The effect of advanced footwear technology on elite male marathon race speed

PURPOSE

The aim of this study was to explore the ergogenic effect of advanced footwear technology (AFT) upon world-class male marathon running speed.

METHOD

A retrospective analysis of 99 world-class male marathon runners' performances between 2012 and 2021 was undertaken, providing a sample size of 971 performances, split into two footwear groups: AFT (n = 299) and traditional (n = 672). Additionally, details regarding the year of the marathon performance and racecourse were extracted. A mixed model for repeated measures (MMRM) analysis were undertaken identifying athlete (Wald Z = 2.821; p = .005) and course (Wald Z = 4.111; p < 0.001) as significant contributors to the variance in marathon running speed and as such were included as random factors with footwear type set as a fixed factor.

RESULTS

World-class male marathon running speeds were significantly faster (p < 0.001) when running in AFT (5.441 m.s-1) when compared with traditional shoes (5.386 m.s-1) with a mean difference of 0.055 m.s-1 (95% CI 0.039-0.071 m.s-1), translating to an improvement in marathon speed of 1.0% or a 79 s improvement in marathon race time.

CONCLUSION

Our findings demonstrate an improvement in world-class male marathon running speed of 1% when running in AFT, a near identical degree of improvement to the male marathon world record ran in AFT. Whilst a 1% improvement in marathon running times associated with AFT is smaller than previously predicted utilizing laboratory-based models, this still reflects a significant degree of improvement at the elite level.

Reduced influence of perceptual context in mild traumatic brain injury is not an illusion

Perceptual grouping is impaired following mild traumatic brain injury (mTBI). This may affect visual size perception, a process influenced by perceptual grouping abilities. We conducted two experiments to evaluate visual size perception in people with self-reported history of mTBI, using two different size-contrast illusions: the Ebbinghaus Illusion (Experiment 1) and the Müller-Lyer illusion (Experiment 2). In Experiment 1, individuals with mTBI and healthy controls were asked to compare the size of two target circles that were either the same size or different sizes. The target circles appeared by themselves (no-context condition), or were surrounded by smaller or larger circles (context condition). Similar levels of accuracy were evident between the groups in the no-context condition. However, size judgements by mTBI participants were more accurate in the context condition, suggesting that they processed the target circles separately from the surrounding circles. In Experiment 2, individuals with mTBI and healthy controls judged the length of parallel lines that appeared with arrowheads (context condition) or without arrowheads (no context condition). Consistent with Experiment 1, size judgements by mTBI participants were more accurate than size judgements by control participants in the context condition. These findings suggest that mTBI influences size perception by impairing perceptual grouping of visual stimuli in near proximity.

A similar injury profile observed in franchise men's and women's cricket in England and Wales: injury surveillance analysis from the first three 'The Hundred' competitions

Objectives

To describe the injury profile of a novel format cricket competition ('The Hundred') and compare injury incidence and prevalence between the men's and women's competitions.

Methods

Medical staff prospectively collected injury data from the eight men's and women's teams during the 2021-2023 competitions. Injury definitions and incidence calculations followed the international consensus statement.

Results

In the men's competition, 164 injuries were recorded, compared with 127 in the women's competition. Tournament injury incidence was 36.6 (95% CI 31.4 to 42.7) and 32.5 (95% CI 27.3 to 38.7)/100 players/tournament in the men's and women's competition, respectively. Non-time-loss incidence (men's 26.6 (95% CI 22.2 to 31.8), women's 24.6 (95% CI 20.1 to 30.0)/100 players/tournament) was higher than time-loss incidence (men's 10.0 (95% CI 7.5 to 13.5), women's 7.9 (95% CI 5.6 to 11.3)/100 players/tournament). Injury prevalence was 2.9% and 3.6% in the men's and women's competitions, respectively. Match fielding was the most common activity at injury in both competitions. The thigh and hand were the most common body location time-loss injury in the men's and women's competitions, respectively.

Conclusion

A similar injury profile was observed between the men's and women's competition. Preventative strategies targeting thigh injuries in the men's competition and hand injuries in the women's competition would be beneficial. Compared with published injury rates, 'The Hundred' men's presents a greater risk of injury than Twenty20 (T20), but similar to one-day cricket, with 'The Hundred' women's presenting a similar injury risk to T20 and one-day cricket. Additional years of data are required to confirm these findings.

English and Welsh men's domestic cricket injury risk by activity and cricket type: A retrospective cohort study from 2010 to 2019

OBJECTIVES

Explore whether injury profiles and mechanisms differ between red (First-Class multi-day) ball cricket and white (One-Day and Twenty20 limited over) ball cricket in elite men's domestic cricket from 2010 to 2019.

DESIGN

Retrospective cohort analysis.

METHODS

Injury incidence calculated according to the updated international consensus statement on injury surveillance in cricket, along with seasonal days lost and injury severity descriptive statistics.

RESULTS

Across both cricket types, bowling resulted in the most seasonal days lost (mean 1942, 95 % confidence interval: 1799-2096) and highest mean injury severity (30 days, 95 % confidence interval: 28-33), with the lumbar spine the body region with the most seasonal days lost (mean 432 seasonal days; 95 % confidence interval: 355-525) from bowling. Injury incidence was higher in white ball compared to red ball cricket (per unit of time), with bowling (and its various phases) the most frequently occurring mechanism in both cricket types (white ball: 67.0 injuries per 1000 days of play [95 % confidence interval: 59.6-75.3]; red ball: 32.4 injuries per 1000 days of play [95 % confidence interval: 29.1-36.1]). When bowling, the abdomen and thigh were the body regions most injured from white (13.4 injuries per 1000 days of play [95 % confidence interval: 10.3-17.4]), and red ball (6.4 injuries per 1000 days of play [95 % confidence interval: 5.0-8.2]) cricket respectively. Overall, clear differences emerged in the nature and mechanism of injuries between red ball cricket and white ball cricket.

CONCLUSIONS

Bowling presents the highest injury risk (across both cricket types), as well as highlighting the increased risk of injuries from diving during fielding and running between the wickets when batting, in shorter white ball cricket.

Exploring the issue of 'functionality' in isokinetic dynamometry

Strength is a primary and modifiable contributor to performance, injury risk, and rehabilitative success. The gold standard measure of strength is the isokinetic dynamometer, providing the clinician with the opportunity to manipulate contraction modality, range, and speed about a joint. However, criticism has highlighted a lack of functional relevance, with arbitrary selection of speed across the full range. To better understand function, biomechanical analysis of movement can inform a bespoke isokinetic data collection protocol. In this case, we use walking gait, a function goal for daily living and clinically assessed following knee replacement surgery for example. Concentric knee flexor and extensor demand was evident at an average angular velocity of 70°·s-1, whilst eccentric knee flexor and extensor demands were evident at speeds of 192°·s-1 and 165°·s-1, respectively. The efficacy of isokinetic dynamometry can be enhanced with bespoke data collection protocols, which better reflect the functional demands of the clinical movement objective.

The gait abnormality index: A summary metric for three-dimensional gait analysis

BACKGROUND

This paper proposes an easy to calculate and adaptable summary gait metric, the Gait Abnormality Index (GAI), which is capable of simultaneously including kinematic and kinetic data, overcoming a key limitation of existing metrics.

RESEARCH QUESTION

To determine the validity, reliability and sensitivity of the GAI.

METHODS

The GAI is calculated by averaging Gait Abnormality Scores, which are normalised distance metrics used to describe the deviation of pathological gait data from that of healthy controls. Validity was assessed using Pearson's correlation analysis to explore relationships between the GAI and the Gait Profile Score. Test-retest reliability of the GAI was assessed using intra-class correlation coefficients (ICC) and standard error of the measurement (SEM), and data from total hip arthroplasty patients. An independent samples t-test was used to compare GAI scores between knee osteoarthritis and total hip arthroplasty patients to explore the metrics sensitivity.

RESULTS

A strong positive correlation (r ≥ 0.896; p < 001) was reported between the GAI and the Gait Profile Score. Good test-retest reliability (ICC =0.830) was reported for the GAI. Knee osteoarthritis patients displayed significantly (p = .017; Hedge's g effect size = 0.98) greater GAI scores compared to total hip arthroplasty patients, with the mean difference (0.34 a.u) above the SEM (0.15 a.u).

SIGNIFICANCE

The GAI offers an easy to calculate summary metric for three-dimensional gait analysis, which displays good validity and reliability, and is sensitive to different pathological conditions.

Exploring pelvis and thigh movement and coordination patterns during walking in patients after total hip arthroplasty

BACKGROUND

Patients after total hip arthroplasty (THA) have altered hip kinematics compared to healthy controls, specifically hip extension and range of motion are lower. Exploring pelvis-thigh coordination patterns and coordination variability may help to elucidate why differences in hip kinematics are evident in patients following THA.

RESEARCH QUESTION

Do sagittal plane hip, pelvis and thigh kinematics, and pelvis-thigh movement coordination and coordination variability differ between patients following THA and healthy controls during walking?

METHODS

Sagittal plane hip, pelvis and thigh kinematics were collected using a three-dimensional motion capture system while 10 patients who had undergone THA and 10 controls walked at a self-selected pace. A modified vector coding technique was used to quantify pelvis-thigh coordination and coordination variability patterns. Peak hip, pelvis and thigh kinematics and ranges of motion, and movement coordination and coordination variability patterns were quantified and compared between groups.

RESULTS

Patients after THA have significantly (p ≤ .036; g ≥ 0.995) smaller peak hip extension and range of motion, and peak thigh anterior tilt and range of motion compared to controls. Additionally, patients following THA have significantly (p ≤ .037; g ≥ 0.646) more in-phase distally and less anti-phase distally dominated pelvis-thigh movement coordination patterns compared to controls.

SIGNIFICANCE

The smaller peak hip extension and range of motion displayed by patients following THA is due to smaller peak anterior tilt of the thigh, which in turn limits thigh range of motion. The lower sagittal plane thigh, and in turn hip, motion used by patients after THA may be due to increases in the in-phase coordination of pelvis-thigh motion patterns, which cause the pelvis and thigh to work as a singular functional unit.

Do patients with well-functioning total hip arthroplasty achieve typical sagittal plane hip kinematics? A proof of concept study

BACKGROUND

Total hip arthroplasty (THA) patients have been shown to not achieve normal sagittal plane hip kinematics. However, previous studies have only conducted group level analysis and as such lack the sensitivity to highlight whether individual patients do achieve normal hip kinematics. As such this study looked to determine whether some patients with well-functioning THA achieve typical sagittal plane hip kinematics.

METHODS

Sagittal plane hip kinematics were collected on 11 well-functioning THA patients (Oxford Hip Score = 46 ± 3) and 10 asymptomatic controls using a 3-dimensional motion analysis system during self-paced walking. High-functioning THA patients were identified as those who displayed sagittal plane hip kinematics that were within the variance of the control group on average, and low-functioning patients as those who did not.

RESULTS

5 THA patients were identified as high-functioning, displaying hip kinematics within the variance of the control group. High-functioning THA patients displayed peak hip flexion and extension values more closely aligned to asymptomatic control group than low-functioning patients. However, hip range of motion was comparable between high- and low-functioning total hip arthroplasty patients and reduced compared to controls.

CONCLUSION

The presence of high-functioning THA patients who display comparable sagittal plane hip kinematics to controls suggests these patients do achieve normative function and challenges the conclusions of previous group level analysis. Understanding why some patients achieve better function post-operatively will aid pre- and post-operative practices to maximise functional recovery.

Fatigue related changes in rearfoot eversion: a means of functionally grouping runners?

Fatigue alters rearfoot kinematics on an individual basis and may offer a means of functionally grouping runners. This proof of concept study aimed to determine whether fatigue related changes in rearfoot eversion could be used to functionally group runners. Sixteen male recreational runners had their frontal plane rearfoot kinematics recorded by a three-dimensional motion capture system before and after a 5km run. The magnitude of change in frontal plane rearfoot kinematics pre- to post-fatigue was calculated and K-means clustering used to identify functional groups based upon these changes. T-tests with statistical parametric mapping were used to compare fatigue related changes both within and between clusters. Two clusters or functional groups were evident within the data set. Nine participants were allocated to cluster 1 and displayed small and insignificant changes in frontal plane rearfoot motion post-fatigue. In contrast, the remaining seven participants were assigned to cluster 2 and displayed significant increases in rearfoot eversion between 3 and 84% of the stance phase post-fatigue. These findings prove the concept that fatigue related changes in rearfoot eversion can be used to functionally group participants. Additionally, the differing fatigue related changes reported by each group may alter the injury risk, training and footwear needs of each group. HighlightsFatigue related changes in frontal plane rearfoot motion can be used to functionally group individuals.Cluster 1 display small and insignificant fatigue related changes, which suggests they can maintain their habitual movement pathway.Cluster 2 displayed significant increases in rearfoot eversion for the majority of the stance phase, suggesting an inability to maintain their habitual movement pathway, which may increase injury risk.

The Effects of Fixture Congestion on Injury in Professional Male Soccer: A Systematic Review

BACKGROUND

Professional soccer teams are often required to compete with ≤ 4 days recovery between matches. Since congested schedules reduce recovery time between matches, players are possibly at an increased injury risk. To date, there are no published systematic reviews on the impact of match congestion on injuries during professional male soccer.

OBJECTIVE

The aim of this systematic review was to assess the effects of fixture congestion on injuries during professional soccer.

METHODS

Following pre-registration on the Open Science Framework ( https://osf.io/86m25/ ) and conforming with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, systematic searches of four electronic databases (PubMed, Scopus, SPORTDiscus, and Web of Science) were conducted by independent researchers from inception until February 2022. Articles were included if they were original articles written in English and contained relevant time-loss injury data (injury that results in unavailability for training and/or match-play) for male professional soccer players regarding periods of fixture congestion (a minimum of two matches with ≤ 4 days recovery).

RESULTS

A total of eight articles were included in the review. Five studies identified that congested fixture schedules expose players to increased match injury incidence, although layoff duration was typically lower during congested periods. Two studies identified that training and overall injury incidence were higher during congested periods, with another study identifying a lower training injury incidence during congested periods.

CONCLUSION

Injury risk is, overall, increased during fixture-congested periods; however, the layoff duration is typically shorter. The current findings have implications for practitioners regarding the management, periodisation, monitoring, and design of training and competition schedules.

Running shoes for preventing lower limb running injuries in adults

BACKGROUND

Lower-limb running injuries are common. Running shoes have been proposed as one means of reducing injury risk. However, there is uncertainty as to how effective running shoes are for the prevention of injury. It is also unclear how the effects of different characteristics of running shoes prevent injury.

OBJECTIVES

To assess the effects (benefits and harms) of running shoes for preventing lower-limb running injuries in adult runners.

SEARCH METHODS

We searched the following databases: CENTRAL, MEDLINE, Embase, AMED, CINAHL Plus and SPORTDiscus plus trial registers WHO ICTRP and ClinicalTrials.gov. We also searched additional sources for published and unpublished trials. The date of the search was June 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs involving runners or military personnel in basic training that either compared a) a running shoe with a non-running shoe; b) different types of running shoes (minimalist, neutral/cushioned, motion control, stability, soft midsole, hard midsole); or c) footwear recommended and selected on foot posture versus footwear not recommended and not selected on foot posture for preventing lower-limb running injuries. Our primary outcomes were number of people sustaining a lower-limb running injury and number of lower-limb running injuries. Our secondary outcomes were number of runners who failed to return to running or their previous level of running, runner satisfaction with footwear, adverse events other than musculoskeletal injuries, and number of runners requiring hospital admission or surgery, or both, for musculoskeletal injury or adverse event.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and performed data extraction and risk of bias assessment. The certainty of the included evidence was assessed using GRADE methodology.

MAIN RESULTS

We included 12 trials in the analysis which included a total of 11,240 participants, in trials that lasted from 6 to 26 weeks and were carried out in North America, Europe, Australia and South Africa. Most of the evidence was low or very low certainty as it was not possible to blind runners to their allocated running shoe, there was variation in the definition of an injury and characteristics of footwear, and there were too few studies for most comparisons. We did not find any trials that compared running shoes with non-running shoes. Neutral/cushioned versus minimalist (5 studies, 766 participants) Neutral/cushioned shoes may make little or no difference to the number of runners sustaining a lower-limb running injuries when compared with minimalist shoes (low-certainty evidence) (risk ratio (RR) 0.77, 95% confidence interval (CI) 0.59 to 1.01). One trial reported that 67% and 92% of runners were satisfied with their neutral/cushioned or minimalist running shoes, respectively (RR 0.73, 95% CI 0.47 to 1.12). Another trial reported mean satisfaction scores ranged from 4.0 to 4.3 in the neutral/ cushioned group and 3.6 to 3.9 in the minimalist running shoe group out of a total of 5. Hence neutral/cushioned running shoes may make little or no difference to runner satisfaction with footwear (low-certainty evidence). Motion control versus neutral / cushioned (2 studies, 421 participants) It is uncertain whether or not motion control shoes reduce the number of runners sustaining a lower-limb running injuries when compared with neutral / cushioned shoes because the quality of the evidence has been assessed as very low certainty (RR 0.92, 95% CI 0.30 to 2.81). Soft midsole versus hard midsole (2 studies, 1095 participants) Soft midsole shoes may make little or no difference to the number of runners sustaining a lower-limb running injuries when compared with hard midsole shoes (low-certainty of evidence) (RR 0.82, 95% CI 0.61 to 1.10). Stability versus neutral / cushioned (1 study, 57 participants) It is uncertain whether or not stability shoes reduce the number of runners sustaining a lower-limb running injuries when compared with neutral/cushioned shoes because the quality of the evidence has been assessed as very low certainty (RR 0.49, 95% CI 0.18 to 1.31). Motion control versus stability (1 study, 56 participants) It is uncertain whether or not motion control shoes reduce the number of runners sustaining a lower-limb running injuries when compared with stability shoes because the quality of the evidence has been assessed as very low certainty (RR 3.47, 95% CI 1.43 to 8.40). Running shoes prescribed and selected on foot posture (3 studies, 7203 participants) There was no evidence that running shoes prescribed based on static foot posture reduced the number of injuries compared with those who received a shoe not prescribed based on foot posture in military recruits (Rate Ratio 1.03, 95% CI 0.94 to 1.13). Subgroup analysis confirmed these findings were consistent between males and females. Therefore, prescribing running shoes and selecting on foot posture probably makes little or no difference to lower-limb running injuries (moderate-certainty evidence). Data were not available for all other review outcomes.

AUTHORS' CONCLUSIONS

Most evidence demonstrates no reduction in lower-limb running injuries in adults when comparing different types of running shoes. Overall, the certainty of the evidence determining whether different types of running shoes influence running injury rates was very low to low, and as such we are uncertain as to the true effects of different types of running shoes upon injury rates. There is no evidence that prescribing footwear based on foot type reduces running-related lower-limb injures in adults. The evidence for this comparison was rated as moderate and as such we can have more certainty when interpreting these findings. However, all three trials included in this comparison used military populations and as such the findings may differ in recreational runners.  Future researchers should develop a consensus definition of running shoe design to help standardise classification. The definition of a running injury should also be used consistently and confirmed via health practitioners. More researchers should consider a RCT design to increase the evidence in this area. Lastly, future work should look to explore the influence of different types or running shoes upon injury rates in specific subgroups.

The impact of COVID-19 related disruption on injury rates in elite men's domestic cricket

This study aimed to investigate the impact of COVID-19 enforced prolonged training disruption and shortened competitive season, on in-season injury and illness rates. Injury incidence and percent proportion was calculated for the 2020 elite senior men's domestic cricket season and compared to a historical average from five previous regular seasons (2015 to 2019 inclusive). The injury profile for the shortened 2020 season was generally equivalent to what would be expected in a regular season, except for a significant increase in medical illness as a proportion of time loss (17% compared to historic average of 6%) and in-season days lost (9% compared to historic average of 3%) due to COVID-19 related instances (most notably precautionary isolation due to contact with a confirmed or suspected COVID-19 case). There was a significant increase in the proportion of in-season days lost to thigh injuries (24% compared to 9%) and a significant decrease in the proportion of days lost to hand (4% compared to 12%) and lumbar spine (7% compared to 21%) injuries. These findings enhance understanding of the impact prolonged period of training disruption and shortened season can have on cricket injuries and the challenges faced by practitioners under such circumstances.

Modified conventional gait model vs. Six degrees of freedom model: A comparison of lower limb kinematics and associated error

BACKGROUND

The conventional gait model (CGM) is commonly utilised within clinical motion analysis but has a number of inherent limitations. To overcome some of these limitations modifications have been made to the CGM and six-degrees of freedom models (6DoF) have been developed.

RESEARCH QUESTION

How comparable are lower limb kinematics calculated using modified CGM and 6DoF models and what is the error associated with the output of each model during walking?

METHODS

Ten healthy males attended two gait analysis sessions, in which they walked at a self-selected pace, while a 10-camera motion capture system recorded lower limb kinematics. Hip, knee and ankle joint kinematics in all three anatomical planes were calculated using a modified CGM, with medial anatomical markers and a three-dimensional foot added, and 6DoF. Mean absolute differences were calculated on a point-by-point basis over the walking gait cycle and interpreted relative to a 5° threshold to explore the comparability of model outputs. The standard error of the measurement (SEM) was also calculated on a point-by-point basis over the walking gait cycle for each model.

RESULTS

Mean absolute differences above 5° were reported between the two model outputs in 58-86% of the walking gait cycle at the knee in the frontal plane, and over the entire walking gait cycle at the hip and knee in the transverse plane. SEM was typically larger for the modified CGM compared to the 6DoF, with the highest SEM values reported at the knee in the frontal plane, and the hip and the knee in the transverse plane.

SIGNIFICANCE

Caution should be taken when looking to compare findings between studies utilising modified CGM and 6DoF outside of the sagittal plane, especially at the hip and knee. The reduced SEM associated with the 6DoF suggests this modelling approach may be preferable.

Comparison of Transverse Plane Tibial and Frontal Plane Rearfoot Motion and Movement Coordination Between Runners With Medial Tibial Stress Syndrome and Healthy Controls

Medial tibial stress syndrome (MTSS) is a common running-related injury. Alterations in movement patterns and movement coordination patterns have been linked to the development of overuse injuries. The aim of this study was to compare transverse plane tibial and frontal plane rearfoot motion and the coordination of these movements between runners with MTSS and healthy controls. A total of 10 recreational runners with MTSS and 10 healthy controls ran at 11 km/h on a treadmill. A 3-camera motion analysis system operating at 200 Hz was used to calculate tibia and rearfoot motion. Stance phase motion patterns were compared between groups using multivariate analysis, specifically, Hotelling T2 test with statistical parametric mapping. A modified vector coding technique was used to classify the coordination of transverse plane tibial and frontal plane rearfoot motion. The frequency of each coordination pattern displayed by each group was compared using independent samples t tests. Individuals with MTSS displayed significantly (P = .037, d = 1.00) more antiphase coordination (tibial internal rotation with rearfoot inversion) despite no significant (P > .05) differences in stance phase kinematics. The increased antiphase movement may increase the torsional stress placed upon the medial aspect of the tibia, contributing to the development of MTSS.

Injuries in England and Wales elite men's domestic cricket: A nine season review from 2010 to 2018

OBJECTIVES

This study primarily aimed to explore injury incidence rates in the three main domestic competition formats in England and Wales (First-Class, One-Day and Twenty20 [T20]). For the first time, the study also describes the epidemiology of elite men's domestic cricket injuries across nine seasons (2010-2018 inclusive).

DESIGN

Prospective cohort analysis.

METHODS

Injury incidence and prevalence from all injuries calculated according to the updated international consensus statement on injury surveillance in cricket, with statistical process control charts (SPC) used to detect trends in the data.

RESULTS

The average match injury incidence was 102 injuries/1000 days of play, with highest incidence in One-Day (254 injuries/1000 days of play), followed by T20 (136 injuries/1000 days of play) and First-Class Cricket (68 injuries/1000 days of play). Most match injuries were sustained during bowling (41.6 injuries/1000 days of play), followed by fielding (26.8 injuries/1000 days of play) and batting (22.3 injuries/1000 days of play). The thigh was the body area most commonly injured (7.4 injuries/100 players per season), with lumbar spine injuries the most prevalent (1.3% of players unavailable on any given day during the season). On average, 7.5% of players were unavailable on any given day during the domestic season when all injuries were considered (match and training). The SPC charts showed relatively consistent match injury incidence for all competitions, reproduced across all nine seasons.

CONCLUSION

These findings provide a robust empirical base for the extent of the injury problem in domestic cricket played in England and Wales, with similar injury profiles across the three formats.

The cumulative and residual fatigue response associated with soccer-specific activity performed on different playing surfaces

This study aimed to assess the effect of playing surface (Natural [NT] and Artificial [AT] Turf) on the fatigue response to a soccer-specific exercise protocol (SSEP). Eighteen male soccer players completed the SSEP on NT and AT with pre-, post-, and 48 h post-assessments of eccentric knee flexor (eccKF) and concentric knee extensor peak torque (PT), peak countermovement (CMJ) and squat jump (SJ) height, and Nordic hamstring break angle. No significant main effects for surface or any surface and time interactions were observed for any of the outcome measures, except for eccKF PT recorded at 3.14 rad·s^-1, which was significantly lower 48 h post-trial in the AT condition (AT = 146.3 ± 20.4 Nm; NT = 158.8 ± 24.7 Nm). Main effects for time were observed between pre- and post-trial measures for eccKF PT at all angular velocities, Nordic break angle, CMJ and SJ height. Nordic break angle, and both CMJ and SJ height were significantly impaired 48 h post-trial when compared to pre-trial. The findings of the current study suggest surface dependent changes in eccKF PT which may have implications for recovery and subsequent performance after competition on AT.

The effectiveness of a practical half-time re-warm-up strategy on performance and the physical response to soccer-specific activity

The aim of this study was to assess the influence of a half-time (HT) re-warm up (RWU) strategy on measures of performance and the physical and perceptual response to soccer-specific activity. Ten male soccer players completed a control (CON) and RWU trial, in which participants completed 60 min (4 x 15-min periods with a 15-min HT interspersing the third and fourth periods) of a soccer-specific exercise protocol. The CON trial comprised a passive 15-min HT, whilst the RWU trial comprised a passive 12-min period, followed by a 3-min RWU. The RWU elicited an improvement in 20 m sprint times (d= 0.6; CON: 3.42 ± 0.20 s; RWU: 3.32 ± 0.12 s), and both squat (d= 0.6; CON: 26.96 ± 5.00 cm; RWU: 30.17 ± 5.13 cm) and countermovement jump height (d= 0.7; CON: 28.15 ± 4.72 cm; RWU: 31.53 ± 5.43 cm) following the RWU and during the initial stages of the second half. No significant changes were identified for 5 m or 10 m sprint performance, perceived muscle soreness, or PlayerLoad^TM. Ratings of perceived exertion were however higher (~2 a.u) following the RWU. These data support the use of a HT RWU intervention to elicit acute changes in performance.

The influence of different pelvic technical marker sets upon hip kinematics during gait

BACKGROUND

The pelvis is commonly tracked during three-dimensional motion analysis using markers located on the anterior and posterior superior iliac spines. However, these markers are prone to soft tissue artefact and marker occlusion, highlighting the need for alternative technical marker sets.

RESEARCH QUESTION

How comparable are hip joint kinematics calculated using two alternative pelvic technical marker sets and a conventionally modelled pelvis?

METHODS

Fourteen participants undertook 3D gait analysis, walking overground at a self-selected pace (1.38 ± 0.14 m·s^-1), barefoot. Hip joint kinematics were compared using root mean square error (RMSE) between a conventionally tracked pelvis and two alternative technical marker sets; (1) posterior cluster and (2) additional iliac crest markers.

RESULTS

The average RMSE in the sagittal, frontal and transverse planes was 2.5° ± 2.8°, 1.6° ± 0.4° and 0.8° ± 0.4°, respectively for the posterior cluster, and 1.3° ± 0.7°, 0.8° ± 0.3° and 1.4° ± 0.5° for the iliac crest marker set. The RMSE was significantly larger for the posterior cluster compared to the iliac crest model in the sagittal (p =  .05, d = .28) and frontal planes (p <  .001, d = 7.65). In contrast, the RMSE was significantly lower for the posterior cluster in the transverse plane (p =  .01, d = -2.85).

SIGNIFICANCE

The findings of this study suggest that either a posterior cluster or additional iliac crest markers offer means of accurately calculating hip joint kinematics within 3° of the conventional pelvic model. Therefore, either technical marker set offers a viable alternative to the conventional pelvic model for calculating hip joint kinematics.

Incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers, association with bowling workload and seasonal variation

OBJECTIVES

Since much of the previous epidemiological research into lumbar stress fracture was conducted, there has been a marked increase in the amount of cricket being played. The aims were to determine the incidence and prevalence of lumbar stress fracture in English County Cricket fast bowlers between 2010 and 2016, determine the association with match bowling workload and observe seasonal variation in workload and injury.

METHODS

Lumbar stress fracture incidence and prevalence rates were calculated using new international methods for epidemiology in 368 professional English fast bowlers from 2010 to 2016. Workload variables were compared between lumbar stress fracture case and non-injured control groups, before entry in a logistic regression.

RESULTS

Fifty-seven lumbar stress fractures (mean age 22.81) were reported. Injury was most common in July and September. Match incidence was 0.16 lumbar stress fractures per 10 000 deliveries, annual incidence was 2.46 lumbar stress fractures per 100 fast bowlers and annual prevalence of lumbar stress fractures was 1.67% of squad days. Significant workload variables were observed between cases and controls. A peak 7-day workload of greater than 234 deliveries significantly increased the odds of sustaining a lumbar stress fracture 11-fold compared with bowling fewer than 197 deliveries.

CONCLUSION

Lumbar stress fractures are common in young fast bowlers possibly due to immaturity of the lumbar spine. The condensed early and late-season schedule may be causing periods of overuse, resulting in an increase in incidence of lumbar stress fracture. Reduction of workload in young fast bowlers is needed to reduce incidence.

Clinical measures of static foot posture do not agree

BACKGROUND

The aim of this study was to determine the level of agreement between common clinical foot classification measures.

METHODS

Static foot assessment was undertaken using the Foot Posture Index (FPI-6), rearfoot angle (RFA), medial longitudinal arch angle (MLAA) and navicular drop (ND) in 30 participants (29 ± 6 years, 1.72 ± 0.08 m, 75 ± 18 kg). The right foot was measured on two occasions by one rater within the same test environment. Agreement between the test sessions was initially determined for each measure using the Weighted Kappa. Agreement between the measures was determined using Fleiss Kappa.

RESULTS

Foot classification across the two test occasions was almost perfect for MLAA (Kw = .92) and FPI-6 (Kw = .92), moderate for RFA (Kw = .60) and fair for ND (Kw = .40) for comparison within the measures. Overall agreement between the measures for foot classification was moderate (Kf = .58).

CONCLUSION

The findings reported in this study highlight discrepancies between the chosen foot classification measures. The FPI-6 was a reliable multi-planar measure whereas navicular drop emerged as an unreliable measure with only fair agreement across test sessions. The use of this measure for foot assessment is discouraged. The lack of strong consensus between measures for foot classification underpins the need for a consensus on appropriate clinical measures of foot structure.

International consensus statement on injury surveillance in cricket: a 2016 update

Cricket was the first sport to publish recommended methods for injury surveillance in 2005. Since then, there have been changes to the nature of both cricket and injury surveillance. Researchers representing the major cricket playing nations met to propose changes to the previous recommendations, with an agreed voting block of 14. It was decided that 10 of 14 votes (70%) were required to add a new definition element and 11 of 14 (80%) were required to amend a previous definition. In addition to the previously agreed 'Match time-loss' injury, definitions of 'General time-loss', 'Medical presentation', 'Player-reported' and 'Imaging-abnormality' injuries are now provided. Further, new injury incidence units of match injuries per 1000 player days, and annual injuries per 100 players per year are recommended. There was a shift towards recommending a greater number of possible definitions, due to differing contexts and foci of cricket research (eg, professional vs amateur; injury surveillance systems vs specific injury category studies). It is recommended that researchers use and report as many of the definitions as possible to assist both comparisons between studies within cricket and with those from other sports.

Myostatin in muscle growth and repair

Myostatin, a member of the TGF beta superfamily, regulates skeletal muscle size by controlling embryonic myoblast proliferation. Recent results show that myostatin may also have a role in muscle regeneration and muscle wasting of adult animals. This review summarizes the recent developments in the regulation of myostatin gene expression and mechanism of its function.

Myostatin, a negative regulator of muscle growth, functions by inhibiting myoblast proliferation

Myostatin, a member of the transforming growth factor-beta (TGF-beta) superfamily, has been shown to be a negative regulator of myogenesis. Here we show that myostatin functions by controlling the proliferation of muscle precursor cells. When C(2)C(12) myoblasts were incubated with myostatin, proliferation of myoblasts decreased with increasing levels of myostatin. Fluorescence-activated cell sorting analysis revealed that myostatin prevented the progression of myoblasts from the G(1)- to S-phase of the cell cycle. Western analysis indicated that myostatin specifically up-regulated p21(Waf1, Cip1), a cyclin-dependent kinase inhibitor, and decreased the levels and activity of Cdk2 protein in myoblasts. Furthermore, we also observed that in myoblasts treated with myostatin protein, Rb was predominately present in the hypophosphorylated form. These results suggests that, in response to myostatin signaling, there is an increase in p21 expression and a decrease in Cdk2 protein and activity thus resulting in an accumulation of hypophosphorylated Rb protein. This, in turn, leads to the arrest of myoblasts in G(1)-phase of cell cycle. Thus, we propose that the generalized muscular hyperplasia phenotype observed in animals that lack functional myostatin could be as a result of deregulated myoblast proliferation.

Milk whey protein concentration and mRNA associated with beta-lactoglobulin phenotype

Two common genetic variants of β-lactoglobulin (β-lg), A and B, exist as co- dominant alleles in dairy cattle (Aschaffenburg, 1968). Numerous studies have shown that cows homozygous for β-lg A have more β-lg and less α-lactalbumin (α-la) and casein in their milk than cows expressing only the B variant of β-lg (Ng-Kwai-Hang et al. 1987; Graml et al. 1989; Hill, 1993; Hill et al. 1995, 1997). These differences have a significant impact on the processing characteristics of the milk. For instance, the moisture-adjusted yield of Cheddar cheese is up to 10% higher using milk from cows of the β-lg BB phenotype compared with milk from cows expressing only the A variant (Hill et al. 1997). All these studies, however, describe compositional differences associated with β-lg phenotype in established lactation only. No information is available on the first few weeks of lactation, when there are marked changes in the concentrations of β-lg and α-la (Pérez et al. 1990).

Introduction of a proximal Stat5 site in the murine alpha-lactalbumin promoter induces prolactin dependency in vitro and improves expression frequency in vivo

In order to establish a possible correlation between in vitro prolactin induction and the transcriptional activity of mammary gene promoters in transgenic mice, a functional Stat5-binding site was created by means of site-directed mutagenesis at position -70 on a 560 bp murine alpha-lactalbumin promotor linked to a CAT reporter gene. Surprisingly, the wild-type promoter was constitutively active in vitro and could not be induced by prolactin. Introducing the proximal Stat5 site abolished this constitutive activity and resulted in prolactin dependence in both CHO-K1- and HC11-transfected cells. In transgenic mice, both the frequency of lines expressing the transgene and the prevalence of mid to late pregnancy expression were increased.

Rescue of an MMTV transgene by co-integration reveals novel locus control properties of the ovine beta-lactoglobulin gene that confer locus commitment to heterogeneous tissues

In an attempt to enhance the frequency and level of expression of a poor-performing MMTV-driven transgene, we co-integrated this construct with the ovine beta-lactoglobulin (BLG) gene in transgenic mice. Seven lines of transgenic mice possessing co-integrated BLG and MMTV-RZ5 transgenes were compared with 12 lines of mice that possessed only the MMTV-RZ5 construct. Co-integration enhanced the frequency of expression in the mammary gland from two out of 12 lines for the MMTV-RZ5 transgene alone, to five out of seven when co-integrated with BLG. Surprisingly, co-integration also resulted in co-expression of the two transgenes in the salivary gland, lung and spleen in addition to the mammary gland. Furthermore, both transgenes were expressed in virgin animals, and throughout pregnancy and lactation, suggesting that the developmental regulation of the locus follows that of the MMTV-promoter. These findings represent a novel locus control property of the ovine BLG gene that confers commitment of the locus to the mammary gland, but also to a range of heterogeneous tissues possibly defined by the second promoter at the locus.

Perceptions, safety behaviors, and learning needs of parents of children brought to an emergency department

INTRODUCTION

This study was conducted at a level II Pediatric Trauma Center to assess the perceptions, safety behaviors, and learning needs of parents who brought their children to the emergency department.

METHODS

Surveys were distributed in the emergency department, and 412 parents/caretakers responded. A descriptive design provided the framework for data analysis.

RESULTS

A profile of caretakers of children in three age groups (1 to 4, 5 to 12, and 13 to 15 years) emerged. Whereas most parents and older children knew how to call 911, only half of the parents knew child CPR. Parents tended to underestimate their children's risks for motor vehicle-related and immersion injuries and were more concerned about kidnapping and assault. Less than half of the parents believed that most injuries can be prevented. Learning needs were indicated by 34% of parents, and CPR was mentioned most frequently. Parents' desires for learning tended to focus on care after injuries happened.

DISCUSSION

Health professionals need to spend more time teaching parents about the link between child development and risks for injury, to emphasize prevention. Interventions based on study results include the hospital Safety Helmet Discharge Plan.

Patterns of injury in pediatric patients in one Florida community and implications for prevention programs

OBJECTIVES

To meet community needs, injury prevention programs for children should be based on an understanding of the patterns of different mechanisms of injury. This study was conducted by the staff of a level II pediatric trauma center to describe the patterns of injury in pediatric patients with traumatic injuries.

METHODS

We conducted a retrospective review of medical records of all 184 pediatric "trauma alert" patients seen during a 1-year period. The trauma alert status is assigned to children with serious injuries or when the mechanism of injury is severe. Data analysis used descriptive statistics.

RESULTS

Pedestrian-versus-automobile injuries were the most common and most severe injuries, followed in frequency by falls, motor vehicle occupant, and bicycle-versus-automobile injuries. Younger children tended to have injuries as a result of falls; school-age children were involved more often in pedestrian and bicycle injuries, and adolescents had more motor vehicle occupant injuries. Failure to use safety devices, such as helmets and seat belts, was a common finding.

DISCUSSION

Patterns of injury were similar to those described in national studies. An extensive helmet campaign directed at child bicyclists was developed as a result of the priorities generated from the study. Other community programs included bicycle rodeos and a mix-off of nonalcoholic beverages.