide the relevant exercise therapy and nutritional support to those patients in need.

The Competition-Day Preparation Strategies of Strongman Athletes

Winwood, PW, Pritchard, HJ, Wilson, D, Dudson, M, and Keogh, JWL. The competition-day preparation strategies of strongman athletes. J Strength Cond Res 33(9): 2308-2320, 2019-This study provides the first empirical evidence of the competition-day preparation strategies used by strongman athletes. Strongman athletes (n = 132) (mean ± SD: 33.7 ± 8.1 years, 178.2 ± 11.1 cm, 107.0 ± 28.6 kg, 12.8 ± 8.0 years general resistance training, 5.9 ± 4.8 years strongman implement training) completed a self-reported 4-page internet survey on their usual competition-day preparation strategies. Analysis of the overall group and by sex, age, body mass, and competitive standard was conducted. Ninety-four percent of strongman athletes used warm-ups in competition, which were generally self-directed. The typical warm-up length was 16.0 ± 8.9 minutes, and 8.5 ± 4.3 minutes was the perceived optimal rest time before the start of an event. The main reasons for warming up were injury prevention, to increase activation, and increase blood flow/circulation, temperature, and heart rate. Athletes generally stated that competition warm-ups were practiced in training. Dynamic stretching, foam rolling, and myofascial release work were performed during warm-ups. Warm-up intensity was monitored using the rate of perceived exertion, perceived speed of movement, and training load (as a percentage of 1 repetition maximum). Cognitive strategies were used to improve competition performance, and psychological arousal levels needed to increase or be maintained in competition. Electrolyte drinks, caffeine, and preworkout supplements were the commonly used supplements. These data will provide strongman athletes and coaches some insight into common competition-day preparation strategies, which may enhance competition performances. Future research could compare different competition-day preparation strategies in an attempt to further improve strongman competition performance and injury prevention.

The Biomechanics and Applications of Strongman Exercises: a Systematic Review

Background

The sport of strongman is becoming increasingly popular, catering for females, lightweight, and Masters competitors, with strongman exercises also being used by strength and conditioning coaches for a range of athletic groups. Thus, a systematic review was conducted to examine researchers’ current understanding of the biomechanics of strongman exercises, with a view to improve strongman athlete performance, provide biomechanical evidence supporting the transferability of strongman exercises to strength and conditioning/rehabilitation programs, and identify gaps in the current knowledge of the biomechanics of strongman exercises.

Methods

A two-level search term strategy was used to search five databases for studies relevant to strongman exercises and biomechanics.

Results

Eleven articles adherent to the inclusion criteria were returned from the search. The studies provided preliminary biomechanical analysis of various strongman exercises including the key biomechanical performance determinants of the farmer’s walk, heavy sled pull, and tire flip. Higher performing athletes in the farmer’s walk and heavy sled pull were characterized by a greater stride length and stride rate and reduced ground contact time, while higher performing athletes in the tire flip were characterized by a reduced second pull phase time when compared with lower performing athletes. Qualitative comparison of carrying/walking, pulling and static lifting strongman, traditional weight training exercises (TWTE), and common everyday activities (CEA), like loaded carriage and resisted sprinting, were discussed to further researchers’ understanding of the determinants of various strongman exercises and their applications to strength and conditioning practice. A lack of basic quantitative biomechanical data of the yoke walk, unilateral load carriage, vehicle pull, atlas stone lift and tire flip, and biomechanical performance determinants of the log lift were identified.

Conclusions

This review has demonstrated the likely applicability and benefit of current and future strongman exercise biomechanics research to strongman athletes and coaches, strength and conditioning coaches considering using strongman exercises in a training program, and tactical operators (e.g., military, army) and other manual labor occupations. Future research may provide a greater understanding of the biomechanical determinants of performance, potential training adaptations, and risks expected when performing and/or incorporating strongman exercises into strength and conditioning or injury rehabilitation programs.

Sarc-F and muscle function in community dwelling adults with aged care service needs: baseline and post-training relationship

Background

This study sought to better understand the psychometric properties of the SARC-F, by examining the baseline and training-related relationships between the five SARC-F items and objective measures of muscle function. Each of the five items of the SARC-F are scored from 0 to 2, with total score of four or more indicative of likely sarcopenia.

Methods

This manuscript describes a sub-study of a larger step-wedge, randomised controlled 24-week progressive resistance and balance training (PRBT) program trial for Australian community dwelling older adults accessing government supported aged care. Muscle function was assessed using handgrip strength, isometric knee extension, 5-time repeated chair stand and walking speed over 4 m. Associations within and between SARC-F categories and muscle function were assessed using multiple correspondence analysis (MCA) and multinomial regression, respectively.

Results

Significant associations were identified at baseline between SARC-F total score and measures of lower-body muscle function (r =  - 0.62 to 0.57; p ≤ 0.002) in 245 older adults. MCA analysis indicated the first three dimensions of the SARC-F data explained 48.5% of the cumulative variance. The initial dimension represented overall sarcopenia diagnosis, Dimension 2 the ability to displace the body vertically, and Dimension 3 walking ability and falls status. The majority of the 168 older adults who completed the PRBT program reported no change in their SARC-F diagnosis or individual item scores (56.5-79.2%). However, significant associations were obtained between training-related changes in SARC-F total and item scores and changes in walking speed and chair stand test performance (r =  - 0.30 to 0.33; p < 0.001 and relative risk ratio = 0.40-2.24; p < 0.05, respectively). MCA analysis of the change score data indicated that the first two dimensions explained 32.2% of the cumulative variance, with these dimensions representing whether a change occurred and the direction of change, respectively.

Discussion

The results advance our comprehension of the psychometric properties on the SARC-F, particularly its potential use in assessing changes in muscle function. Older adults' perception of their baseline and training-related changes in their function, as self-reported by the SARC-F, closely matched objectively measured muscle function tests. This is important as there may be a lack of concordance between self-reported and clinician-measured assessments of older adults' muscle function. However, the SARC-F has a relative lack of sensitivity to detecting training-related changes, even over a period of 24 weeks.

Conclusions

Results of this study may provide clinicians and researchers a greater understanding of how they may use the SARC-F and its potential limitations. Future studies may wish to further examine the SARC-F's sensitivity of change, perhaps by adding a few additional items or an additional category of performance to each item.

Kettlebell training in clinical practice: a scoping review

BACKGROUND

A scoping review of scientific literature on the effects of kettlebell training. There are no authoritative guidelines or recommendations for using kettlebells within a primary care setting. Our review objectives were to identify the extent, range and nature of the available evidence, to report on the types of evidence currently available to inform clinical practice, to synthesise key concepts, and identify gaps in the research knowledge base.

METHODS

Following the PRISMA-ScR Checklist, we conducted a search of 10 electronic databases from inception to 1 February 2019. There were no exclusions in searching for publications. A single reviewer screened the literature and abstracted data from relevant publications. Articles were grouped and charted by concepts and themes relevant to primary care, and narratively synthesised. Effect sizes from longitudinal studies were identified or calculated, and randomised controlled trials assessed for methodological quality.

RESULTS

Eight hundred and twenty-nine records were identified to 1 February 2019. Four hundred and ninety-six were screened and 170 assessed for eligibility. Ninety-nine publications met the inclusion criteria. Effect sizes were typically trivial to small. One trial used a pragmatic hardstyle training program among healthy college-age participants. Two trials reported the effects of kettlebell training in clinical conditions. Thirty-three studies explicitly used 'hardstyle' techniques and 4 investigated kettlebell sport. Also included were 6 reviews, 22 clinical/expert opinions and 3 case reports of injury. Two reviewers independently evaluated studies using a modified Downs & Black checklist.

CONCLUSIONS

A small number of longitudinal studies, which are largely underpowered and of low methodological quality, provide the evidence-informed therapist with little guidance to inform the therapeutic prescription of kettlebells within primary care. Confidence in reported effects is low to very low. The strength of recommendation for kettlebell training improving measures of physical function is weak, based on the current body of literature. Further research on reported effects is warranted, with inclusion of clinical populations and investigations of musculoskeletal conditions common to primary care. There is a need for an externally valid, standardised approach to the training and testing of kettlebell interventions, which better informs the therapeutic use of kettlebells in primary care.

Exploring the feasibility, sustainability and the benefits of the GrACE + GAIT exercise programme in the residential aged care setting

Background

The feasibility and benefits of a 24-week targeted progressive supervised resistance and weight-bearing exercise programme (Group Aged Care Exercise + GAIT (GrACE + GAIT)) in the residential aged care (RAC) setting was investigated as very little peer-reviewed research has been conducted in relation to exercise programmes of this duration in this cohort.

Methods

A quasi-experimental study design consisting of two groups (control and exercise) explored a 24-week targeted progressive supervised resistance and weight-bearing exercise programme (GrACE + GAIT) in two RAC facilities in Northern New South Wales, Australia. A total of 42 adults consented to participate from a total of 68 eligible residents (61.7%). The primary outcome measures were feasibility and sustainability of the exercise programme via intervention uptake, session adherence, attrition, acceptability and adverse events. Secondary measures included gait speed and the spatio-temporal parameters of gait, handgrip muscle strength and sit to stand performance.

Results

Twenty-three residents participated in the exercise intervention (mean (SD) 85.4 (8.1) years, 15 females) and 19 in the control group (87.4 (6.6) years 13 females). Exercise adherence was 79.3%, with 65% of exercise participants attending ≥70% of the sessions; 100% of those originally enrolled completed the programme and strongly agreed with the programme acceptability. Zero exercise-related adverse events were reported. ANCOVA results indicated that post-intervention gait speed significantly increased (p < 0.001) with an 18.8% increase in gait speed (m/s).

Discussion

The GrACE + GAIT programme was shown to be feasible and significantly improve adults living in RAC facilities gait speed, handgrip strength and sit to stand performance. These results suggest that the GrACE + GAIT programme is suitable for use in the RAC sector and that it has the potential to reduce disability and improve function and quality of life of the residents.

A systematic review of the biomechanical research methods used in strongman studies

As the sport of strongman is becoming increasingly popular, and such exercises are being commonly used by strength and conditioning coaches for a wide range of athletic groups, a greater understanding of the biomechanics of strongman exercises is warranted. To improve the quality of research, this systematic review summarised the research methodology used in biomechanical studies of strongman exercises and identified potential improvements to current approaches. A search of 5 databases found 10 articles adherent to the pre-defined inclusion criteria. The studies assessed 8 strongman exercises and included male participants of relatively similar body mass but varying training backgrounds. Due to the complexity of strongman exercises and the challenges in collecting advanced biomechanical data in the field, most studies used simplified measurement/analysis methods (e.g., 2D motion capture). Future strongman biomechanical studies should: assess under/un-researched strongman exercises; include a greater number of experienced and female strongman athletes; utilise more advanced (e.g., 3D motion capture and/or inertial sensor) technology so to provide a broader range and greater quality of data. Such approaches will provide strength and conditioning coaches, strongman coaches and athletes with a greater understanding of strongman exercises, thereby further improving exercise prescription, athlete performance and minimising risk of injury.

Reliability and validity of clinically accessible smartphone applications to measure joint range of motion: A systematic review

Measuring joint range of motion is an important skill for many allied health professionals. While the Universal Goniometer is the most commonly utilised clinical tool for measuring joint range of motion, the evolution of smartphone technology and applications (apps) provides the clinician with more measurement options. However, the reliability and validity of these smartphones and apps is still somewhat uncertain. The aim of this study was to systematically review the literature regarding the intra- and inter-rater reliability and validity of smartphones and apps to measure joint range of motion. Eligible studies were published in English peer-reviewed journals with full text available, involving the assessment of reliability and/or validity of a non-videographic smartphone app to measure joint range of motion in participants >18 years old. An electronic search using PubMed, Medline via Ovid, EMBASE, CINAHL, and SPORTSDiscus was performed. The risk of bias was assessed using a standardised appraisal tool. Twenty-three of the eligible 25 studies exceeded the minimum 60% score to be classified as a low risk of bias, although 3 of the 13 criteria were not achieved in >50% of the studies. Most of the studies demonstrated adequate intra-rater or inter-rater reliability and/or validity for >50% of the range of motion tests across all joints assessed. However, this level of evidence appeared weaker for absolute (e.g. mean difference ± limit of agreement, minimal detectable change) than relative (e.g. intraclass correlation, correlation) measures; and for spinal rotation than spinal extension, flexion and lateral flexion. Our results provide clinicians with sufficient evidence to support the use of smartphones and apps in place of goniometers to measure joint motion. Future research should address some methodological limitations of the literature, especially including the inclusion of absolute and not just relative reliability and validity statistics.

Establishing an Operational Definition of Sarcopenia in Australia and New Zealand: Delphi Method Based Consensus Statement

BACKGROUND

Globally there are several operational definitions for sarcopenia, complicating clinical and research applications.

OBJECTIVE

The objective of the Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR) Task Force on Diagnostic Criteria for Sarcopenia was to reach consensus on the operational definition of sarcopenia for regional use by clinicians and researchers.

METHOD

A four-Phase modified Delphi process was undertaken in which 24 individuals with expertise or a recognised interest in sarcopenia from different fields across Australia and New Zealand were invited to be Task Force members. An initial face-to-face meeting was held in Adelaide, South Australia, in November 2017, followed by two subsequent online Phases conducted by electronic surveys. A final Phase was used to approve the final statements. Responses were analysed using a pre-specified strategy. The level of agreement required for consensus was 80%.

RESULTS

In Phase 2, 94.1% of Task Force respondents voted in favour of adopting an existing operational definition of sarcopenia. In Phase 3, 94.4% of respondents voted in favour of adopting the European Working Group on Sarcopenia in Older People (EWGSOP) definition as the operational definition for sarcopenia in Australia and New Zealand.

CONCLUSION

With consensus achieved, the ANZSSFR will adopt, promote and validate the EWGSOP operational definition of sarcopenia for use by clinicians and researchers in Australia and New Zealand.

Using stiffness to assess injury risk: comparison of methods for quantifying stiffness and their reliability in triathletes

Background

A review of the literature has indicated that lower body stiffness, defined as the extent to which the lower extremity joints resists deformation upon contact with the ground, may be a useful measure for assessing Achilles injury risk in triathletes. The nature of overuse injuries suggests that a variety of different movement patterns could conceivably contribute to the final injury outcome, any number and combination of which might be observed in a single individual. Measurements which incorporate both kinetics and kinematics (such as stiffness) of a movement may be better able to shed light on individuals at risk of injury, with further analysis then providing the exact mechanism of injury for the individual. Stiffness can be measured as vertical, leg or joint stiffness to model how the individual interacts with the environment upon landing. However, several issues with stiffness assessments limit the effectiveness of these measures to monitor athletes’ performance and/or injury risk. This may reflect the variety of common biomechanical stiffness calculations (dynamic, time, true leg and joint) that have been used to examine these three stiffness levels (vertical, leg and joint) across a variety of human movements (i.e. running or hopping) as well as potential issues with the reliability of these measures, especially joint stiffness. Therefore, the aims of this study were to provide a comparison of the various methods for measuring stiffness during two forms of human bouncing locomotion (running and hopping) along with the measurement reliability to determine the best methods to assess links with injury risk in triathletes.

Methods

Vertical, leg and joint stiffness were estimated in 12 healthy male competitive triathletes on two occasions, 7 days apart, using both running at 5.0 ms⁻¹ and hopping (2.2 Hz) tasks.

Results

Inter-day reliability was good for vertical (ICC = 0.85) and leg (ICC = 0.98) stiffness using the time method. Joint stiffness reliability was poor when assessed individually. Reliability was improved when taken as the sum of the hip, knee and ankle (ICC = 0.86). The knee and ankle combination provided the best correlation with leg stiffness during running (Pearson’s Correlation = 0.82).

Discussion

The dynamic and time methods of calculating leg stiffness had better reliability than the “true” method. The time and dynamic methods had the best correlation with the different combinations of joint stiffness, which suggests that they should be considered for biomechanical screening of triathletes. The knee and ankle combination had the best correlation with leg stiffness and is therefore proposed to provide the most information regarding lower limb mechanics during gait in triathletes.

Tapering Practices of Strongman Athletes

Winwood, PW, Dudson, MK, Wilson, D, Mclaren-Harrison, JKH, Redjkins, V, Pritchard, HJ, and Keogh, JWL. Tapering practices of strongman athletes. J Strength Cond Res 32(5): 1181-1196, 2018-This study provides the first empirical evidence of how strongman athletes taper for strongman competitions. Strongman athletes (n = 454) (mean ± SD: 33.2 ± 8.0 years, 178.1 ± 10.6 cm, 108.6 ± 27.9 kg, 12.6 ± 8.9 years general resistance training, 5.3 ± 5.0 years strongman implement training) completed a self-reported 4-page internet survey on tapering practices. Analysis by sex (male and female), age (≤30 and >30 years), body mass (≤105 and >105 kg), and competitive standard (local/regional amateur, national amateur and professional) was conducted. Eighty-seven percent (n = 396) of strongman athletes reported that they used a taper. Athletes stated that their typical taper length was 8.6 ± 5.0 days, with the step taper the most commonly performed taper (52%). Training volume decreased during the taper by 45.5 ± 12.9%, and all training ceased 3.9 ± 1.8 days out from competition. Typically, athletes reported that training frequency and training duration stayed the same or decreased and training intensity decreased to around 50% in the last week. Athletes generally stated that tapering was performed to achieve recovery, rest, and peak performance; the deadlift, yoke walk, and stone lifts/work took longer to recover from than other lifts; assistance exercises were reduced or removed in the taper; massage, foam rolling, nutritional changes, and static stretching were strategies used in the taper; and, poor tapering occurred when athletes trained too heavy/hard or had too short a taper. These data will assist strongman athletes and coaches in the optimization of tapering variables leading to more peak performances. Future research could investigate the priming and preactivation strategies strongman athletes use on competition day.

The Epidemiology of Injuries Across the Weight-Training Sports

BACKGROUND

Weight-training sports, including weightlifting, powerlifting, bodybuilding, strongman, Highland Games, and CrossFit, are weight-training sports that have separate divisions for males and females of a variety of ages, competitive standards, and bodyweight classes. These sports may be considered dangerous because of the heavy loads commonly used in training and competition.

OBJECTIVES

Our objective was to systematically review the injury epidemiology of these weight-training sports, and, where possible, gain some insight into whether this may be affected by age, sex, competitive standard, and bodyweight class.

METHODS

We performed an electronic search using PubMed, SPORTDiscus, CINAHL, and Embase for injury epidemiology studies involving competitive athletes in these weight-training sports. Eligible studies included peer-reviewed journal articles only, with no limit placed on date or language of publication. We assessed the risk of bias in all studies using an adaption of the musculoskeletal injury review method.

RESULTS

Only five of the 20 eligible studies had a risk of bias score ≥75 %, meaning the risk of bias in these five studies was considered low. While 14 of the studies had sample sizes >100 participants, only four studies utilized a prospective design. Bodybuilding had the lowest injury rates (0.12-0.7 injuries per lifter per year; 0.24-1 injury per 1000 h), with strongman (4.5-6.1 injuries per 1000 h) and Highland Games (7.5 injuries per 1000 h) reporting the highest rates. The shoulder, lower back, knee, elbow, and wrist/hand were generally the most commonly injured anatomical locations; strains, tendinitis, and sprains were the most common injury type. Very few significant differences in any of the injury outcomes were observed as a function of age, sex, competitive standard, or bodyweight class.

CONCLUSION

While the majority of the research we reviewed utilized retrospective designs, the weight-training sports appear to have relatively low rates of injury compared with common team sports. Future weight-training sport injury epidemiology research needs to be improved, particularly in terms of the use of prospective designs, diagnosis of injury, and changes in risk exposure.

Effect of acute augmented feedback on between limb asymmetries and eccentric knee flexor strength during the Nordic hamstring exercise

Background

Hamstring strain injuries (HSI) are one of the most prevalent and serious injuries affecting athletes, particularly those in team ball sports or track and field. Recent evidence demonstrates that eccentric knee flexor weakness and between limb asymmetries are possible risk factors for HSIs. While eccentric hamstring resistance training, e.g. the Nordic hamstring exercise (NHE) significantly increases eccentric hamstring strength and reduces HSI risk, little research has examined whether between limb asymmetries can be reduced with training. As augmented feedback (AF) can produce significant acute and chronic increases in muscular strength and reduce injury risk, one way to address the limitation in the eccentric hamstring training literature may be to provide athletes real-time visual AF of their NHE force outputs with the goal to minimise the between limb asymmetry.

Methods

Using a cross over study design, 44 injury free, male cricket players from two skill levels performed two NHE sessions on a testing device. The two NHE sessions were identical with the exception of AF, with the two groups randomised to perform the sessions with and without visual feedback of each limb's force production in real-time. When performing the NHE with visual AF, the participants were provided with the following instructions to 'reduce limb asymmetries as much as possible using the real-time visual force outputs displayed in front them'. Between limb asymmetries and mean peak force outputs were compared between the two feedback conditions (FB1 and FB2) using independent t-tests to ensure there was no carryover effect, and to determine any period and treatment effects. The magnitude of the differences in the force outputs were also examined using Cohen d effect size.

Results

There was a significant increase in mean peak force production when feedback was provided (mean difference, 21.7 N; 95% CI [0.2-42.3 N]; P = 0.048; d = 0.61) and no significant difference in between limb asymmetry for feedback or no feedback (mean difference, 5.7%; 95% CI [-2.8% to 14.3%]; P = 0.184; d = 0.41). Increases in force production under feedback were a result of increased weak limb (mean difference, 15.0 N; 95% CI [1.6-28.5 N]; P = 0.029; d = 0.22) force contribution compared to the strong limb.

Discussion

The results of this study further support the potential utility of AF in improving force production and reducing risk in athletic populations. While there are currently some financial limitations to the application of this training approach, even in high-performance sport, such an approach may improve outcomes for HSI prevention programs. Further research with more homogenous populations over greater periods of time that assess the chronic effect of such training practices on injury risk factors and injury rates are also recommended.

Joint-level energetics differentiate isoinertial from speed-power resistance training-a Bayesian analysis

Background

There is convincing evidence for the benefits of resistance training on vertical jump improvements, but little evidence to guide optimal training prescription. The inability to detect small between modality effects may partially reflect the use of ANOVA statistics. This study represents the results of a sub-study from a larger project investigating the effects of two resistance training methods on load carriage running energetics. Bayesian statistics were used to compare the effectiveness of isoinertial resistance against speed-power training to change countermovement jump (CMJ) and squat jump (SJ) height, and joint energetics.

Methods

Active adults were randomly allocated to either a six-week isoinertial (n = 16; calf raises, leg press, and lunge), or a speed-power training program (n = 14; countermovement jumps, hopping, with hip flexor training to target pre-swing running energetics). Primary outcome variables included jump height and joint power. Bayesian mixed modelling and Functional Data Analysis were used, where significance was determined by a non-zero crossing of the 95% Bayesian Credible Interval (CrI).

Results

The gain in CMJ height after isoinertial training was 1.95 cm (95% CrI [0.85–3.04] cm) greater than the gain after speed-power training, but the gain in SJ height was similar between groups. In the CMJ, isoinertial training produced a larger increase in power absorption at the hip by a mean 0.018% (equivalent to 35 W) (95% CrI [0.007–0.03]), knee by 0.014% (equivalent to 27 W) (95% CrI [0.006–0.02]) and foot by 0.011% (equivalent to 21 W) (95% CrI [0.005–0.02]) compared to speed-power training.

Discussion

Short-term isoinertial training improved CMJ height more than speed-power training. The principle adaptive difference between training modalities was at the level of hip, knee and foot power absorption.

Physical Activity Promotion, Beliefs, and Barriers Among Australasian Oncology Nurses

PURPOSE/OBJECTIVES

To describe the physical activity (PA) promotion practices, beliefs, and barriers of Australasian oncology nurses and gain preliminary insight into how PA promotion practices may be affected by the demographics of the nurses.
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DESIGN

Cross-sectional survey.
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SETTING

Australia and New Zealand.
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SAMPLE

119 registered oncology nurses.
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METHODS

Self-reported online survey completed once per participant.
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MAIN RESEARCH VARIABLES

Questions assessed the PA promotion beliefs (e.g., primary healthcare professionals responsible for PA promotion, treatment stage), PA benefits (e.g., primary benefits, evidence base), and PA promotion barriers of oncology nurses.
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FINDINGS

Oncology nurses believed they were the major providers of PA advice to their patients. They promoted PA prior to, during, and post-treatment. The three most commonly cited benefits of PA for their patients were improved quality of life, mental health, and activities of daily living. Lack of time, lack of adequate support structures, and risk to patient were the most common barriers to PA promotion. Relatively few significant differences in the oncology nurses' PA promotion practices, beliefs, and barriers were observed based on hospital location or years of experience.
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CONCLUSIONS

Despite numerous barriers, Australasian oncology nurses wish to promote PA to their patients with cancer across multiple treatment stages because they believe PA is beneficial for their patients.
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IMPLICATIONS FOR NURSING

Hospitals may need to better support oncology nurses in promoting PA to their patients and provide better referral pathways to exercise physiologists and physiotherapists.

Anthropometric, physical function and general health markers of Masters athletes: a cross-sectional study

Once the general decline in muscle mass, muscle strength and physical performance falls below specific thresholds, the middle aged or older adult will be diagnosed as having sarcopenia (a loss of skeletal muscle mass and strength). Sarcopenia contributes to a range of adverse events in older age including disability, hospitalisation, institutionalisation and falls. One potentially relevant but understudied population for sarcopenia researchers would be Masters athletes. Masters sport is becoming more common as it allows athletes (typically 40 years and older) the opportunity to participate in individual and/or team sports against individuals of similar age. This study examined a variety of measures of anthropometric, physical function and general health markers in the male and female Masters athletes who competed at the 2014 Pan Pacific Masters Games held on the Gold Coast, Australia. Bioelectrical impedance analysis was used to collect body fat percentage, fat mass and fat-free mass; with body mass, height, body mass index (BMI) and sarcopenic status also recorded. Physical function was quantified by handgrip strength and habitual walking speed; with general health described by the number of chronic diseases and prescribed medications. Between group analyses utilised ANOVA and Tukey's post-hoc tests to examine the effect of age group (40-49, 50-59, 60-69 and >70 years old) on the outcome measures for the entire sample as well as the male and female sub-groups. A total of 156 athletes (78 male, 78 female; mean 55.7 years) provided informed consent to participate in this study. These athletes possessed substantially better anthropometric, physical function and general health characteristics than the literature for their less physically active age-matched peers. No Masters athletes were categorised as being sarcopenic, although one participant had below normal physical performance and six participants had below normal muscle strength. In contrast, significant age-related reductions in handgrip strength and increases in the number of chronic diseases and prescribed medications were observed for the overall cohort as well as the male and female sub-groups. Nevertheless, even those aged over 70 years only averaged one chronic disease and one prescribed medication. These results may suggest that participation in Masters sport helps to maintain anthropometry, physical function and general health in middle-aged and older adults. However, it is also possible that only healthier middle-aged and older adults with favourable body composition and physical function may be able to participate in Masters sport. Future research should therefore utilise longitudinal research designs to determine the health and functional benefits of Master sports participation for middle-aged and older adults.