Neuromechanics of finger hangs with arm lock-offs: analyzing joint moments and muscle activations to improve practice guidelines for climbing

Introduction

Climbing imposes substantial demands on the upper limbs and understanding the mechanical loads experienced by the joints during climbing movements is crucial for injury prevention and optimizing training protocols. This study aimed to quantify and compare upper limb joint loads and muscle activations during isometric finger hanging exercises with different arm lock-off positions.

Methods

Seventeen recreational climbers performed six finger dead hangs with arm lock-offs at 90° and 135° of elbow flexion, as well as arms fully extended. Upper limb joint moments were calculated using personalized models in OpenSim, based on three-dimensional motion capture data and forces measured on an instrumented hang board. Muscle activations of upper limb muscles were recorded with surface electromyography electrodes.

Results

Results revealed that the shoulder exhibited higher flexion moments during arm lock-offs at 90° compared to full extension (p = 0.006). The adduction moment was higher at 135° and 90° compared to full extension (p < 0.001), as well as the rotation moments (p < 0.001). The elbows exhibited increasing flexion moments with the increase in the arm lock-off angle (p < 0.001). Muscle activations varied across conditions for biceps brachii (p < 0.001), trapezius (p < 0.001), and latissimus dorsi, except for the finger flexors (p = 0.15).

Discussion

Our findings indicate that isometric finger dead hangs with arms fully extended are effective for training forearm force capacities while minimizing stress on the elbow and shoulder joints. These findings have important implications for injury prevention and optimizing training strategies in climbing.

A Qualitative Analysis of Beliefs about Masculinity and Gender Socialization among US Mothers and Fathers of School-Age Boys

Internalization of culturally dominant masculine gender role norms can have harmful impacts on the physical and emotional health of men and boys. Although parents play an important role in influencing gender-related beliefs in their children, limited research has examined how contemporary parents conceptualize masculinity and their role in gender socialization. The current study conducted 13 focus groups with Black, Latino, and White parents (N = 83) of school-age boys from rural and urban areas in a large southeastern state in the US. Parent beliefs about masculinity existed across a spectrum from "rigid" (representing narrow, culturally dominant masculine norms) to "flexible" (defining a broader set of behaviors and attitudes as masculine). In general, more flexible beliefs were expressed by mothers than fathers, and by White than Black and Latino parents. Most parents reacted positively to messages about potential harms associated with restrictive masculinity norms; however, many saw these issues primarily as parenting challenges (e.g., teaching boys to resist negative peer influences) rather than related to gender socialization. Some unique themes also emerged within racial/ethnic groups, with Black parents noting the impact of racial discrimination on societal expectations for Black men and fathers, and Latino parents describing generational shifts towards more equitable gender role attitudes and parenting practices. These findings highlight the need for more complex and nuanced messages about masculinity norms and their relationship to health and well-being and can help inform the development of interventions to promote healthy masculine gender socialization, increase health equity, and prevent injury and violence.

Neuromuscular Response during Different Side-Cutting Maneuvers and Its Influence on the Risk of Knee Injuries

BACKGROUND

The objective of this study was to investigate the impact of a customized exercise program on electromyographic (EMG) variables during side-cutting maneuvers.

METHODS

Fifty-seven physically active volunteers were recruited and randomized into two groups: a control group (CG) and an experimental group (EG). The CG maintained their regular physical activity, while the EG followed an individualized, integrated exercise regimen that included strength, neuromuscular, proprioceptive, eccentric training, and whole-body vibration (WBV) exercises, lasting for 12 weeks. EMG-Root Means Square (RMS) values for the quadriceps (Q) and hamstrings (H) were measured immediately following initial foot contact at 50, 100, 150, and 200 milliseconds. Changes in EMG activity were evaluated before and after a twelve-week intervention, and the effect size (ES, 90% confidence limit [90%CL]) was calculated.

RESULTS

The results showed that the EG participants exhibited enhanced co-contraction as measured by the hamstring/quadriceps ratio (H/Q ratio) during both open and cross-cutting side maneuvers after the twelve-week intervention.

CONCLUSION

Furthermore, the customized, integrated exercise program that combined strength, neuromuscular, proprioceptive, eccentric training, and WBV exercises were could potentially serve as a beneficial neuromuscular and biomechanical strategy for addressing knee injury risk in non-professional, physically active populations at high risk for such injuries.

Educational intervention promotes injury prevention adherence in club collegiate men's lacrosse athletes

CONTEXT

Club sports are intercollegiate athletics that are student-led and not university-funded, many of which are without professional credentialing. Collegiate club athletes have an increased rate of injury compared to their NCAA counterparts. Education and implementation of stretching and strength training have demonstrated decreased rates of noncontact injuries.

OBJECTIVES

Educational intervention was given to club collegiate athletes to determine its effect on injury rates, perceived pain, and compliance toward injury-prevention practices.

METHODS

Intramural collegiate athletes were educated on injury prevention that focused on targeted stretching. Surveys designed to assess the impact of the education were distributed to three men's club lacrosse teams in Utah at the beginning and end of the season. The questions measured pain and time missed due to noncontact injury.

RESULTS

Two-tailed unpaired t tests demonstrated p values <0.05 for: overall decreased levels of pain (p<0.0001); increased range of motion (ROM, p<0.0001); increased frequency of stretching the muscle groups psoas (p<0.0001), calves (p=0.0081), and piriformis (p<0.0001); decreased pain levels for the hamstring (p=0.0274); and increased frequency of stretching after practice (p<0.0001).

CONCLUSIONS

The increased frequency of stretching suggests increased compliance toward injury prevention practices. Decreased self-reported levels of overall pain, and decreased pain in the hamstring, show that the subjects surveyed in the sample reported less pain and increased time stretching at the end of the season compared with the beginning of the season. Educational intervention offers an affordable measure to provide club collegiate athletes with resources to reduce injury rates through athlete compliance to targeted stretches.

How Subtalar Kinematics Affects Knee Laxity in Soccer Players After Anterior Cruciate Ligament Injury?

Purpose The goal of the current study was to ascertain whether there is an association between foot pronation and anterior cruciate ligament (ACL) injury in a group of elite professional soccer players. Methods Two groups of soccer players were studied, all of whom played in the Greek Super League. The ACL group included players who had suffered an ACL injury in the last 2 years. The non-ACL group was composed of players who had never suffered an ACL injury. We used a 3D baropodometric laser scanner to measure pronation or overpronation (navicular drop phenomenon) of the subtalar joint and how this affects the subtalar joint while standing. We assessed ACL laxity using the Genourob Rotab. Results ACL-injured patients, regardless of the mechanism of injury, exhibited greater navicular drop values than a randomly selected group of subjects with no history of ACL injury. Conclusion Greater knee joint laxity and subtalar pronation may be associated with an increased risk of ACL injury. Pronation of the foot appears to be a risk factor for ACL injury. These findings should be integrated into future studies to better define how neuromuscular control related to lower extremity biomechanics is associated with ACL injury.

Addressing Exoskeleton Implementation Challenges: Case Studies of Non-Acceptance in Agriculture

OBJECTIVES

The objective of this study was to detect success and failure factors for the implementation of passive exoskeletons in agriculture. Exoskeletons have been shown to reduce musculoskeletal loads during lab-based manual tasks, but long-term implementation experiences in agriculture are lacking.

METHODS

We analyzed four intervention studies in agriculture focusing on methodological and contextual reasons why the trials were successful or unsuccessful. The study context, attempted intervention, and data collection of each field trial is compared. In the absence of long-term studies investigating the implementation and effectiveness of exoskeletons in agriculture, a set of multi-week pilot trials were initiated among German market vegetable farms and French vineyards from 2019 to 2022. Participant ratings, farm characteristics (e.g. employment duration and payment scheme) and intervention implementation characteristics (e.g. participation in implementation or language barriers) were analyzed using a mixed-methods approach to identify success and failure factors.

RESULTS

The comparison of the studies showed that despite the organizational issues, there were several practical issues that limit the success of exoskeleton use in agriculture. We observed that participant rejection of the intervention is a major barrier to successfully conducting long-term field trials in agriculture. Factors like pain, discomfort, heat stress, or a lack of perceived benefits have been identified as failure factors but also the implementation process itself.

CONCLUSION

In addition to careful targeting of trial sites and inclusion of participatory elements in the implementation plan, successful implementation of exoskeletons in agriculture requires fundamental human factors development of the exoskeletons themselves. This will require better matching the physical needs of the workers, the production needs of the tasks, and compatibility with the environment.

A multicomponent neuromuscular warm-up program reduces lower-extremity injuries in trained basketball players: a cluster randomized controlled trial

OBJECTIVE

To assess the effects of a novel multicomponent neuromuscular warm-up program on lower-extremity injury incidence in basketball players competing at the regional level.

METHODS

A cluster randomized controlled experimental design was adopted to compare injury incidence between players exposed to the injury prevention warm-up program and those exposed to a typical warm-up program across an entire basketball season. Four teams consisting of 57 players (male: n = 42; female: n = 15) were allocated to the intervention group (age: 21.6 ± 2.5 years; height: 186.2 ± 8.8 cm; body mass: 80.0 ± 10.4 kg) and four teams consisting of 55 players (male: n = 43; female: n = 12) were allocated to the control group (age: 21.6 ± 2.6 years; height: 186.9 ± 9.1 cm; body mass: 81.5 ± 10.9 kg). The novel warm-up combined running exercises with active stretching, plyometrics, balance, strength, and agility drills. Coaching and medical staff provided details on injury incidence each week. Data analyses included the use of poisson regression analyses and the incidence rate ratio (IRR) with 95% confidence intervals (CI).

RESULTS

The intervention group experienced a significantly lower ankle sprain incidence rate (IRR = 0.26, 95% CI = 0.05, 0.98, p = 0.02) and a tendency toward a lower knee injury incidence rate (IRR = 0.32, 95% CI = 0.03, 1.78, p = 0.07) compared to the control group. Considering only non-contact lower-extremity injuries of any type, the intervention group experienced a significantly lower incidence rate compared to the control group (IRR = 0.26, 95% CI = 0.05, 0.98, p < 0.001).

CONCLUSION

This multi-team study demonstrated a novel multicomponent warm-up program resulted in less lower-extremity injuries, particularly ankle sprains and knee injuries, compared to a typical warm-up program in regional-level male and female basketball players.

Injury, Training, Biomechanical, and Physiological Profiles of Professional Breakdancers

Background

Breakdancing or breaking will enter the Olympics in 2024, however, there is a paucity of literature exploring the epidemiology, demands, and performance.

Purpose

The purpose of this study was to describe injury and training profiles, along with the results of a short performance test battery, in a group of elite breakers.

Study Design

Cross-sectional study (retrospective).

Methods

Fourteen breakdancers (breakers) (4 Bgirls, 10 Bboys) participated in an interview regarding their injury and training history, endurance test (cycle VO2max testing), counter movement jump, squat jump, drop jump, isometric hip abduction, adduction, shoulder external and internal rotation strength testing on a fixed-frame dynamometer. Breakers were divided into elite (n=10) and developing (n=4) based on their qualification for a world finals competition; Wilcoxen rank sums were used to compare the two groups, or in the case of strength testing between those with and without an injury history.

Results

The breakers had a median 11.0 [10.0 - 14.0] years breaking experience and trained 24.4 [20.5 - 30.0] hours per week. The knee was the most commonly injured body part and most frequently injured joint, with the thigh being the most common site for muscle injuries. There were no differences in endurance testing or jump height testing results between elite and developing breakers. There was no difference in shoulder external or internal rotation strength between athletes with a history of shoulder injury and those without. Similarly, there was no difference in hip abduction or adduction strength in those with a history of hip injury and those without.

Conclusion

The results of this study should be viewed with caution due to the small sample size. However, this study is the first to publish functional and physiological descriptives on breakers. The authors hope these results support clinicians treating breakers as well as encourages future research related to breaking.

Level of Evidence

2b.

Reference Values and Determinants of Spatiotemporal and Kinetic Variables in Recreational Runners

Background

Identifying atypical lower limb biomechanics may help prevent the occurrence or recurrence of running-related injuries. No reference values for spatiotemporal or kinetic variables in healthy recreational runners are available in the scientific literature to support clinical management.

Purpose

To (1) present speed- and sex-stratified reference values for spatiotemporal and kinetic variables in healthy adult recreational runners; (2) identify the determinants of these biomechanical variables; and (3) develop reference regression equations that can be used as a guide in a clinical context.

Study Design

Descriptive laboratory study.

Methods

This study involved 860 healthy recreational runners (age, 19-65 years [38.5% women]) tested on an instrumented treadmill at their preferred running speed in randomly allocated, standardized running shoes with either hard or soft cushioning. Twelve common spatiotemporal and kinetic variables-including contact time, flight time, duty factor, vertical oscillation, step cadence, step length, vertical impact peak (VIP), time to VIP, vertical average loading rate, vertical stiffness, peak vertical ground-reaction force (GRF), and peak braking force-were derived from GRF recordings. Reference values for each biomechanical variable were calculated using descriptive statistics and stratified by sex and running speed category (≤7, 8, 9, 10, 11, 12, 13, 14, and ≥15 km/h). Correlations and multiple regression analyses were performed to identify potential determinants independently associated with each biomechanical variable and generate reference equations.

Results

The mean running speed was 10.5 ± 1.3 km/h and 9 ± 1.1 km/h in men and women, respectively. While all potential predictors were significantly correlated with many of the 12 biomechanical variables, only running speed showed high correlations (r > 0.7). The adjusted R2 of the multiple regression equations ranged from 0.19 to 0.88.

Conclusion

This study provides reference values and equations that may guide clinicians and researchers in interpreting spatiotemporal and kinetic variables in recreational runners.

Clinical Relevance

The reference values can be used as targets for clinicians working with recreational runners in cases where there is a clinical suspicion of a causal relationship between atypical biomechanics and running-related injury.

Perceptions of Physical Therapy and The Role of Physical Therapists In Injury Prevention Among Professional Basketball Players: A Qualitative Study

Background

Injury prevention is critical in competitive professional sports, however, the role of physical therapists in this aspect of healthcare is not fully understood.

Purpose

The purpose of this study was to describe professional basketball players' perceptions of physical therapy (PT) and physical therapists' role in injury prevention.

Study Design

Qualitative, semi-structured interview.

Methods

Thirty-five professional basketball players (mean age 23.1 years ± 3.9; 42% female; 72% African American; 90% college graduates) from over 20 teams participated. Athletes participated in semi-structured interviews that focused on injury prevention and utilization of PT services. Two researchers coded the transcripts, organized the findings into general categories, and created major themes. Data saturation was reached when no new information emerged.

Results

Over half (62.9%) stated that PT mainly addressed post-injury and return-to-sport rehabilitation. An overwhelming majority of players highlighted the use of an athletic trainer (AT) over physical therapists in injury prevention due to perceived expertise and trust.

Conclusion

While PTs are educated in preventive care and acute injury management, professional basketball players viewed their role primarily for return-to-sport rehabilitation. The organizational structure of healthcare in professional basketball may promote closer professional relationships with ATs while limiting those with physical therapists. The result is that elite athletes may miss out on treatment specific to the PT profession.

Level of Evidence

Level 4.

Contemporary practices of physical trainers in professional soccer: A qualitative study

Introduction

Physical trainers (PTs) are integral for managing load, reducing injury and optimizing performance in professional soccer. However, little is known about how this practitioners operate in the applied setting and how some of the nuances experienced influence practice.

Methods

This study explored the contemporary practices of PTs in professional soccer. Semi-structured interviews were undertaken with eight PTs from different professional teams in European and South American leagues. Interview questions were designed to extract information on the evaluation of physical abilities, monitoring and control of training and injury prevention. Subsequently, the interviews were video-recorded, transcribed, translated and analyzed using a content analysis approach.

Results

The results suggest that the evaluation of physical capacities is carried out by PTs at the beginning of the preseason. It also appears that it is attempted that this process of regular testing is applied during the competitive period, with most participants conducting partial physiological and physical evaluations at different stages throughout the competitive season. In relation to the monitoring and control of training, subjective feedback scales are used to estimate the internal load, and the use of GPS devices is common to quantify external loads. Injury prevention programmes were implemented by all participants and were generally in a multi-component format focused on preventing or optimizing physical capabilities.

Discussion

These insights can be used as a scientific reference point to inform applied practice in professional soccer, especially for practitioners that are inexperienced and aspiring to enhance how they operate in the field. Future investigations should explore the practices of PTs in detail and across a wider network in order to gain deeper and comprehensive insights into the applied soccer environment.

Development of a Cutting Technique Modification Training Program and Evaluation of its Effects on Movement Quality and Cutting Performance in Male Adolescent American Football Players

This study developed a cutting technique modification training program and investigated its effects on cutting performance and movement quality in adolescent American football players. For six weeks, an intervention group (IG) of 11 players participated in 25 min cutting technique modification training sessions integrated into team training twice a week, while a control group (CG) of 11 players continued their usual team training. Movement quality was assessed by evaluating 2D high-speed videos, obtained during preplanned 45° and 90° cutting tests, using the Cutting Movement Assessment Score (CMAS) qualitative screening tool. Cutting performance was assessed based on change of direction deficit (CODD). Significant interaction effects of time × group were found for CMAS in 45° and 90° cuttings (p < 0.001, ηp2 = 0.76, p < 0.001, ηp2 = 0.64, respectively), with large improvements in the IG (p < 0.001, g = -2.16, p < 0.001, g = -1.78, respectively) and deteriorations in the CG for 45° cuttings (p = 0.002, g = 1.15). However, no statistically significant differences in CODD were observed pre-to-post intervention. The cutting technique modification training was effective at improving movement quality without impairing cutting performance, and it can be used by practitioners working with adolescent athletes.

Cycling-related cranio-spinal injuries admitted to a Major Trauma Centre in the cycling capital of the UK

BACKGROUND

The increased popularity of cycling is leading to an anticipated increase in cycling-related traffic accidents and a need to better understand the demographics and epidemiology of craniospinal injuries in this vulnerable road user group. This study aims to systematically investigate and characterise cycling-related head and spine injuries seen in the Major Trauma Centre for the Eastern region, which has the highest cycling rates in the UK.

METHODS

We performed a retrospective cohort study comparing the incidence, patterns, and severity of head and spine injuries in pedal cyclists presenting to the Major Trauma Centre in Cambridge between January 2012 and December 2020. Comparisons of injury patterns, characteristics, and associations were made according to mechanism of injury, helmet use, patient age and gender.

RESULTS

A total of 851 patients were admitted after being involved in cycling-related collisions over the study period, with 454 (53%) sustaining head or spine injuries. The majority of victims (80%) were male and in mid-adulthood (median age 46 years). Head injuries were more common than spine injuries, with the most common head injuries being intracranial bleeds (29%), followed by skull fractures (12%), and cerebral contusions (10%). The most common spine injuries were cervical segment fractures, particularly C6 (9%), C7 (9%), and C2 (8%). Motorised collisions had a higher prevalence of spine fractures at each segment (p < 0.001) and were associated with a higher proportion of multi-vertebral fractures (p < 0.001). These collisions were also associated with impaired consciousness at the scene and more severe systemic injuries, including a lower Glasgow coma scale (R = -0.23, p < 0.001), higher injury severity score (R = 0.24, p < 0.001), and longer length of stay (R = 0.21, p < 0.001). Helmet use data showed that lack of head protection was associated with more severe injuries and poorer outcomes.

CONCLUSION

As cycling rates continue to increase, healthcare providers may expect to see an increase in bicycle-related injuries in their practice. The insights gained from this study can inform the treatment of these injuries while highlighting the need for future initiatives aimed at increasing road safety and accident prevention.

Running-Related Overuse Injuries and Their Relationship with Run and Resistance Training Characteristics in Adult Recreational Runners: A Cross-Sectional Study

This study aimed to characterize running-related injuries (RRIs), explore their relationship with run and resistance training (RT) parameters, and identify perceived prevention measures among adult recreational runners. An anonymous online survey was designed and distributed via social media and email. Data were analyzed with chi-square, t-test, or analysis of variance (ANOVA), with significance accepted at p ≤ 0.05. Data from 616 participants (76.8% female, age: 42.3 ± 10.5 y) were analyzed. Most runners (84.4%) had an injury history, with 44.6% experiencing one in the past year. The most common RRI sites included the foot/ankle (30.9%) and knee (22.2%). RRI prevalence was higher in those running >19 miles weekly (48.4%, p = 0.05), but there were no differences based on RT participation status. Among those using RT, relatively more RRIs were observed in runners who trained the hip musculature (50.3%, p = 0.005) and did not include the upper body (61.6%, p < 0.001). A disproportionately high RRI prevalence was found for several of the other risk-reduction strategies. RRIs remain a substantial problem, particularly around the ankle/foot and knee. Higher run volume and performance motives were positively associated with RRIs. Most runners incorporated RRI risk-reduction techniques, with over half using RT. The current study did not determine whether preventative strategies were implemented before or after injury; therefore, prospective studies controlling for previous injuries are required to evaluate the effectiveness of RT in preventing future RRIs.

Monitoring Muscle Oxygen Asymmetry as a Strategy to Prevent Injuries in Footballers

Purpose: It has been hypothesized that sports injury risk is explained by muscle metabolism. The objective was to evaluate the muscle oxygen saturation slopes (ΔSmO2 slopes) and muscle oxygenation asymmetry (MO2Asy) at rest and to study their associations with injuries during the pre-season. Methods: A total of 16 male and 10 female footballers participated in this study. Injuries were diagnosed and classified by level of severity during the pre-season. The workload was also evaluated using the rate of perceived exertion × training time, from which the accumulated loads. The SmO2 was measured at rest in the gastrocnemius muscle using the arterial occlusion method in the dominant and non-dominant legs. The repeated measures ANOVA, relative risk, and binary logistic regression were applied to assess the probability of injury with SmO2 and workload. Results: Higher MO2Asy and ΔSmO2 Slope 2 were found among footballer who suffered high-severity injuries and those who presented no injuries. In addition, an MO2Asy greater than 15% and an increase in accumulated load were variables that explained a greater probability of injury. Conclusion: This study presents the new concept of muscle oxygenation asymmetry in sports science and its possible application in injury prevention through the measurement of SmO2 at rest.

Peak torque angle, acceleration time and time to peak torque as additional parameters extracted from isokinetic test in professional soccer players: a cross-sectional study

This study investigated additional and traditional variables from isokinetic test of thigh muscles in soccer players across different field positions. One hundred and eighty-nine athletes performed maximal concentric isokinetic knee contractions on dominant (DL) and non-dominant limb (NDL) at 60º/s and 240º/s. The additional outcomes peak torque angle (AngPT), acceleration time (AcT) and time to peak torque (TPT) and traditional outcomes Peak torque (PT), total work (TW) and power (Pw) were extracted from the exam. Goalkeepers (GK), side backs (SB), central backs (CB), central defender midfielders (CDM), central attacking midfielders (CAM) and forwards (FW) were considered. Comparisons between limbs and positions demonstrated that SB extensors of the DL presented TPT lower (p = 0.006) and AngPT higher (p = 0.011) than NDL at 60°/s. CDM extensors of the DL showed lower TPT at 60°/s (p = 0.003) and 240°/s (p = 0.024). CAM flexors of the DL showed lower TPT (p = 0.026) and AcT (p = 0.021) at 240°/s than NDL. CB, CDM and CAM extensors of the NDL showed higher PT, TW and Pw than DL (p < 0.05). In conclusion, there are muscle imbalances between limbs in SB, CDM and CAM and across different field positions.

Predicting Postoperative Injury and Military Discharge Status After Knee Surgery in the US Army

BACKGROUND

Researchers have assessed postoperative injury or disability predictors in the military setting but typically focused on 1 type of surgical procedure at a time, used relatively small sample sizes, or investigated mixed cohorts with civilian populations.

PURPOSE

To identify the relationship between baseline variables and injury incidence or military discharge status in US Army soldiers after knee surgery.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were obtained from a repository containing personnel, performance, and medical records for all active-duty US Army soldiers. Multivariate logistic regressions were used to estimate the effects of numerous variables on postoperative injury or on medical discharge. Variable selection and model validation were conducted using the k-fold method.

RESULTS

A total of 7567 soldiers underwent knee surgery between 2017 and 2019. Meniscal procedures were the most common type of surgery (39%), and approximately 71% of the cohort had a postoperative injury. Significant predictors for sustaining a postoperative injury included having a previous nonknee injury (odds ratio [OR], 1.5), female sex (OR, 1.3), and Black race (OR, 1.2). Within 4 years after surgery, 17% of soldiers were discharged from the military because of knee-related disability. Significant predictors for discharge from duty included enlisted rank (OR, 2.3), recent fitness test failure (OR, 1.9), number of previous knee surgeries (OR, 1.7), and having a previous nonknee injury (OR, 1.6).

CONCLUSION

After knee surgery, nearly three-fourths of the soldiers in this cohort sustained a postoperative injury and almost one-fifth of soldiers were medically discharged from the military within 4 years. This study identified variables that indicate statistically increased risk for these postoperative outcomes and highlighted potentially modifiable factors.

High Compliance with the 11+ Injury Prevention Program Results in Better Win-Loss Records

Background

The 11+ injury prevention program (IPP) has been shown to decrease injury rates. However, few studies have investigated compliance and its overall relationship to team performance.

Hypothesis/Purpose

To examine if level of compliance while implementing the 11+ would impact team performance outcomes (wins, losses and ties). The authors hypothesized that higher team compliance to the IPP would be consistent with improved overall team performance (more wins and fewer losses).

Study Design

Prospective, cluster randomized controlled trial.

Methods

This study was conducted in NCAA men's soccer teams for one season and examined the efficacy of the 11+ IPP. The outcome variables examined were levels of compliance and team performance record: wins, losses, and ties. Twenty-seven teams (n=675 players) served as the intervention group (IG) and used the 11+ program while 34 teams (n=850 players) served as the control group (CG). Compliance and team performance were recorded. There were three compliance categories that were defined prospectively, low (LC, < 1 dose/week), moderate (MC, >1 and <2 doses/week), and high (HC, >2 doses/week). Descriptive and inferential tests were used to compare the CG, the IG, and compliance to team performance. Three independent t-tests were used to analyze outcome to group (IG vs. CG). A one way-MANOVA test was used to analyze compliance to win/loss/tie record, followed up by one-way ANOVA tests to analyze how compliance impacted wins, losses and ties, independently. Partial η2 measures were calculated to determine the effect size of level of compliance on outcome. A Tukey post-hoc analysis was used to analyze specific differences between levels of compliance and specific outcome measures.

Results

There were significantly more wins (IG: 10.67±2.63 versus CG: 8.15±3.83, CI, 7.95 - 9.69, p = 0.005) and fewer losses (IG: 5.56±1.97 versus CG: 8.12±3.59, CI, 5.66 to 7.43, p = 0.002) recorded for the teams using the 11+ program. There was a statistically significant difference between levels of compliance (high, moderate or low) on the dependent variables (wins, losses, and ties), F(3, 22) = 3.780, p =0.004; Wilks' Λ = .435; partial η2 = .340.

Conclusion

The 11+ has the capacity to improve overall team performance in male collegiate soccer teams. The higher the compliance, the more favorable the team performance. This research may be a vital addition when attempting to persuade coaching staffs to adopt an IPP into their training regimen.

Level of Evidence

Level I.

Access to Firearms: Initiation of Firearm Screening Among Psychiatric Patients in a Pediatric Emergency Department

OBJECTIVE

Increase provider screening rates for firearm access among patients presenting to the pediatric emergency department (PED) for a psychiatric chief complaint.

METHODS

In this resident-driven quality improvement project, a retrospective chart review examined firearm access screening rates among patients presenting to the PED with the chief complaint of "psychiatric evaluation." After establishing our baseline screening rate, the first phase of our plan, do, study, act (PDSA) cycle included implementing Be SMART education for pediatric residents. We made Be SMART handouts available in the PED, created electronic medical record (EMR) templates to facilitate documentation, and emailed routine reminders to residents during their PED block. In the second PDSA cycle, the pediatric emergency medicine (PEM) fellows expanded our efforts to increase project awareness from a supervisory role.

RESULTS

The baseline screening rate was 14.7% (50 of 340). After PDSA 1, a center line shift occurred, and screening rates increased to 34.3% (297 of 867). After PDSA 2, screening rates increased to 35.7% (226 of 632). In the intervention phase, providers who received training screened 39.5% (238 of 603) of encounters versus providers who did not receive training screened 30.8% (276 of 896) of encounters. Of all encounters screened, 39.2% (205 of 523) screened positive for in-home firearms.

CONCLUSIONS

We improved firearm access screening rates in the PED using provider education, EMR prompts, and PEM fellow participation. Opportunities remain to promote firearm access screening and secure storage counseling in the PED.

Predicting Injury and Illness with Machine Learning in Elite Youth Soccer: A Comprehensive Monitoring Approach over 3 Months

The search for monitoring tools that provide early indication of injury and illness could contribute to better player protection. The aim of the present study was to i) determine the feasibility of and adherence to our monitoring approach, and ii) identify variables associated with up-coming illness and injury. We incorporated a comprehensive set of monitoring tools consisting of external load and physical fitness data, questionnaires, blood, neuromuscular-, hamstring, hip abductor and hip adductor performance tests performed over a three-month period in elite under-18 academy soccer players. Twenty-five players (age: 16.6 ± 0.9 years, height: 178 ± 7 cm, weight: 74 ± 7 kg, VO2max: 59 ± 4 ml/min/kg) took part in the study. In addition to evaluating adherence to the monitoring approach, data were analyzed using a linear support vector machine (SVM) to predict illness and injuries. The approach was feasible, with no injuries or dropouts due to the monitoring process. Questionnaire adherence was high at the beginning and decreased steadily towards the end of the study. An SVM resulted in the best classification results for three classification tasks, i.e., illness prediction, illness determination and injury prediction. For injury prediction, one of four injuries present in the test data set was detected, with 96.3% of all data points (i.e., injuries and non-injuries) correctly detected. For both illness prediction and determination, there was only one illness in the test data set that was detected by the linear SVM. However, the model showed low precision for injury and illness prediction with a considerable number of false-positives. The results demonstrate the feasibility of a holistic monitoring approach with the possibility of predicting illness and injury. Additional data points are needed to improve the prediction models. In practical application, this may lead to overcautious recommendations on when players should be protected from injury and illness.

Mental Fatigue Impairs Tackling Technique in Amateur Rugby Union Players

PURPOSE

To test the effects of mental fatigue (MF) on tackling technique on the dominant and nondominant shoulders in rugby union.

METHODS

Twenty male amateur rugby union players and a total of 953 tackles were analyzed. A randomized crossover counterbalanced design was used across a non-MF (control) and an MF condition. During each condition, each player performed 24 tackles, divided into 4 sets of 6 tackles (3 tackles on each shoulder). In the MF condition, players performed the Stroop Task between each set of tackles. A video recording of each tackle was used to evaluate each player's technical proficiency. A score of 1 point was awarded if a specific technique was performed correctly, and 0 point was given if not. The total score, measured in arbitrary units (AU) out of 11, represents the player's overall tackling proficiency.

RESULTS

Overall, players displayed a significantly lower technical proficiency score in the MF condition compared to control (set 2: control 7.30 [7.04-7.57] AU vs MF 6.91 [6.70-7.12] AU, P = .009, effect size (ES) = 0.30 small and set 3: control 7.34 [7.11-7.57] AU vs MF 6.88 [6.66-7.11] AU, P = .002, ES = 0.37 small). For the nondominant shoulder, players had a significantly lower technical proficiency score during the MF condition at set 2 (control 7.05 [6.68-7.41] AU vs MF 6.69 [6.42-6.96] AU, P = .047, ES = 0.29 small) and set 3 (control 7.14 [6.83-7.45] AU vs MF 6.61 [6.35-6.87] AU, P = .007, ES = 0.49 small).

CONCLUSIONS

MF can diminish a player's overall tackling proficiency, especially when tackling on the nondominant shoulder. The physiological mechanism for this finding may be impaired executive function and suboptimal functioning of neural signals and pathways, which result in less skillful coordination of movement. To further understand and explain MF-induced physiological changes in tackling, the feasibility of monitoring brain activity (such as electroencephalogram) and neuromuscular function (such as electromyogram) needs to be investigated. The findings from this study may also contribute to the development of more effective tackle training programs for injury prevention and performance.

Factors associated with booster seat use among Indigenous peoples in Canada

OBJECTIVE

Booster seat use among the general population remains relatively low, despite their effectiveness in preventing injury among children when involved in motor vehicle collisions. Given the prevention of injuries that booster seats provide, understanding the factors that hinder or facilitate the use of these seats is critical, particularly in communities that are often overlooked when conducting general population studies. To date, no studies have examined the prevalence and predictors of booster seat use among Indigenous peoples in Canada. The purpose of this study was to examine the use of booster seat use among Indigenous peoples across Canada and the factors that impact their use.

METHODS

Data were collected from a survey of participants from First Nations communities and organizations serving Indigenous peoples nationwide. Hypotheses arising from known predictors of booster seat use across the general population were tested using logistic regression models.

RESULTS

The strongest predictor of booster seat use, even when all other study factors were accounted for, was the reduction of barriers related to the use of booster seats, such as a child's resistance to being placed or staying in the passive safety restraint or a parent, guardian, or other caregiver being unwilling to use or unsure of how to install/setup the booster seat.

CONCLUSION

Most Indigenous participants consistently used booster seats to safely secure children being transported in vehicles. However, this compliance rate is well below that of the general population. Accessibility and affordability of child safety restraints and/or children's refusal to use booster seats, as well as having more than 1 child to secure, were identified as mitigating factors. Access to and the affordability of booster seats, coupled with clear and understandable information on how to use them, are critical components to compliance. Raising awareness among Indigenous peoples communities regarding the importance of using booster seats is imperative. To achieve this, Indigenous peoples must lead discussions to ensure that child safety strategies not only are based on research and best practices but are culturally connected and community driven. Through meaningful collaboration, vehicle-related injuries and mortality among Indigenous children can be significantly reduced.

Community Readiness Assessment of the "Take TIME for Your Child's Health" Intervention

Take TIME (Tobacco-free, Injury-free, Moving daily, Eating healthy) was an early intervention strategy targeting community readiness to support healthy lifestyles for young children in Uxbridge, Canada. This study aimed to assess the effectiveness of Take TIME using the Community Readiness Model adapted for childhood obesity prevention. Six interviews were completed in Uxbridge, before and after the intervention, with purposively selected community leaders in education, political, business, religious, not-for-profit, and healthcare fields. Each interview was rated independently by two scorers. Interview content was scored (scale from 1 to 9, with 1 being no awareness and 9 being a high level of community ownership) according to the Community Readiness Model criteria on six dimensions, with overall readiness calculated as the mean score of all dimensions. T-tests compared readiness by time-point and between communities. Overall community readiness significantly improved (p = 0.03) in Uxbridge from pre-intervention (3.63 ± 1.14 vague awareness) to post-intervention (5.21 ± 0.97 preparation). Seven interviews were also completed with leaders in the matched town of Rockwood, Canada which served as the control community. Rockwood readiness was close to the Uxbridge post-intervention score (5.35 ± 1.11). Results indicated increased awareness and leadership support post-intervention in Uxbridge, but further improvements in community knowledge, formalized efforts, and additional leadership support are desired. Take TIME increased community readiness to support healthy lifestyles for young children and may be useful to other communities at similar stages, given its theoretical alignment with the community readiness model. Future research should investigate the impact of Take TIME in demographically diverse communities and appropriate interventions to move communities from the preparation to the action stage.

Evaluating the effect of child home safety training upon three family support practitioner groups: a mixed-methods study

AIMS

Unintentional injuries in the home contribute substantially to preschool child morbidity and mortality. Practitioners such as health visitors, family mentors and children's centre staff are well-positioned to facilitate child injury prevention by providing home safety advice to families, and training may enhance their ability to do so. We aimed to assess the impact of child home safety training for these practitioners.

METHODS

An explanatory mixed-methods design was used. Practitioners completed questionnaires before, and up to 7 months after, receiving child home safety training and took part in interviews. Seventy-eight health visitors, 72 family mentors and 11 children's centre staff members completed questionnaires. Items were used to calculate scores on home safety knowledge, confidence to provide home safety advice and belief that child home safety promotion is important. Thematic analysis of interviews with seven health visitors and nine family mentors, open-ended responses to the questionnaires and an additional evaluation form was conducted to explore attendees' perceptions of the training and its impact. In addition, seven health visitors and six children's centre staff who had received no training were interviewed.

RESULTS

Knowledge was greater post-training than pre-training across all participants (p < .001). When practitioner groups were analysed separately, there were significant increases in family mentors' knowledge (p < .001) and belief (p = .016), and health visitors' confidence (p = .0036). Qualitative findings indicated that most training session attendees valued the training, believed their practice relating to child home safety had improved as a result, and felt further similar training sessions would be beneficial. Those who had not attended the sessions described a need for more child home safety training.

CONCLUSIONS

Delivering training to practitioners providing child home safety promotion to families with preschool children can enhance injury prevention knowledge, beliefs and confidence and positively impact on home safety promotion by practitioners.

Lessons Learned From Integrating Anti-Oppression Pedagogy in a Graduate-Level Course in Epidemiology

Despite the high burden of injury and violence globally and disproportionate burden on marginalized communities, few US schools of public health and departments of epidemiology offer classes focused on injury and violence, and even fewer are taught with an antiracist or anti-oppression framework. Recent years have brought renewed focus to incorporating antiracist and anti-oppression principles to pedagogy. Public health professionals have increasingly grappled with how we teach, conduct research, and advocate for just policies, which are shaped by interlocking systems of oppression. Although all areas of epidemiology are shaped by these structures, motivations for those who study injury and violence ought to be especially keen. In this commentary, we illustrate how anti-oppression can be integrated into course development and delivery with a case study of a graduate-level course at the University of Washington School of Public Health on injury and violence epidemiology. We include feedback from an epidemiology faculty reviewer, as well as narratives from students describing what worked and what did not. We offer our reflections and lessons learned, hoping to encourage others within public health and epidemiology to adopt an anti-oppression framework in developing classes and programs, particularly those related to injury and violence.

Effect of the 2018 NCAA Kickoff Rule Change on Concussion Rates in Collegiate Football: Results From a Division 1 Conference

Background

Kickoff plays in American football are associated with an increased risk of concussion compared with other play types. In 2018, the National Collegiate Athletic Association (NCAA) Football Rules Committee altered the kickoff rules so a fair catch inside the 25-yard line results in a touchback, with the ensuing drive starting on the 25-yard line. The intention was to decrease the number of kickoff returns with a corresponding decrease in the rate of concussions on kickoff plays.

Purpose

To determine whether the 2018 rule changes had the intended effects in an NCAA Division 1 Conference.

Study Design

Cohort study; Level of evidence, 3.

Methods

The study population included football athletes in the NCAA Pacific-12 (Pac-12) Conference. Data on the total number of plays, punts, kickoffs, touchbacks, and fair catches were obtained for all in-conference games from the 2016 to 2021 seasons. The number of game concussions and the play type were provided by each conference institution. Incidence of concussions occurring during kickoff plays before (2016-2017) and after (2018-2021) the rule change were compared with a difference-in-difference analysis using Poisson general linear models.

Results

There were 242 concussions in 108,774 total plays in the study period, with an overall concussion rate of 2.2 per 1000 plays. The percentage of touchbacks increased significantly from 45% to 51% (P < .001) and the percentage of fair catches increased from 1% to 7% (P < .001) from before to after the rule change. Kickoffs accounted for 6% of plays both before and after the rule change and 11% of concussions before and 14% after the change. The mean annual concussion rate (per 1000 plays) on kickoffs was 3.42 before and 5.31 after the rule change (rate difference: 1.89; 95% confidence interval, -1.22 to 5.01).

Conclusion

Touchbacks and fair catches increased after the kickoff rule change, but there was not a corresponding decrease in concussions during kickoff plays as anticipated. Concussions occurring during other football plays remained stable.

Two-Dimensional and Three-Dimensional Biomechanical Factors During 90° Change of Direction are Associated to Non-Contact ACL injury in Female Soccer Players

Background

The two-dimensional (2D) video-analysis of the change of direction (COD) technique has never been used to attempt to predict the risk of ACL injury in female football players.

Hypothesis/Purpose

The purpose of the present pilot study was to prospectively investigate the biomechanical predictors of ACL injury during a COD task in female football players using both gold standard 3D motion capture and a qualitative scoring system based on 2D video-analysis.

Study Design

Prospective cohort study.

Methods

Sixteen competitive female football (soccer) players (age 21.4 ± 4.3) performed a series of pre-planned 90° COD tasks. 3D motion data was recorded through 10 stereophotogrammetric cameras and a force platform. 2D frontal and transverse plane joint kinematics were computed through video-analysis from three high-speed cameras. A scoring system based on five criteria was adopted: limb stability, pelvis stability, trunk stability, shock absorption, and movement strategy. The players were prospectively followed for the next two consecutive football seasons and the occurrence of severe knee injuries was registered.

Results

Four players (25%) experienced an ACL injury. In 3D analysis, ACL-injured players showed greater knee valgus, knee internal rotation, and lower knee flexion (p= 0.017 - 0.029). Lower hip flexion coupled with greater external rotation (p= 0.003 - 0.042), ankle eversion, and contralateral pelvic drop (p<0.001) were also noted. In 2D analysis, ACL-injured players showed greater internal foot rotation, contralateral pelvic drop, lower knee flexion, and contralateral trunk tilt (moderate-to-large effect size). Pelvis stability and trunk stability showed the highest predictive value towards ACL injury. Total score was significantly lower in ACL-injured players with a moderate effect size (d=0.45).

Conclusions

Both 3D and 2D methodologies depicted biomechanical risk factors and offered predictive insights towards the ACL injury risk. Awareness should rise in women's football regarding the high risk of ACL injury and the strategies to assess and mitigate it.

Level of Evidence

3©The Author(s).

Recreational windsurfing-related acute injuries: a narrative review. Part 2: injury prevention and a proposal for a set of potential prevention strategies with a holistic approach

Objective

The purpose of this review was to identify existing prevention strategies for recreational windsurfing-related acute injuries and provide clinicians with a practical overview of current evidence supporting proposed potential prevention strategies.

Methods

A literature search was conducted through March 8, 2023, using relevant keywords with Boolean operators, such as "windsurfing" AND "injury prevention" and "windsurfing" AND "exercise interventions," from the PubMed and Google Scholar databases. Only peer-reviewed English-articles were included.

Results

Existing prevention strategies, right-of-way rules, a new proposed set of eight potential primary to tertiary prevention strategies for windsurfing-related acute injuries, and proposed definitions of injury prevention levels equivalent to Haddon's matrix were identified and tabled.

Conclusions

The proposed potential prevention strategies may facilitate clinicians in preventing recreational windsurfing-related acute injuries. Injury prevention for recreational windsurfing is under-researched. Future studies should focus on large prospective clinical trials evaluating the efficacy of prevention strategies for recreational windsurfing-related injuries.

The Validity and Reliability of a Smartphone Application for Break-Point Angle Measurement during Nordic Hamstring Exercise

Background

A recently developed smartphone application (Nordic Angle) allows the automatic calculation of the break-point angle (BPA) during Nordic hamstring exercise (NHE) without transferring the collected data to a computer. The BPA is the point at which the hamstrings are unable to withstand force. However, the validity of the BPA values obtained by this method has not been examined.

Hypothesis/Purpose

This study aimed to evaluate the validity and reliability of the Nordic Angle by comparing the BPA values of the Nordic Angle with those of two-dimensional motion analysis software that can calculate the angles and angular velocities of various joints.

Study Design

Cohort assessing Validity and Reliability.

Methods

The validity of the Nordic Angle BPA data was verified by Spearman's correlation test for consistency with the movement analysis data, and the magnitude of the correlation was indicated by rs. The agreement between these measurements was examined using the Bland-Altman analysis. The reliability of the Nordic Angle and motion analysis was examined using the intraclass correlation coefficient (ICC) (1,k) based on data from repeated trials within a day.

Results

Although the spearman correlation between the Nordic angle and the angle determined using motion analysis did not reach statistical significance (p = 0.052), a very large correlation was present (rs = 0.75). The difference between the mean values of the Nordic Angle and motion analysis was 0.4 ± 2.1°, and the limits of agreement ranged from -3.9° to 4.6°. In two BPA measurements, the Nordic Angle showed perfect reliability (ICC = 1.00, p < 0.001), while motion analysis showed nearly perfect reliability (ICC = 0.97, p < 0.001).

Conclusion

The Nordic Angle, which has both validity and reliability, may be appropriate for field measurement because it allows immediate feedback of BPA and the measurement of many athletes.

Level of evidence

3b©The Author(s).

Blood alcohol concentration as a measure of risk among pedestrian fatalities in the U.S., 2016-2020

OBJECTIVE

In the United States, deaths among pedestrians have increased dramatically since 2009 relative to other vulnerable road users, with substance use described as an important risk factor. This study aimed to explore blood alcohol concentrations (BAC g/dL) among pedestrian fatalities in the United States between 2016 and 2020. Exploring the presence of alcohol among pedestrian cases will support targeted interventions designed to reduce risk.

METHODS

This study utilized pedestrian fatality and alcohol screening data provided by the Fatality Analysis Reporting System (FARS). Logistic models were examined to identify statistical associations (ORs, 95% CI) by age, race, and sex relative to positive BAC exposure (BAC > 0.0 g/dL), mild exposure (BAC > 0.0 < .079 g/dL), moderate to severe alcohol exposure (BAC 0.08-.299 g/dL), and severe exposure (BAC ≥ 0.30 g/dL).

RESULTS

Between 2016 and 2020, 33,375 pedestrian fatalities were reported to FARS with 75.1% of cases retained for analysis (n = 25,077). Fatalities were more likely to be White (69.3%), male (69.9%), and between 25-64 years of age (67.3%). 74.0% of fatalities were tested for alcohol, with 40.9% screening positive. Females, cases ≥ 75 years of age, and those identified as Asians reported the lowest odds of being positive for alcohol exposure.

CONCLUSIONS

Results suggest an ongoing threat to pedestrians due to alcohol consumption and that exposure odds vary by demographic characteristics. Unfortunately, analytical approaches to understanding the roles played by drugs and alcohol among vulnerable road users tend to be marginalized in the literature. Analytical, evidence-based investigations are needed to curtail the risk of pedestrian fatalities in the U.S.

Community Fire Risk Reduction: Longitudinal Assessment for HomeSafe Fire Prevention Program in Canada

(1) Background: Residential fires represent the third leading cause of unintentional injuries globally. This study aims to offer an overview and a longitudinal evaluation of the HomeSafe program implemented in Surrey in 2008 and to assess its effectiveness in mitigating fire-related outcomes. (2) Methods: Data were collected over a 12-year period (2008-2019). Assessed outcomes comprised frequency of fire incidents, residential fires, casualties, functioning smoke alarms, and contained fires. The effectiveness of each initiative was determined by comparing the specific intervention group outcome and the city-wide outcome to the pre-intervention period. (3) Results: This study targeted 120,349 households. HomeSafe achieved overwhelming success in decreasing fire rates (-80%), increasing functioning smoke alarms (+60%), increasing the percentage of contained fires (+94%), and decreasing fire casualties (-40%). The study findings confirm that the three most effective HomeSafe initiatives were firefighters' visits of households, inspections and installations of smoke alarms, and verifications of fire crew alarms at fire incidents. Some initiatives were less successful, including post-door hangers (+12%) and package distribution (+15%). (4) Conclusions: The HomeSafe program effectively decreased the occurrence and magnitude of residential fires. Lessons learned should be transferred to similar contexts to implement an evidence-based, consistent, and systematic approach to sustainable fire prevention initiatives.

Speed Matters in Nordic Hamstring Exercise: Higher Peak Knee Flexor Force during Fast Stretch-Shortening Variant Compared to Standard Slow Eccentric Execution in Elite Athletes

Hamstring strain injuries are prevalent in many sports. Research has demonstrated that the Nordic hamstring exercise (NHE), a knee-dominant exercise addressing the posterior chain muscles, can aid in reducing the risk of hamstring injuries in athletes. However, most research on hamstring injury prevention has focused on performing the eccentric version of the NHE (NHE_ECC). In contrast, in sports, it is quite frequent for athletes to use an eccentric-concentric version of the NHE. Additionally, eccentric NHE is typically performed using a slow, controlled tempo. The effect of a fast stretch-shortening cycle NHE (NHE_SSC) compared to standard slow NHE_ECC on peak knee flexor force has not been investigated. The aim of the study was therefore to investigate fast NHE_SSC vs. standard slow NHE_ECC. Our hypothesis posited that peak knee flexor force would be greater for fast NHE_SSC compared with standard slow NHE_ECC. The study involved 22 elite athletes (actively competing in both national and international events) consisting of female (n = 10) and male (n = 7) track and field athletes and male football players (n = 5), aged 17-31 years. The participants performed maximum trials of slow NHE_ECC and fast NHE_SSC repetitions in which measurement of bilateral peak knee flexor force was conducted at the ankle with the use of a load cell. During the NHEs, a linear encoder was used to measure both the position where the peak knee flexor force was recorded and the average eccentric velocity. SSC contributed to an enhanced NHE performance, where bilateral absolute peak knee flexor force was 13% higher for fast NHE_SSC vs. standard slow NHE_ECC (822 vs. 726 N, p < 0.01, ES = 0.54). Participants achieved a 32% greater forward distance at the breakpoint stage during NHE_ECC compared to the coupling phase for NHE_SSC (54 vs. 41 cm, p < 0.001, ES = 1.37). Eccentric average velocity was more than three times higher for NHE_SSC compared with NHE_ECC (0.38 vs. 0.12 m/s, p < 0.001, ES = 3.25). The key findings of this study were that SSC contributed to an enhanced NHE performance, where absolute peak knee flexor force was 13% greater for fast NHE_SSC compared to standard slow NHE_ECC. The fast NHE_SSC could therefore be an interesting alternative to the standard slow NHE_ECC execution, as it may offer potential advantages for sprint performance, as well as hamstring injury prevention and rehabilitation.

Factors Associated With Awareness, Adoption, and Implementation of Anterior Cruciate Ligament Injury Prevention in Youth Sports

BACKGROUND

Anterior cruciate ligament (ACL) injuries are among the most common injuries in adolescent athletes and result in significant financial and physical morbidity. Evidence-based programs designed to prevent ACL injury are effective. However, their adoption remains low. We sought to evaluate the awareness, evidence-based implementation, and barriers to implementation of ACL injury prevention programs (ACL-IPP) among youth athletic coaches.

HYPOTHESIS

Higher education level of the coach, higher level of training, number of teams coached, and coaching female teams would be associated with ACL-IPP implementation.

STUDY DESIGN

Cross-sectional survey.

LEVEL OF EVIDENCE

Level 4.

METHODS

We conducted an email survey sent to all 63 school districts within Section VI of the New York State Public High School Athletic Association. We employed descriptive statistics and tests of correlation to identify factors associated with ACL-IPP implementation.

RESULTS

A total of 73% of coaches said they were aware of ACL-IPP, and only 12% of coaches implemented ACL-IPP according to best evidence. Coaches of higher competitive levels were more likely to adopt ACL-IPP (P = 0.01), more likely to use them multiple times per week (P = 0.03), and for ≥1 seasons (P = 0.02). Coaches of multiple teams were more likely to adopt ACL-IPP (P = 0.01). There were no differences in evidence-based implementation of ACL-IPP with gender coached or level of education of the coach.

CONCLUSION

Overall awareness, adoption, and evidence-based implementation of ACL-IPP remain low. These results suggest that coaches at higher levels of play and multiple teams tend to use ACL-IPP more often. Gender coached and level of education do not appear to be associated with awareness or implementation.

CLINICAL RELEVANCE

Evidence-based ACL-IPP implementation remains low. Targeting coaches of younger athletes and fewer teams with local outreach programs and ACL-IPP may increase the implementation of ACL-IPP.

Provision of Concussion Information From Coaches and the Presence of Athletic Trainers: Findings From the 2021 YouthStyles Survey

Coaches play an important role in concussion safety, and their views on concussion influence those of their athletes and the athletes' reporting behaviors. In this 2021 survey of youth, we examined how often coaches provide concussion safety information to their athletes and the association between coaches' provision of concussion information to athletes and the presence of athletic trainers (ATs) at a team's games and practices. More than 4 in 10 youth who played sports reported that their coaches did not provide any sort of concussion education or information to them in the past 12 months. Among those youth who always or sometimes had ATs at practices or games, 76.3% received some type of coach education on concussion in the past 12 months, compared with 31.9% of those who rarely or never had ATs at practices or games (P < .0001). Increasing access to ATs and adapting current concussion training and educational materials for coaches to increase coach-athlete communication may be beneficial.

Description, Prediction, and Causation in Sport and Exercise Medicine Research: Resolving the Confusion to Improve Research Quality and Patient Outcomes

SYNOPSIS: Researchers often assign a label (such as a risk factor or predictor) to a characteristic that is statistically associated with an outcome (such as future injury). Labeling signifies that the characteristic has an established clinical value. More often than not, these labels are assigned prematurely and haphazardly. The rampant practice conflates research goals, the ultimate clinical value of the findings, and many risk factors/predictors that may not warrant the label. To address these issues and improve injury prevention research, we (1) outline the problem; (2) clarify the key differences between the research goals of description, causation, and prediction/prognosis (along with labeling conventions); (3) differentiate the clinical implications for each label; and (4) frame an appropriate scientific process to follow before applying a label. J Orthop Sports Phys Ther 2023;53(7):1-7. Epub: 26 April 2023. doi:10.2519/jospt.2023.11773.

Individual Variation in Adaptive Ability of the Anticipated Postural Stability During a Dual-Task Single-Leg Landing in Female Athletes

Background

Precise postural control helps prevent anterior cruciate ligament injury. However, it is unknown whether the anticipated postural stability can be improved during a physically uncertain and cognitively demanding task.

Hypothesis

Anticipated postural stability will improve through unanticipated single-leg landing with a rapid foot placement target tracking.

Study Design

Controlled laboratory study.

Methods

A total of 22 healthy female university-level athletes performed a novel dual-task paradigm: an unanticipated single-leg landing with foot placement target tracking. In the normal condition (60 trials), the participants jumped from a 20 cm-high box onto the landing target with their dominant leg as softly as possible. In the subsequent perturbation condition (PC) (60 trials), the initially assigned landing target was abruptly switched randomly, requiring participants to modify their preplanned foot placement position to the newly assigned position. The center-of-pressure trajectory length within the first 100 ms after foot impact (CoP₁₀₀) was calculated as a measure of anticipated postural stability for each trial. In addition, the peak vertical ground-reaction force (Fz_Peak) was quantified to assess landing load, and the degree of postural adaptation during PC was quantified by fitting an exponential function to trial-by-trial changes in CoP₁₀₀. Participants were divided into 2 groups according to increase or decrease in CoP₁₀₀, and results were compared between the groups.

Results

The direction and magnitude of postural sway alterations of the 22 participants showed a spectrum-like variation during the repeated trials. Twelve participants (sway-decreased group) exhibited a gradual reduction in postural sway (CoP₁₀₀) during the PC, while the remaining 10 participants (sway-increased group) showed a gradual increase in CoP₁₀₀. The Fz_Peak during the PC was significantly less in the sway-decreased group compared with the sway-increased group (P < .05).

Conclusion

Variation in the direction and magnitude of postural sway alteration among participants suggested that there was individual variation in an athlete's adaptive ability of the anticipated postural stability.

Clinical Relevance

The novel dual-task paradigm described in this study may be useful for rating individual injury risk based on an athlete's postural adaptation ability and may aid in targeted prevention strategies.

Quantifying head impact exposure, mechanisms and kinematics using instrumented mouthguards in female high school lacrosse

Current debate exists regarding the need for protective headwear in female lacrosse. To inform this issue, the current study quantified head impact exposure, mechanisms and kinematics in female lacrosse using instrumented mouthguards. A female high school varsity lacrosse team of 17 players wore the Stanford Instrumented Mouthguard (MiG) during 14 competitive games. Video footage was reviewed to remove false-positive recordings and verify head impacts, which resulted in a rate of 0.32 head impacts per athlete-exposure. Of the 31 video-confirmed head impacts, 54.8% were identified as stick contacts, 38.7% were player contacts and 6.5% were falls. Stick contacts had the greatest peak head kinematics. The most common impact site was the side of the head (35.5%), followed by the face/jaw (25.8%), forehead (6.5%), and crown (6.5%). Impacts to the face/jaw region of the head had significantly (p < 0.05) greater peak kinematics compared to other regions of the head, which may have resulted from the interaction of the impacting surface, or the lower jaw, and the sensor. The current study provides initial data regarding the frequency, magnitude and site of impacts sustained in female high school lacrosse. A larger sample size of high quality head impact data in female lacrosse is required to confirm these findings.

Irish Dancing Injuries and Associated Risk Factors: A Systematic Review

Irish dance is growing in popularity, evolving to a more athletic and demanding dance style. The aim of this study is to conduct a systematic review, previously registered with PROSPERO, to identify the prevalence, incidence, and the injury pattern among Irish dancers and analyse the associated risk factors. Six online databases and two dance-specific science publications were searched systematically. Studies were included if the patterns of injuries among Irish dancers were evaluated or the factors associated with injury were analysed, published in English or Portuguese, in peer-reviewed scientific journals. Four reviewers assessed the quality and level of evidence using the Downs and Black criteria and a modified Oxford Centre of Evidence-Based Medicine 2009 model, respectively. Eleven articles were included, eight of Level 3c (cross-sectional) and three of Level 3b (prospective). Mean DB percentage score was 63% ± 7.2%. Prevalence ranged from 72.2% to 92.6%, affecting mostly the foot/ankle complex. Only two articles reported incidence, which ranged from 3.4 to 10.6 injuries/1000 h danced depending on injury definition. Psychological factors, elite level, and insufficient/poor sleep were associated with musculoskeletal injury. Injury prevalence and incidence is high in Irish dancers, with the foot and ankle being more affected. Due to heterogeneity in injury definitions, methods, and populations, along with the need for improvement in studies quality, recommendations were made for future research.

Proof of Concept Testing of Safe Patient Handling Intervention Using Wearable Sensor Technology

BACKGROUND

Healthcare workers make up one of the occupations in the United States that experience the most musculoskeletal injuries. These injuries are often related to the movement and repositioning of patients. Despite previous injury prevention attempts, injury rates remain at an unsustainable level. The purpose of this proof-of-concept study is to provide preliminary testing of the impact of a lifting intervention on common biomechanical risk factors for injury during high-risk patient movements.; Methods: A before-and-after (quasi-experimental) design was utilized to compare biomechanical risk factors before and after a lifting intervention. Kinematic data were collected using the Xsens motion capture system, while muscle activations were collected with the Delsys Trigno EMG system.

RESULTS

Improvements were noted in the lever arm distance, trunk velocity, and muscle activations during the movements following the intervention; Conclusions: The contextual lifting intervention shows a positive impact on the biomechanical risk factors for musculoskeletal injury among healthcare workers without increasing the biomechanical risk. A larger, prospective study is needed to determine the intervention's ability to reduce injuries among healthcare workers.

In-Game Workload Demands of Position Players in Major League Baseball

BACKGROUND

Athletes who are well prepared for the physical demands of competition are less susceptible to injury. Defining and then preparing athletes for these in-game demands is critical to athlete health and performance. The injury burden within Major League Baseball (MLB) is significant and differs by position. Despite its importance, the workload demands have not been described for position players in MLB.

HYPOTHESIS

That running demands would be significantly higher for outfielders, followed by infielders, and catchers, respectively, while batting and baserunning metrics would be similar across positions.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Total and high-speed running distance (>75% Vmax), high-speed running count, hard accelerations (>2.78 m/s/s), defensive and baserunning minutes, total and hard throws (>75% max), and bat swing counts were calculated from Statcast data. Players with 100 games or more in the 2018 season (n = 126) were included for analysis.

RESULTS

All offensive and baserunning metrics were similar across positions; however, significant positional differences were observed for defensive and overall workload metrics. High-speed running was highest among outfielders (F_1,7 = 27.1, P < 0.01), followed by infielders, then catchers. Hard accelerations (F_1,7 = 12.9, P < 0.01) were highest among first basemen, then outfielders, remaining infielders, and catchers. Total throws (F_1,7 = 17.7, P < 0.01) were highest among middle infielders. Hard throws (P < 0.01) were highest among shortstops and third basemen.

CONCLUSION

In-game workloads differ significantly by defensive position in MLB. These differences in running, throwing, and hitting volumes have significant implications for physical preparation and injury return-to-play progressions to optimize performance and minimize injury and reinjury risk for these athletes.

CLINICAL RELEVANCE

These data provide insight into how best to prepare athletes of different positions for the demands of the game both in terms of preseason preparation as well as return-to-play benchmarks following injury. These data should also serve as a platform for future research into the relationship between workload and injury among professional baseball players.

Participatory Action Design and Engineering of Powered Personal Transfer System for Wheelchair Users: Initial Design and Assessment

Caregivers that assist with wheelchair transfers are susceptible to back pain and occupational injuries. The study describes a prototype of the powered personal transfer system (PPTS) consisting of a novel powered hospital bed and a customized Medicare Group 2 electric powered wheelchair (EPW) working together to provide a no-lift solution for transfers. The study follows a participatory action design and engineering (PADE) process and describes the design, kinematics, and control system of the PPTS and end-users' perception to provide qualitative guidance and feedback about the PPTS. Thirty-six participants (wheelchair users (n = 18) and caregivers (n = 18)) included in the focus groups reported an overall positive impression of the system. Caregivers reported that the PPTS would reduce the risk of injuries and make transfers easier. Feedback revealed limitations and unmet needs of mobility device users, including a lack of power seat functions in the Group-2 wheelchair, a need for no-caregiver assistance/capability for independent transfers, and a need for a more ergonomic touchscreen. These limitations may be mitigated with design modifications in future prototypes. The PPTS is a promising robotic transfer system that may aid in the higher independence of powered wheelchair users and provide a safer solution for transfers.

Virtual Risk Management-Exploring Effects of Childhood Risk Experiences through Innovative Methods (ViRMa) for Primary School Children in Norway: Study Protocol for the ViRMa Project

BACKGROUND

Research indicates that risky play benefits children's risk assessment and risk management skills and offers several positive health effects such as resilience, social skills, physical activity, well-being, and involvement. There are also indications that the lack of risky play and autonomy increases the likelihood of anxiety. Despite its well-documented importance, and the willingness of children to engage in risky play, this type of play is increasingly restricted. Assessing long-term effects of risky play has been problematic because of ethical issues with conducting studies designed to allow or encourage children to take physical risks with the potential of injury.

OBJECTIVE

The Virtual Risk Management project aims to examine children's development of risk management skills through risky play. To accomplish this, the project aims to use and validate newly developed and ethically appropriate data collection tools such as virtual reality, eye tracking, and motion capturing, and to provide insight into how children assess and handle risk situations and how children's past risky play experiences are associated with their risk management.

METHODS

We will recruit 500 children aged 7-10 years and their parents from primary schools in Norway. Children's risk management will be measured through data concerning their risk assessment, risk willingness, and risk handling when completing a number of tasks in 3 categories of virtual reality scenarios: street crossing, river crossing, and playing on playground equipment. The children will move around physically in a large space while conducting the tasks and wear 17 motion-capturing sensors that will measure their movements to analyze motor skills. We will also collect data on children's perceived motor competence and their sensation-seeking personality. To obtain data on children's risk experiences, parents will complete questionnaires on their parental style and risk tolerance, as well as information about the child's practical risk experience.

RESULTS

Four schools have been recruited to participate in data collection. The recruitment of children and parents for this study started in December 2022, and as of April 2023, a total of 433 parents have consented for their children to participate.

CONCLUSIONS

The Virtual Risk Management project will increase our understanding of how children's characteristics, upbringing, and previous experiences influence their learning and ability to handle challenges. Through development and use of cutting-edge technology and previously developed measures to describe aspects of the children's past experiences, this project addresses crucial topics related to children's health and development. Such knowledge may guide pedagogical questions and the development of educational, injury prevention, and other health-related interventions, and reveal essential areas for focus in future studies. It may also impact how risk is addressed in crucial societal institutions such as the family, early childhood education, and schools.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/45857.

Low Stiffness Dance Flooring Increases Peak Ankle Plantar Flexor Muscle Activation During a Ballet Jump

INTRODUCTION

Research in court sports shows that factors which aid in extrinsic shock absorption, that is, flooring and footwear, can help reduce lower extremity injuries. However, since students and performers of ballet or most styles of contemporary dance cannot depend upon footwear, the only extrinsic factor to help them with shock absorption is flooring.

METHODS

We investigated whether doing sauté on a low stiffness dance floor produced a difference in EMG output of the vastus lateralis, gastrocnemius, of soleus compared to a high stiffness floor. Average and average peak amplitude EMG output from 18 dance students or active dancers performing 8 repetitions of sauté on a low stiffness floor (Harlequin® Woodspring) was compared to a maple hardwood floor on concreted subflooring.

RESULTS

The data showed a significant increase in average peak EMG muscle amplitude during jumping on the low stiffness floor compared to a high stiffness floor for the soleus muscle (P = .033) and a trend for increase average peak output for the medial gastrocnemius (P = .088).

CONCLUSION

The difference in average peak amplitude of EMG output is explained through the difference in force absorption between floors. With the high stiffness floor, more force of the landing was returned to the dancers' legs, but the low stiffness floor absorbed some of the force of landing the jump, and therefore muscles needed to contribute more to maintain the same jump height. The force absorption characteristic of the low stiffness floor may decrease injury rates in dance through causing an adjustment in muscle velocity. Rapid eccentric muscle activity carries the greatest possibility of musculotendinous injury and is experienced in lower body muscles controlling all joints during impact absorption, which includes landing of jumps in dance. If a surface can decelerate the landing of a high velocity dance movement, it also decreases the musculotendinous demand for high velocity tension generation.

Evaluation of the Back-in-Action test Battery In Uninjured High School American Football Players

Background

Return to sport testing is an established routine, especially for athletes who have ruptured their anterior cruciate ligament (ACL). Various tests are performed, often combined in test batteries, such as the Back-in-action (BIA) test battery. Unfortunately, pre-injury performance is often unknown, and only few athletes pass the high demands of these test batteries.

Purpose

The aim of the study was to determine the performance of under 18 American football players on the BIA to establish pre-injury sport specific benchmarks for future RTS testing and to compare these values to data from an age-matched reference group.

Methods

Fifty-three healthy male American football players underwent a functional assessment using the "Back-in-action" test battery evaluating agility, speed (Parkour-Jumps and Quick-Feet test), balance (using a PC based balance board), and power (Counter-Movement-Jump [CMJ]) as objective measures. Their results were compared with a previously tested reference group (RP) and within the american football players (AF) through three subgroups according to field playing position.

Results

Overall, the American football (AF) athletes showed lower balance scores for both legs (AF: 3.71/3.57/3.61; RP: 3.4/3.2/3.2; p<0.002) compared to the reference population (RP). CMJ height and Quick-Feet results were not statistically different (p>0.05), Parkour-Jump times (AF: 8.18/ 8.13 sec.; RP: 5.9/5.9sec.; p<0.001) were significantly slower. Power output in all CMJ's (AF: 46.86/36.94/37.36 W/kg; RP: 43.2/29.5/29 W/kg; p<0.001) was significantly higher than the RP. Passing and running game involved players (G2 & G3) showed significantly better balance scores (G2+G3: 3.36/3.27/3.33; G1: 4.22/4.06/4.10; p<0.001), higher jump height (G2&G3: 38.87/24.02/24.96 cm; G1: 32.03/19.50/18.96 cm; p<0.001) and more watts/kg (G2&G3: 48.83/37.21/37.64 W/kg; G1: 43.95/36.88/36.53 W/kg; p<0.001) compared to blocking players like Linemen (G1) and to the age matched reference population (RP).

Conclusion

Only 53% of the healthy athletes would have been cleared for sport using the BIA test criteria, which highlights the challenging passing criteria. Despite significantly greater power measurements, scores of balance and agility were poorer compared to the reference group, especially for linemen. These data may serve as sport and position specific reference for high school American football players, instead of using the non-specific reference group data.

Study design

cross-sectional study.

Level of evidence

IIb.

A Helmet of Her Own?: A Qualitative Study of Key Stakeholder Perspectives on Headgear in Girls' Lacrosse

Introduction

Despite the high incidence rate of concussions in women's lacrosse, there is substantial push back against the use of helmets at the secondary educational and collegiate levels in the U.S. This study examines the social factors influencing the controversy surrounding the use of protective headgear and how the recent development of headgear specific to the women's game has shaped ongoing debates.

Methods

Purposeful sampling was used to recruit interviewees with research knowledge or firsthand experience with injury and protective headgear in girls' lacrosse. Semistructured interviews were conducted and subsequently coded using qualitative research software to identify key themes and patterns.

Results

Sixteen respondents participated in this study; 4 players, 4 coaches, 3 researchers, and 5 administrators were represented in this sample. Overarching themes identified across these interviews included playing through pain, health consequences of concussions, concussion prevention strategies and the potential role of headgear, symbolism of headgear, gender dynamics, autonomy, and decision making.

Conclusions

This qualitative study shows the importance of attention to the unique history of girls' lacrosse and current narratives surrounding headgear in the sport. There is a need for greater collaboration and consensus between all relevant groups to ensure that headgear best addresses the concerns of the people who will ultimately be using it. Future qualitative research should build on this preliminary study with a larger and more diverse sample to follow up on key themes and ultimately inform effective safety measures to protect athletes.

Effects of Multicomponent Injury Prevention Programs on Children and Adolescents' Fundamental Movement Skills: A Systematic Review With Meta-Analyses

OBJECTIVE

Fundamental movement skills (FMS) are essential to participate in physical activity. Understanding the effects of multicomponent injury prevention programs (MIPP) on FMS may help promote safe physical activity. Our objective was to synthesize the evidence on the effects of MIPP on biomechanical outcomes and neuromuscular performance measured on children and adolescents while performing FMS.

DATA SOURCE

We searched PubMed, SPORTDiscus, Web of Science, and SCOPUS.

STUDY INCLUSION AND EXCLUSION CRITERIA

We included peer-reviewed randomized controlled trials, published in English, that analyzed the effects of MIPP on biomechanics and neuromuscular performance of FMS in participants under 18 years of age.

DATA EXTRACTION

Two reviewers screened the articles, assessed the quality of the evidence using the Physiotherapy Evidence Database (PEDro) scale, and synthesized the data.

DATA SYNTHESIS

We conducted meta-analyses and reported the characteristics, outcomes, and risk of bias of studies.

RESULTS

We included 27 articles that reported data from 1,427 participants. Positive effects on FMS were reported in 23 of the 27 included articles. Vertical Jump, running speed, acceleration, and dynamic balance presented positive-significant pooled effect sizes. Dribbling and horizontal jump presented non-significant pooled effect sizes.

CONCLUSION

MIPP can positively affect FMS in children and adolescents in sports-related settings. Lack of participant compliance and implementation fidelity may affect MIPP effectiveness. Including MIPP in physical literacy interventions, physical education classes, and organized physical activity may lead to functional adaptations that help promote safe physical activity.

Epidemiology of Rugby-Related Injuries Presenting to the Emergency Department: A 10-Year Review

Background Rugby is a popular contact sport played with little to no protective clothing. There exist few comprehensive studies investigating emergency department (ED) visit patterns for rugby-related injuries.We hypothesize that male athletes remain the most common patient demographic to present to the ED with rugby-related injuries and that the number of patients diagnosed with soft tissue injuries such as sprains and strains decreased during the COVID-19 pandemic. Methodology The National Electronic Injury Surveillance System database was examined for rugby injuries from January 2012 through December 2021. Cases were stratified by sex, age, and injury type to monitor epidemiological patterns. This is a descriptive epidemiology study. Level of evidence III. Results A total of 2,896 individuals with rugby-related ED visits were identified. ED patients were most common among males (73.9%), Caucasians (45.3%), and in the 15-19-year-old age range (44.9%). Injuries most commonly affected the upper body, specifically the head (23.1%), face (13.8%), and shoulder (12.4%) with fractures and sprains comprising 22.3% and 18.5% of ED diagnoses, respectively. Concussions were the most frequent injury to any one body part (11.2%). During the COVID-19 pandemic, ED patients with rugby-related injuries were significantly more likely to be males presenting with lacerations or hemorrhages. ED visits for sprains and strains significantly decreased in the peri-COVID-19 period. Conclusions Annual ED visits due to rugby injuries are declining. The head and neck are the most common sites of injuries. Decreased presentation to the ED during the COVID-19 pandemic may raise concern for the potential for untreated injuries. Physicians should anticipate the presence of chronic sports-related injuries when evaluating future patients.

Comparison of Peak Shoulder Distraction Forces Between Pain and Pain-Free Youth Baseball Pitchers

Background

Increased shoulder distraction force during a baseball pitch may make a pitcher susceptible to rotator cuff or glenohumeral labral injuries. A precursor to a pitching injury may be pain experienced in the throwing arm.

Purpose

To (1) compare peak shoulder distraction (PSD) forces in youth baseball pitchers with and without upper extremity pain when throwing a fastball and (2) assess if PSD forces across trials differ between pain and pain-free groups.

Study Design

Controlled laboratory study.

Methods

A total of 38 male baseball pitchers aged 11 to 18 years were separated into a pain-free group (n = 19; mean age, 13.2 ± 1.7 years; mean height, 163.9 ± 13.5 cm; mean weight, 57.4 ± 13.5 kg) and a pain group (n = 19; mean age, 13.3 ± 1.8 years; mean height, 164.9 ± 12.5 cm; mean weight, 56.7 ± 14.0 kg). Pitchers in the pain group indicated that they experienced pain in their upper extremity while throwing a baseball. Pitching mechanical data from 3 fastballs per pitcher were recorded with an electromagnetic tracking system and motion capture software. The mean PSD (mPSD) was calculated as the mean PSD of 3 pitches per pitcher, the trial with the highest recorded PSD was determined as the maximum-effort PSD (PSDmax), and the PSD range (rPSD) was defined as the difference of the PSD force of the trial with the highest PSD and the lowest PSD for each pitcher. The PSD force was normalized to the pitcher's body weight (%BW). Pitch velocity was also recorded.

Results

The mPSD force was 114%BW ± 36%BW for the pain group and 89%BW ± 21%BW for the pain-free group. Pitchers in the pain group exhibited a significantly higher PSDmax force (t_30.548 = 2.894; P = .007) and mPSD force (t_29.231 = 2.709; P = .009) compared with those in the pain-free group. There were no significant between-group differences in the rPSD force or pitch velocity.

Conclusion

The normalized PSDmax force was higher in pitchers who experienced pain while throwing fastballs compared with pitchers who were pain-free while throwing.

Clinical Relevance

Baseball pitchers who experience pain in their throwing arm are likely to have higher shoulder distraction forces. Improvement in pitching biomechanics and corrective exercises may assist in the mitigation of pain while pitching.

Saddle Pressures Factors in Road and Off-Road Cyclists of Both Genders: A Narrative Review

The contact point of the pelvis with the saddle of the bicycle could generate abnormal pressure, which could lead to injuries to the perineum in cyclists. The aim of this review was to summarize in a narrative way the current literature on the saddle pressures and to present the factors that influence saddle pressures in order to prevent injury risk in road and off-road cyclists of both genders. We searched the PubMed database to identify English-language sources, using the following terms: "saddle pressures", "pressure mapping", "saddle design" AND "cycling". We also searched the bibliographies of the retrieved articles. Saddle pressures are influenced by factors such as sitting time on the bike, pedaling intensity, pedaling frequency, trunk and hand position, handlebars position, saddle design, saddle height, padded shorts, and gender. The jolts of the perineum on the saddle, especially on mountain bikes, generate intermittent pressures, which represent a risk factor for various pathologies of the urogenital system. This review highlights the importance of considering these factors that influence saddle pressures in order to prevent urogenital system injuries in cyclists.

Calisthenics: Epidemiology of Injury Patterns and Their Risk Factors

Objective

To quantify the prevalence and nature of injuries and their risk factors in calisthenics to, therefore, inform the practitioner what to expect from these athletes.

Methods

This study was an online cross-sectional survey of calisthenics athletes. Data were collected online and the survey was distributed via social media over six months in 2020. The purpose-built survey consisted of demographic, training and loading questions. Participants were provided with an injury definition and reported their total number of injuries sustained during calisthenics including detailed information on three most significant injuries, along with mechanism of injury and risk factors. Multivariate regression analyses were used to determine objective factors associated with the number of injuries.

Results

There were 543 participants describing 1104 injuries. Mean (standard deviation (SD)) injury prevalence was 4.5 (3.3) per person. Of these injuries, 820 (74.3%) required training modification or treatment. Participants missed a mean (SD) 3.4 (5.1) weeks of training and engaged in a mean (SD) 10.9 (9.1) health professional consultations. The most common injuries were upper leg (24.5%), ankle/foot (22.8%) and lumbar spine (19.3%), with the majority being sprains/strains in nature (56.3%). Mechanism of injury included elevated work (27.6%), overuse (38.0%) and specific calisthenics skills (38.9%) - such as lumbar (40.6%) and lower limb (40.3%) extension-based movements. Subjective risk factors included load (66.8%), preparation (55.9%) and environmental factors (21.0%). Objective risk factors associated with higher numbers of injuries included increased years of participation, left leg dominance, increased training hours (regardless of training type) and state team participation (p<0.05).

Conclusion

Practitioners need to be aware that calisthenics athletes demonstrate a high proportion of strain/sprain injuries involving the lower limb and lumbar spine with causative movements being extension-based. Addressing risk factors such as loading, preparation, asymmetry, and the environment related to these movements are important for the treating practitioner.