Sports-related workload and injury risk: simply knowing the risks will not prevent injuries: Narrative review

Evaluation of Patellar Tendon Structural Changes following Biological Treatments: Secondary Analysis of Double-Blinded Clinical Trial of Bone Marrow Mesenchymal Stromal Cells and Leukocyte-Poor Platelet-Rich Plasma

Objective quantification of tendon structural changes through imaging is only achieved by evaluating tendon structure using ultrasound tissue characterization (UTC) technology. This study compares the effects of bone marrow mesenchymal stromal cells (BM-MSC) and leukocyte-poor platelet-rich plasma (Lp-PRP) on tendon structure and clinical outcomes in male patients with patellar tendinopathy measured with UTC at 3, 6, and 12 months after treatment. This is a double-blinded clinical trial with a randomized active control study with 20 male patients diagnosed with patellar tendinopathy who underwent BM-MSC and Lp-PRP. Bilateral ultrasound tissue characterization scans of the patellar tendon were carried out after 3, 6, and 12 months, as well as tests for strength and pain. UTC patellar tendon was analyzed at the insertion, proximal, and mid-tendon. BM-MSC showed a greater capacity to promote further positive changes than Lp-PRP. Lp-PRP presented higher disorganized echo-type II in the mid-tendon (p = 0.04; ES = 1.06) and III (p = 0.02; ES = -1.47) after 3 months in the Lp-PRP group. Similar results were seen after 6 and 12 months. Pain and strength data show improvement in the treated tendon. BM-MSC treatment demonstrates a superior capacity to promote tendon regeneration and organization, restore strength, and reduce pain compared to Lp-PRP, after 3, 6, and 12 months in male patients with patellar tendinopathy.

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 (F1,7 = 27.1, P < 0.01), followed by infielders, then catchers. Hard accelerations (F1,7 = 12.9, P < 0.01) were highest among first basemen, then outfielders, remaining infielders, and catchers. Total throws (F1,7 = 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.

FIFA football nurse - A task sharing approach in sports and exercise medicine practice in grassroots women's football in low- and middle- income settings. A study protocol for a cluster randomised controlled trial

Football (soccer) is a very popular team sport among African women and girls, with player numbers continuing to rise at all levels of the sport. Whereas the participation in football and associated injuries are on the rise, there are not enough sports and exercise medicine (SEM) personnel to attend to these women football players. While Africa may not currently have enough SEM trained medical doctors and/or physiotherapists, it has relatively higher numbers of other healthcare workers; for example, nurses, who lead healthcare services provision from community to tertiary levels. The primary objective of this study will be to compare sports medicine practices; injury prevention behaviours; injury risk parameters; incidence and prevalence of injuries and illnesses in teams with and without a Football Nurse during one competitive season in Malawi's Women's football league. This study will be a cluster randomised control trial will recruit 24 teams from the Women's Football League in Malawi, which will be randomised to either the intervention group or the control group. A cohort of 12 nurses will receive training in basic football medicine; after which they will be attached to a total of 12 women's football teams (intervention group) during one competitive season. The Football Nurses will be directly report to a physiotherapist or doctor in their district to whom they will refer serious injuries for investigations, or further management. The teams with Football Nurses will be compared to other teams that will not have Football Nurses. We expect to develop a low cost, sustainable and context relevant solution to manage the treatment gap of football injuries/illnesses in underserved communities such as women's football. Trial registration number: Pan African Clinical Trial Registry (PACTR202205481965514).

Players', Head Coaches', And Medical Personnels' Knowledge, Understandings and Perceptions of Injuries and Injury Prevention in Elite-Level Women's Football in Ireland

BACKGROUND

To manage injuries effectively, players, head coaches, and medical personnel need to have excellent knowledge, attitudes, and behaviours in relation to the identification of risk factors for injuries, the implementation of injury prevention initiatives, as well as the implementation of effective injury management strategies. Understanding the injury context, whereby specific personal, environmental, and societal factors can influence the implementation of injury prevention initiatives and injury management strategies is critical to player welfare. To date, no qualitative research investigating the context of injuries, has been undertaken in elite-level women's football. The aim of our study was to explore the knowledge, attitudes, and behaviours of players, head coaches, and medical personnel in the Irish Women's National League (WNL) to injury prevention and injury management.

METHODS

We used qualitative research methods to explore the knowledge, attitudes, and behaviours of players, head coaches, and medical personnel in the Irish WNL to injury prevention and injury management. Semi-structured interviews were undertaken with 17 players, 8 medical personnel, and 7 head coaches in the Irish WNL. The data were analysed using thematic analysis. Our study is located within an interpretivist, constructivist research paradigm.

RESULTS

The participants had incomplete knowledge of common injuries in elite-level football, and many held beliefs about risk factors for injuries, such as menstrual cycle stage, which lacked evidence to support them. Jumping and landing exercises were commonly used to reduce the risk of injuries but evidence-based injury prevention exercises and programmes such as the Nordic hamstring curl, Copenhagen adduction exercise, and the FIFA 11+ were rarely mentioned. Overall, there was dissatisfaction amongst players with their medical care and strength and conditioning (S & C) support, with resultant inadequate communication between players, head coaches, and medical personnel.

CONCLUSION

Poor quality and availability of medical care and S & C support were considered to be a major obstacle in the effective implementation of injury risk reduction strategies and successful return-to-sport practices. More original research is required in elite-level women's football to explore injury risk factors, injury prevention initiatives, and contextual return-to-sport strategies, so that players, head coaches, and medical personnel can use evidence that is both up-to-date and specific to their environment.

Assessment of Training Load, Sleep, Injuries, and Operational Physical Performance During Basic Military Qualification

INTRODUCTION

Optimizing training load (TL) and sleep is essential to maximize physical performance and prevent musculoskeletal injuries (MSKIs) for Canadian forces recruits during the 10-week basic military qualification (BMQ) course. The purpose of this study was to assess the TL, sleep duration, the occurrence of MSKIs during the BMQ, and the operation fitness performance during the BMQ.

MATERIALS AND METHODS

Forty Canadian recruits, eight females and 32 males, (age 24 ± 5 years; height 176.4 ± 10.4 cm), were monitored with an accelerometer (GENEActiv) on their wrist between weeks 1 and 9 to evaluate the TL and sleep duration. During weeks 2 and 10, the recruits completed an operational fitness evaluation. Injury surveillance was performed over 10 weeks.

RESULTS

TL intensity was significantly different (P = 0.0001) from week to week. The weekly average total time of moderate and vigorous physical activity was 189.7 ± 48.1 min and 44.7 ± 15.2 min, respectively. The average sleep duration was 5.4 ± 0.4 h per night and decreased to 4.2 h ± 0.4 during field exercises. A significant difference in sleep duration was observed between recruits with and without a MSKI. The recruits accumulated a total of 95 days under medical restrictions with an average of 3.8 consecutive days. The VO2peak estimated from the Fitness for Operational Requirements of Canadian Armed Forces Employment job-based simulation test significantly improved from weeks 2 to 10 (pre, 47.1 ± 6.3; post: 50.2 ± 5.8; P = 0.001).

CONCLUSIONS

TL is of high magnitude and varies from week to week. The reported mean sleep duration per week may perhaps negatively impact the occurrence of MSKI. No significant improvement was detected in operational fitness by the end of the BMQ.

Aetiological Factors of Running-Related Injuries: A 12 Month Prospective "Running Injury Surveillance Centre" (RISC) Study

BACKGROUND

Running-related injuries (RRIs) are a prevalent issue for runners, with several factors proposed to be causative. The majority of studies to date are limited by retrospective study design, small sample sizes and seem to focus on individual risk factors in isolation. This study aims to investigate the multifactorial contribution of risk factors to prospective RRIs.

METHODS

Recreational runners (n = 258) participated in the study, where injury history and training practices, impact acceleration, and running kinematics were assessed at a baseline testing session. Prospective injuries were tracked for one year. Univariate and multivariate Cox regression was performed in the analysis.

RESULTS

A total of 51% of runners sustained a prospective injury, with the calf most commonly affected. Univariate analysis found previous history of injury < 1 year ago, training for a marathon, frequent changing of shoes (every 0-3 months), and running technique (non-rearfoot strike pattern, less knee valgus, greater knee rotation) to be significantly associated with injury. The multivariate analysis revealed previous injury, training for a marathon, less knee valgus, and greater thorax drop to the contralateral side to be risk factors for injury.

CONCLUSION

This study found several factors to be potentially causative of injury. With the omission of previous injury history, the risk factors (footwear, marathon training and running kinematics) identified in this study may be easily modifiable, and therefore could inform injury prevention strategies. This is the first study to find foot strike pattern and trunk kinematics to relate to prospective injury.

Managing the Wellbeing of Elite Rugby Union Players from an Occupational Safety and Health Perspective

The intense, physical contact nature of rugby union often encourages the normalization of risk-taking behaviour resulting in a relatively high acceptance of risk. This study aims to explore safety culture in rugby union from an OSH perspective, with the purpose of assisting coaches and management in their decision-making processes to improve players' health, welfare, and long-term well-being. In terms of data collection, this study involved semi-structured interviews with senior support staff (n = 15) in elite rugby union. Interview transcripts underwent inductive analysis prior to an abductive analysis that was guided by an established occupational-safety-and-health (OSH) framework. Rugby union players' safety can be considered from two dimensions: management's commitment to safety (i.e., safety prioritization, safety empowerment, and safety justice), players' involvement in safety (i.e., safety prioritization, and trust in other players' safety competence, and players' safety concern for the opposition players). Within the themes identified, players' attitude towards their opponents' safety which has been rarely considered as a factor for injury prevention is also discussed in this study. If sport support staff (i.e., managers/coaches/medical) can become more involved in players' performance-orientated training using OSH management processes to aid in their decision-making, their exists the capacity to benefit players' safe return to play after injury rehabilitation. Meanwhile, directing the development of appropriate behavioural educational interventions to raise safety-awareness amongst players can improve their long-term health and well-being and provide them with the necessary safety and health information to support their own decision-making processes. As a multidisciplinary design, this study contributes new multidisciplinary insights that have the potential to advance managerial practices utilizing an OSH perspective, including decision-making supporting risk alleviation for safety and long-term health and wellbeing initiatives in competitive team sports.

Analysis of the Association between Internal and External Training Load Indicators in Elite Soccer; Multiple Regression Study

The aim of this study was to identify the external training load (ETL) variables that are most influential on the session rating of perceived exertion (sRPE) during elite soccer training. The participants (n = 29) were adult male soccer players from a single team that competed in Croatia’s highest national soccer competition in the 2021/2022 season. Data were collected using the 10 Hz Global Positioning System from 66 training sessions, and a total of 1061 training observations were undertaken. The univariate and multivariate relationships among the predictors (ETL variables) and the criterion (sRPE) were assessed using forward stepwise multiple regressions and Pearson’s correlations, respectively. ETL variables explained 63% of the variance in the sRPE (Multiple R = 0.79; p < 0.01), and the model was successfully cross-validated. The significant partial regressors were total distance (β = 0.66), metres per minute (β = −0.47), high-intensity accelerations (β = 0.22) and decelerations (β = 0.18), and sprint distance (β = 0.14). All ETL variables were significantly correlated with the sRPE (all p < 0.01), with the highest correlations found for total distance covered (r = 0.70) and high-intensity accelerations and decelerations (r = 0.62 and 0.65, respectively). Such results show that (i) the total distance and acceleration rates during the training sessions are the most important predictors of the sRPE, and (ii) a combination of different ETL variables predicts the sRPE better than any individual parameter alone. This study shows that both the volume and intensity of training are related to players’ internal responses. The findings ultimately provide further evidence to support the use of sRPE as a global measure of training load in soccer players.

Machine Learning for Understanding and Predicting Injuries in Football

Attempts to better understand the relationship between training and competition load and injury in football are essential for helping to understand adaptation to training programmes, assessing fatigue and recovery, and minimising the risk of injury and illness. To this end, technological advancements have enabled the collection of multiple points of data for use in analysis and injury prediction. The full breadth of available data has, however, only recently begun to be explored using suitable statistical methods. Advances in automatic and interactive data analysis with the help of machine learning are now being used to better establish the intricacies of the player load and injury relationship. In this article, we examine this recent research, describing the analyses and algorithms used, reporting the key findings, and comparing model fit. To date, the vast array of variables used in analysis as proxy indicators of player load, alongside differences in approach to key aspects of data treatment-such as response to data imbalance, model fitting, and a lack of multi-season data-limit a systematic evaluation of findings and the drawing of a unified conclusion. If, however, the limitations of current studies can be addressed, machine learning has much to offer the field and could in future provide solutions to the training load and injury paradox through enhanced and systematic analysis of athlete data.

Association between SARS-COV-2 infection and muscle strain injury occurrence in elite male football players: a prospective study of 29 weeks including three teams from the Belgian professional football league

OBJECTIVES

The aim of this study was to investigate the association between SARS-CoV-2 infection and muscle strain injury in elite athletes.

METHODS

A prospective cohort study in three Belgian professional male football teams was performed during the first half of the 2020-2021 season (June 2020-January 2021). Injury data were collected using established surveillance methods. Assessment of SARS-CoV-2 infection was performed by a PCR test before each official game.

RESULTS

Of the 84 included participants, 22 were infected with SARS-CoV-2 and 14 players developed a muscle strain during the follow-up period. Cox's proportional hazards regression analyses demonstrated a significant association between SARS-CoV-2 infection and the development of muscle strain (HR 5.1; 95% CI 1.1 to 23.1; p=0.037), indicating an increased risk of developing muscle strains following SARS-CoV-2 infection. All athletes who sustained a muscle strain after infection were injured within the first month (15.71±11.74 days) after sports resumption and completed a longer time in quarantine (14.57±6.50 days) compared with the infected players who did not develop a muscle strain (11.18±5.25 days).

CONCLUSION

This study reported a five times higher risk of developing a muscle strain after a SARS-CoV-2 infection in elite male football players. Although this association should be examined further, it is possible that short-term detraining effects due to quarantine, and potentially pathological effects of the SARS-CoV-2 infection are associated with a higher risk of muscle strain injury.

Relationship Between Physical Activity, Coronary Artery Disease Risk Factors and Musculoskeletal Injuries in the City of Cape Town Fire and Rescue Service

Musculoskeletal injuries in firefighters are a common occurrence, that increase as firefighters age, and may be related to the firefighters’ physical activity habits outside of the job. Certain CAD risk factors, such as obesity, cigarette smoking and ageing may be linked to increased injury risk in firefighters. Although firefighters may meet the recommended minimum physical activity minutes, they may remain at risk for sustaining musculoskeletal injuries. Therefore, this study aims to determine the relationship between physical activity and CAD risk factors, between CAD risk factors and musculoskeletal injuries and between physical activity and musculoskeletal injuries. A total of 124 full-time firefighters, males and females, were conveniently recruited from the City of Cape Town Fire and Rescue Service. A researcher-generated questionnaire was used to collect injury, CAD risk factor and physical activity data. The proportion of firefighters who participated in leisure-time physical activity (LTPA) was 63.7%, and those who were physically inactive was 69.4%. The prevalence musculoskeletal injuries among all firefighters was 27.4%. The most prevalent musculoskeletal injury was shoulder injuries in 35.3% of firefighters, followed by multiple injuries in 26.5% and back injuries in 14.7%. Age was a significant predictor of physical inactivity in firefighters [P = .002, OR = 1.08], BMI was a significant predictor of physical inactivity [P = .050, OR = 1.08], cigarette smoking was a significant predictor of firefighters not exercising [P = .007, OR = 2.31] and the total amount of vigorous-intensity exercise was a significant predictor of musculoskeletal injuries [P = .050, OR = 1.00]. In conclusion, older firefighters were more physically inactive and had a higher prevalence of musculoskeletal injuries, and the latter decreased significantly after the age of 50 years. Emphasis should be placed on firefighters exercising in their leisure-time, especially as they aged.

Prevalence and incidence of injuries among female cricket players: a systematic review and meta-analyses

OBJECTIVE

The objective of the review was to describe the incidence and prevalence of injuries among female cricket players of all ages, participating in all levels of play.

INTRODUCTION

Cricket, a bat-and-ball sport, is becoming popular among women of all ages and abilities worldwide. However, cricket participation carries a risk of injury. Injuries negatively affect sport participation, performance, and short- and long-term health and well-being. Injury prevention, therefore, is the key to safe, long-term cricket participation as a physical activity goal. Epidemiological data are needed to underpin evidence-based injury-prevention strategies.

INCLUSION CRITERIA

Studies reporting incidence and prevalence of injuries in female cricket players of all ages, participating in all levels of play, were included in this review, including studies that report data by sex or by sport. Studies without enough data to calculate prevalence or incidence, that do not distinguish female injury data from males', that focus on athletes participating in other sports, or that focus on case studies were excluded.

METHODS

A systematic review and meta-analyses were conducted according to the JBI and PRISMA 2020 guidelines. MEDLINE, SPORTDiscus, Physiotherapy Evidence Database (PEDro), EBSCO MasterFILE Premier, EBSCO CINAHL Complete, ProQuest Health and Medical Complete, Scopus, and Science Direct were systematically searched from inception to August 2021. Additionally, Cochrane Controlled Trials Register and ClincalTrail.gov were searched. EBSCO MegaFile Premier (EBSCO), OpenGrey (SIGLE), WorldCat, Grey Matters, Grey Literature, and Google Scholar databases were searched for gray literature. Full-text articles that met the inclusion criteria were critically appraised using JBI-tools, and were extracted and synthesized in narrative summary and tabular forms. Three meta-analyses were conducted: injury incidence rate, injury prevalence proportions, and injury incidence proportions. Heterogeneity was assessed using the I2 statistic and the random-effects model.

RESULTS

Of the 7057 studies were identified and only 4256 screened after duplicates removed, 23 studies met the inclusion criteria. Risk of bias was low for 21 studies. The injury incidence rate for elite cricket was 71.9 (SE 21.3, 95% CI 30.2-113.6) injuries per 1000 player hours, time-loss injury incidence rate was 13.3 (SE 4.4, 95% CI 4.6-22.0) injuries per 1000 player hours, and non-time-loss injury incidence rate was 58.5 (SE 16.9, 95% CI 25.6-91.7) injuries per 1000 player hours. The injury prevalence proportions for community to elite cricket was 65.2% (SE 9.3, 95% CI 45.7-82.3) and injury prevalence proportions for community cricket was 60% (SE 4.5, 95% CI 51.1-68.6). The injury incidence proportions for community cricket was 5.6 (SE 4.4, 95% CI 0.1-18.3) injuries per 10,000 participants. Elite cricket players were more frequently injured than community cricket players. The most prevalent body regions injured were the shoulder and knee, and most were sustained by fast bowlers. Injuries to the hand, wrist, and fingers had the highest incidence and were most sustained by fielders.

CONCLUSIONS

The study's findings can help stakeholders (including players, coaches, clinicians, and policymakers) make informed decisions about cricket participation by informing and implementing strategies to promote cricket as a vehicle for positive public health outcomes. This review also identified gaps in the available evidence base and addressing these through future research would enhance women's cricket as a professional sport.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020166052.

Physiotherapy Rehabilitation in Subjects Diagnosed with Subacromial Impingement Syndrome Does Not Normalize Periscapular and Rotator Cuff Muscle Onset Time of Activation

Clinicians suggest that rehabilitation of Subacromial Impingement Syndrome (SIS) should target improving movement patterns to ensure better clinical outcomes. Understanding changes in onset time of activation patterns and associated changes in clinical outcomes could improve our understanding of rehabilitation strategies. In this prospective longitudinal study, we examined neuromuscular firing patterns and clinical features before and after a standardized physiotherapy program in subjects diagnosed with SIS. Electromyography (EMG) recordings of eleven shoulder muscles were taken at the initial and discharge consultation in 34 male volunteers diagnosed with SIS. EMG recording was performed during flexion, scaption, and abduction at slow, medium, and fast speeds with a loaded (3 kg) and unloaded arm, as well as rotational motion, rotational strength, pain, and shoulder function. Completion of standardized shoulder physiotherapy program for SIS resulted in improvements in clinical outcomes. Resulted showed inconsistent differences of onset time of activation mainly in some of the periscapular muscles for all movements. No differences were seen on the EMG recordings for rotator cuff muscles. Differences in range of motion, strength and function were shown. Despite some changes in onset time of activation, this study was not able to demonstrate consistent changes of onset time of activation of the periscapular and rotator cuff muscles.

Sleep and Injury Risk

ABSTRACT

Sleep has been found to have wide-ranging effects on sports performance and overall well-being. Recent research has found evidence relating chronic suboptimal sleep with the risk of musculoskeletal pain and sports injury. The amount of sleep that consistently has been found to be associated with increased risk of injury is ≤7 h of sleep, which when sustained for periods of at least 14 d has been associated with 1.7 times greater risk of musculoskeletal injury. However, it is unknown if sleep loss predisposes the athlete to specific types of musculoskeletal injuries. The role of sleep on musculoskeletal pain is important to understand as studies in both children and adults have found that suboptimal sleep more consistently predicts next-day pain as compared with pain predicting subsequent sleep loss. Despite the evidence that certain aspects of sleep behavior seem to increase the risk of musculoskeletal injury and pain, sleep should be considered as only a part of the athlete's overall health and well-being when assessing the athlete for risk of injury.

The Training Characteristics of Recreational-Level Triathletes: Influence on Fatigue and Health

Little is known about how recreational triathletes prepare for an Olympic distance event. The aim of this study was to identify the training characteristics of recreational-level triathletes within the competition period and assess how their preparation for a triathlon influences their health and their levels of fatigue. During the 6 weeks prior to, and the 2 weeks after, an Olympic distance triathlon, nine recreational athletes (five males, four females) completed a daily training log. Participants answered the Daily Analysis of Life Demands Questionnaire (DALDA), the Training Distress Scale (TDS) and the Alberta Swim Fatigue and Health Questionnaire weekly. The Recovery-Stress Questionnaire (REST-Q) was completed at the beginning of the study, on the day before the competition, and at the end of week 8. Training loads were calculated using session-based rating of perceived exertion (sRPE). The data from every week of training was compared to week 1 to determine how athletes’ training and health changed throughout the study. No changes in training loads, duration or training intensity distribution were seen in the weeks leading up to the competition. Training duration was significantly reduced in week 6 (p = 0.041, d = 1.58, 95% CI = 6.9, 421.9), while the number of sessions was reduced in week 6 (Z = 2.32, p = 0.02, ES = 0.88) and week 7 (Z = 2.31, p = 0.02, ES = 0.87). Training was characterized by large weekly variations in training loads and a high training intensity. No significant changes were seen in the DALDA, TDS or REST-Q questionnaire scores throughout the 8 weeks. Despite large spikes in training load and a high overall training intensity, these recreational-level triathletes were able to maintain their health in the 6 weeks of training prior to an Olympic distance triathlon.

Is the Acute: Chronic Workload Ratio (ACWR) Associated with Risk of Time-Loss Injury in Professional Team Sports? A Systematic Review of Methodology, Variables and Injury Risk in Practical Situations

BACKGROUND

The acute: chronic workload ratio (ACWR) is an index of the acute workload relative to the cumulative chronic workloads. The monitoring of physical workloads using the ACWR has emerged and been hypothesized as a useful tool for coaches and athletes to optimize performance while aiming to reduce the risk of potentially preventable load-driven injuries.

OBJECTIVES

Our goal was to describe characteristics of the ACWR and investigate the association of the ACWR with the risk of time-loss injuries in adult elite team sport athletes.

DATA SOURCES

PubMed, EMBASE and grey literature databases; inception to May 2019.

ELIGIBILITY CRITERIA

Longitudinal studies that assess the relationship of the ACWR and time-loss injury risk in adult professional or elite team sports.

METHODS

We summarized the population characteristics, workload metrics and ACWR calculation methods. For each workload metric, we plotted the risk estimates for the ACWR in isolation, or when combined with chronic workloads. Methodological quality was assessed using a modified version of the Downs and Black scale.

RESULTS

Twenty studies comprising 2375 injuries from 1234 athletes (all males and mean age of 24 years) from different sports were included. Internal (65%) and external loads (70%) were collected in more than half of the studies and the session-rating of perceived exertion and total distance were the most commonly collected metrics. The ACWR was commonly calculated using the coupled method (95%), 1:4 weekly blocks (95%) and subsequent week injury lag (80%). There were 14 different binning methods with almost none of the studies using the same binning categories.

CONCLUSION

The majority of studies suggest that athletes are at greater risk of sustaining a time-loss injury when the ACWR is higher relative to a lower or moderate ACWR. The heterogenous methodological approaches not only reflect the wide range of sports studied and the differing demands of these activities, but also limit the strength of recommendations.

PROSPERO REGISTRATION NUMBER

CRD42017067585.

Accelerometry-based variables in professional soccer players: comparisons between periods of the season and playing positions

The aim of this study was to provide reference data of variation in external training loads for weekly periods within the annual season. Specifically, we aimed to compare the weekly acute load, monotony, and training strain of accelerometry-based measures across a professional soccer season (pre-season, first and second halves of the season) according to players' positions. Nineteen professional players were monitored daily for 45 weeks using an 18-Hz global positioning system to obtain measures of high metabolic load distance (HMLD), impacts, and high intensity accelerations and decelerations. Workload indices of acute load, training monotony, and training strain were calculated weekly for each of the measures. The HMLD had greater training strain values in the pre-season than in the first (p ≤ 0.001; d = 0.793) and second halves of the season (p ≤ 0.001; d = 0.858). Comparisons between playing positions showed that midfielders had the highest weekly acute load of HMLD (6901 arbitrary units [AU]), while central defenders had the lowest (4986 AU). The pre-season period was associated with the highest acute and strain load of HMLD and number of impacts, with a progressive decrease seen during the season. In conclusion, coaches should consider paying greater attention to variations in HMLD and impacts between periods of the season and between players to individualize training accordingly.

How Much? How Fast? How Soon? Three Simple Concepts for Progressing Training Loads to Minimize Injury Risk and Enhance Performance

BACKGROUND

When progressing an athlete from rehabilitation to peak performance, load must exceed load capacity. When gradual, systematic increases in load are applied, load capacity will improve. However, if the applied load greatly exceeds load capacity, then tissue tolerance is exceeded and injury may occur.

CLINICAL QUESTION

It is well established that a balance exists between providing an adequate training stimulus to elicit performance benefits and minimizing the risk of injury. How can practitioners determine how much training is too much? Following injury, how soon can training loads be progressed? How quickly can athletes return to competition?

KEY RESULTS

When developing rehabilitation or performance programs, 3 concepts are critical: the "floor," the "ceiling," and time. The floor represents the athlete's current capacity, whereas the ceiling represents the capacity needed to perform the specific activities of the sport. A challenge in most sporting environments is the time required to progress from the floor to the ceiling. If athletes' training loads are progressed too rapidly, they will be at increased risk of injury and underperformance.

CLINICAL APPLICATION

Rehabilitation practitioners should consider and plan the appropriate amount of time required to progress from the floor (eg, rehabilitation) to the ceiling (eg, return to performance). The resilience and robustness that come from training take time, and different physical capacities will adapt at different rates. Progressive, gradual, and systematic increases in training load allow athletes to safely progress to the ceiling, reducing injury risk, improving availability, and enhancing performance. J Orthop Sports Phys Ther 2020;50(10):570-573. Epub 15 Nov 2019. doi:10.2519/jospt.2020.9256.

Injury and Player Availability in Women's International Pathway Cricket from 2015 to 2019

This prospective cohort study aimed to describe injury and illness epidemiology within women's international pathway cricket, understanding what influences player availability in this unique context where players are contracted part-time. Approximately 8.4% of players were impacted by injury or illness during the year, with an average 2.3% of players completely unavailable on any given day. Most medical complaints occurred during training (111.2 injuries/100 players per year). Of all complaints, medical illness had the highest overall incidence (45.0 complaints/100 players), followed by hand injuries (24.7 injuries/100 players). Gradual onset injuries were most common. Overall average match time-loss complaint prevalence rate was 4.1% and average match time-loss injury incidence rate was 7.0 injuries/1000 days of play. Fielding (56.4 injuries/100 players per year) was the activity resulting in the highest average overall and time-loss injury incidence rates, though 'other' activities (e. g. those occurring outside of cricket participation) collectively accounted for 78.3 injuries/100 players per year. The high incidence of medical illness relative to other complaints may be a distinct feature of the women's cricket international pathway compared to other cricket samples. The high occurrence of injuries arising from 'other' activities, likely due to part-time participation, presents an opportunity for targeted injury prevention strategies.• The first study on an international women's cricket pathway, contributes to the empirical base for specific injury risks associated with the women's cricket game, which is an emerging research area for a developing sport.• Some of the findings may be a distinct feature of the women's cricket international pathway, highlighting potential opportunities for targeted prevention strategies.• With the upcoming development of an elite domestic structure these preliminary findings will provide a good starting point for physiotherapy and medical staff working in these contexts.

Weekly Load Variations of Distance-Based Variables in Professional Soccer Players: A Full-Season Study

The aim of this study was two-fold: (1) to analyze the variations of acute load, training monotony, and training strain among early (pre-season), mid (first half of season), and end season (second half of season) periods; (2) to compare these training indicators for playing positions in different moments of the season. Nineteen professional players (age: 26.5 ± 4.3 years; experience as professional: 7.5 ± 4.3 years) from a European First League team participated in this study. The players were monitored daily over a 45-week period for the total distance (TD), distance covered (DC) at 14 km/h⁻¹ or above (DC > 14 km/h), high-speed running above 19.8 km/h⁻¹ (HSR) distance, and number of sprints above 25.2 km/h⁻¹. The acute load (sum of load during a week), training monotony (mean of training load during the seven days of the week divided by the standard deviation of the training load of the seven days), and training strain (sum of the training load for all training sessions and matches during a week multiplied by training monotony) workload indices were calculated weekly for each measure and per player. Results revealed that training monotony and training strain for HSR were meaningfully greater in pre-season than in the first half of the in-season (p ≤ 0.001; d = 0.883 and p ≤ 0.001; d = 0.712, respectively) and greater than the second half of the in-season (p ≤ 0.001; d = 0.718 and p ≤ 0.001; d = 0.717). The training monotony for the sprints was meaningfully greater in pre-season than in the first half of in-season (p < 0.001; d = 0.953) and greater than the second half of in-season (p ≤ 0.001; d = 0.916). Comparisons between playing positions revealed that small-to-moderate effect sizes differences mainly for the number of sprints in acute load, training monotony, and training strain. In conclusion, the study revealed that greater acute load, training monotony, and training strain occurred in the pre-season and progressively decreased across the season. Moreover, external defenders and wingers were subjected to meaningfully greater acute load and training strain for HSR and number of sprints during the season compared to the remaining positions.

Epidemiology and Financial Burden of Musculoskeletal Injuries as the Leading Health Problem in the Military

INTRODUCTION

Musculoskeletal injuries (MSIs) have direct impact on occupational readiness and task performance in military populations. Until this date, no epidemiologic data have been published concerning MSI incidence in the Netherlands Armed Forces (NAF). The aim of this study was to assess the MSI incidence and related costs in the NAF.

METHODS

In this descriptive epidemiologic study, we collected injury surveillance data from the electronic patient records of multiple military units of the NAF. Using data of all new consultations with a military physician from January 1, 2014 to December 31, 2016, we calculated MSI incidence rates per 100 person-years, with a 95% confidence interval (CI). Physician care costs were determined based on the number of physician consults and the charge per appointment. We used two methods to determine productivity costs; the top-down microcosting method and the friction cost method.

RESULTS

Our study sample included 22% (n = 8,847) of the total NAF population of 2016 (n =40,178). In this sample, consultations of MSIs accounted for 23.2% (n = 7,815) of all new consultations (n = 33,666). MSI incidence rates per unit ranged from 12.5 to53.3 per 100 person-years. In the total sample, MSI incidence rates were highest in the back (6.73, 95% CI 6.39-7.10), knee (5.04, 95% CI 4.74-5.35), and foot (4.79, 95% CI 4.50-5.10). The estimated costs for physician visits for MSIs in our sample were €0.69 million. Limited duty days accounted for €1.10 million productivity costs using top-down microcosting method.

CONCLUSION

Our study provided evidence that MSIs result in substantial financial burden. Injuries of the back, knee, and foot account for the majority of demands on curative care for MSIs.

Determining the role of sport coaches in promoting athlete mental health: a narrative review and Delphi approach

Background

Coaches have the potential to support athlete mental wellness, but many are unsure what to do and concerned they may unintentionally engage in behaviours that negatively impact their athletes. Education has the potential to help coaches engage in primary, secondary and tertiary preventive behaviours related to athlete mental health; however, there exists no empirical or consensus basis for specifying the target behaviours that should be included in such education.

Objective

The aim of this research was to review extant literature about the role of sport coaches in mental health prevention and promotion, and obtain expert consensus about useful, appropriate and feasible coach behaviours.

Design

Modified Delphi methodology with exploration (ie, narrative review) and evaluation phase.

Data sources

Twenty-one articles from PubMed, PsycINFO and ProQuest, and grey literature published by prominent sport organisations.

Eligibility criteria for selecting studies

All studies were English-language articles that focused on the role of coaches as they relate to (1) culture setting in sport, (2) addressing athlete mental health and (3) providing ongoing support to athletes with mental health concerns. No study design, publication date limits or sport characteristics were applied.

Results

The coach's role should include fostering team cultures that support athlete mental health, encouraging care-seeking and supporting athletes currently receiving mental healthcare.

Summary/Conclusion

The behaviours specified herein have implications for coach education programme development. This study is the first to use a structured Delphi process to develop specific recommendations about the role coaches can play in supporting athlete mental health.

Content validity of the SOS-WRIST questionnaire for timely identification of wrist overuse in young athletes

Objectives: Young athletes do not always seek medical help for overuse wrist injuries, risking invalidating long-term consequences resulting from late diagnosis. This study aimed to develop a questionnaire to identify overuse wrist injuries in young athletes. Methods: According to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria, items were collected from literature and 6 focus groups of sports physicians and of young athletes with (previous) overuse wrist injuries. An expert panel and 40 Delphi study participants performed item reduction. Young athletes evaluated comprehensiveness during interviews and English translation was performed according to linguistic validation guidelines. Results: In total 323 items were generated and 110 were marked important by focus group participants. The resulting questionnaire consists of 18 multiple-choice questions about wrist pain during sports (e.g. pain during training, skipping training sessions/elements) and daily life activities (e.g. writing, turning a key), and other symptoms (e.g. reduced strength, swelling). Conclusion: The SOS-WRIST questionnaire for identification of overuse wrist injuries in young athletes has good content validity. It can be used to promote awareness and timely treatment of overuse wrist injuries in young athletes.

Ankle Sprain Versus Muscle Strain Injury in Professional Men's Basketball: A 9-Year Prospective Follow-up Study

Background:

Ankle sprain is the most common injury in basketball players. However, in our routine clinical evaluation, we observe a high frequency of muscle injury. Currently, no reliable information is available regarding the magnitude of these types of injury.

Purpose:

To describe the type and rate of muscle injuries in male basketball players and discuss clinical management and prevention strategies.

Study Design:

Descriptive epidemiology study.

Methods:

A total of 59 professional male basketball players were evaluated over 9 seasons (2007-2015). All injuries during the study period were registered through use of a validated electronic medical record system.

Results:

We analyzed 463 injuries, of which 207 resulted in time loss and 256 required medical attention, for a total exposure time of 42,678 hours for the 59 players involved in the study. Muscle strains and ankle sprains accounted for 21.2% (n = 98) and 11.9% (n = 55) of all injuries, respectively. The global incidence rate was 10.8 injuries per 1000 player-hours (95% CI, 9.9-11.9). The global injury burden was 53.9 days lost due to injuries per 1000 hours for a total exposure time. The incidence rate of muscle strains (2.3; 95% CI, 1.9-2.8) was higher than that of ankle sprains (1.3; 95% CI, 1-1.7). The incidence rate for muscle injuries for the entire study period was 1.8 times higher (95% CI, 1.28-2.49) than that for ankle sprains.

Conclusion:

In this study, muscle injuries were more commonly observed compared with ankle sprains. Prevention strategies for muscle injuries may be worth discussing.

Epidemiology of elite sprint kayak injuries: A 3-year prospective study

OBJECTIVES

To analyse the characteristics of injuries sustained by elite sprint kayak athletes, to investigate relationships between initial and subsequent injuries, and to examine injury differences between male and female athletes.

DESIGN

Descriptive epidemiology study.

METHODS

Data from 63 athletes (37 male, 26 female) of the Australian national sprint kayak squad were prospectively collected over three continuous years (September 2014-August 2017). All medical attention injuries were recorded irrespective of time-loss and modality of training. Descriptive analyses were performed, and frequency comparisons across genders assessed with chi squared tests.

RESULTS

Forty-nine athletes (78%) sustained 146 injuries (median=2, interquartile range=1-4, range=0-12). Most injuries were to the upper limb (48%), with the shoulder being the most common body site injured (27%). Thirty-one athletes (49%) sustained at least one subsequent injury, equating to 97 subsequent injuries. The majority (68%) of subsequent injuries occurred at a different site and nature to previous injuries. Male athletes were more likely to sustain an injury than remain injury free compared to female athletes (Chi²₍₁₎=6.75, p=0.009), but there was no difference between males and females who thereafter sustained a subsequent injury (Chi²₍₁₎=0.84, p=0.359).

CONCLUSIONS

Injury occurrence is common in sprint kayak, with many athletes experiencing more than one injury. Small variations in injury characteristics exist between male and female athletes in sprint kayak. This study identifies upper limb and trunk, and joint and muscle injuries as the most prevalent sprint kayak injuries, providing a focus for the development of future injury prevention strategies.

A 12-Year Cohort Study of Doc-Stoppage in Professional Mixed Martial Arts

Purposes: To determine actions during bouts that generate serious enough injury to stop the bout; verifying the injury incidence, types, and prevalence of doctor stoppages (doc-stoppage); and identify potential risk factors by analyzing technical-tactical profiles for injury in sanctioned mixed martial arts bouts taking place over a 12-y period. Methods: This research analyzed 440 paired mixed martial arts matches separated by doc-stoppage (n = 220) and no doc-stoppage (n = 220) from 2002 to 2014. Technical knockouts for doc-stoppage were diagnosed and managed by attending ringside doctors, and the time–motion variables were categorized into total combat time separated by low- or high-intensity activities per round, stand-up, or groundwork actions, P ≤ .05. Results: The main cause of injuries in doc-stoppage situations was due to facial injuries (>90%), with 87.1% occurring after striking actions during the second round. Lacerations were the leading type of injury, which occurred with 80% frequency. The results showed differences between doc-stoppage and no doc-stoppage for standing combat with low-intensity actions (130.6 [8.5] s vs 83.3 [6.9] s for first round; 115.7 [10.5] s vs 100.1 [9.6] s for second round, and 121.5 [19.5] s vs 106.3 [11.7] s for third round) and total strike attempts (34.5, 23.0–51.8 vs 25.0, 12.0–40.8); in standing combat, head strike attempts (21, 10–33 vs 11, 4–21) and body strikes (2.5, 1.0–5.8 vs 1.0–2), and in groundwork combat, head strikes landed (0.0–3.0 vs 0.0–5.0). Conclusions: This research showed higher values of strike attempts with 2 main orientations, namely the head (on the ground and in stand-up actions) and body (in stand-up actions), and may provide important information regarding the technical knockout and when it can be called by officials supervising mixed martial arts bouts.

Towards a complex systems approach in sports injury research: simulating running-related injury development with agent-based modelling

OBJECTIVES

There have been recent calls for the application of the complex systems approach in sports injury research. However, beyond theoretical description and static models of complexity, little progress has been made towards formalising this approach in way that is practical to sports injury scientists and clinicians. Therefore, our objective was to use a computational modelling method and develop a dynamic simulation in sports injury research.

METHODS

Agent-based modelling (ABM) was used to model the occurrence of sports injury in a synthetic athlete population. The ABM was developed based on sports injury causal frameworks and was applied in the context of distance running-related injury (RRI). Using the acute:chronic workload ratio (ACWR), we simulated the dynamic relationship between changes in weekly running distance and RRI through the manipulation of various 'athlete management tools'.

RESULTS

The findings confirmed that building weekly running distances over time, even within the reported ACWR 'sweet spot', will eventually result in RRI as athletes reach and surpass their individual physical workload limits. Introducing training-related error into the simulation and the modelling of a 'hard ceiling' dynamic resulted in a higher RRI incidence proportion across the population at higher absolute workloads.

CONCLUSIONS

The presented simulation offers a practical starting point to further apply more sophisticated computational models that can account for the complex nature of sports injury aetiology. Alongside traditional forms of scientific inquiry, the use of ABM and other simulation-based techniques could be considered as a complementary and alternative methodological approach in sports injury research.

The Association Between Changes in Weekly Running Distance and Running-Related Injury: Preparing for a Half Marathon

BACKGROUND

Sudden changes in training load may play a key role in the development of running-related injury (RRI). Because the injury mechanism depends on the runner's musculoskeletal load capacity, the running schedule followed prior to sudden change in training load may influence the amount of change that a runner can tolerate before the runner is at a higher risk of RRI.

OBJECTIVES

To investigate the association between change in weekly running distance and RRI, and to examine whether the association may be modified by the running schedule the runner follows.

METHODS

Two hundred sixty-one healthy (noninjured) runners were included in this prospective cohort study over a period of 14 weeks. Data on running activity were collected daily and objectively, using a global positioning system watch or smartphone. Instances of RRIs were collected using weekly e-mailed questionnaires. Primary exposure was defined as changes in weekly running distance. Data were analyzed with time-to-event models that produced cumulative risk difference as the measure of association.

RESULTS

A total of 56 participants (21.5%) sustained an RRI during the 14-week study period. Twenty-one days into the study period, significantly more runners were injured when they increased their weekly running distance by 20% to 60% compared with those who increased their distance by less than 20% (risk difference, 22.6%; 95% confidence interval: 0.9%, 44.3%; P = .041). No significant difference was found after 56 and 98 days. No significant effect-measure modification by running schedule was found.

CONCLUSION

Significantly more runners were injured 21 days into the study period when they increased their weekly running distances by 20% to 60% compared with those who increased their distances by less than 20%.

LEVEL OF EVIDENCE

Prognosis, level 1b. J Orthop Sports Phys Ther 2019;49(4):230-238. Epub 7 Dec 2018. doi:10.2519/jospt.2019.8541.

Periodic Health Examination and Injury Prediction in Professional Football (Soccer): Theoretically, the Prognosis is Good

In professional soccer and other elite sports, medical and performance screening of athletes (also termed periodic health examination or PHE) is common practice. The purposes of this are: (1) to assist in identifying prevalent conditions that may be a threat to safe participation, (2) to assist in setting benchmark targets for rehabilitation or performance purposes and (3) to assist clinicians in determining which athletes may be at risk of future injury and selecting appropriate injury prevention strategies to reduce the perceived risk. However, when using PHE as an injury prevention tool, are clinicians seeking to identify potential causes of injury or to predict future injury? This Current Opinion aims to examine the conceptual differences between aetiology and prediction of injury while relating these areas to the capabilities of PHE in practice. We also introduce the concept of prognosis—a broader approach that is closely related to prediction—and why this may have greater applicability to PHE of professional athletes.

A systematic review of injuries in gymnastics

OBJECTIVES

To identify all studies of gymnastics injuries and assess injury rates, types, locations, and causes.

METHODS

Seven electronic and two grey literature databases were searched. Two reviewers independently assessed titles/abstracts, abstracted data, and calculated average rates weighted by study size.

RESULTS

One study (n = 963) of three Olympic games (2008,2012,2016) provided injury rates for females of 86.4/1000gymnasts and males 79.9. For 29 databases one study of males (n = 64) provided a rate of 8.8 injuries/1000hours/AE (AE = athletic-exposure) and three of females varied rates (8.5, 9.4, and 91). Three studies for males (n = 153) provided a weighted average rate of 1.4 injuries/1000hours/training, and for females six studies (n = 476) 1.5 injuries. Four studies of males (n = 286) provided a weighted average of 678 injuries/1000gymnasts per year and eight studies of females (n = 1,764) a rate of 306. Of 19 surveys, eight provided rates for females (n = 1,463) of 596 injuries/gymnast per year and two for males (n = 40) a rate of 1,036. In the Olympics injuries were preponderately lower limb (63%) then trunk (23%) and upper limb (14%); injury type was sprains (35%) followed by tendinopathy/arthritis/impingements (17%), contusions (10%), and fractures (7%). Five database studies provided injury location data for 274 males: averages weighted by study size were upper extremity 42.8%, lower extremity 33.6%, torso/spine 11.8%, and head/neck 4.9% and 12 studies with 843 females provided average rates for lower extremity 51%, upper extremity 30.8%, torso/spine 13% and head/neck 0.8%. Official gymnastics organizations' websites provide no readily available data about injury rates or methods of prevention.

CONCLUSIONS

Studies need to collect comprehensive data for injury rates by training/competitions, gender, age, injury location/type/cause. Studies could assess whether trainers and physiotherapists monitoring gymnasts closely for injury risk would reduce injuries. Studies including randomized controlled trials (RCTs) of interventions in training, videotaping and performance feedback to reduce injury rates would be helpful.

Time-to-event analysis for sports injury research part 1: time-varying exposures

BACKGROUND

'How much change in training load is too much before injury is sustained, among different athletes?' is a key question in sports medicine and sports science. To address this question the investigator/practitioner must analyse exposure variables that change over time, such as change in training load. Very few studies have included time-varying exposures (eg, training load) and time-varying effect-measure modifiers (eg, previous injury, biomechanics, sleep/stress) when studying sports injury aetiology.

AIM

To discuss advanced statistical methods suitable for the complex analysis of time-varying exposures such as changes in training load and injury-related outcomes.

CONTENT

Time-varying exposures and time-varying effect-measure modifiers can be used in time-to-event models to investigate sport injury aetiology. We address four key-questions (i) Does time-to-event modelling allow change in training load to be included as a time-varying exposure for sport injury development? (ii) Why is time-to-event analysis superior to other analytical concepts when analysing training-load related data that changes status over time? (iii) How can researchers include change in training load in a time-to-event analysis? and, (iv) Are researchers able to include other time-varying variables into time-to-event analyses? We emphasise that cleaning datasets, setting up the data, performing analyses with time-varying variables and interpreting the results is time-consuming, and requires dedication. It may need you to ask for assistance from methodological peers as the analytical approaches presented this paper require specialist knowledge and well-honed statistical skills.

CONCLUSION

To increase knowledge about the association between changes in training load and injury, we encourage sports injury researchers to collaborate with statisticians and/or methodological epidemiologists to carefully consider applying time-to-event models to prospective sports injury data. This will ensure appropriate interpretation of time-to-event data.

A Narrative Review of the Physical Demands and Injury Incidence in American Football: Application of Current Knowledge and Practices in Workload Management

The sport of American football (AmF) exposes athletes to high-velocity movements and frequent collisions during competition and training, placing them at risk of contact and non-contact injury. Due to the combative nature of the game, the majority of injuries are caused by player contact; however, a significant number are also non-contact soft-tissue injuries. The literature suggests that this mechanism of injury can be prevented through workload monitoring and management. The recent introduction of microtechnology into AmF allows practitioners and coaches to quantify the external workload of training and competition to further understand the demands of the sport. Significant workload differences exist between positions during training and competition; coupling this with large differences in anthropometric and physical characteristics between and within positions suggests that the training response and physiological adaptations will be highly individual. Effective athlete monitoring and management allows practitioners and coaches to identify how athletes are coping with the prescribed training load and, subsequently, if they are prepared for competition. Several evidence-based principles exist that can be adapted and applied to AmF and could decrease the risk of injury and optimise athletic performance.

Improvement of Prediction of Noncontact Injury in Elite Australian Footballers With Repeated Exposure to Established High-Risk Workload Scenarios

OBJECTIVES

To assess the effect of multiple high-risk-scenario (HRS) exposures on noncontact injury prediction in elite Australian footballers.

DESIGN

Retrospective cohort study.

METHODS

Sessional workload data (session rating of perceived exertion, global positioning system-derived distance, sprint distance, and maximum velocity) from 1 club (N = 60 players) over 3 seasons were collated; several established HRSs were also defined. Accumulated HRS sessional exposures were calculated retrospectively (previous 1-8 wk). Noncontact injury data were documented. Univariate and multivariate Poisson regression models determined injury incidence rate ratios (IRRs) while accounting for moderating effects (preseason workload volume and playing experience). Model performance was evaluated using receiver operating characteristics (area under curve).

RESULTS

Very low (0-8 sessions: IRR = 5.76; 95% confidence interval [CI], 1.69-19.66) and very high (>15 sessions: IRR = 4.70; 95% CI, 1.49-14.87) exposures to >85% of an individual's maximal velocity over the previous 8 wk were associated with greater injury risk compared with moderate exposures (11-12 sessions) and displayed the best model performance (area under curve = 0.64). A single session corresponding to a very low chronic load condition over the previous week for all workload variables was associated with increased injury risk, with sprint distance (IRR = 3.25; 95% CI, 1.95-5.40) providing the most accurate prediction model (area under curve = 0.63).

CONCLUSIONS

Minimal exposure to high-velocity efforts (maximum speed exposure and sprint volume) was associated with the greatest injury risk. Being underloaded may be a mediator for noncontact injury in elite Australian football. Preseason workload and playing experience were not moderators of this effect.

Progression in Running Intensity or Running Volume and the Development of Specific Injuries in Recreational Runners: Run Clever, a Randomized Trial Using Competing Risks

BACKGROUND

It has been proposed that training intensity and training volume are associated with specific running-related injuries. If such an association exists, secondary preventive measures could be initiated by clinicians, based on symptoms of a specific injury diagnosis.

OBJECTIVES

To test the following hypotheses: (1) a running schedule focusing on running intensity (S-I) would increase the risk of sustaining Achilles tendinopathy, gastrocnemius injuries, and plantar fasciitis compared with hypothesized volume-related injuries; and (2) a running schedule focusing on running volume (S-V) would increase the risk of sustaining patellofemoral pain syndrome, iliotibial band syndrome, and patellar tendinopathy compared with hypothesized intensity-related injuries.

METHODS

In this randomized clinical trial and etiology study, healthy recreational runners were included in a 24-week follow-up, divided into 8-week preconditioning and 16-week specific-focus training periods. Participants were randomized to 1 of 2 running schedules: S-I or S-V. The S-I group progressed the amount of high-intensity running (88% maximal oxygen consumption [VO₂max] or greater) each week, and the S-V group progressed total weekly running volume. A global positioning system watch or smartphone collected data on running. Running-related injuries were diagnosed based on a clinical examination. Estimates were reported as risk difference and 95% confidence interval (CI).

RESULTS

Of 447 runners, a total of 80 sustained an injury (S-I, n = 36; S-V, n = 44). Risk differences (95% CIs) of intensity injuries in the S-I group were -0.8% (-5.0%, 3.4%) at 2 weeks, -0.8% (-6.7%, 5.1%) at 4 weeks, -2.0% (-9.2%, 5.2%) at 8 weeks, and -5.1% (-16.5%, 6.3%) at 16 weeks. Risk differences (95% CIs) of volume injuries in the S-V group were -0.9% (-5.0%, 3.2%) at 2 weeks, -2.0% (-7.5%, 3.5%) at 4 weeks, -3.2% (-9.1%, 2.7%) at 8 weeks, and -3.4% (13.2%, 6.2%) at 16 weeks.

CONCLUSION

No difference in risk of hypothesized intensity- and volume-specific running-related injuries exists between the 2 running schedules focused on progression in either running intensity or volume.

LEVEL OF EVIDENCE

Etiology, level 1b. J Orthop Sports Phys Ther 2018;48(10):740-748. Epub 12 Jun 2018. doi:10.2519/jospt.2018.8062.

Injury rate and patterns of Sydney grade cricketers: a prospective study of injuries in 408 cricketers

Background

The grade cricket competition, also known as premier cricket, supplies players to the state and national teams in Australia. The players involved are generally high-performing amateur (subelite) club cricketers. However, to date, there is no study on the injury epidemiology of Australian grade cricket.

Aim

To conduct injury surveillance across all teams playing Sydney Grade Cricket (SGC) competition during the 2015–2016 season.

Methods

A cohort study was conducted to track injuries in 408 male cricketers in 20 teams playing SGC competition. Players were tracked through the MyCricket website’s scorebook every week. Cricket New South Wales physiotherapists were alerted if there were changes to the playing XI from the last game. If any changes were made due to injury, then an injury incident was registered.

Results

During the course of the season, a total of 86 injuries were registered from 65 players, resulting in a loss of 385 weeks of play. The overall injury incidence rate was 35.54 injuries/10 000 playing hours with an average weekly injury prevalence of 4.06%. Lower back injuries (20%) were the most common injuries followed by foot (14%), hand (13.75%), knee (7.5%) and calf (7.5%). Linear regression analysis showed that the likelihood of injury increased as the mean age of the teams increased (R=0.5, p<0.05).

Conclusion

The injury rate in SGC is lower than that reported at elite level. However, the high rate of lower back injuries (20%) highlights an area of concern in this cohort. High workloads or inadequate physical conditioning may contribute to such injuries. This study sets the foundation for understanding injury epidemiology in grade cricket and examines the links between injury and performance, these results may assist coaches and administrators to develop and implement cricket-specific injury prevention programmes.

Study protocol of a 52-week Prospective Running INjury study in Gothenburg (SPRING)

INTRODUCTION

It is assumed that a running-related (overuse) injury occurs when a specific structure of the human body is exposed to a load that exceeds that structures' load capacity. Therefore, monitoring training load is an important key to understanding the development of a running-related injury. Additionally, other distribution, magnitude and capacity-related factors should be considered when aiming to understand the causal chain of injury development. This paper presents a study protocol for a prospective cohort study that aims to add comprehensive information on the aetiology of running-related injuries and present a new approach for investigating changes in training load with regard to running-related injuries.

METHODS AND ANALYSIS

This study focused on recreational runners, that is, runners exposed to a minimum weekly average of 15 km for at least 1 year. Participants will undergo baseline tests consisting of a clinical/anthropometrical examination and biomechanical measurements. Furthermore, participants will log all training sessions in a diary on a weekly basis for 1 year. The primary exposure variable is changes in training load. A medical practitioner will examine runners suffering from running-related pain and, if possible, make a clear diagnosis. Finally, additional time-varying exposure variables will be included in the main analysis, whereas the analysis for the secondary purpose is based on time-fixed baseline-related risk factors.

ETHICS AND DISSEMINATION

Ethical approval (DNR: 712-15) for the study and its design was obtained from the Gothenburg regional ethical review board. The results of the study will be published in peer-reviewed journals.

Training Load and Fatigue Marker Associations with Injury and Illness: A Systematic Review of Longitudinal Studies

Background

Coaches, sport scientists, clinicians and medical personnel face a constant challenge to prescribe sufficient training load to produce training adaption while minimising fatigue, performance inhibition and risk of injury/illness.

Objective

The aim of this review was to investigate the relationship between injury and illness and longitudinal training load and fatigue markers in sporting populations.

Methods

Systematic searches of the Web of Science and PubMed online databases to August 2015 were conducted for articles reporting relationships between training load/fatigue measures and injury/illness in athlete populations.

Results

From the initial 5943 articles identified, 2863 duplicates were removed, followed by a further 2833 articles from title and abstract selection. Manual searching of the reference lists of the remaining 247 articles, together with use of the Google Scholar ‘cited by’ tool, yielded 205 extra articles deemed worthy of assessment. Sixty-eight studies were subsequently selected for inclusion in this study, of which 45 investigated injury only, 17 investigated illness only, and 6 investigated both injury and illness. This systematic review highlighted a number of key findings, including disparity within the literature regarding the use of various terminologies such as training load, fatigue, injury and illness. Athletes are at an increased risk of injury/illness at key stages in their training and competition, including periods of training load intensification and periods of accumulated training loads.

Conclusions

Further investigation of individual athlete characteristics is required due to their impact on internal training load and, therefore, susceptibility to injury/illness.

Relationships Between the External and Internal Training Load in Professional Soccer: What Can We Learn From Machine Learning?

Purpose: Machine learning may contribute to understanding the relationship between the external load and internal load in professional soccer. Therefore, the relationship between external load indicators (ELIs) and the rating of perceived exertion (RPE) was examined using machine learning techniques on a group and individual level. Methods: Training data were collected from 38 professional soccer players over 2 seasons. The external load was measured using global positioning system technology and accelerometry. The internal load was obtained using the RPE. Predictive models were constructed using 2 machine learning techniques, artificial neural networks and least absolute shrinkage and selection operator (LASSO) models, and 1 naive baseline method. The predictions were based on a large set of ELIs. Using each technique, 1 group model involving all players and 1 individual model for each player were constructed. These models’ performance on predicting the reported RPE values for future training sessions was compared with the naive baseline’s performance. Results: Both the artificial neural network and LASSO models outperformed the baseline. In addition, the LASSO model made more accurate predictions for the RPE than did the artificial neural network model. Furthermore, decelerations were identified as important ELIs. Regardless of the applied machine learning technique, the group models resulted in equivalent or better predictions for the reported RPE values than the individual models. Conclusions: Machine learning techniques may have added value in predicting RPE for future sessions to optimize training design and evaluation. These techniques may also be used in conjunction with expert knowledge to select key ELIs for load monitoring.

Monitoring and Managing Fatigue in Basketball

The sport of basketball exposes athletes to frequent high intensity movements including sprinting, jumping, accelerations, decelerations and changes of direction during training and competition which can lead to acute and accumulated chronic fatigue. Fatigue may affect the ability of the athlete to perform over the course of a lengthy season. The ability of practitioners to quantify the workload and subsequent fatigue in basketball athletes in order to monitor and manage fatigue levels may be beneficial in maintaining high levels of performance and preventing unfavorable physical and physiological training adaptations. There is currently limited research quantifying training or competition workload outside of time motion analysis in basketball. In addition, systematic research investigating methods to monitor and manage athlete fatigue in basketball throughout a season is scarce. To effectively optimize and maintain peak training and playing performance throughout a basketball season, potential workload and fatigue monitoring strategies need to be discussed.

Run Clever - No difference in risk of injury when comparing progression in running volume and running intensity in recreational runners: A randomised trial

Background/aim

The Run Clever trial investigated if there was a difference in injury occurrence across two running schedules, focusing on progression in volume of running intensity (Sch-I) or in total running volume (Sch-V). It was hypothesised that 15% more runners with a focus on progression in volume of running intensity would sustain an injury compared with runners with a focus on progression in total running volume.

Methods

Healthy recreational runners were included and randomly allocated to Sch-I or Sch-V. In the first eight weeks of the 24-week follow-up, all participants (n=839) followed the same running schedule (preconditioning). Participants (n=447) not censored during the first eight weeks entered the 16-week training period with a focus on either progression in intensity (Sch-I) or volume (Sch-V). A global positioning system collected all data on running. During running, all participants received real-time, individualised feedback on running intensity and running volume. The primary outcome was running-related injury (RRI).

Results

After preconditioning a total of 80 runners sustained an RRI (Sch-I n=36/Sch-V n=44). The cumulative incidence proportion (CIP) in Sch-V (reference group) were CIP_{2 weeks} 4.6%; CIP_{4 weeks} 8.2%; CIP_{8 weeks} 13.2%; CIP_{16 weeks} 28.0%. The risk differences (RD) and 95% CI between the two schedules were RD_{2 weeks}=2.9%(−5.7% to 11.6%); RD_{4 weeks}=1.8%(−9.1% to 12.8%); RD_{8 weeks}=−4.7%(−17.5% to 8.1%); RD_{16 weeks}=−14.0% (−36.9% to 8.9%).

Conclusion

A similar proportion of runners sustained injuries in the two running schedules.

Effectiveness of online tailored advice to prevent running-related injuries and promote preventive behaviour in Dutch trail runners: a pragmatic randomised controlled trial

BACKGROUND

Trail running is popular worldwide, but there is no preventive intervention for running-related injury (RRI).

AIM

To evaluate the effectiveness of adding online tailored advice (TrailS₆ ) to general advice on (1) the prevention of RRIs and (2) the determinants and actual preventive behaviour in Dutch trail runners.

METHODS

Two-arm randomised controlled trial over 6 months. 232 trail runners were randomly assigned to an intervention or control group. All participants received online general advice on RRI prevention 1 week after baseline. Every 2 weeks, participants in the intervention group received specific advice tailored to their RRI status. The control group received no further intervention. Bayesian mixed models were used to analyse the data.

RESULTS

Trail runners in the intervention group sustained 13% fewer RRIs compared with those in the control group after 6 months of follow-up (absolute risk difference -13.1%, 95% Bayesian highest posterior credible interval (95% BCI) -23.3 to -3.1). A preventive benefit was observed in one out of eight trail runners who had received the online tailored advice for 6 months (number needed to treat 8, 95% BCI 3 to 22). No significant between-group difference was observed on the determinants and actual preventive behaviours.

CONCLUSIONS

Online tailored advice prevented RRIs among Dutch trail runners. Therefore, online tailored advice may be used as a preventive component in multicomponent RRI prevention programmes. No effect was observed on determinants and actual preventive behaviours.

TRIAL REGISTRATION NUMBER

The Netherlands National Trial Register (NTR5431).

Identifying high risk loading conditions for in-season injury in elite Australian football players

OBJECTIVES

To examine different timeframes for calculating acute to chronic workload ratio (ACWR) and whether this variable is associated with intrinsic injury risk in elite Australian football players.

DESIGN

Prospective cohort study.

METHODS

Internal (session rating of perceived exertion: sRPE) and external (GPS distance and sprint distance) workload and injury data were collected from 70 players from one AFL club over 4 seasons. Various acute (1-2 weeks) and chronic (3-8 weeks) timeframes were used to calculate ACWRs: these and chronic load categories were then analysed to determine the injury risk in the subsequent month. Poisson regression with robust errors within a generalised estimating equation were utilised to determine incidence rate ratios (IRR).

RESULTS

Altering acute and/or chronic timeframes did not improve the ability to detect high injury risk conditions above the commonly used 1:4 week ACWR. Twenty-seven ACWR/chronic load combinations were found to be "high risk conditions" (IRR>1, p<0.05) for injury within 7 days. Most (93%) of these conditions occurred when chronic load was low or very low and ACWR was either low (<0.6) or high (>1.5). Once a high injury risk condition was entered, the elevated risk persisted for up to 28 days.

CONCLUSIONS

Injury risk was greatest when chronic load was low and ACWR was either low or high. This heightened risk remained for up to 4 weeks. There was no improvement in the ability to identify high injury risk situations by altering acute or chronic time periods from 1:4 weeks.

A Profile of Injuries Sustained by Law Enforcement Officers: A Critical Review

Due to the unpredictable, varied and often physical nature of law enforcement duties, police officers are at a high risk of work-related physical injury. The aim of this critical narrative review was to identify and synthesize key findings of studies that have investigated musculoskeletal injuries sustained by law enforcement officers during occupational tasks. A systematic search of four databases using key search terms was conducted to identify potentially relevant studies, which were assessed against key inclusion and exclusion criteria to determine studies to be included in the review. Included studies were critically appraised and the level of evidence determined. Relevant data were extracted, tabulated and synthesized. The 16 identified studies ranged in percentage quality scores from 25.00% to 65.00%, with a mean score of 41.25% and high interrater agreement in scores reflected in a Cohen’s Kappa coefficient, κ = 0.977. The most common body site of injury was the upper extremity, the most common injury types were soft-tissue sprains and strains and the most common cause of injury was a non-compliant offender, often involving assault. However, there was limited peer reviewed research in this area and the published research had a narrow focus and was of low to fair methodological quality.

Stress-related psychological factors for back pain among athletes: Important topic with scarce evidence

Health issues represent a frequent problem for athletes, as this particular demographic is repeatedly confronted with physically and psychologically stressful situations. Back pain (BP) materialises as comparatively common health problem being regarded as functionally limiting and psychologically straining burden for athletes. According to research conducted on athletes with BP, biomechanical and physiological mechanisms emerge as influential, whereas stress-related psychological factors appear to be neglected. For athletic injuries, the essential impact of psychological processes on injury occurrence and return from injury has already been corroborated. Hence, the aim of this literature review is to: (1) introduce a conceptual differentiation between injuries and BP; (2) summarise the results obtained regarding stress-related psychological aspects for injuries; and (3) connect the injury research to the state-of-the-art evidence regarding stress-related factors for BP among athletes. A distinction between injuries and BP could be established based on previous definitions, despite the fact that a considerable overlap between both concepts prevails. Injuries can be attributed to a physical origin, whereas BP frequently lacks this physical criterion. For BP, our enquiry yielded four studies including psychological measures of stress - with two studies specifically examining the association between BP and psychological stress among athletes longitudinally. Abundant findings from the general population support the importance of considering psychological and specifically stress-related factors in BP prevention and rehabilitation, but evidence related to the athletic field remains elusive. Further scientific investigations with a wider methodological approach are needed to deepen the knowledge about the crucial relationship between psychological stress, BP, and athletes.