Short-term Periodization Models: Effects on Strength and Speed-strength Performance

Effects of focal vibration on changes in sports performance in amateur athletes: A randomized clinical trial

The aim of this study was to evaluate the effectiveness of a focal vibration protocol added to an activation protocol with active muscle contractions and to see what repercussions it has on sprint, countermovement jump (CMJ), and lower limb isometric strength. A double-blind randomized clinical trial was conducted in the Functional Anatomy Laboratory and the sample consisted of 70 athletes. The main outcome measures were knee extension force, CMJ, sprint, and surface electromyography. Repeated-measures analysis of variance revealed significant improvements. They were found in the within-group analysis for the Experimental Group in the isometric extension force (p < 0.001; η2 = 0.368), CMJ (p < 0.001; η2 = 0.301) and 30 m sprint (p < 0.001; η2 = 0.376). In the electromyography, there are changes in the Sham Group in all muscles, in CMJ and Sprint tests, and no differences in the Experimental Group, except for the RF muscle. In the between-group analysis, statistically significant differences were found only in favor of the Experimental Group in CMJ (p = 0.017; η2 = 0.81) and 30 m sprint (p < 0.001; η2 = 0.152). These results confirm a significant improvement in the sprint, CMJ performance, and quadriceps strength, after a focal vibration protocol, added to a muscle active contraction, compared to a focal vibration sham protocol. Therefore, our results suggest that the focal vibration can be a very useful tool in sports involving high-powered actions.

The Effect of Traditional Strength Training on Sprint and Jump Performance in 12- to 15-Year-Old Elite Soccer Players: A 12-Month Controlled Trial

ABSTRACT

Skratek, J, Kadlubowski, B, and Keiner, M. The effect of traditional strength training on sprint and jump performance in 12- to 15-year-old elite soccer players: a 12-month controlled trial. J Strength Cond Res XX(X): 000-000, 2024-The aim of the study was to evaluate the effect of traditional strength training on maximum strength (1 repetition maximum in front squat [FS] and back squat [BS]), jump (squat and countermovement jump), and linear sprint (LS) performance (5, 10, and 30 m) in elite young soccer players. A 12-month longitudinal design was chosen, and 48 elite male youth soccer players (age: 12-15 years) were included. The subjects were divided in 2 groups (a strength training group [STG] and a control group [CG]). The intervention group trained for 1 year over a competitive soccer season with additional sessions to their regular soccer practice (4 sessions per week), while the CG did not complete any additional sessions to the regular soccer training (4 sessions per week). The additional strength training (2 sessions per week [each approximately 30 minutes]) consisted of either parallel FS or BS. The squat variants switched in each session. Data were analyzed using a 2 × 3 (group × time) repeated-measures analysis of variance. The main findings of this study were that the STG resulted in significant pretest and post-test improvements in maximum strength (d = 3.75-5.58), jump (d = 0.84-1.14), and LS performance (d = -0.25 to 0.44), while for the CG, smaller increases or performance decreases were measured (maximum strength: d = 1.64-2.7; jump: d = 0.12-0.31; sprint: d = 0.00-025). A significant interaction effect in all variables indicated significant (p < 0.05) stronger performance improvements compared with the CG. Traditional strength training in elite youth soccer players is recommended to increase strength and speed-strength (jump and sprint performance) and should be considered in long-term athletic development programs.

Knee and Hip Muscle Strength of Male Soccer Players from Different Competitive Levels

In soccer, knee and hip muscle strength assessments have been recommended for injury prevention. The aims of this study were threefold: (1) to compare knee and hip muscle strength between professional players competing at different levels; (2) to compare strength performance according to the preferred leg (PL) and the non-preferred leg (NPL); and (3) to compare knee and hip muscle strength performance at two moments of the season. This study included 33 professional soccer players: 13 were in the elite group (EG), and 20 were in the sub-elite group (SEG). Body composition, isokinetic knee strength at 60º/s, and hip adduction strength were assessed at two different moments (M1 and M2). Values of peak torque (PT), peak torque/bodyweight (PT/BW), and the hamstring-to-quadriceps strength ratio (H:Q) for knee extensors (KEs) and knee flexors (KFs) for both legs were used for analysis. The statistical analysis included the Mann-Whitney U and the Wilcoxon Signed Rank tests. At M1, the EG presented a significantly better performance in KF PT/BW and in the squeeze strength test for the PL and the NPL (p ≤ 0.01). At M2, the EG performed substantially better in KE PT/BW and KF PT/BW (p ≤ 0.01). No substantial strength differences were observed in knee and hip muscle performance between the PL and the NPL. From M1 to M2, significant increases were found in knee strength in both groups (p ≤ 0.01). Overall, the EG players outperformed significantly their lower-division peers in strength assessments. The results indicate significant knee and hip muscle strength increases during the season, probably as a response to the exposure to training and competition.

Standardized vs. Relative Intensity in CrossFit

CrossFit is characterized by being a standardized training program that improves physical performance through the provision of several stimuli regardless of the participant's strength level. This study aimed to compare the acute response in total repetitions as a measurement of performance, jump ability, physiological demand (heart rate and blood lactate), and perceived effort considering the participants' strength level with individualized intensity in CrossFit. Thirty-five participants were assessed and asked to participate on two separate days in a standardized and relative 'As Many Repetitions As Possible' (AMRAP) CrossFit circuit. Both AMRAPs comprised strength, gymnastic and aerobic exercises, although only strength was individualized according to the participant's level. Before the statistical analysis, participants were allocated to higher- or lower-strength groups following the one-repetition maximum-bodyweight ratio in the push press exercise. Results support the existence of a strong relationship between strength level and total repetitions in both AMRAPs. In addition, differences in total repetitions and rate of perceived exertion between strength groups are discarded when AMRAP intensity is individualized while physiological demand and jump ability are maintained. Thus, the higher-strength participants may benefit from similar responses with a lower number of repetitions. Therefore, CrossFit trainers should be encouraged to prescribe strength tasks based on the percentage of 1RM for every training.

Perspectives on Concurrent Strength and Endurance Training in Healthy Adult Females: A Systematic Review

BACKGROUND

Both strength and endurance training are included in global exercise recommendations and are the main components of training programs for competitive sports. While an abundance of research has been published regarding concurrent strength and endurance training, only a small portion of this research has been conducted in females or has addressed their unique physiological circumstances (e.g., hormonal profiles related to menstrual cycle phase, menstrual dysfunction, and hormonal contraceptive use), which may influence training responses and adaptations.

OBJECTIVE

The aim was to complete a systematic review of the scientific literature regarding training adaptations following concurrent strength and endurance training in apparently healthy adult females.

METHODS

A systematic electronic search for articles was performed in July 2021 and again in December 2022 using PubMed and Medline. This review followed, where applicable, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included studies was assessed using a modified Downs and Black checklist. Inclusion criteria were (1) fully published peer-reviewed publications; (2) study published in English; (3) participants were healthy normal weight or overweight females of reproductive age (mean age between > 18 and < 50) or presented as a group (n > 5) in studies including both females and males and where female results were reported separately; (4) participants were randomly assigned to intervention groups, when warranted, and the study included measures of maximal strength and endurance performance; and (5) the duration of the intervention was ≥ 8 weeks to ensure a meaningful training duration.

RESULTS

Fourteen studies met the inclusion criteria (seven combined strength training with running, four with cycling, and three with rowing or cross-country skiing). These studies indicated that concurrent strength and endurance training generally increases parameters associated with strength and endurance performance in female participants, while several other health benefits such as, e.g., improved body composition and blood lipid profile were reported in individual studies. The presence of an "interference effect" in females could not be assessed from the included studies as this was not the focus of any included research and single-mode training groups were not always included alongside concurrent training groups. Importantly, the influence of concurrent training on fast-force production was limited, while the unique circumstances affecting females were not considered/reported in most studies. Overall study quality was low to moderate.

CONCLUSION

Concurrent strength and endurance training appears to be beneficial in increasing strength and endurance capacity in females; however, multiple research paradigms must be explored to better understand the influence of concurrent training modalities in females. Future research should explore the influence of concurrent strength and endurance training on fast-force production, the possible presence of an "interference effect" in athletic populations, and the influence of unique circumstances, such as hormone profile, on training responses and adaptations.

The effects of cognitive-motor dual-task training on athletes' cognition and motor performance

Background

Cognitive-Motor Dual Task (CMDT) training has been widely utilized in rehabilitation and sports practice. However, whether CMDT training can better enhance athletes' cognitive-motor performance compared to traditional single-task (ST) training remains unclear.

Method

A systematic review that complied with PRISMA was carried out (Prospero registration number: CRD42023443594). The electronic databases used for the systematic literature search from the beginning through 13 June 2023, included Web of Science, Embase, PubMed, and the Cochrane Library. After obtaining the initial literature, two researchers independently assessed it based on inclusion and exclusion criteria. Finally, the included literature was analyzed to compare the differences between ST training and CMDT training.

Results

After screening 2,094 articles, we included 10 acute studies and 7 chronic studies.

Conclusion

This systematic review shows that athletes typically show a degradation of performance in CMDT situations as opposed to ST when evaluated transversally. However, this performance decline is notably reduced following longitudinal training in CMDT, indicating the effectiveness of sustained CMDT training in enhancing cognitive-motor performance under dual-task conditions. Our study provides new insights into the application of CMDT in the field of sports training. Practitioners can utilize CMDT to assess athletic skill levels or optimize cognitive-motor performance of athletes, taking into account the specific needs of each sport.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023443594.

Gaining more from doing less? The effects of a one-week deload period during supervised resistance training on muscular adaptations

Background

Based on emerging evidence that brief periods of cessation from resistance training (RT) may re-sensitize muscle to anabolic stimuli, we aimed to investigate the effects of a 1-week deload interval at the midpoint of a 9-week RT program on muscular adaptations in resistance-trained individuals.

Methods

Thirty-nine young men (n = 29) and women (n = 10) were randomly assigned to 1 of 2 experimental, parallel groups: An experimental group that abstained from RT for 1 week at the midpoint of a 9-week, high-volume RT program (DELOAD) or a traditional training group that performed the same RT program continuously over the study period (TRAD). The lower body routines were directly supervised by the research staff while upper body training was carried out in an unsupervised fashion. Muscle growth outcomes included assessments of muscle thickness along proximal, mid and distal regions of the middle and lateral quadriceps femoris as well as the mid-region of the triceps surae. Adaptions in lower body isometric and dynamic strength, local muscular endurance of the quadriceps, and lower body muscle power were also assessed.

Results

Results indicated no appreciable differences in increases of lower body muscle size, local endurance, and power between groups. Alternatively, TRAD showed greater improvements in both isometric and dynamic lower body strength compared to DELOAD. Additionally, TRAD showed some slight psychological benefits as assessed by the readiness to train questionnaire over DELOAD.

Conclusion

In conclusion, our findings suggest that a 1-week deload period at the midpoint of a 9-week RT program appears to negatively influence measures of lower body muscle strength but has no effect on lower body hypertrophy, power or local muscular endurance.

Female Soccer Periodization on Anaerobic Power/Capacity

ABSTRACT

Purdom, TM, Levers, KS, Ryan, GA, Brown, L, Giles, J, and McPherson, C. Female soccer periodization on anaerobic power/capacity. J Strength Cond Res 37(12): 2405-2410, 2023-The purpose of this study was to observe changes in anaerobic power and capacity (resistance to fatigue) over an annual training cycle (ATC) in 14 Division I female soccer athletes (19.4 ± 1.0 years, 60.8 ± 5.4 kg, 164.9 ± 6.2 cm, 19.5 ± 3.2% body fat, and 48.9 ± 3.9 kg fat free mass). All subjects were evaluated across the ATC at 5 testing blocks (B1-B5) representing seasonal transitions: postcompetition I (B1), prespring (B2), postspring training (B3), precompetition (B4), and postcompetition II (B5) using 3 tests: countermovement vertical jump to measure peak vertical power (PVP), 40-yard sprint to measure peak horizontal power (PHP), and 35-m running anaerobic sprint test to measure anaerobic capacity via fatigue index (FI). Repeated measures analysis of variance was used with the Bonferroni post hoc test when relevant along with Cohen's d to evaluate effect size. Data are represented as mean ± SD ; significance set to p < 0.05. Significant performance increases were observed from postseason I to spring season training (B1-B3) in PVP (6.61 ± 3.18 and 7.71 ± 3.20; p < 0.01, d = 1.12) while changes occurred from prespring season to postspring season (B2-B3) in PVP (6.84 ± 3.15 and 7.71 ± 3.20; p = 0.03, d = 0.93) and PHP (6.65 ± 0.97 and 7.55 ± 1.26; p < 0.01, d = 1.06) with no change in body composition. No other significant changes were observed across the ATC ( p > 0.05). Increases in PHP and PVP occurred with directed training after B3 and then declined remaining so across the competitive season. Peak horizontal power and PVP may be more sensitive to coaching style and seasonal transition compared with FI and body composition changes.

Strength training as a dynamical model of motor learning

This paper outlines a framework for strength training as a dynamical model of perceptual-motor learning. We show, with emphasis on fixed-point attractor dynamics, that strength training can be mapped to the general dynamical principles of motor learning that arise from the constraints on action, including the distribution of practice/training. The time scales of the respective dynamics of performance change (increment and decrement) in discrete strength training and motor learning tasks reveal superposition of exponential functions in fixed-point dynamics, but distinctive attractor and parameter dynamics in oscillatory limit cycle and more continuous tasks, together with unique timescales to process influences (including practice, learning, strength, fitness, fatigue, warm-up decrement). Increments and decrements of strength can be viewed within a dynamical model of change in motor performance that reflects the integration of practice and training processes at multiple levels of learning and skill development.

Influence of Strength Training Variables on Neuromuscular and Morphological Adaptations in Prepubertal Children: A Systematic Review

Strength training in prepubertal children is one of the topics that has aroused the most interest and controversy among training professionals in recent years. Therefore, the aim of the present study was to analyze the available scientific evidence on the influence of strength training variables on morphological and/or neuromuscular adaptations in healthy prepubertal populations with no previous experience in this type of training according to the descriptive sample characteristics. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis, 22 studies were selected after a systematic search and selection process using four electronic databases: Google Scholar, PubMed, Scopus, and SPORT Discus. Furthermore, the internal validity of the studies included was assessed using the modified PEDro scale. The sample consisted of 604 prepubertal children (age, 10.02 ± 0.75 years), of whom 473 were boys and 131 were girls, with 104 strength training programs recorded. Strength training resulted in a significant increase in jumping (n = 29) and sprinting (n = 13) abilities. Moreover, muscle strength was increased in 100% of the cases. Morphologically, strength training resulted in a decrease in body fat percentage (n = 19) and an increase in lean body mass (n = 17). With regard to gender, increases in general sport skills and basic physical abilities were significant in males but not in females. Thus, the results are more heterogeneous in girls due to the small number of studies carried out. Therefore, this research provides practical applications for coaches to design and implement more effective training programs to maximize adaptations, enhance physical performance, and reduce injury risk.

Strength and Conditioning Practices of Brazilian Olympic Sprint and Jump Coaches

Olympic coaches are likely to have adequate knowledge and implement effective training programs. This study aimed to describe and critically examine the strength and conditioning practices adopted by Brazilian Olympic sprint and jump coaches. Nineteen Olympic coaches (age: 50.2 ± 10.8 years; professional experience: 25.9 ± 13.1 years) completed a survey consisting of eight sections: 1) background information; 2) strength-power development; 3) speed training; 4) plyometrics; 5) flexibility training; 6) physical testing; 7) technology use; and 8) programming. It was noticed that coaches prioritized the development of explosiveness, power, and sprinting speed in their training programs, given the specific requirements of sprint and jump events. Nevertheless, unexpectedly, we observed: (1) large variations in the number of repetitions performed per set during resistance training in the off-season period, (2) a higher volume of resistance training prescribed during the competitive period (compared to other sports), and (3) infrequent use of traditional periodization models. These findings are probably related to the complex characteristics of modern competitive sports (e.g., congested competitive schedule) and the individual needs of sprinters and jumpers. Identification of training practices commonly used by leading track and field coaches may help practitioners and sport scientists create more effective research projects and training programs.

Reverse Periodization for Improving Sports Performance: A Systematic Review

Background

Reverse periodization is commonly touted as a salient planning strategy to improve sport performance in athletes, but benefits have not been clearly described.

Objectives

We sought to identify the main characteristics of reverse periodization, and the influence of training volume and periodization models on enhancing physiological measures and sports performance.

Design

Systematic review.

Methods

The electronic databases Scopus, PubMed and Web of Science were searched using a comprehensive list of relevant terms.

Results

A total of 925 studies were identified, and after removal of duplicates and studies based on title and abstract screening, 17 studies remained, and 11 finally included in the systematic review. There was a total of 200 athletes in the included studies. Reverse periodization does not provide superior performance improvements in swimming, running, muscular endurance, maximum strength, or maximal oxygen uptake, compared to traditional or block periodization. The quality of evidence levels for the reverse periodization studies was 1b (individual randomized controlled trial) for two investigations, 2b (individual cohort study) for the remaining studies and a mean of 4.9 points in the PEDro scale (range 0–7).

Conclusions

It appears that reverse periodization is no more effective than other forms of periodization in improving sports performance. More comparative studies on this alternative version of periodization are required to verify its effectiveness and utility across a range of endurance sports.

Internet Survey of Risk Factors Associated With Training and Competition in Dogs Competing in Agility Competitions

Objective: To describe risk factors associated with training and competition in relation to frequency and severity of injuries experienced by agility dogs.

Procedures: An internet-based survey collected data on competition level variables and training level variables. The primary outcome was history of any injury and a secondary outcome considered history of severe injury (injury lasting > 3 months). Logistic regression was used to estimate associations and final models were obtained via backward selection to identify the strongest associations within variables.

Results: There were 4,197 dogs included in this analysis. Injury was reported for 1,737 (41.4%) dogs and severe injury was reported for 629 (15.0%). In the model with competition level factors, jumping 4” (OR: 1.50) or 2–4” (OR: 1.31) over shoulder height compared to jumping 0–2” lower and competing at national events was associated with increased injury risk, while competing 6+ times on rubber matting was associated with lower risk (OR: 0.62). Training level variables associated with injury risk were age starting jump, teeter, and weave training, with the highest risk observed for dogs starting jump training between 3 and 18 months but starting weave and teeter training after 18 months of age.

Conclusion and Clinical Relevance: Many variables thought to be associated with injury risk were not significant in the final model. Starting jump training at an earlier age was associated with greater risk of injury relative to starting after 18 months. It is possible that the high impact of jump training before skeletal maturity may increase the risk of injuries or musculoskeletal conditions. The increased risk of injury in dogs that jump 2–4, or 4+ inches higher than shoulder height may be due to increased biomechanical forces during takeoff and landing. Faster dogs may be at higher risk of injury; handlers planning competition around big events or competing at the national level are likely to have faster dogs, and may be less likely to compete on rubber matting. These data provide valuable current insight into the possible effects that training and competition variables may have on injury risk in agility dogs.

Effects of plyometric jump training versus power training using free weights on measures of physical fitness in youth male soccer players

This study aimed to contrast the effects of power training (PT) and plyometric-jump-training (PJT) programmes on measures of physical fitness in prepubertal male soccer players. Thirty-three participants were randomly allocated to PT group (n = 11), PJT group (n = 11), and an active control group (CG; n = 11). Before and after 12 weeks of training, tests were performed for the assessment of sprint-speed , change-of-direction (CoD) speed, muscular strength , and aerobic-endurance (AE). Findings indicated significant group×time interaction effects for all sprint-speed intervals, CoD speed, AE, and strength (d = 0.20-0.32). Post-hoc analyses revealed significant, moderate-to-large improvements in all sprint-speed intervals, CoD speed, AE, and muscle strength following PT (ES = 0.71 to 1.38). The PJT induced significant, moderate-to-large enhancements in 10 m, 20 m, and 30 m sprint, CoD speed, and AE (ES = 0.51 to 0.96) with no significant changes for 5 m sprint-speed and muscle strength (ES = 0.71 and 0.16, respectively). No significant pre-post changes were observed for the CG . Overall, PT and PJT are effective means to improve various measures of physical fitness in prepubertal male soccer players. Notably, to additionally improve acceleration and muscle strength, PT has an advantage over PJT.

The Effect of Intensity, Frequency, Duration and Volume of Physical Activity in Children and Adolescents on Skeletal Muscle Fitness: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Physical activity could improve the muscle fitness of youth, but the systematic analysis of physical activity elements and muscle fitness was limited. This systematic review and meta-analysis aim to explore the influence of physical activity elements on muscle fitness in children and adolescents. We analyzed literature in Embase, EBSCO, Web of Science, and PubMed databases from January 2000 to September 2020. Only randomized controlled studies with an active control group, which examined at least 1 muscle fitness evaluation index in individuals aged 5–18 years were included. Articles were evaluated using the Jaded scale. Weighted-mean standardized mean differences (SMDs) were calculated using random-effects models. Twenty-one studies and 2267 subjects were included. Physical activity had moderate effects on improving muscle fitness (SMD: 0.58–0.96, p < 0.05). Physical activity element subgroup analysis showed that high-intensity (SMD 0.68–0.99, p < 0.05) physical activity <3 times/week (SMD 0.68–0.99, p < 0.05), and <60 min/session (SMD 0.66–0.76, p < 0.01) effectively improved muscle fitness. Resistance training of ≥3 sets/session (SMD 0.93–2.90, p < 0.01) and <10 repetitions/set (SMD 0.93–1.29, p < 0.05) significantly improved muscle fitness. Low-frequency, high-intensity, and short-duration physical activity more effectively improves muscle fitness in children and adolescents. The major limitation of this meta-analysis was the low quality of included studies. The study was registered in PROSPERO with the registration number CRD42020206963 and was funded mainly by the Ministry of Education of Humanities and Social Science project, China.

Effects of Resistance Training Methods on Golf Clubhead Speed and Hitting Distance: A Systematic Review

ABSTRACT

Uthoff, A, Sommerfield, LM, and Pichardo, AW. Effects of resistance training methods on golf clubhead speed and hitting distance: A systematic review. J Strength Cond Res 35(9): 2651-2660, 2021-Resistance training is widely regarded within the golfing community to improve golf performance by increasing clubhead speed (CHS) and drive distance and can be classified into 3 categories: nonspecific, specific, and combined. However, it is currently unclear which resistance training methods are most effective in improving predictors of golf performance. Therefore, the purpose of this review is to compare the effectiveness of nonspecific, specific, and combined strength training methods on CHS and drive distance. A systematic search strategy was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to identify eligible articles through PubMed, SPORTDiscus, MEDLINE (EBSCO), and Google Scholar. The searches identified 4,557 potentially relevant results, with 20 studies that met the inclusion criteria and were included in the final review. Thirteen studies investigated nonspecific resistance training, one study investigated specific resistance training, and 7 studies investigated combined resistance training. Collectively, resistance training positively impacts golf CHS and hitting distance, but adaptations vary depending on the type and intensity of training, as well as subject's characteristics. Using a combination of nonspecific and golf-specific training (average increase of 4.1% CHS and 5.2% hitting distance) seems to enhance golf performance more than nonspecific strength training (average increase of 1.6% CHS and 4.8% hitting distance). Eight-week programs including golf-specific movements at high velocities for 3 to 4 sets of 5 to 15 repetitions are the most effective in increasing CHS and hitting distance. Future research investigating how golf-specific training influences CHS and hitting distance in various subgroups may provide further insight regarding prescription of this training type.

Molecular Differences in Skeletal Muscle After 1 Week of Active vs. Passive Recovery From High-Volume Resistance Training

ABSTRACT

Vann, CG, Haun, CT, Osburn, SC, Romero, MA, Roberson, PA, Mumford, PW, Mobley, CB, Holmes, HM, Fox, CD, Young, KC, and Roberts, MD. Molecular differences in skeletal muscle after 1 week of active vs. passive recovery from high-volume resistance training. J Strength Cond Res 35(8): 2102-2113, 2021-Numerous studies have evaluated how deloading after resistance training (RT) affects strength and power outcomes. However, the molecular adaptations that occur after deload periods remain understudied. Trained, college-aged men (n = 30) performed 6 weeks of whole-body RT starting at 10 sets of 10 repetitions per exercise per week and finishing at 32 sets of 10 repetitions per exercise per week. After this period, subjects performed either active (AR; n = 16) or passive recovery (PR; n = 14) for 1 week where AR completed ∼15% of the week 6 training volume and PR ceased training. Variables related to body composition and recovery examined before RT (PRE), after 6 weeks of RT (POST), and after the 1-week recovery period (DL). Vastus lateralis (VL) muscle biopsies and blood samples were collected at each timepoint, and various biochemical and histological assays were performed. Group × time interactions (p < 0.05) existed for skeletal muscle myosin heavy chain (MHC)-IIa mRNA (AR > PR at POST and DL) and 20S proteasome activity (post-hoc tests revealed no significance in groups over time). Time effects (P < 0.05) existed for total mood disturbance and serum creatine kinase and mechano growth factor mRNA (POST > PRE &D L), VL pressure to pain threshold and MHC-IIx mRNA (PRE&DL > POST), Atrogin-1 and MuRF-1 mRNA (PRE < POST < DL), MHC-I mRNA (PRE < POST & DL), myostatin mRNA (PRE & POST < DL), and mechanistic target of rapamycin (PRE > POST & DL). No interactions or time effects were observed for barbell squat velocity, various hormones, histological metrics, polyubiquitinated proteins, or phosphorylated/pan protein levels of 4E-BP1, p70S6k, and AMPK. One week of AR after a high-volume training block instigates marginal molecular differences in skeletal muscle relative to PR. From a practical standpoint, however, both paradigms elicited largely similar responses.

Relationship Between Training Factors and Injuries in Stand-Up Paddleboarding Athletes

Stand-up paddleboarding (SUP) is an increasingly popular sport but, as in other sports, there is an injury ratio associated with practicing it. In other types of sport, some factors have been linked to the likelihood of suffering an injury, among which stretching, core training and resistance training may be considered the most significant. Therefore, the main aim of this study was to identify the training factors that could influence injuries suffered by participants in international SUP competitions. Ninety-seven questionnaires were collected from paddlers who participated in an international SUP circuit, with epidemiological data being gathered about injuries and different questions related to the training undertaken. A multi-factor ANOVA test was used to identify the factors which influence the state of injury. Results showed that almost 60% of injuries occurred in the arms or in the upper thoracic region, around 65% of which were in tendons or muscles and, in almost half of cases, were related to overuse. Likewise, the results showed that athletes with injury performed fewer resistance training sessions per week (p = 0.028), over fewer months per year (p = 0.001), more weekly training sessions (p = 0.004) and, lastly, a greater volume of weekly training (p = 0.003) than athletes without injury. Moreover, the most important training factors that reduce the likelihood of suffering an injury were taken into account-in. particular, resistance training alone (p = 0.011) or together with CORE training (p = 0.006) or stretching (p = 0.012), and the dominant side of paddling (p = 0.032). In conclusion, resistance training would seem to reduce the likelihood of injury among SUP practitioners, and such benefits could be obtained by resistance training alone or in combination with CORE training or stretching.

Periodization: Variation in the Definition and Discrepancies in Study Design

Over the past several decades, periodization has been widely accepted as the gold standard of training theory. Within the literature, there are numerous definitions for periodization, which makes it difficult to study. When examining the proposed definitions and related studies on periodization, problems arise in the following domains: (1) periodization has been proposed to serve as the macro-management of the training process concerning the annual plan, yet research on long-term effects is scarce; (2) periodization and programming are being used interchangeably in research; and (3) training is not periodized alongside other stressors such as sport (i.e., only resistance training is being performed without the inclusion of sport). Overall, the state of the literature suggests that the inability to define periodization makes the statement of its superiority difficult to experimentally test. This paper discusses the proposed definitions of periodization and the study designs which have been employed to examine the concept.

Activation patterns of pelvic floor muscles in women with incontinence while running: a randomized controlled trial

INTRODUCTION AND HYPOTHESIS

Running is known to cause urinary leakage in women with stress urinary incontinence (SUI). Task-specific fiber-type recruitment while running can be estimated using wavelets. The aim of this study was to compare the effect of a new physiotherapy program including involuntary, reflexive training with a standard physiotherapy program on pelvic floor muscle (PFM) activation patterns and fiber-type recruitment behavior while running.

METHODS

In this triple-blinded randomized controlled trial, women with SUI were randomly allocated to the control group (CON), which performed a standard physiotherapy program, or the experimental group (EXP), which received additional involuntary, reflexive training. PFM electromyography (EMG) was recorded during 10 s at three running speeds and analyzed using Morse wavelets. The relative distribution of power (%) over the frequencies from 20 to 200 Hz was extracted and analyzed within six-time intervals of 30 ms. Statistical nonparametric mapping was performed to identify power spectra differences.

RESULTS

Thirty-nine (CON) and 38 (EXP) women were included. The power spectra showed no statistically significant group differences. The time intervals from 30 ms before to 30 ms after initial contact showed significantly lower intensities than the intervals from 30 to 150 ms after initial contact in the lowest and higher intensities in the highest frequencies for all running speeds and both groups.

CONCLUSIONS

Power spectra shifts toward higher frequency bands in the pre-initial contact phase could indicate a feed-forward anticipation and a muscle tuning for the expected impact of initial contact event in order to maintain continence.

Comparative Meta-Analysis of the Effect of Concentrated, Hydrolyzed, and Isolated Whey Protein Supplementation on Body Composition of Physical Activity Practitioners

Whey protein (WP) is a dairy food supplement and, due to its effects on fat-free mass (FFM) gain and fat mass (FM) loss, it has been widely consumed by resistance training practitioners. This review analyzed the impact of WP supplementation in its concentrated (WPC), hydrolyzed (WPH) and isolated (WPI) forms, comparing it exclusively to isocaloric placebos. Random effect meta-analyses were performed from the final and initial body composition values of 246 healthy athletes undergoing 64.5 ± 15.3 days of training in eight randomized clinical trials (RCT) collected systematically from five scientific databases. The weighted mean difference (WMD) was statistically significant for FM loss (WMD = −0.96, 95% CI = −1.37, −0.55, p < 0.001) and, in the analysis of subgroups, this effect was maintained for the WPC (WMD = −0.63, 95% CI = −1.19, −0.06, p = 0.030), with protein content between 51% and 80% (WMD = −1.53; 95% CI = −2.13, −0.93, p < 0.001), and only for regular physical activity practitioners (WMD = −0.95; 95% CI = −1.70, −0.19, p = 0.014). There was no significant effect on FFM in any of the scenarios investigated (p > 0.05). Due to several and important limitations, more detailed analyses are required regarding FFM gain.

Comparison of maximum muscle strength and isokinetic knee and core muscle functions according to pedaling power difference of racing cyclist candidates

The purpose of this study was to investigate differences of maximum muscle strength and isokinetic knee and core muscle functions according to pedaling power of racing cyclist candidate. Subjects for this study were 200 racing cyclist candidates and divided into four groups: top 10% peak power group (TPP, n=20), low 10% peak power group (LPP, n=20), top 10% average power group (TAP, n=20), and low 10% average power group (LAP, n=20). The maximum muscle strength was consisted of grip strength, bench press and squat measured by Ariel device, and isokinetic knee and core muscle functions were analyzed by Humac Norm device. Significant differences between groups were determined with one-way repeated analysis of variance. As the result of this study, TPP and TAP groups showed significantly decreased body-fat mass and increased free fat mass when compared to LPP and LAP groups. The maximum strength of grip and squat was significantly higher in TPP and TAP than in other groups. Isokinetic knee extension and flexion strength was higher in TPP and TAP groups as well as isokinetic trunk extension and flexion functions were highest in TPP group. Thus, our findings suggest new evidence that muscle mass, maximal muscle strength, and isokinetic muscle functions might be important predictors of racing cyclist performance.

Carbohydrate restriction: Friend or foe of resistance-based exercise performance?

It is commonly accepted that adequate carbohydrate availability is necessary for optimal endurance performance. However, for strength- and physique-based athletes, sports nutrition research and recommendations have focused on protein ingestion, with far less attention given to carbohydrates. Varying resistance exercise protocols, such as differences in intensity, volume, and intraset rest prescriptions between strength-training and physique-training goals elicit different metabolic responses, which may necessitate different carbohydrate needs. The results of several acute and chronic training studies suggest that although severe carbohydrate restriction may not impair strength adaptations during a resistance training program, consuming an adequate amount of carbohydrate in the days leading up to testing may enhance maximal strength and strength-endurance performance. Although several molecular studies demonstrate no additive increases in postexercise mammalian target of rapamycin 1 phosphorylation with carbohydrate and protein compared with protein ingestion alone, the effects of chronic resistance training with carbohydrate restriction on muscle hypertrophy are conflicting and require further research to determine a minimal carbohydrate threshold necessary to optimize muscle hypertrophy. This review summarizes the current knowledge regarding carbohydrate availability and resistance training outcomes and poses new research questions that will better help guide carbohydrate recommendations for strength and physique athletes. In addition, given that success in physique sports is based on subjective appearance, and not objective physical performance, we also review the effects of subchronic carbohydrate ingestion during contest preparation on aesthetic appearance.

Effects of Short-Term Plyometric Training on Physical Performance in Male Handball Players

The aim of this study was to compare the effects of plyometric and jump training on physical performance in young male handball players. Twenty-six young male handball players were divided into two sub-groups to perform a five-week pre-season training programme supplemented with two ground-reactive protocols with an equal number of jumping exercises referred as to ground contacts: plyometric training (PLY; n = 14) and standard jump training (CON; n = 12). Before and after training, repeated sprint ability (RSA), jumping ability (JA), maximal oxygen uptake (VO2max) and aerobic power at the anaerobic threshold (PAT) were measured. A two-factor analysis revealed significant time effects with improvements in fat mass (p = 0.012), maximal power during the incremental cycling test (p = 0.001) and PAT (p < 0.001), power decline (PDEC) and maximal power (Pmax) in the 5th repetition (p < 0.05 and p < 0.01, respectively). The training-induced changes in absolute and relative peak power in the RSA test and absolute VO2max approached significance (p = 0.06, p = 0.053 and p = 0.06). No intervention time × exercise protocol effects were observed for any indices of JA, RSA and aerobic capacity. A five-week pre-season conditioning programme supplemented with only 15 sessions of plyometric exercise did not induce any additional benefits, compared to a matched format of standard jump training, in terms of improving jumping performance and maximal power in the RSA test. Aerobic capacity and the fatigue index in RSA were maintained under these two training conditions.

Strength training as superior, dose-dependent and safe prevention of acute and overuse sports injuries: a systematic review, qualitative analysis and meta-analysis

Objective

This review aims to analyse strength training-based sports injury prevention randomised controlled trials (RCT) and present best evidence recommendations for athletes and future research. A priori PROSPERO registration; CRD42015006970.

Design

Systematic review, qualitative analysis and meta-analysis. Sorting of studies and quality assessments were performed by two independent authors. Qualitative analyses, relative risk (RR) estimate with robustness and strength of evidence tests, formal tests of publication bias and post-hoc meta-regression were performed.

Data sources

PubMed, Embase, Web of Science and SPORTDiscus were searched to July 2017.

Eligibility criteria for selecting studies

RCTs on strength training exercises as primary prevention of sports injuries.

Results

Six studies analysed five different interventions with four distinct outcomes. 7738 participants aged 12–40 years were included and sustained 177 acute or overuse injuries. Studies were published in 2003–2016, five from Europe and one from Africa. Cluster-adjusted intention-to-treat analysis established RR 0.338 (0.238–0.480). The result was consistent across robustness tests and strength of evidence was high. A 10% increase in strength training volume reduced the risk of injury by more than four percentage points. Formal tests found no publication bias.

Conclusion

The included studies were generally well designed and executed, had high compliance rates, were safe, and attained consistently favourable results across four different acute and overuse injury outcomes despite considerable differences in populations and interventions. Increasing strength training volume and intensity were associated with sports injury risk reduction. Three characteristically different approaches to prevention mechanisms were identified and incorporated into contemporary strength training recommendations.

Neuromuscular Effects to 6 Weeks of Loaded Countermovement Jumping With Traditional and Daily Undulating Periodization

Ullrich, B, Pelzer, T, and Pfeiffer, M. Neuromuscular effects to 6 weeks of loaded countermovement jumping with traditional and daily undulating periodization. J Strength Cond Res 32(3): 660-674, 2018-Loaded vertical jumps are routinely used to enhance athlete's power production in the lower extremity and to optimize jumping and sprinting performance. This study compared traditional (TP) and daily undulating (DUP) periodization on muscle strength, jumping performance, electromyographic (EMG) muscle activity, and muscle architecture during preseason loaded jump training. Twenty-two athletes from different team sports (age: 24.3 ± 2.6 years, height: 175.9 ± 7.5 cm, body mass: 72.2 ± 8.4 kg, 12 males/10 females, strength training experience: 5.1 ± 2.2 years) performed 6 weeks of loaded countermovement jumping (CMJ) (18 sessions) during which subjects arranged the experimental training loads with either TP or DUP. Therefore, loading conditions corresponding to 0, 15, and 30% of individual body mass were used by manipulating weighted training vests and the intensity zones and training volume were equated between the groups. Pre- to post-training, center of mass (COM) maximal CMJ performance, isometric maximal voluntary contractive capacity of the leg extensors (MVC), EMG maximal voluntary muscle activity of knee extensor muscles, and vastus lateralis and rectus femoris muscle architecture were examined. Repeated measures multivariate analysis of variances (MANOVA with factors: time × training group) revealed moderate (5-16%) but significant (p ≤ 0.006) temporal increases in COM jumping height, leg extensor MVC and muscle architecture in both groups. Importantly, these temporal alterations were similar using either TP or DUP. Therefore, our data indicate that both periodization models can be effectively applied to increase leg extensor strength, vertical jumping performance, and muscle architecture during short-term preseason loaded jump training.

An Integrated, Multifactorial Approach to Periodization for Optimal Performance in Individual and Team Sports

Sports periodization has traditionally focused on the exercise aspect of athletic preparation, while neglecting the integration of other elements that can impact an athlete's readiness for peak competition performances. Integrated periodization allows the coordinated inclusion of multiple training components best suited for a given training phase into an athlete's program. The aim of this article is to review the available evidence underpinning integrated periodization, focusing on exercise training, recovery, nutrition, psychological skills, and skill acquisition as key factors by which athletic preparation can be periodized. The periodization of heat and altitude adaptation, body composition, and physical therapy is also considered. Despite recent criticism, various methods of exercise training periodization can contribute to performance enhancement in a variety of elite individual and team sports, such as soccer. In the latter, both physical and strategic periodization are useful tools for managing the heavy travel schedule, fatigue, and injuries that occur throughout a competitive season. Recovery interventions should be periodized (ie, withheld or emphasized) to influence acute and chronic training adaptation and performance. Nutrient intake and timing in relation to exercise and as part of the periodization of an athlete's training and competition calendar can also promote physiological adaptations and performance capacity. Psychological skills are a central component of athletic performance, and their periodization should cater to each athlete's individual needs and the needs of the team. Skill acquisition can also be integrated into an athlete's periodized training program to make a significant contribution to competition performance.

Effect of high-intensity resistance circuit-based training in hypoxia on aerobic performance and repeat sprint ability

Recent acute studies have shown that high-intensity resistance circuit-based (HRC) training in hypoxia increases metabolic stress. However, no intervention studies have yet proven their effectiveness. This study aimed to analyze the effect of 8 weeks of HRC in hypoxia on aerobic performance, resting energy expenditure (REE), repeat sprint ability (RSA) and hematological variables. Twenty-eight subjects were assigned to hypoxia (FiO₂  = 15%; HRC_hyp : n = 15; age: 24.6 ± 6.8 years; height: 177.4 ± 5.9 cm; weight: 74.9 ± 11.5 kg) and normoxia (FiO₂  = 20.9%; HRC_norm : n = 13; age: 23.2 ± 5.2 years; height: 173.4 ± 6.2 cm; weight: 69.4 ± 7.4 kg) groups. Each training session consisted of two blocks of three exercises (Block 1: bench press, leg extension, front pull down; 2: deadlift, elbow flexion, ankle extension). Each exercise was performed at 6 repetitions maximum. Participants exercised twice weekly for 8 weeks and before and after the training program blood test, REE, RSA and treadmill running test were performed. Fatigue index in the RSA test was significantly decreased in the HRC_hyp (-0.9%; P < .01; ES = 2.75) but not in the HRC_norm . No changes were observed in REE and hematological variables. Absolute (4.5%; P = .014; ES = 0.42) and relative (5.2%; P = .008; ES = 0.43) maximal oxygen uptake (VO₂ max), speed at VO₂ max (4%; P = .010; ES = 0.25) and time to exhaustion (4.1%; P = .012; ES = 0.26) were significantly increased in HRC_hyp but not in the HRC_norm . No significant differences between groups were found. Compared with normoxic conditions, 8 weeks of HRC training under hypoxic conditions efficiently improves aerobic performance and RSA without changes in REE and red blood O₂ -carrying capacity.

Strength improvements through occlusal splints? The effects of different lower jaw positions on maximal isometric force production and performance in different jumping types

Objective

The influence of the jaw position on postural control, body posture, walking and running pattern has been reported in the literature. All these movements have in common that a relatively small, but well controlled muscle activation is required. The induced effects on motor output through changed jaw positions have been small. Therefore, it has been questioned if it could still be observed in maximal muscle activation.

Method

Twenty-three healthy, mid age recreational runners (mean age = 34.0 ± 10.3 years) participated in this study. Three different jump tests (squat jump, counter movement jump, and drop jumps from four different heights) and three maximal strength tests (trunk flexion and extension, leg press of the right and left leg) were conducted. Four different dental occlusion conditions and an additional familiarization condition were tested. Subjects performed the tests on different days for which the four occlusion conditions were randomly changed.

Results

No familiarization effect was found. Occlusion conditions with a relaxation position and with a myocentric condylar position showed significantly higher values for several tests compared to the neutral condition and the maximal occlusion position. Significance was found in the squat jump, countermovement jump, the drop jump from 32cm and 40cm, trunk extension, leg press force and rate of force development. The effect due to the splint conditions is an improvement between 3% and 12% (min and max). No influence of the jaw position on symmetry or balance between extension and flexion muscle was found.

Conclusion

An influence of occlusion splints on rate of force development (RFD) and maximal strength tests could be confirmed. A small, but consistent increase in the performance parameters could be measured. The influence of the occlusion condition is most likely small compared to other influences as for example training status, age, gender and circadian rhythm.

A biomechanical comparison of countermovement performance after short-term traditional and daily-undulated loaded vertical jump training

In order to assess lower extremity muscle mechanical properties in athletes, power-load characteristics during multi-joint tasks are frequently examined. This work compared 6 weeks of traditional (TP) and daily-undulated (DUP) periodized loaded countermovement jumping (CMJ). 20 amateur athletes (age: 24.2 ± 2.6 years, height: 175.6 ± 7.1 cm, body mass: 71.5 ± 7.7 kg, 10 males/10 females) exercised three times weekly using maximal CMJs with loads corresponding to 0%, 15% and 30% of body mass. Prior to the training period, subjects were once-only assigned by random to either the TP or DUP training scheme. Pre-to-post training, maximal center of mass (COM) -height, -take-off velocity, -power output and -impulse were compared during CMJ with additional loads corresponding to 0-30% of body mass. ANOVA (time * group) with repeated measures revealed significant (P < 0.05) temporal gains of maximal COM-height (2-11%), -take-off velocity (1-7%), -power (2-8%) and -impulse (3-9%) over most loading conditions for TP and DUP. However, ANOVA indicated no group effects for any outcome. Independent from the periodization model, maximal power output remained statistically unchanged with increased testing loads. For short-term conditioning periods, TP and DUP were equally effective in enhancing biomechanical jumping variables under varying loading conditions.

Bench-to-Bedside Approaches for Personalized Exercise Therapy in Cancer

The past 2 decades have witnessed a growing body of work investigating the feasibility and efficacy of exercise therapy on a broad array of outcomes in many different oncology scenarios. Despite this heterogeneity, the exercise therapy prescription approach and the dose tested has been largely similar. Thus, current exercise therapy prescriptions in the oncology setting adopt a one-size-fits-all approach. In this article, we provide an overview of personalization of exercise therapy in cancer using the principles of training as an overarching framework. Specifically, we first review the fundamentals of exercise prescription in chronic disease before focusing attention on application of these principles to optimize the safety and efficacy of exercise therapy on (1) cancer treatment-induced cardiovascular toxicity and (2) tumor progression and metastasis.

Resistance Training Status and Effectiveness of Low-Frequency Resistance Training on Upper-Body Strength and Power in Highly Trained Soccer Players

Hertzog, M, Rumpf, MC, and Hader, K. Resistance training status and effectiveness of low-frequency resistance training on upper-body strength and power in highly trained soccer players. J Strength Cond Res 34(4): 1032-1039, 2020-Soccer is classified as a contact/collision sport with many player-to-player duels. Winning these duels, shielding the ball or fending off an opponent requires upper-body strength and power. Therefore, this study aimed (a) to examine the time-related effect of an upper-body resistance training (RT) on maximal strength and power changes in highly trained soccer players and (b) to investigate if the RT status influences these changes throughout a competitive season. Twenty-eight soccer players participated in this study and were divided into an untrained group (UG) and a trained group (TG), according to their RT status. Both groups performed the same upper-body RT once a week, over 30 weeks. Maximal strength (1 repetition maximum [1RM]) and maximal power (MP) were assessed before, during, and after the competitive season. Both groups significantly improved 1RM and MP over the entire competitive season, with a moderate (TG, 13%) to very large (UG, 21%) magnitude in 1RM and with a small (TG, 8%) to moderate (UG, 13%) magnitude in MP. After the initial 10 weeks of RT, UG presented significant and slightly (1RM) to moderately (MP) greater improvements than TG. For all other time intervals, the between-groups' changes in 1RM were rated as similar. For the last 20 weeks of the RT, the change in MP was significantly lower for UG compared with TG. One upper-body RT session per week will provide sufficient stimulus to enable an almost certain improvement in strength and power throughout a competitive season for all players disregarding their initial RT status.