A kinetic analysis of four high velocity, horizontally focused step-up variations for acceleration training.

Step-up variations are frequently used in sports performance to develop coordinated and powerful movements that transfer to running. This study aimed to quantify the kinetic characteristics of the first foot contact of four different step-up variations. Ten professional rugby league players participated in this study and performed the Barbell One Box Step-Up with Catch (BB1), Barbell Two Box Step-Up (BB2), Vest Two Box Run (VEST) and Step-Up Jump (JUMP) as part of routine in-season strength training sessions during one season. Peak force, total impulse and maximal rate of force development (RFD) were measured from first foot contact on the step-up box. Significantly greater peak force and RFD were observed in JUMP than any other variation (standardized mean difference; SMD: 3.9-5.5; p < 0.001). Total impulse was equal between JUMP and BB1, and significantly greater in JUMP than BB2 and VEST (SMD: 1.3-2.3; p < 0.001), and in BB1 than BB2 and VEST (SMD: 1.8-2.8; p < 0.001). Significantly larger peak force and RFD were observed in BB2 and VEST than BB1 (SMD: 0.6-0.7) and in total impulse in BB2 than VEST (SMD: 1.6) (p < 0.05). The results of this study highlight that step-up exercise variations maximize different kinetic characteristics, which may transfer differently to athlete running performance.

Ankle sprain, concussion, and anterior cruciate ligament injuries are common and burdensome in sub-elite female Australian football players.

OBJECTIVES: To describe the epidemiology of injuries in sub-elite female Australian Football (AF). DESIGN: Prospective cohort. METHODS: 424 athletes were tracked across a 12-match season. Injury characteristics (location, severity, mechanism) were reported. Injury incidence (injuries per 1000 h) and injury burden (days absent per 1000 h) were calculated. Severity was considered as the number of days missed between injury onset and return to full training. Incidence was compared using incidence rate ratios, and severity using a Mann-Whitney U test. RESULTS: Total injury incidence was 10.8 (95 % confidence interval [CI] = 9.0, 12.8) injuries per 1000 h. Match incidence was 34.6 (95 % CI = 28.0, 42.4) injuries per 1000 h. Ankle sprain injuries (2.2 per 1000 h, 95 % CI = 1.4, 3.1) and concussion (1.6 per 1000 h, 95 % CI = 1.0, 2.5) injuries were the most frequent, followed by anterior cruciate ligament (ACL) injuries (0.9 per 1000 h, 95 % CI = 0.4, 1.6). ACL (40.4 days per 1000 h, 95 % CI = 36.9, 44.1), ankle sprain injuries (31.4 per 1000 h, 95 % CI =28.4, 34.7), and concussion (19.9 per 1000 h, 95 % CI = 17.5, 22.5) injuries were also the most burdensome. There were 78 mild, 34 moderate, and 21 severe injuries. ACL injuries were the most severe injury (56.0 [77.0] in-season days missed). CONCLUSIONS: This research describes the first large-scale injury profile of sub-elite female AF, reporting time-loss measures of incidence and burden for many injury types. Ankle sprain injuries, concussions, and ACL injuries are common and burdensome, and should be prioritised for prevention.

IMUs Can Estimate Hip and Knee Range of Motion during Walking Tasks but Are Not Sensitive to Changes in Load or Grade.

The ability to estimate lower-extremity mechanics in real-world scenarios may untether biomechanics research from a laboratory environment. This is particularly important for military populations where outdoor ruck marches over variable terrain and the addition of external load are cited as leading causes of musculoskeletal injury As such, this study aimed to examine (1) the validity of a minimal IMU sensor system for quantifying lower-extremity kinematics during treadmill walking and running compared with optical motion capture (OMC) and (2) the sensitivity of this IMU system to kinematic changes induced by load, grade, or a combination of the two. The IMU system was able to estimate hip and knee range of motion (ROM) with moderate accuracy during walking but not running. However, SPM analyses revealed IMU and OMC kinematic waveforms were significantly different at most gait phases. The IMU system was capable of detecting kinematic differences in knee kinematic waveforms that occur with added load but was not sensitive to changes in grade that influence lower-extremity kinematics when measured with OMC. While IMUs may be able to identify hip and knee ROM during gait, they are not suitable for replicating lab-level kinematic waveforms.

Swimming for low back pain: A scoping review.

BACKGROUND: Guidelines recommend exercise for treatment of chronic low back pain and prevention, but the amount and quality of evidence for different exercise modes is highly variable. Swimming is commonly recommended by health professionals, but the extent and quality of research supporting its relationship with back pain is not clear. OBJECTIVES: The aim of this scoping review was to map the extent, characteristics and findings of research investigating the relationship between swimming and low back pain. DESIGN: Scoping review. METHOD: Four electronic databases (MEDLINE, EMBASE, CINAHL, and SPORT Discus) were searched from inception to February 2023. We included primary studies and reviews that reported an association between swimming and low back pain. Hydrotherapy studies were excluded. RESULTS: 3093 articles were identified, and 44 studies included. Only one randomised controlled trial and one longitudinal cohort study were included. Most studies were cross-sectional (37/44; 84.1%), included competitive athletes (23/39; 59.0%), and did not primarily focus on the association between swimming and low back pain in the aims (41/44; 93.2%). Instead, most data available were largely incidentally collected or a secondary outcome. The reported associations between swimming and low back pain were highly variable regardless of whether the comparison was to other sports (odds ratio: 0.17 to 17.92) or no sport (odds ratio: 0.54 to 3.01). CONCLUSION: Most available literature investigating swimming and low back pain is cross-sectional in design. We did not identify any clear pattern of association between swimming and low back pain, based on the available literature.

Orthotic interventions for restoring proximal interphalangeal joint motion for patients with hand injuries or conditions: A systematic review and meta-analysis.

BACKGROUND: Limitations to proximal interphalangeal joint (PIPJ) motion can result in significant functional impairment for people with hand injuries and conditions. The role of orthotic intervention to improve PIPJ motion has been studied; however, high-quality systematic reviews and meta-analyses are lacking. PURPOSE: This study aimed to determine the effectiveness of orthotic intervention for restoring PIPJ extension/flexion following hand injuries or conditions. STUDY DESIGN: Systematic review. METHODS: A comprehensive literature search was completed in MEDLINE, CINAHL, Embase, Cochrane Central, and PEDro using terms related to orthoses, finger PIPJ range of motion, and randomized controlled trial design. Methodological quality was assessed using the PEDro score, study outcomes were pooled wherever possible using random effects meta-analysis, and certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation. RESULTS: Twelve trials were included (PEDro score: 4-7/10). The addition of orthotic intervention was not more effective than hand therapy alone following Dupuytren's release for improving total active extension (mean difference [MD] -2.8°, 95% confidence interval [CI]: -9.6° to 4.0°, p = 0.84), total active flexion (MD -5.8°, 95% CI: -12.7° to 1.2°, p = 0.70), Disability of the Arm, Shoulder and Hand scores (MD 0.4, 95% CI: -2.7 to 3.6, p = 0.79), or patient satisfaction (standardized MD 0.20, 95% CI: -0.49 to 0.09, p = 0.17). Orthotic intervention was more effective than hand therapy alone for improving PIPJ extension for fixed flexion deformities following traumatic finger injury or surgery (MD -16.7°, 95% CI: -20.1° to -13.3°, p < 0.001). No studies evaluated orthotic intervention to improve PIPJ flexion. CONCLUSION: The addition of an extension orthosis following procedures to manage Dupuytren's contracture is no better than hand therapy alone for improving PIPJ extension. In contrast, the addition of a PIPJ extension orthosis in the presence of traumatic PIPJ fixed flexion deformities is more effective for improving PIPJ extension than hand therapy alone. Future studies are needed to evaluate the role of orthotic intervention for improving PIPJ flexion.

Sensor location influences the associations between IMU and motion capture measurements of impact landing in healthy male and female runners at multiple running speeds.

This study investigated the relationships between inertial measurement unit (IMU) acceleration at multiple body locations and 3D motion capture impact landing measures in runners. Thirty healthy runners ran on an instrumented treadmill at five running speeds (9-17 km/h) during 3D motion capture. Axial and resultant acceleration were collected from IMUs at the distal and proximal tibia, distal femur and sacrum. Relationships between peak acceleration from each IMU location and patellofemoral joint (PFJ) peak force and loading rate, impact peak and instantaneous vertical loading rate (IVLR) were investigated using linear mixed models. Acceleration was positively related to IVLR at all lower limb locations (p < 0.01). Models predicted a 1.9-3.2 g peak acceleration change at the tibia and distal femur, corresponding with a 10% IVLR change. Impact peak was positively related to acceleration at the distal femur only (p < 0.01). PFJ peak force was positively related to acceleration at the distal (p = 0.03) and proximal tibia (p = 0.03). PFJ loading rate was positively related to the tibia and femur acceleration in males only (p < 0.01). These findings suggest multiple IMU lower limb locations are viable for measuring peak acceleration during running as a meaningful indicator of IVLR.

Optimizing Wearable Device and Testing Parameters to Monitor Running-Stride Long-Range Correlations for Fatigue Management in Field Settings.

PURPOSE: There are important methodological considerations for translating wearable-based gait-monitoring data to field settings. This study investigated different devices' sampling rates, signal lengths, and testing frequencies for athlete monitoring using dynamical systems variables. METHODS: Secondary analysis of previous wearables data (N = 10 runners) from a 5-week intensive training intervention investigated impacts of sampling rate (100-2000 Hz) and signal length (100-300 strides) on detection of gait changes caused by intensive training. Primary analysis of data from 13 separate runners during 1 week of field-based testing determined day-to-day stability of outcomes using single-session data and mean data from 2 sessions. Stride-interval long-range correlation coefficient α from detrended fluctuation analysis was the gait outcome variable. RESULTS: Stride-interval α reduced at 100- and 200- versus 300- to 2000-Hz sampling rates (mean difference: -.02 to -.08; P ≤ .045) and at 100- compared to 200- to 300-stride signal lengths (mean difference: -.05 to -.07; P < .010). Effects of intensive training were detected at 100, 200, and 400 to 2000 Hz (P ≤ .043) but not 300 Hz (P = .069). Within-athlete α variability was lower using 2-session mean versus single-session data (smallest detectable change: .13 and .22, respectively). CONCLUSIONS: Detecting altered gait following intensive training was possible using 200 to 300 strides and a 100-Hz sampling rate, although 100 and 200 Hz underestimated α compared to higher rates. Using 2-session mean data lowers smallest detectable change values by nearly half compared to single-session data. Coaches, runners, and researchers can use these findings to integrate wearable-device gait monitoring into practice using dynamic systems variables.

Just Run: Development of a theory-based motivational online intervention for promoting ongoing running participation.

Running is a popular form of physical activity yet discontinuation is common. Interventions targeting physical activity adoption have shown modest effects, often with little translation into long-term participation, which may limit the health benefits available to the wider community. This paper details the development of a new online running intervention (Just Run) aimed at improving continuation of running activity in new runners through a motivational and psychological lens, including aspects of design, content, refinement, and usability testing. A six-step intervention mapping process was used to develop a theory-based online intervention using a mix of research designs. Key stakeholders including runners, coaches and relevant experts in physical activity and behavior change provided valuable insight, feedback and refinement of the education to be delivered. The final Just Run intervention included ten modules delivered online over twelve weeks to promote ongoing running participation through videos, testimonials, and activities. Key themes identified through the literature and stakeholder engagement process related to goal setting, self-efficacy, intrinsic motivation, social support and overcoming barriers to running participation. Usability testing confirmed the quality and suitability of the education to the target population. Just Run has been developed with a range of stakeholders to address an area of unmet need in the adoption and promotion of running. Just Run is a robust online intervention that has been designed and pre-tested with positive feedback and unique insights from key stakeholders. Further investigation is required to support its implementation to the wider community.

Cumulative patellofemoral force and stress are lower during faster running compared to slower running in recreational runners.

Management strategies for patellofemoral pain often involve modifying running distance or speed. However, the optimal modification strategy to manage patellofemoral joint (PFJ) force and stress accumulated during running warrants further investigation. This study investigated the effect of running speed on peak and cumulative PFJ force and stress in recreational runners. Twenty recreational runners ran on an instrumented treadmill at four speeds (2.5-4.2 m/s). A musculoskeletal model derived peak and cumulative (per 1 km of continuous running) PFJ force and stress for each speed. Cumulative PFJ force and stress decreased with faster speeds (9.3-33.6% reduction for 3.1-4.2 m/s vs. 2.5 m/s). Peak PFJ force and stress significantly increased with faster speeds (9.3-35.6% increase for 3.1-4.2 m/s vs. 2.5 m/s). The largest cumulative PFJ kinetics reductions occurred when speeds increased from 2.5 to 3.1 m/s (13.7-14.2%). Running at faster speeds increases the magnitude of peak PFJ kinetics but conversely results in less accumulated force over a set distance. Selecting moderate running speeds (~3.1 m/s) with reduced training duration or an interval-based approach may be more effective for managing cumulative PFJ kinetics compared to running at slow speeds.

The use of exercise relative motion orthoses to improve proximal interphalangeal joint motion: A survey of Australian hand therapy practice.

STUDY DESIGN: Cross-sectional online survey. INTRODUCTION: Exercise relative motion (RM) orthoses are prescribed by hand therapists to improve finger motion but there is limited scientific evidence to guide practice. PURPOSE OF THE STUDY: To describe Australian hand therapists' use of exercise RM orthoses to improve PIPJ motion, including trends in orthosis design, prescription, clinical conditions, and their opinions on orthosis benefits and limitations. METHODS: 870 Australian Hand Therapy Association members were sent an electronic survey that included multiple choice, Likert scale and open-ended questions under four subgroups: demographics, design trends, prescription, and therapist opinions. Data analysis consisted of predominantly descriptive statistics and verbatim transcription. RESULTS: 108 Australian therapists completed the survey, over a third with ≥ 20 years of clinical experience. Exercise RM orthoses were prescribed weekly to monthly (82%) for between 2-6 weeks duration (81%) and used during exercise and function (87%). The most common differential MCPJ position was 11-30° extension (98%) or flexion (92%). Four-finger designs were most common for border digits (OR ≥3.4). Exercise RM orthoses were more commonly used for active and extension deficits compared to passive (OR ≥3.7) and flexion deficits (OR ≥1.4), respectively. Clinicians agreed that the orthosis allowed functional hand use (94%), increased non-intentional exercise (98%), and was challenging to use with fluctuating oedema (60%). DISCUSSION: This survey highlights notable clinical trends despite only reaching a small sample of Australian hand therapists. Exercise RM orthoses were frequently being used for active PIPJ extension and flexion deficits. A common MCPJ differential angle was reported, while the number of fingers incorporated into the design depended on the digit involved. Therapists' preferences mostly agreed with the limited available evidence. CONCLUSION(S): This limited survey identified common exercise RM orthosis fabrication and prescription trends amongst Australian therapists. These insights may inform future biomechanical and clinical research on this underexplored topic.

The impact of concussion on subsequent injury risk in elite junior Australian football athletes.

OBJECTIVES: Concussion increases injury risk. However, this has not been investigated in junior Australian football and it is unknown whether the location, severity, and mechanism of subsequent injuries differ after concussion vs. non-concussion injury. DESIGN: Prospective cohort. METHODS: 1455 elite adolescent male Australian footballers were tracked across seven seasons to determine whether subsequent injury risk was greater after concussion compared to non-concussion index injury using multilevel survival analysis. Mixed-effects logistic regression compared location and mechanism. Mixed-effects Poisson regression compared severity. RESULTS: Of 1455 athletes, 632 were injured and included in subsequent-injury analysis. There were no differences in injury incidence after a concussion compared to upper- (hazard ratio = 1.0, 0.6 to 1.9, P = 0.892; trivial effect) and lower (hazard ratio = 1.1, 0.6 to 1.9, P = 0.810; trivial effect) index injury, or in location. Subsequent injuries were more likely to be contact-based after a non-concussion injury than concussion (odds ratio = 4.6, 1.3 to 16.0; P = 0.017; large effect). There was no difference in subsequent injury severity after lower- (3.4 ±â€¯3.0 missed matches; incidence rate ratio = 1.4, 0.9 to 2.1; P ≤ 0.117; small effect) and upper-limb injuries (3.4 ±â€¯3.1 missed matches; incidence rate ratio = 1.4, 0.9 to 2.2; P = 0.189; small effect) compared to concussion (2.4 ±â€¯2.0 missed matches). CONCLUSIONS: Subsequent injury risk, severity, and location in junior Australian football are similar following concussion compared to non-concussion index injuries, although contact injuries are less likely.

Does changing the Functional Movement Screen composite score threshold influence injury risk estimation in junior Australian football players?

This study aimed to identify whether a revised lower Functional Movement Screen (FMS) composite score threshold would be associated with a greater injury risk for junior athletes than the common threshold of≤14. This prospective cohort study included tracking of 809 elite junior male Australian football players for injuries that resulted in a missed game. All athletes completed pre-season FMS testing and a 12-month self-reported retrospective injury questionnaire. Analyses examined the relationship between composite score thresholds of≤14, ≤13, and≤12 and the risk of injury. The relationship between prospective injury and the common composite threshold score of ≤ 14 was dependent on the presence of a recent injury history (relative risk [RR] = 1.45, p = 0.004) in comparison to no recent injury history (RR = 0.98, p = 0.887). Scoring≤12 in the presence of a recent injury history had the greatest diagnostic accuracy but only a trivial increase in injury risk (RR = 1.59, p = 0.001, sensitivity = 0.35, specificity = 0.80, negative and positive likelihood ratios = 0.81 and 1.75). Whilst some small statistical relationships existed between prospective injury and the FMS composite score thresholds, all three thresholds were not associated with a clinically meaningful relationship with prospective injury and were no more effective than retrospective injury for determining athletes at risk of injury.

A Minimal Sensor Inertial Measurement Unit System Is Replicable and Capable of Estimating Bilateral Lower-Limb Kinematics in a Stationary Bodyweight Squat and a Countermovement Jump.

This study aimed to validate a 7-sensor inertial measurement unit system against optical motion capture to estimate bilateral lower-limb kinematics. Hip, knee, and ankle sagittal plane peak angles and range of motion (ROM) were compared during bodyweight squats and countermovement jumps in 18 participants. In the bodyweight squats, left peak hip flexion (intraclass correlation coefficient [ICC] = .51), knee extension (ICC = .68) and ankle plantar flexion (ICC = .55), and hip (ICC = .63) and knee (ICC = .52) ROM had moderate agreement, and right knee ROM had good agreement (ICC = .77). Relatively higher agreement was observed in the countermovement jumps compared to the bodyweight squats, moderate to good agreement in right peak knee flexion (ICC = .73), and right (ICC = .75) and left (ICC = .83) knee ROM. Moderate agreement was observed for right ankle plantar flexion (ICC = .63) and ROM (ICC = .51). Moderate agreement (ICC > .50) was observed in all variables in the left limb except hip extension, knee flexion, and dorsiflexion. In general, there was poor agreement for peak flexion angles, and at least moderate agreement for joint ROM. Future work will aim to optimize methodologies to increase usability and confidence in data interpretation by minimizing variance in system-based differences and may also benefit from expanding planes of movement.

Effects of Cold-Water Immersion Compared with Other Recovery Modalities on Athletic Performance Following Acute Strenuous Exercise in Physically Active Participants: A Systematic Review, Meta-Analysis, and Meta-Regression.

BACKGROUND: Studies investigating the effects of common recovery modalities following acute strenuous exercise have reported mixed results. OBJECTIVES: This systematic review with meta-analysis and meta-regression compared the effects of cold-water immersion (CWI) against other common recovery modalities on recovery of athletic performance, perceptual outcomes, and creatine kinase (CK) following acute strenuous exercise in physically active populations. STUDY DESIGN: Systematic review, meta-analysis, and meta-regression. METHODS: The MEDLINE, SPORTDiscus, Scopus, Web of Science, Cochrane Library, EmCare, and Embase databases were searched up until September 2022. Studies were included if they were peer reviewed, published in English, included participants who were involved in sport or deemed physically active, compared CWI with other recovery modalities following an acute bout of strenuous exercise, and included measures of performance, perceptual measures of recovery, or CK. RESULTS: Twenty-eight studies were meta-analysed. CWI was superior to other recovery methods for recovering from muscle soreness, and similar to other methods for recovery of muscular power and flexibility. CWI was more effective than active recovery, contrast water therapy and warm-water immersion for most recovery outcomes. Air cryotherapy was significantly more effective than CWI for the promotion of recovery of muscular strength and the immediate recovery of muscular power (1-h post-exercise). Meta-regression revealed that water temperature and exposure duration were rarely exposure moderators. CONCLUSION: CWI is effective for promoting recovery from acute strenuous exercise in physically active populations compared with other common recovery methods. PROTOCOL REGISTRATION: Open Science Framework: https://doi.org/10.17605/OSF.IO/NGP7C.

Epidemiology of injuries in amateur boxing: A systematic review and meta-analysis.

OBJECTIVES: To synthesise competition and training injury data in amateur boxing. DESIGN: Systematic review and meta-analysis. Pooled estimates of competition injury incidence rates per 1000 athlete-exposures (IIRAE) and per 1000 min of exposure (IIRME), and training injury incidence rates per 1000 h of exposure (IIRHE) were obtained by fitting random-effects models. METHODS: MEDLINE, Embase, AMED, AUSPORT, and SPORTDiscus databases were searched from inception to 27 May 2022. Cohort studies with prospectively collected injury and exposure data from amateur boxing competition or training published in peer-reviewed journals were eligible for inclusion. RESULTS: Seventeen studies were eligible for inclusion. The competition IIRAE and IIRME summary estimates were 54.7 (95 % CI 33.8-88.4) and 6.8 (95 % CI 4.2-10.9), respectively. The training IIRHE summary estimate was 1.3 (95 % CI 0.2-7.0). The most commonly injured body regions in the competition and training settings were the head and neck (median: 72 %; range: 46 % to 100 %) and upper limb (median: 49 %; range: 40 % to 53 %), respectively. The predominant types of injury were contusions (median: 35 %; range: 5 % to 100 %) and lacerations and abrasions (median: 20 %; range: 0 % to 69 %) in the competition setting, and sprains and strains (median: 60 %; range: 50 % to 81 %) in the training setting. CONCLUSIONS: Amateur boxing athletes sustain, on average, 1 injury every 2.5 h of competition and every 772 h of training. There is a need for identifying injury mechanisms and modifiable risk factors that can be targeted by preventive measures to reduce the burden of injury in amateur boxing.

Changes in acceleration load as measured by inertial measurement units manifest in the upper body after an extended running task.

The purpose of this study was to investigate the behaviour of physiological load measures as well as ground reaction forces (GRF) and acceleration load during a prolonged running task that simulated the running demands of an intermittent team sport. Nineteen males completed a maximal aerobic fitness test and an extended running protocol across two sessions. Participants wore a portable metabolic system, and four inertial measurement units (IMU), one on each foot, the lower back and upper back. GRF were measured via an instrumented treadmill. Change in metabolic, IMU and GRF variables across five blocks during the running protocol were assessed using a one-way repeated measures ANOVA. The running protocol elicited large increases in heart rate and oxygen consumption over time. No statistically significant changes in any peak impact accelerations were observed. Resultant acceleration area under the curve (AUC) increased at the lower and upper back locations but was unchanged at the foot. GRF active peak but not impact peak increased during the prolonged run. The results of this study indicate that the effect of an extended running task on IMU measures of external mechanical load is manifested in the upper body, and is effectively measured by AUC.

Not All Physical Performance Tests Are Related to Early Season Match Running Performance in Professional Rugby League.

ABSTRACT: Glassbrook, DJ, Fuller, JT, Wade, JA, and Doyle, TLA. Not all physical performance tests are related to early season match running performance in professional rugby league. J Strength Cond Res 36(7): 1944-1950, 2022-This study aimed to determine which physical tests correlate with early season running performance. Sixteen professional rugby league players performed the 30-15 intermittent fitness test (IFT), 1.2-km time trial, 1 repetition maximum (RM) barbell back squat, isometric midthigh pull (IMTP), countermovement jump (CMJ), barbell squat jump (SJ), and ballistic bench press throw (BBP). Bivariate Pearson's correlations and linear regression were used to compare physical tests with peak match running intensities recorded by a portable Global Positioning System and represented by peak match velocity and acceleration, as well as peak 1-, 4-, 6-, and 8-minute instantaneous acceleration/deceleration periods of play. Significant (p < 0.05) negative correlations (r = -0.55 to -0.60) were observed between the IFT and relative 1-, 4-, 6-, and 8-minute peaks, and between the relative 1RM back squat and relative 1-, 4-, 6-, and 8-minute peaks. Significant positive correlations (r = 0.52-0.84) were observed between the following physical tests and match performance pairs: IFT and peak acceleration; relative 1RM back squat and peak acceleration; SJ peak power (relative and absolute) and peak acceleration; CMJ peak force (relative and absolute) and peak acceleration; CMJ peak power (relative and absolute) and peak acceleration and 1-, 4-, 6-, and 8-minute peaks; and relative BBP peak power and peak velocity and peak acceleration. The results of this study highlight that not all generic tests of physical qualities are related to peak match running performance and only those with significant correlations are likely to be able to indicate how players may perform during match-play.

Senior and Junior Rugby League Players Improve Lower-Body Strength and Power Differently During a Rugby League Season.

ABSTRACT: Wade, JA, Fuller, JT, Devlin, PJ, and Doyle, TLA. Senior and junior rugby league players improve lower-body strength and power differently during a rugby league season. J Strength Cond Res 36(5): 1367-1372, 2022-This investigation evaluated lower-body strength and power changes across a rugby league season in elite junior and senior athletes. Twenty-five senior and 20 junior rugby league players performed an isometric midthigh pull and countermovement jump at 3 time points in a National Rugby League training season (mid-preseason, end-preseason, and in-season). Linear fixed-effects models were used to compare isometric midthigh pull force and countermovement jump power between player experience groups (senior vs. junior) across the season phases (mid-preseason vs. end-preseason vs. and in-season). Cohen's effect sizes (ES) with 95% confidence intervals were calculated for pairwise comparisons. For senior players, absolute and relative strength (ES = 0.38, p < 0.007) and power (ES = 0.64, p < 0.008) increases were observed at end-preseason compared with mid-preseason, but there were no changes in-season (ES = 0.02, p > 0.571). For junior players, strength did not change (ES < 0.01, p > 0.738) and absolute power decreased (ES = 0.29, p < 0.014) at end-preseason compared with mid-preseason; large increases were evident for absolute and relative strength (ES = 1.43, p < 0.001) and power (ES = 0.62, p < 0.001) in-season. This research demonstrates senior and junior rugby league players exhibit unique patterns of improvements in lower-body strength and power across different phases of the season. This highlights the importance for training programs to differ between junior and senior athletes and target different physical qualities for both groups at different times of the season, thus providing guidance for strength and conditioning coaches.

Negative Consequences of Pressure on Marksmanship May be Offset by Early Training Exposure to Contextually Relevant Threat Training: A Systematic Review and Meta-Analysis.

OBJECTIVE: The purpose of this meta-analytic review is to examine the relationship between increased psychological pressure and Use of Force (UOF) behaviours, identifying current training methodologies and effectiveness of transfer of training interventions in high threat-simulated scenarios. BACKGROUND: Data from UOF performance within Law Enforcement indicates a low transfer of marksmanship training into real-world UOF, resulting in unnecessary damage to property, personal injury and increased risk to loss of life. This meta-analysis examines both the impact of increased pressure and current training interventions. METHOD: A meta-analysis was conducted across a wide range of published research to answer the primary research questions. RESULTS: Increased levels of perceived pressure demonstrated an average decrease in marksmanship accuracy of 14.8%, together with a small increase in incorrect Decision Making (DM) and faster reaction Times (RT). Experience demonstrated a mitigating effect for pressure for marksmanship with a 1.1% increase for every one year of service but no effect on DM or RT. Training interventions utilizing a variety of early contextually relevant exposures to increased pressure improved performance over traditional training on average by 10.6%. CONCLUSION: The outcomes illustrate the negative effect of pressure on marksmanship and UOF behaviours, and that early exposure to contextually relevant pressure may increase the transfer of training to real-world performance. APPLICATION: Occupational experience is an important component in reducing the impact of pressure on UOF performance, and transfer of training may be enhanced through training methodologies that combine early exposure to contextually relevant pressure, that may replicate the benefits of experience.

The Relationship Between Performance and Injury in Junior Australian Football Athletes.

PURPOSE: Determine the impact of preseason and between-seasons changes in individual physical performance on injury risk in elite junior Australian football players and if injuries sustained during a season impact subsequent-season performance improvement. METHODS: This prospective cohort study assessed individual performance measures (sprint speed, jump, agility, and aerobic endurance) during preseason over 4 consecutive seasons. Injury status (injured/not injured) was tracked weekly to determine the relationship between individual performance and in-season injury occurrence. Mixed models were used to determine the relationship between physical performance and injury, and the effect of injury on physical performance improvement. RESULTS: A total of 206 players played 2 consecutive seasons and were included (17.6 y, 181.9 cm, 75.7 kg). Faster players during preseason experienced higher injury incidence (injuries/season) during that playing season (incidence rate ratio = 0.127; P = .034). Injury incidence was not influenced by between-seasons change in any performance measure. Players injured during their first season maintained their aerobic fitness, which declined in noninjured players (d = 0.39; P = .013). Players who sustained a lower-limb injury during their first season saw smaller improvements in sprint speed than players who did not get injured (d = 0.39; P = .035). CONCLUSION: Faster players experience higher injury incidence than slower players and may require specific prevention interventions. Players who experience a lower-limb injury during the playing season do not improve sprint speed between seasons to the same extent as players who do not get injured, highlighting the need for targeted high-speed running ability development as part of rehabilitation.