The Adductor Strengthening Programme prevents groin problems among male football players: a cluster-randomised controlled trial

Effects of a Groin Pain Prevention Program in Male High School Soccer Players: A Cluster-Randomized Controlled Trial

Background

Groin pain is frequently reported by soccer players. A prevention program incorporating the Copenhagen adduction exercise (CAE) has been shown effective in decreasing adductor muscle injury in semi-professional soccer players. However, the effect of such programs on groin pain in high school soccer players is unknown. No reports have examined the effects of combining the CAE with other targeted exercises such as the Nordic hamstrings exercise (NHE).

Purpose

To evaluate the preventative effects of exercise on groin pain in high school soccer players in three groups comprising NHE alone, combined NHE and CAE, and a control group.

Design

Randomized Controlled Clinical Trial.

Methods

A cluster randomized controlled trial spanning 16 weeks was conducted on 202 high school soccer players from seven high schools in a Japanese under 18 Soccer League. Players were allocated to either group A (three schools, 66 players) receiving the CAE alone, or group B (two schools, 73 players) receiving the CAE and NHE, or control group C (two schools, 63 players) who performed their usual training. This study compared the number of injuries, injury rate, and severity of the injury of groin pain in these three groups.

Results

The number of players injured was less in group B (4 players) compared to C (18 players), and time-lost to soccer was less in groups A (6 players) and B (3 players) compared to group C (16 players). Injury rates were significantly lower in groups A and B, with the relative risk of injury compared to group C of 0.42 (95% CI 0.19% to 0.90%) in group A and 0.19 (95% CI 0.07 to 0.54) in group B.

Conclusion

A 16-week program incorporating the CAE in training sessions in high school soccer players reduced the incidence of groin pain and which may be related to injury severity according to time -lost to soccer, however the combination of both the CAE and NHE may be more effective than the CAE alone.

Level of Evidence

2b.

Effects of Copenhagen Adduction Exercise on Muscle Architecture and Adductor Flexibility

Groin injuries are one of the most prevalent in sports, especially due to the hip adductor muscles’ weakness, which is considered as a risk factor. The Copenhagen adduction exercise (CAE) has been demonstrated to increase the strength of adductor muscles, but its effects on the architectural characteristics and flexibility of the adductors has been little studied. The aim of the present study was to analyse the impact on the muscular architecture and flexibility of the adductor musculature after 8 weeks of CAE-based training and after 4 weeks of subsequent detraining. A sample of 45 active subjects (26.1 ± 2.8 years old) were randomly divided into a control group with no intervention and an experimental group with an intervention based on 8 weeks of CAE training and 4 weeks of subsequent detraining. The muscle thickness of adductors was measured before and after training and detraining using ultrasound imaging and hip abduction range with goniometry. A significant increase in muscle thickness (left leg: +17.83%, d = 1.77, p < 0.001//right leg: +18.38%, d = 1.82, p < 0.001) and adductor flexibility was found in the experimental group (left leg: +7.3%, d = 0.96, p < 0.05//right leg: +7.15%, d = 0.94, p < 0.05), and after detraining, both variables returned to their initial values. These results could indicate that CAE would be a suitable strategy to modify the architecture of the adductors and thus form part of training protocols designed for the prevention and rehabilitation of muscle injuries.

Risk Factors for Groin Pain in Male High School Soccer Players Undergoing an Injury Prevention Program: A Cluster Randomized Controlled Trial

Little is known about the risk factors for developing groin pain in high school soccer players. Therefore, the purpose of the study is to investigate the risk factors for developing inguinal pain in high school soccer players who are undergoing an injury prevention program. A cluster randomized controlled trial was conducted on 202 high school soccer players. Players were allocated to either group A (3 schools, 66 players) receiving the Copenhagen adduction exercise (CAE) alone, or group B (2 schools, 73 players) receiving the CAE and Nordic hamstrings exercise, or group C, the control group without any intervention (2 schools, 63 players). Hip range of motion (ROM) and strength measures were assessed prior to a groin injury prevention program and used in univariate and multivariate analysis to predict development of groin pain. Logistic regression analysis identified that hip abduction ROM and eccentric adductor strength of the dominant leg were factors in the development of groin pain. Increased abduction ROM and decreased eccentric adductor muscle strength of the dominant leg were risk factors for the development of groin pain.

Injury incidence and prevalence in Finnish top-level football - one-season prospective cohort study

OJECTIVE

To investigate the injury characteristics in Finnish male football players.

DESIGN

One-season prospective epidemiological study. Data were collected via injury reports from the medical staff and directly from the players using the Olso Sports Trauma Research Center Health Questionnaire.

PARTICIPANTS

The first team squads of Finnish football league (n = 12 teams, 236 players).

MAIN OUTCOME MEASUREMENT

Injury incidence.

RESULTS

A total of 541 injuries occurred during the exposure of 62 878 hours. Injury incidence per 1000 exposure hours was 8.6 (30.6 in matches and 3.4 in training). A player sustained on average 2.3 (median 2, range 0-13) injuries during the study. Thigh and ankle were the most commonly injured body parts for acute injuries and hip/groin were the most commonly injured body part for overuse injuries. The median absence time for all injuries was 12 (range 0-107) days, 12 (range 0-107) for acute, and 8 (range 0-61) for overuse injuries. Thigh injuries caused the greatest consequences in terms of absence from full participation (median 5 days, range 0-88).

CONCLUSION

Lower limb muscle injuries were the most prevalent injuries in the study. Collecting data directly from the players enabled to report more injuries compared to what was reported only by the medical staff.

In Professional Male Soccer Players, Time-Loss Groin Injury Is More Associated With the Team Played for Than With Training/Match-Play Duration

OBJECTIVE

To investigate the relationship between training/match-play duration and time-loss groin injury in professional male soccer players, and to determine whether previously identified intrinsic risk factors influenced this relationship.

DESIGN

Prospective cohort study.

METHODS

A total of 579 professional male soccer players were prospectively followed from July 2013 to June 2015. Time-loss groin injuries and individual training and match-play duration were recorded using standardized surveillance methods. Acute training/match-play duration and chronic training/match-play duration were considered as interacting variables. Nonlinear Cox regression analysis (modeled using restricted cubic splines), clustered by player identification number, examined the relationship between training/match-play duration and groin injury. Previously identified intrinsic risk factors of previous groin injury and eccentric adduction strength were included in the multivariable regression analysis.

RESULTS

There was no clinically meaningful relationship between training/match-play duration and groin injury risk. Team played for had the strongest influence on groin injury risk (relative log hazard ratio -2.28 to 0.97). Groin injury risk was highest when accumulated chronic and acute training duration was also highest, but large confidence intervals indicate considerable uncertainty around this finding. Previous groin injury and eccentric adduction strength were not associated with groin injury risk when training/match-play duration and team were included in the model.

CONCLUSION

In professional male soccer players, there was no clinically meaningful relationship between groin injury risk and training/match-play duration. Team played for either protected against or increased groin injury risk, indicating that team-related factors not measured in this study had greater effect on groin injury risk than training/match-play duration. J Orthop Sports Phys Ther 2022;52(4):217-223. Epub 5 Feb 2022. doi:10.2519/jospt.2022.10845.

Multicomponent stretching and rubber band strengthening exercises do not reduce overuse shoulder injuries: a cluster randomised controlled trial with 579 handball athletes

Objectives

Handball is associated with a high risk of overuse shoulder injury. This study investigated if an injury prevention programme effectively reduces overuse injury to the throwing shoulder of handball athletes.

Methods

61 men’s and women’s handball teams (u-19 and senior athletes) were cluster-randomised into an intervention and a control group in the 2019–2020 season. Players of the intervention group regularly carried out an injury prevention programme. Both groups documented overuse shoulder injuries via an online questionnaire every second week. The primary endpoint was the prevalence of overuse injury to the throwing shoulder. Secondary endpoints were the influence of compliance on the primary endpoint and intensity of overuse shoulder symptoms measured by a shortened, handball-specific Western Ontario Shoulder Index (WOSI).

Results

31 teams (295 players) in the intervention group and 30 teams (284 players) in the control group were included for analyses. The overall questionnaire response rate was 61%. The average prevalence of overuse shoulder injury did not significantly differ between the intervention group (n=109, 38.4% (95% CI 32.9% to 44.2%)) and the control group (n=106, 35.9% (95% CI 30.7% to 41.6%), p=0.542). Compliance with the intervention programme did not significantly affect overuse shoulder injury (p=0.893). Using generalised estimating equations for WOSI, the estimated mean for the intervention group was 44.6 points (95% CI 42.0 to 47.1) and 47.6 points for the control group (95% CI 44.9 to 50.3, p=0.111).

Conclusions

A multicomponent exercise programme using rubber bands and stretching did not significantly reduce the prevalence or symptoms of overuse throwing shoulder injury in handball athletes of both sexes. Randomised controlled study; level of evidence I.

Trial registration number

ISRCTN99023492.

Adductor Muscle Injuries in UEFA Soccer Athletes: A Matched-Cohort Analysis of Injury Rate, Return to Play, and Player Performance From 2000 to 2015

Background:

The effects of adductor muscle injury on performance in soccer athletes are unknown.

Purpose:

To (1) determine the rate and time to return to play (RTP) after adductor muscle injury, (2) investigate the rate of reinjury after RTP, and (3) investigate any long-term effects of injury on elite soccer player performance.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Using publicly available records, athletes sustaining adductor muscle injury were identified across the 5 major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A) between 2000 and 2015. Injured athletes were matched to controls by demographic characteristics and performance metrics from 1 season before the index timepoint. Investigations included the rate of RTP, reinjuries, player characteristics associated with RTP within 2 seasons, player availability, field time, and performance metrics during the 4 seasons after injury.

Results:

A total of 671 players with adductor muscle injury were included. Based on time to RTP, 86% of injuries were mild to moderate (4-28 days missed), and 4% required surgical intervention. Players with adductor muscle injury were absent for a median of 22 days (range, 1-700 days) and 4 games (range, 1-76 games). A total of 521 (78%) players returned at the same level, with no demographic or clinical characteristics associated with RTP on the multivariable regression. Of those returning to play, 143 (21%) experienced adductor reinjury. After RTP, defenders demonstrated decreased field time compared with controls (P < .05). As compared with controls, defenders and midfielders scored more points and goals per game during the season of the injury (P < .01), while attackers recorded more goals and assists per game the season after injury (P < .05).

Conclusion:

Only 3 in 4 players (78%) returned to participate in an official match, and the reinjury rate was high (21%). After RTP, defenders demonstrated decreased field time versus controls. On the other hand, defenders and midfielders recorded more points and goals per game, while attackers recorded more goals and assists per game versus controls. Although the multivariable analysis results did not identify player characteristics associated with RTP, there was a position-dependent association on player performance after RTP.

Incidence, Prevalence, and Severity of and Risk Factors for Hip and Groin Problems in Swedish Male Ice Hockey Players: A 1-Season Prospective Cohort Study

CONTEXT

The epidemiologic focus on time loss may underestimate the true magnitude of hip and groin problems in male ice hockey players.

OBJECTIVE

To describe the prevalence, incidence, and severity of hip and groin problems (time loss and non-time loss) in Swedish ice hockey players over the course of a season and explore potential preseason risk factors for these conditions.

DESIGN

Prospective 1-season cohort study.

SETTING

Professional and semiprofessional Swedish ice hockey players.

PATIENTS OR OTHER PARTICIPANTS

A total of 12 professional and semiprofessional male ice hockey teams were invited to participate. Of those, 9 teams agreed, and 163 players were included in the analyses.

MAIN OUTCOME MEASURE(S)

Hip and groin problems in the previous season (time loss, non-time loss), isometric adduction and abduction strength, and 5-second squeeze test results were recorded before the season and served as independent variables in the risk factor analysis. Main outcome measures were cumulative incidence of hip and groin problems, average prevalence, and odds ratios (ORs) for groin problems in season.

RESULTS

Cumulative incidence was 45.4% (95% CI = 37.6%, 53.4%) for all problems and 19% (95% CI = 13.3%, 25.9%) for substantial problems. Average prevalence was 14.1% (95% CI = 10.8%, 17.5%) for all and 5.7% (95% CI = 4.3%, 7.2%) for substantial problems. Among reported problems, 69.2% had a gradual onset, and only 17% led to time loss. Players with non-time-loss problems in the previous season had higher odds for new problems (all: OR = 3.3 [95% CI = 1.7, 6.3]; substantial: OR = 3.6 [95% CI = 1.8, 8.4]). Preseason strength was not significantly associated with the odds for subsequent problems.

CONCLUSION

Hip and groin problems are common in ice hockey players and may lead to substantial impairments in performance. Only 1 in 5 problems led to time loss, and 7 in 10 had a gradual onset. Non-time-loss problems in the previous season were a significant risk factor for new problems, whereas decreased preseason hip-adduction and -abduction strength was not.

Physical exercises for preventing injuries among adult male football players: A systematic review

BACKGROUND

Football is the most practised sport in the world and is associated with the risk of injuries in the players. Some studies have been published that identify injury prevention programs, but there is no review of the full body of evidence on injury prevention programs for use by football coaches. The aim of this article was to carry out a systematic review of published studies on injury prevention programs for adult male footballers, identify points of common understanding and establish recommendations that should be considered in the design of injury prevention strategies.

METHODS

PubMed and EMBASE databases were used to identify relevant published articles using the following keywords: "soccer" AND "injury" AND "prevention".

RESULTS

A total of 2512 studies were identified initially, but only 11 studies met the inclusion criteria, and their outcomes are presented. Results revealed that injury prevention programs in football have focused on strength training, proprioceptive training, multicomponent programs (balance, core stability, and functional strength and mobility), and warm-up programs.

CONCLUSION

Based on results from the studies analyzed, football players can lower the incidence of match and training injuries by participating in dynamic warm-up programs that include preventive exercises before games or during training sessions, and by adding strength, balance, and mobility training to the training sessions.

Effects of Copenhagen Adduction Exercise on the Architectural Characteristics of Adductors in U-17 Male Soccer Players: A Randomized Controlled Trial

Groin injuries are one of the most prevalent in male soccer players, especially due to the hip adductor muscles’ weakness which is considered as a risk factor in these injuries. The Copenhagen adduction (CA) exercise has been demonstrated to increase the strength of adductor muscles, but its effects on the architectural characteristics of adductor muscles have not been studied yet. This study aimed to analyze the effects of the CA exercise on the muscle thickness of the adductors. Twelve male U-17 soccer players were randomized into two groups: the control group with no intervention and the experimental group with an intervention based on an eight-week training with CA exercise. The muscle thickness of adductors was measured before and after the intervention using ultrasound imaging. A significant increase in muscle thickness was found in both control (p = 0.002) and experimental group (p < 0.001), but the experimental group did not show additional effects in comparison with the control group. In conclusion, an 8-week CA exercise intervention does not increase the muscle thickness of adductors in U-17 soccer players more than their regular training.

Long-standing pubic-related groin pain in professional academy soccer players: a prospective cohort study on possible risk factors, rehabilitation and return to play

Background

Despite being a common overuse entity in youth soccer, scientific data on risk factors, rehabilitation and return to play for long-standing pubic-related groin pain is still rare. The current prospective cohort study aims to evaluate potential risk-factors, propose a criteria-based conservative rehabilitation protocol and assess return-to-play outcomes among professional youth soccer players suffering from long-standing pubic-related groin pain.

Methods

Male soccer players with long-standing (> 6 weeks) pubic-related groin pain from a professional soccer club’s youth academy were analyzed for possible risk factors such as age, team (U12 - U23), younger/older age group within the team, position and preinjury Functional movement score. All injured players received a conservative, standardized, supervised, criteria-based, 6-level rehabilitation program. Outcome measures included time to return to play, recurrent groin pain in the follow-up period and clinical results at final follow-up two years after their return to play.

Results

A total of 14 out of 189 players developed long-standing pubic-related groin pain in the 2017/2018 season (incidence 7.4%). The average age of the players at the time of the injury was 16.1 ± 1.9 years. Risk factor analysis revealed a significant influence of the age group within the team (p = .007). Only players in the younger age group were affected by long-standing pubic-related groin pain, mainly in the first part of the season. Injured players successfully returned to play after an average period of 135.3 ± 83.9 days. Only one player experienced a recurrence of nonspecific symptoms (7.1%) within the follow-up period. The outcome at the 24-month follow-up was excellent for all 14 players.

Conclusions

Long-standing pubic-related groin pain is an overuse entity with a markedly high prevalence in youth soccer players, resulting in a relevant loss of time in training and match play. In particular, the youngest players in each team are at an elevated risk. Applying a criteria-based rehabilitation protocol resulted in an excellent return-to-play rate, with a very low probability of recurrence.

Trial registration

The trial was retrospectively registered under DRKS00016510 in the German Clinical Trials Register on 19.04.2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04837-x.

Hip and groin function and strength in male ice hockey players with and without hip and groin problems in the previous season- a prospective cohort study

OBJECTIVE

To describe and compare hip and groin strength and function of male ice hockey players over one season in players with and without hip and groin problems in the previous season.

DESIGN

Prospective cohort study.

SETTING

Swedish male ice hockey.

PARTICIPANTS

We followed 193 players from 10 teams during the 2017/2018 season.

MAIN OUTCOME MEASURES

Hip adduction and abduction strength, 5 s squeeze test (5SST), and self-reported hip and groin function (Hip and Groin Outcome Score). Changes over the season and differences between players with and without problems in the previous season were analyzed by linear mixed models.

RESULTS

Adduction strength decreased slightly from pre-to mid-season and abduction strength increased slightly over the full season. However, self-reported function or pain did not change. Players with hip and groin problems in the previous season had significantly worse self-reported function, and more groin pain during the 5SST compared to players without. Strength measurments did not differ between groups.

CONCLUSIONS

Hip muscle strength, groin pain, and self-reported function appear to remain stable throughout the season in male ice hockey players. Remaining impairments in players with problems in the previous season suggest that function does not recover by ice hockey participation alone.

The Neuromuscular Effects of the Copenhagen Adductor Exercise: A Systematic Review

BACKGROUND

Groin strains are one of the most common time-loss injuries in athletes. The Copenhagen Adductor Exercise (CAE) eccentrically strengthens the adductors and may function to prevent adductor strains, similar to the eccentric mechanism in which the Nordic Hamstrings exercise acts to prevent hamstring strains.

OBJECTIVE

The purpose of this study was to systematically review the literature on the CAE and its effects on adductor muscle strength and muscle activity in athletes.

STUDY DESIGN

Systematic Review.

METHODS

A systematic search of the literature was performed in the following databases: Pubmed; Medline (EBSCO); Sportdiscus; Scopus; Web of Science; CINAHL; Proquest; Cochrane Library; Physiotherapy Evidence Database (PEDro). Inclusion criteria consisted of 1) implements CAE, 2) includes athletes of any age participating in at least one sport, 3) study type is a cohort study or randomized control trial. Studies were excluded if they were not written in English or did not measure strength as an outcome. Data were extracted on eccentric hip adductor strength (EHAD), eccentric hip abductor strength (EHAB), EHAD:EHAB ratio, and electromyography (EMG) activity of the adductor muscles. Quality assessment was performed on all included studies using Quality Assessment Tool for Quantitative Studies.

RESULTS

Five articles were identified for inclusion, four of which received a strong rating, and one a moderate rating on the Quality Assessment Tool for Quantitative Studies. The CAE significantly increased EHAD in four of the four studies that examined it; significantly increased EHAB and EHAD:EHAB in three of the three studies that examined them, and increased the EMG activity of the adductors in the dominant leg 108%.

CONCLUSION

Overall, the CAE increases EHAD, EHAB, EHAD:EHAB, and EMG activity in the hip adductors in male soccer players. The increase in strength may reduce adductor muscle injuries, although more research needs to be done in this area to identify a clear relationship between the CAE and groin injury prevention.

LEVEL OF EVIDENCE

1b.

Indirect Structural Muscle Injuries of Lower Limb: Rehabilitation and Therapeutic Exercise

Muscle injuries are the most common trauma in team and individual sports. The muscles most frequently affected are those of the lower limb, and in particular hamstrings, adductors, rectus femoris and calf muscles. Although several scientific studies have tried to propose different rehabilitation protocols, still too often the real rehabilitation process is not based on scientific knowledge, especially in non-elite athletes. Moreover, the growing use of physical and instrumental therapies has made it increasingly difficult to understand what can be truly effective. Therefore, the aim of the present paper is to review proposed therapeutic algorithms for muscle injuries, proposing a concise and practical summary. Following a three-phase rehabilitation protocol, this review aims to describe the conservative treatment of indirect structural muscle injuries, which are the more routinely found and more challenging type. For each phase, until return to training and return to sport are completed, the functional goal, the most appropriate practitioner, and the best possible treatment according to current evidence are expressed. Finally, the last section is focused on the specific exercise rehabilitation for the four main muscle groups with a structured explanatory timetable.

Moving Beyond One-Size-Fits-All Approaches to Injury Prevention: Evaluating How Tailored Injury Prevention Programs Are Developed and Implemented in Academy Soccer

OBJECTIVE

To evaluate the real-world development and implementation of tailored injury prevention exercise programs (IPEPs) in academy soccer players.

DESIGN

A mixed-methods process evaluation employing the Consolidated Framework for Implementation Research.

METHODS

The participants were 38 players and staff members (eg, coaches, physical therapists) from 4 male teams in 1 European soccer academy. The content and nature of the 4 teams' IPEPs and the degree of implementation across 1 playing season were evaluated. Additionally, participants took part in semi-structured interviews and focus groups, focusing on the development of tailored IPEPs and implementation barriers and facilitators.

RESULTS

Teams employed multiple IPEPs, developed by the team physical therapists and strength and conditioning coaches. A range of sources, including scientific literature, guidelines, individual player screening data, and previous experience, influenced IPEP development. Across all teams, 76% of IPEP sessions were completed as originally planned and a further 11% were completed in modified form. The key barriers to implementation during the season were related to scheduling changes and managing player workload. Thematic coding of interviews and focus groups identified 25 IPEP implementation barriers (eg, time and scheduling, player workload) and 41 facilitators (eg, program adaptability, facilities and equipment).

CONCLUSION

In a male soccer academy setting, physical therapists and strength and conditioning coaches played the key role in IPEP development. Teams employed a range of different, internally developed programs. The key implementation factors were related to time and scheduling and managing player workload. J Orthop Sports Phys Ther 2021;51(9):432-439. doi:10.2519/jospt.2021.10513.

Facilitators and barriers for implementation of a load management intervention in football

BACKGROUND

In a recent randomised controlled trial, we found that a commonly used training load management approach was not effective in preventing injuries and illnesses in Norwegian elite youth footballers.

AIM

To investigate players' and coaches' barriers and facilitators to a load management approach to prevent injuries and illnesses and their attitudes and beliefs of load management and injuries and illnesses in general.

METHODS

We asked players and coaches about their views on injury risk in football, the benefits and limitations of load management in general and implementation of load management in football. The questionnaires used were based on similar studies using the Reach, Effectiveness, Adoption, Implementation and Maintenance framework.

RESULTS

We recorded answers from 250 players and 17 coaches. Most players (88%) reported that scientific evidence showing improved performance from the intervention measures is a key facilitator to completing the intervention. Similarly, coaches reported that the most important facilitator was scientific evidence that the preventive measures were effective (100%). Players reported that the coach's attitude to preventive measures was important (86%), and similarly, 88% of coaches reported that the player's attitude was important.

CONCLUSIONS

By having a mutual positive attitude towards the intervention, players and coaches can positively contribute to each other's motivation and compliance. Both players and coaches reported scientific evidence for load management having injury-preventive and performance-enhancing effect and being time efficient as important facilitators.

TRIAL REGISTRATION NUMBER

Trial registration number.

Injuries in Irish male and female collegiate athletes

OBJECTIVE

To understand the incidence and burden of injury of student-athletes in four of the most popular collegiate sports.

DESIGN

Prospective cohort study.

SETTING

Collegiate sport.

PARTICIPANTS

Gaelic football, hurling/Camogie, soccer and Rugby (n = 672; male = 416, female = 256) student-athletes.

MAIN OUTCOME MEASURE

Injury incidence, burden of injury and total, match and training injury rates, and their 95% confidence intervals were calculated. The frequencies and proportions were also calculated. An injury was defined as any physical condition that prevents a student-athlete from full participation for a period greater than 24 h.

RESULTS

Over a quarter (0.266) of student-athletes sustained an injury in the academic season. Male student-athletes had a higher injury rate than females (21.6 vs 11.3 injuries/1000 h). Rugby (20.8 injuries/1000 h) had the highest injury rates with hurling/Camogie (6.3 injuries/1000 h) the lowest. Lower extremity injuries were predominant (68.8%) with ankle sprains demonstrating a large burden for all sports (20.6-280.2 days absent/1000 h). Hamstring strains (13.7-118.4 days absent/1000 h) had a large burden for all sports except male Rugby. Knee sprains had a large burden on the female Gaelic footballer (84.8 days absent/1000 h). Sprinting (27.4%) and the tackle (20.1%) were the most common mechanism of injury. Injuries were predominantly moderate (8-28 days) or severe (>28 days) (84.7%).

CONCLUSION

Injury reduction needs to be prioritised in the student-athlete, particularly in males. Specific focus is required on the lower extremity, especially in the hamstring muscles and ankle joint owing to the large burden of injury.

Do hip and groin muscle strength and symptoms change throughout a football season in professional male football players? A prospective cohort study with repeated measures

OBJECTIVES

Groin injuries are common in professional male football and result in significant complaints, time-loss and cost. We aimed to study: 1. Normal values of hip muscle strength and self-reported hip and groin function (Hip And Groin Outcome Score (HAGOS)). 2. Changes in these values throughout the season. 3. If previous (groin) injuries, leg dominance or league were associated with these outcome measures.

DESIGN

Prospective cohort study.

METHODS

313 professional male football players (11 clubs) participated. Player characteristics and previous injuries were registered. Hip muscle strength (hand-held dynamometer) and HAGOS measurements were done at the start, middle and end of the season.

RESULTS

Data from 217 players were analysed. Adduction strength (mean±standard deviation, Nm/Kg) was 3.40±0.72 (start), 3.30±0.65 (mid) and 3.39±0.74 (end) (p=0.186). Abduction strength was 3.45±0.67, 3.14±0.57 and 3.28±0.61 (p<0.001). Adduction/abduction ratio was 1.00±0.21, 1.07±0.22 and 1.05±0.23 (p<0.001). Statistically, the HAGOS-subscale 'Pain' (median [interquartile range]) deteriorated slightly during the season (p=0.005), especially from mid-season (97.5 [90.6-100.0]) to end-of-season (95.0 [87.5-100.0]) (p=0.003). Other subscale scores remained unchanged between time points; 85.7 (symptoms), 100.0 (daily living), 96.9 (sports and recreation) 100.0, (physical activities) and 90.0 (quality of life). Previous injuries were associated with lower HAGOS-scores. Dominant legs had higher abduction strength (p<0.001) and lower adduction/abduction ratio (p<0.001). No differences between leagues were found for hip muscle strength and HAGOS-scores.

CONCLUSIONS

In Dutch male professional football players, hip muscle strength and HAGOS-scores remained relatively stable throughout the season. Pain increased slightly, which while statistically significant, was not clinically relevant.

Exercise-Based Strategies to Prevent Muscle Injury in Elite Footballers: A Systematic Review and Best Evidence Synthesis

BACKGROUND

Exercise-based strategies are used to prevent muscle injuries in football and studies on different competitive-level populations may provide different results.

OBJECTIVES

To evaluate the effectiveness of exercise-based muscle injury prevention strategies in adult elite football.

METHODS

A systematic search was conducted in PubMed (MEDLINE), Web of Science, Cochrane Library, and SPORTDiscuss (EBSCO). We considered only elite adult (> 16 year-old) football players with no distinction for gender; the intervention to be any exercise/s performed with the target to prevent lower-limb muscle injuries; the comparison to be no injury prevention exercise undertaken; the outcome to be the number of injuries, injury incidence, and severity. We searched systematic reviews, randomized-controlled trials (RCTs), and non-randomized-controlled trials (NRCTs), limited for English language. Risk of bias was assessed using the Risk of Bias in Systematic Reviews tool, the Cochrane Collaboration's Tool for assessing risk of bias in RCTs, and the Risk of Bias in NRCTs of Interventions tool.

RESULTS

15 studies were included. Three systematic reviews showed inconsistent results, with one supporting (high risk of bias) and two showing insufficient evidence (low risk of bias) to support exercise-based strategies to prevent muscle injuries in elite players. Five RCTs and seven NRCTs support eccentric exercise, proprioception exercises, and a multi-dimensional component to an injury prevention program; however, all were deemed to be at high/critical risk of bias. Only one RCT was found at low risk of bias and supported eccentric exercise for preventing groin problems.

CONCLUSION

We found limited scientific evidence to support exercise-based strategies to prevent muscle injury in elite footballers.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42017077705.

Injury Rates in Major League Baseball During the 2020 COVID-19 Season

Background:

The 2020 Major League Baseball (MLB) season was drastically altered because of the COVID-19 pandemic. The changes included an extended layoff between March and July as well as a shortened preseason.

Purpose/Hypothesis:

To determine the incidence and epidemiology of MLB injuries in the abbreviated 2020 season compared with prior seasons. We hypothesized that there was an increase in the overall injury rate in the 2020 season compared with the 2018-2019 seasons and that it equally affected all body regions.

Study Design:

Descriptive epidemiology study.

Methods:

The MLB transactions database was queried to find players who had been placed on the injury list between 2018 and 2020. Injuries were categorized into upper extremity, lower extremity, spine/core, and other injuries. Incidence per 1000 athlete-exposures was calculated for the prior 2 seasons (2018-2019) and for the 2020 season separately. Incidence for each category was also calculated separately for pitchers and fielders. Incidence rate ratios (IRRs) and confidence intervals were used to compare injury rates in 2018-2019 versus 2020. The z test for proportions was used to determine significant differences between injury incidences.

Results:

In 2020, the overall incidence rate per 1000 athlete-exposures was almost twice the rate compared with the 2 seasons before COVID-19 (8.66 vs 5.13; IRR, 1.69 [95% CI, 1.53-1.87]; P < .001). Injury incidence increased similarly in 2020 for both pitchers (IRR, 1.68 [95% CI, 1.47-1.91]; P < .001) and fielders (IRR, 1.68 [95% CI, 1.45-1.96]; P < .001). Increases in injury incidence were seen in the upper extremity, spine/core, and other injury categories; however, the incidence of the lower extremity did not change significantly.

Conclusion:

There was a significant increase in injury incidence for both pitchers and fielders in 2020. Injury rates increased in anatomic zones of the upper extremity and spine/core but were not significantly changed in the lower extremity. The overall increase in injury rate suggests that irregular or insufficient sport-specific preparation prior to the start of the season placed athletes at a greater risk of injury when play resumed.

The Benefits of Strength Training on Musculoskeletal System Health: Practical Applications for Interdisciplinary Care

Global health organizations have provided recommendations regarding exercise for the general population. Strength training has been included in several position statements due to its multi-systemic benefits. In this narrative review, we examine the available literature, first explaining how specific mechanical loading is converted into positive cellular responses. Secondly, benefits related to specific musculoskeletal tissues are discussed, with practical applications and training programmes clearly outlined for both common musculoskeletal disorders and primary prevention strategies.

Implementing Strength Training Strategies for Injury Prevention in Soccer: Scientific Rationale and Methodological Recommendations

Due to the negative effects that injuries have on performance, club finances, and long-term player health (permanent disability after a severe injury), prevention strategies are an essential part of both sports medicine and performance. Purpose: To summarize the current evidence regarding strength training for injury prevention in soccer and to inform its evidence-based implementation in research and applied settings. Conclusions: The contemporary literature suggests that strength training, proposed as traditional resistance, eccentric, and flywheel training, may be a valid method to reduce injury risk in soccer players. Training strategies involving multiple components (eg, a combination of strength, balance, plyometrics) that include strength exercises are effective at reducing noncontact injuries in female soccer players. In addition, the body of research currently published supports the use of eccentric training in sports, which offers unique physiological responses compared with other resistance exercise modalities. It seems that the Nordic hamstring exercise, in particular, is a viable option for the reduction of hamstring injuries in soccer players. Moreover, flywheel training has specific training peculiarities and advantages that are related to the combination of both concentric and eccentric contraction, which may play an important role in injury prevention. It is the authors’ opinion that strength and conditioning coaches should integrate the strength training methods proposed here in their weekly training routine to reduce the likelihood of injuries in their players; however, further research is needed to verify the advantages and disadvantages of these training methods to injury prevention using specific cohorts of soccer players.

Combining the Copenhagen Adduction Exercise and Nordic Hamstring Exercise Improves Dynamic Balance Among Male Athletes: A Randomized Controlled Trial

BACKGROUND

Copenhagen adduction exercise (CAE) and Nordic hamstring exercise (NHE) reduce the incidence of groin and hamstring injuries. Efficient dynamic balance can improve motor performance and reduce the risk of injuries in athletes. However, the effects of these exercises on dynamic balance have not been investigated.

HYPOTHESIS

CAE and NHE, as well as a combination of both exercises, would improve dynamic balance among amateur male athletes.

STUDY DESIGN

Randomized controlled trial.

LEVEL OF EVIDENCE

Level 1.

METHODS

A total of 200 male athletes aged 21.9 ± 2.4 years were included in the study and randomly assigned to 4 groups: CAE group (n = 50), NHE group (n = 50), CAE and NHE group (n = 50), and a control group (n = 50). A total of 177 male athletes completed the study. The primary outcome measure was the limit of stability (LoS), which was measured using the Biodex Stability System to assess the performance of the dynamic balance. The LoS of the athletes' performance was measured pre- and postintervention after 6 weeks.

RESULTS

The LoS significantly improved in all treatment groups, including CAE (44.5% ± 5.3%), NHE (43.2% ± 5.3%), and CAE + NHE (48.4% ± 5.1%) groups when compared with the control group (28.3% ± 4.8%) after 6 weeks (all Ps < 0.01). The improvement of LoS was significantly greater in the CAE + NHE group compared with other groups (CAE, NHE, and control groups).

CONCLUSION

There was a significant increase in dynamic balance performance postintervention among male athletes. CAE and NHE may improve injury prevention programs.

CLINICAL RELEVANCE

The results of this study provide evidence for athlete trainers and coaches to consider including the CAE and NHE as components of injury prevention programs to improve balance capacity and performance in athletes. Such improvements in balance may prevent injury risk and decrease absenteeism and injury-related financial burdens.

Warm-Ups and Coaches' Perceptions: Searching for Clues to Improve Injury Prevention in Youth Basketball

Introduction: Regular use of neuromuscular training (NMT) warm-up programs improves performance and prevents injuries. However, low level of adoption of these programs remains a problem. Understanding the current warm-ups in youth basketball and coaches' perceptions on injury prevention can guide the design of superior implementation strategies. This study describes warm-ups in youth basketball and coaches' injury prevention-related knowledge, attitudes, beliefs, and information sources.

Methods: Youth basketball coaches (n = 50) completed a preseason questionnaire. The questionnaire covered warm-up length, use of aerobic/agility/balance/strength/other exercises in the warm-up, injury-related knowledge, attitudes, beliefs, and sources of information.

Results: Typical warm-up duration was ≤ 10 min (48.0% of coaches, 95% CI: ±13.8%). All coaches included aerobic exercises in their warm-up. Agility, strength, and balance exercises were utilized by 80.0% (95% CI: ±11.7%), 70.7% (95% CI: ±13.6%), and 26.8% (95% CI: ±13.6%) of coaches, respectively. Most coaches agreed to some extent that basketball injuries are preventable (94%) and that participating in a NMT warm-up program would reduce player's risk of injury (92%). Other coaches were identified as the most common source of information on warm-ups and injury prevention.

Discussion: Coaches use parts of effective NMT warm-up programs, but balance exercises are not well adopted. Considering the level of evidence supporting the importance of balance exercises in injury prevention, it is crucial to improve the implementation of NMT warm-up programs in youth basketball, for example, through educational courses. As fellow coaches were identified as the most important source of information, coaches' role in knowledge translation should be emphasized.

Tendinopathy

Tendinopathy describes a complex multifaceted pathology of the tendon, characterized by pain, decline in function and reduced exercise tolerance. The most common overuse tendinopathies involve the rotator cuff tendon, medial and lateral elbow epicondyles, patellar tendon, gluteal tendons and the Achilles tendon. The prominent histological and molecular features of tendinopathy include disorganization of collagen fibres, an increase in the microvasculature and sensory nerve innervation, dysregulated extracellular matrix homeostasis, increased immune cells and inflammatory mediators, and enhanced cellular apoptosis. Although diagnosis is mostly achieved based on clinical symptoms, in some cases, additional pain-provoking tests and imaging might be necessary. Management consists of different exercise and loading programmes, therapeutic modalities and surgical interventions; however, their effectiveness remains ambiguous. Future research should focus on elucidating the key functional pathways implicated in clinical disease and on improved rehabilitation protocols.

Groin problems from pre- to in-season: a prospective study on 386 male Spanish footballers

This study investigated the weekly prevalence of groin problems over a 3-week football pre-season, compared to a 39-week competitive in-season. We registered time-loss groin injuries, and self-reported weekly groin-pain in 17 amateur male football teams (386 players). The average weekly prevalence of groin problems (prevalence ratio (PR)) was 1.8 times higher (95% CI 1.6 to 2.0) during pre-season (21%) compared to in-season (12%). We found a higher weekly prevalence (PR 1.8; 95% CI 1.6 to 2.1) of groin problems without time loss, during the pre-season (19%) compared to the in-season (10%), but no significant difference in the weekly prevalence of groin problems with time loss (PR 1.5; 95% CI 1.0 to 2.4). Attention should be given to optimal load progression, and early implementation of preventive measures during the football pre-season to reduce the prevalence of groin problems in both pre- and in-season.

Adductor injuries in the National Basketball Association: an analysis of return to play and player performance from 2010 to 2019

Objectives: 1) To evaluate return to play (RTP) timing in National Basketball Association (NBA) athletes following adductor injuries, and 2) to evaluate the effect of adductor injuries on player performance, game availability, and career longevity following RTP. Methods: Adductor injuries in NBA athletes from the 2009-2010 to 2018-2019 seasons were identified utilizing publicly available records via previously validated methodology. RTP time was calculated, and player performance and game availability were compared pre- vs. post-injury. Additionally, an injury-free control group matched for age, BMI, position, and experience was assembled to allow for comparisons in performance, availability, and career length. Results: In total, 79 adductor injuries across 65 NBA athletes were identified. The average injured player was 28.3 ± 4.0 years of age, and had 6.5 ± 4.2 seasons of NBA experience. Guards were injured more frequently than forwards or centers (49% vs 25% vs 25%, respectively). All players were able to RTP following first-time adductor injury after missing an average of 7.7 ± 9.8 games (median [IQR]: 4 [1-9]) and 16.9 ± 20.4 days (median [IQR]: 9 [3.5-20]). Twelve players (18.5%) suffered an adductor re-injury at a mean latency of 509.5 ± 503.9 days. Adductor injuries did not result in significant changes in any major statistical category (points, assists, rebounds, steals, blocks, turnovers, field goal percentage), player efficiency rating (PER), minutes/game, games/season, or a number of all-star selections (all P > 0.05) following RTP. Additionally, when compared to matched controls, no difference was found in pre- to post-injury change of PER, games/season, or minutes/game (all P > 0.05). Career longevity was not significantly different between groups (P = 0.44). Conclusion: Following adductor injury, NBA players returned to gameplay after missing an average of 16 to 17 days, or 7 to 8 games. Adductor injury did not affect player performance, nor game availability or career longevity.

HIP AND GROIN PROBLEMS IN THE PREVIOUS SEASON ARE ASSOCIATED WITH IMPAIRED FUNCTION IN THE BEGINNING OF THE NEW SEASON AMONG PROFESSIONAL FEMALE ICE HOCKEY PLAYERS - A CROSS SECTIONAL STUDY

Background

Hip and groin problems are common in ice hockey but studies on professional female players are sparse. The available literature describes hip and groin problems by reporting incidence of time-loss injuries and may thereby underestimate the scope of these problems, which are often due to overuse and may not lead to absence from ice hockey participation.

Purpose

The purpose of this study was to describe the seasonal prevalence and severity of hip and groin problems in professional female ice hockey players. A further aim was to examine the relation between previous problems and self-reported function in the beginning of the new season.

Study design

Cross-sectional study.

Methods

Female ice hockey players from the highest league in Sweden [n=69 (19 goalkeepers, 18 defenders, 30 forwards)], responded to an online survey, retrospectively assessing the prevalence of hip and groin problems (time loss and non-time loss) and their duration during the previous season. Furthermore, players reported current self-reported function on the Copenhagen Hip and Groin Outcome Score (HAGOS).

Results

Two thirds of the players experienced hip and groin problems during the previous season [62.3% (N=43)]. A quarter of the players experienced a hip and groin problem leading to time loss [26.1% (N=18)]. The majority of problems were of short (1-2 weeks) or medium (3-5 weeks) duration [29% (N=20) of players, respectively], while longstanding problems ( ≥ 6 weeks) were rare [4,4% (N=3)]. Players that retrospectively reported hip and groin problems during the previous season reported statistically significant impairments on all HAGOS subscales in the beginning of the new season (p ≤ 0.011).

Conclusion

Hip and groin problems are prevalent in professional female ice hockey players, experienced by 62% during the previous season with resulting time-loss in 26.1%. Reported problems were rarely of longstanding nature, but players who reported problems in the previous season had significantly impaired hip and groin function in the beginning of the new season. Even though results of this study are based on retrospective player reports this may be a first step toward a greater understanding of the true burden of hip and groin players in professional female ice hockey players.

Level of evidence

3b.

Does load management using the acute:chronic workload ratio prevent health problems? A cluster randomised trial of 482 elite youth footballers of both sexes

BACKGROUND

The acute:chronic workload ratio (ACWR) is commonly used to manage training load in sports, particularly to reduce injury risk. However, despite its extensive application as a prevention intervention, the effectiveness of load management using ACWR has never been evaluated in an experimental study.

AIM

To evaluate the effectiveness of a load management intervention designed to reduce the prevalence of health problems among elite youth football players of both sexes.

METHODS

We cluster-randomised 34 elite youth football teams (16 females, 18 males) to an intervention group (18 teams) and a control group (16 teams). Intervention group coaches planned all training based on published ACWR load management principles using a commercially available athlete management system for a complete 10-month season. Control group coaches continued to plan training as normal. The prevalence of health problems was measured monthly in both groups using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems.

RESULTS

The between-group difference in health problem prevalence (primary outcome) was 1.8%-points (-4.1 to 7.7 %-points; p=0.55) with no reduction in the likelihood of reporting a health problem in the intervention group (relative risk 1.01 (95% CI 0.91 to 1.12); p=0.84) compared with the control group.

CONCLUSIONS

We observed no between-group difference, suggesting that this specific load management intervention was not successful in preventing health problems in elite youth footballers.

TRIAL REGISTRATION NUMBER

ISRCTN18177140.

Totally extraperitoneal repair for the 'sportsman's groin' via 'the Manchester Groin Repair': a comparison of elite versus amateur athletes

BACKGROUND

Surgery has a recognised role in the treatment of 'sportsman's groin'. This study hypothesises that elite athletes have a superior advantage in both pre- and post-op rehabilitation and therefore will present and resume sporting activities quicker.

METHODS

A retrospective analysis on a secure database of athletes presenting with groin pain that underwent surgery for 'inguinal disruption'. All data were explored via appropriate descriptive statistics and comparisons made between elite and amateur athletes.

RESULTS

All patients were male (n = 144). The median age 33 years (range 14-72). The median return to sporting activity was 4.5 weeks (range 2.0-16.0) with one amateur athlete being unable to return to sporting activity. Using the mean of both sides, a comparison of VAS pain scores at pre-operative and 1 month post-operative time points showed a significant reduction (p < 0.001). Comparing 'elite' versus 'amateur' athletes, significant differences were seen in patient age (median 26 vs 40 years; p < 0.001), lead time to clinic presentation (median 62.0 vs 111.5 days; p = 0.004), and time to return to sporting activity (4 vs 5 weeks; p = 0.019). Additional MRI findings within the groin girdle were found in 89 patients (66.4%) and 34 patients (23.6%) had an MRI finding within the adductor tendon.

CONCLUSION

The Manchester Groin Rrepair is an effective surgical management for 'inguinal disruption'. Elite athletes present quicker and return to sport sooner. Given the prevalence of other findings, a multidisciplinary approach to the 'sportsman's groin' is required.

The Training-Performance Puzzle: How Can the Past Inform Future Training Directions?

Over the past 20 years, research on the training-load-injury relationship has grown exponentially. With the benefit of more data, our understanding of the training-performance puzzle has improved. What were we thinking 20 years ago, and how has our thinking changed over time? Although early investigators attributed overuse injuries to excessive training loads, it has become clear that rapid spikes in training load, above what an athlete is accustomed, explain (at least in part) a large proportion of injuries. In this respect, it appears that overuse injuries may arise from athletes being underprepared for the load they are about to perform. However, a question of interest to both athletic trainers (ATs) and researchers is why some athletes sustain injury at low training loads, while others can tolerate much greater training loads? A higher chronic training load and well-developed aerobic fitness and lower body strength appear to moderate the training-injury relationship and provide a protective effect against spikes in load. The training-performance puzzle is complex and dynamic-at any given time, multiple inputs to injury and performance exist. The challenge facing researchers is obtaining large enough longitudinal data sets to capture the time-varying nature of physiological and musculoskeletal capacities and training-load data to adequately inform injury-prevention efforts. The training-performance puzzle can be solved, but it will take collaboration between researchers and clinicians as well as an understanding that efficacy (ie, how training load affects performance and injury in an idealized or controlled setting) does not equate to effectiveness (ie, how training load affects performance and injury in the real-world setting, where many variables cannot be controlled).

Adductor Muscles Strength and Strength Asymmetry as Risk Factors for Groin Injuries among Professional Soccer Players: A Prospective Study

The aim of this study was to prospectively examine the association between isometric hip adductor strength and between-limb strength asymmetry to groin injuries in male professional soccer players. Isometric hip adductor strength and between-limb strength asymmetry of 45 professional outfield soccer players from three First Division teams were tested during the 2017/2018 preseason. Players were then monitored throughout the 2017/2018 season for groin injuries. Ten groin injuries were recorded. When compared with uninjured players, players who sustained groin injury had significantly lower strength of respective muscle groups and significantly higher between-limb strength asymmetries (all p < 0.05; ES = 1.16 and 0.88; mean % difference = 26% and 51%). Isometric hip adductor strength had a significant inverse relationship with the incidence of occurring groin injuries (p = 0.016). No significant relationship between hip adductor strength asymmetry and the incidence of future groin injury was observed (p = 0.09). Finally, players' age and previous groin injury were not significantly associated with the incidence of future groin injuries (all p > 0.05). These results generally suggest that isometric adductor strength is a significant predictor of future groin injuries in men's professional football; however, due to the relatively low sample size, further studies are required.

The effect of targeted resistance training on bench press performance and the alternation of prime mover muscle activation patterns

Targeted muscle strengthening might improve performance or help overcome training stagnation; therefore, the aim of the present study was to investigate changes in muscle activity patterns before and after six weeks of targeted resistance training. Twenty-seven resistance-trained men were divided into three groups according to their prime mover activity, as measured by surface electromyography during a bench press (BP). Each group underwent a six-week block of targeted exercises for one of the following muscles: anterior deltoid (AD), pectoralis major (PM) or triceps brachii (TB). ANOVA showed that each group increased their 1 repetition maximum (1RM) (p < 0.05) and the activity of the exercised muscle group during an isometric bench press (p < 0.01) and during a dynamic bench press (p < 0.01) at 85% of the 1RM. During the isometric BP, the TB training group had an increase in TB activity in comparison to the other groups. Targeted muscle training is a useful method for muscle activity increase and increasing the maximum strength in complex exercise, when applied in activity-deficient muscle groups. Strengthening the TB elicits changes in all prime movers and results in TB activity domination during a bench press.

Diagnosis, prevention and treatment of common lower extremity muscle injuries in sport - grading the evidence: a statement paper commissioned by the Danish Society of Sports Physical Therapy (DSSF)

This statement summarises and appraises the evidence on diagnosis, prevention and treatment of the most common lower extremity muscle injuries in sport. We systematically searched electronic databases, and included studies based on the highest available evidence. Subsequently, we evaluated the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework, grading the quality of evidence from high to very low. Most clinical tests showed very low to low diagnostic effectiveness. For hamstring injury prevention, programmes that included the Nordic hamstring exercise resulted in a hamstring injury risk reduction when compared with usual care (medium to large effect size; moderate to high quality of evidence). For prevention of groin injuries, both the FIFA 11+programme and the Copenhagen adductor strengthening programme resulted in a groin injury risk reduction compared with usual care (medium effect size; low to moderate quality of evidence). For the treatment of hamstring injuries, lengthening hamstring exercises showed the fastest return to play with a lower reinjury rate compared with conventional hamstring exercises (large effect size; very low to low quality of evidence). Platelet-rich plasma had no effect on time to return-to-play and reinjury risk (trivial effect size; moderate quality of evidence) after a hamstring injury compared with placebo or rehabilitation. At this point, most outcomes for diagnosis, prevention and treatment were graded as very low to moderate quality of evidence, indicating that further high-quality research is likely to have an important impact on the confidence in the effect estimates.

Preseason Hip/Groin Strength and HAGOS Scores Are Associated With Subsequent Injury in Professional Male Soccer Players

DESIGN

Prospective cohort.

OBJECTIVE

To explore the association between preseason assessments of (1) isometric hip adductor and abductor strength using a novel field test and (2) the Copenhagen Hip and Groin Outcome Score (HAGOS) and subsequent hip/groin injury in male professional soccer players.

METHODS

In total, 204 male elite soccer players from 10 professional A-League and English Football League Championship clubs underwent assessments of hip adductor and abductor strength and completed the HAGOS in the 2017-2018 preseason. All subsequent hip/groin injuries were reported by team medical staff. Data reduction was conducted using principal-component analysis. The principal component for the HAGOS and 3 principal components for strength and imbalance measures were entered, with age and prior hip/groin injury, into a multivariable logistic regression model to determine their association with prospectively occurring hip/groin injury.

RESULTS

Twenty-four players suffered at least 1 hip/groin injury throughout the 2017-2018 season. The principal component for between-limb abduction imbalance (peak strength in the preferred kicking limb - nonpreferred limb) (odds ratio [OR] = 0.58; 95% confidence interval [CI]: 0.38, 0.90; P = .011), the principal component for peak adduction and abduction strength (OR = 0.71; 95% CI: 0.51, 1.00; P = .045), and the principal component for the HAGOS (OR = 0.77; 95% CI: 0.62, 0.96; P = .022) were independently associated with a reduced risk of future hip/groin injury. Receiver operating characteristic curve analysis of the whole model revealed an area under the curve of 0.76, which indicates a fair combined sensitivity and specificity of the included variables but an inability to correctly identify all subsequently injured players.

CONCLUSION

Hip abduction imbalance favoring the preferred kicking limb, higher levels of hip adductor and abductor strength, and superior HAGOS values were associated with a reduced likelihood of future hip/groin injury in male professional soccer players. J Orthop Sports Phys Ther 2020;50(5):234-242. Epub 17 Sep 2019. doi:10.2519/jospt.2020.9022.

Copenhagen Adduction Exercise to Increase Eccentric Strength: A Systematic Review and Meta-Analysis

Background: The purpose of this study was to systematically review the scientific literature about the benefits of using the Copenhagen Adductor (CA) exercise to improve eccentric hip adduction strength (EHAD), as well as to provide directions for training. Methods: A systematic search was conducted in three electronic databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The inclusion criteria were: (a) EHAD as outcome variable, with means and standard deviations before and after the intervention, (b) the study was a randomized controlled trial using the CA in the program intervention, (c) the article was written in English. The quality of evidence was evaluated according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines. A mini meta-analysis was performed to determine the overall effect. Results: Three studies were selected and included in this systematic review and mini meta-analysis. All articles reported significant enhancement in EHAD in football (soccer) players. The overall effect for the EHAD test was significant in favor to CA group (mean difference = 0.61; 95% CI from 0.20 to 1.01; p = 0.003) with large heterogeneity. Conclusions: CA exercise performed 2–3 times for 8 weeks is useful for improving EHAD in football players.

Making football safer for women: a systematic review and meta-analysis of injury prevention programmes in 11 773 female football (soccer) players

Objective

To evaluate the effects of injury prevention programmes on injury incidence in any women’s football code; explore relationships between training components and injury risk; and report injury incidence for women’s football.

Design

Systematic review and meta-analysis.

Data sources

Nine databases searched in August 2019.

Eligibility criteria

Randomised controlled trials evaluating any injury prevention programme (eg, exercise, education, braces) were included. Study inclusion criteria were: ≥20 female football players in each study arm (any age, football code or participation level) and injury incidence reporting.

Results

Twelve studies, all in soccer, met inclusion criteria, with nine involving adolescent teams (aged <18 years). All studies (except one) had a high risk of bias. Eleven studies examined exercise-based programmes, with most (9/11) including multiple (≥2) training components (eg, strength, plyometric, balance exercises). Multicomponent exercise programmes reduced overall (any reported) injuries (incidence rate ratio (IRR) 0.73, 95% CI 0.59 to 0.91) and ACL injuries (IRR 0.55, 95% CI 0.32 to 0.92). For exercise-based strategies (single-component and multicomponent), hamstring injuries were also reduced (IRR 0.40, 95% CI 0.17 to 0.95). While exercise-based strategies resulted in less knee, ankle and hip/groin injuries, and the use of multiple training components was associated with greater reductions in overall and knee injuries, further studies would be required to increase the precision of these results. The incidence of overall injuries in women’s football was 3.4 per 1000 exposure hours; with ankle injuries most common.

Conclusion

In women’s football, there is low-level evidence that multicomponent, exercise-based programmes reduce overall and ACL injuries by 27% and 45%, respectively.

PROSPERO registration number

CRD42018093527.

Prevention of severe knee injuries in men's elite football by implementing specific training modules

PURPOSE

Injury prevention of knee injuries by means of training and warm-up exercises has been investigated in several studies in amateur football. However, the number of investigations in elite football is limited despite the currently higher injury incidence of severe knee injuries. Therefore, the purpose of this study was to investigate whether specifically adapted preventive training modules may reduce severe knee injuries in elite football.

METHODS

In a prospective controlled cohort study of elite football players in Germany, an injury prevention programme with 5 modules was implemented in the season of 2015-2016. The training modules were specifically adapted to this skill level and based on scientific evidence, team coach preferences, and the specific environment of this playing level. Of the 62 teams taking part in this study, 26 used the new trainings modules and 36 continued their standard programme as a control group. Success of the programme was documented by means of an injury report over one season. The primary outcome was reduction in severe knee injuries.

RESULTS

A pre-seasonal investigation had identified five modules to be implemented in the training routine. Postural stability, mobilisation of lower extremity joints, leg and trunk stabilisation, jumping, and landing exercises as well as agility movements were incorporated into the programme to prevent severe knee injuries in elite football. Over the season, the study group (529 players) with the adapted training modules had sustained 52 severe knee injuries (incidence: 0.38 per 1000 h football exposure; prevalence: 9.8%) compared to 108 severe knee injuries in the control group (601 players) using the standard programme (incidence: 0.68 per 1000 h football exposure; prevalence: 18.0%; p < 0.05). The overall injury incidence for any other type of injury was comparable between the two groups (3.3 vs. 3.4 in h 1000 football, n.s.).

CONCLUSION

Appropriate preventive training modules reduce severe knee injuries in elite football significantly. The key for the sustainability of preventive training measures are programmes specifically adapted to the demands of the playing level and to the preferences of the coaches LEVEL OF EVIDENCE: II.

Exercise-based injury prevention for community-level adolescent cricket pace bowlers: A cluster-randomised controlled trial

OBJECTIVES

To investigate if an exercise-based injury prevention program (IPP) can modify risk factors for injury in community-level adolescent cricket pace bowlers.

DESIGN

Cluster-randomised controlled trial.

METHODS

Eight cricket organisations (training two times per week and no previous involvement in a structured IPP) participated in this cluster-randomised trial. Participants were aged 14-17 years, injury free, and not currently performing a rehabilitation/exercise program. Cricket organisations (clusters) were block-randomised by computerised number generation into an intervention group (performed an eight-week IPP at training) or control group (continued their usual cricket activity). Participants were not blinded to group allocation. Strength, endurance, and neuromuscular control were assessed at baseline and follow-up. Treatment effects were estimated using linear mixed models.

RESULTS

Sixty-five male adolescent pace bowlers (intervention n=32 and control n=33) were randomised. There were significant treatment effects favouring the intervention group for shoulder strength (90°/s) 0.05 (95% CI 0.02-0.09) Nm/kg, hamstring strength (60°/s) 0.32 (95% CI 0.13-0.50) Nm/kg, hip adductor strength dominant 0.40 (95% CI 0.26-0.55) Nm/kg and non-dominant 0.33 (95% CI 0.20-0.47) Nm/kg, SEBT reach distance dominant 3.80 (95% CI 1.63-6.04) percent of leg length (%LL) and non-dominant 3.60 (95% CI 1.43-5.78) %LL, and back endurance 20.4 (95% CI 4.80-36.0) seconds. No differences were observed for shoulder strength (180°/s) (p=0.09), hamstring strength (180°/s) (p=0.07), lumbopelvic stability (p=0.90), and single leg squat knee valgus angle (dominant p=0.06, non-dominant p=0.15).

CONCLUSIONS

Exercise-based IPPs can modify risk factors for injury in community-level adolescent pace bowlers. Future research is needed to confirm if IPPs can also reduce injury risk in this population.

Elite Ice Hockey Goalkeepers Have a High Prevalence of Hip and Groin Problems Associated With Decreased Sporting Function: A Single-Season Prospective Cohort Study

BACKGROUND

The modern style of goalkeeping in ice hockey is thought to predispose athletes to hip and groin problems. However, little is known about the magnitude of these problems in elite goalkeepers.

PURPOSE

To describe the incidence, prevalence, and severity of hip and groin problems in elite ice hockey goalkeepers over the course of a single season.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

We invited all elite Swedish ice hockey goalkeepers (n = 128) to participate in this prospective cohort study. Every second week, players reported hip and groin problems experienced within the past 14 days on the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC-O), classifying problems into "all" and "substantial" hip and groin problems. Three times during the season (pre-, mid-, and end-season), players reported hip and groin function on the Hip and Groin Outcome Score (HAGOS) as well as on the OSTRC-O.

RESULTS

A total of 101 goalkeepers participated in the study (83.3% male [seniors, 44.1%; juniors, 39.2%], 16.7% female). The cumulative incidences of all hip and groin problems and substantial hip and groin problems were 69% (95% CI, 59%-79%) and 36% (95% CI, 26%-46%), respectively. The average biweekly prevalence for all hip and groin problems and substantial hip and groin problems was 28.1% (95% CI, 25.0%-31.3%) and 10% (95% CI, 8.7%-11.4%), respectively. Among all the reported hip and groin problems, 16.9% (n = 70) were acute, 83.1% (n = 343) were because of overuse, and 15.5% (n = 64) led to time loss. HAGOS did not differ in the pre-, mid-, or end-season. Players reporting hip and groin problems on the OSTRC-O had significantly worse HAGOS scores than players without problems (P < .01).

CONCLUSION

Hip and groin problems are highly prevalent in elite ice hockey goalkeepers. During a competitive season, 69% of players experienced hip and groin problems and 36% of players suffered from substantial problems. The vast majority of problems were because of overuse, not leading to time loss but related to reduced self-reported hip and groin function.

Impact of a modified progressive Copenhagen adduction exercise programme on hip adduction strength and postexercise muscle soreness in professional footballers

Background

Reduced hip adduction strength has been identified as a key predisposing factor in developing hip and groin injuries. The Copenhagen adduction programme has been shown to increase hip adduction strength in semiprofessional footballers but can cause muscle soreness. Therefore, a modified progressive Copenhagen adduction (MPCA) programme has been designed to increase hip adduction strength while limiting muscle soreness.

Objective

To investigate the effect of an 8-week MPCA exercise on eccentric hip adduction and abduction strength in senior professional footballers.

Methods

25 senior professional footballers completed an 8-week MPCA strengthening programme. Eccentric hip adduction (EHAD) and eccentric hip abduction (EHAB) strengths were measured. Changes in preintervention and postintervention strengths and EHAD:EHAB ratios were calculated. The statistical significance between strength changes was assessed with dependent t-tests and Wilcoxon signed-rank tests due to the distribution of the data (p<0.05). Delayed onset of muscle soreness (DOMS) and rate of perceived exertion were measured throughout the programme.

Results

There were statistically significant increases in EHAD strength (24% and 25%, left and right), EHAB strength (10% and 13%, left and right) and the EHAD:EHAB ratio (12% and 10%, left and right) (p<0.01).

Professional footballers were able to complete the MPCA exercise with low levels of DOMS.

Conclusion

An 8-week MPCA exercise elicited significant EHAD and EHAB strength increases with reduced levels of muscle soreness in senior professional footballers.

Could a specific exercise programme prevent injury in elite orienteerers? A randomised controlled trial

OBJECTIVES

To determine the effect of a specific exercise programme on preventing lower extremity injury in adult elite orienteerers.

DESIGN

Randomised controlled trial.

SETTING

Elite orienteering.

PARTICIPANTS

Sixty-two orienteerers (n = 32/30, male/female) were randomized and followed over 14 weeks. The intervention group completed an exercise programme 4 times per week.

MAIN OUTCOME MEASURES

Number of substantial injuries, average substantial injury prevalence and incidence of ankle sprains over the competitive season. In per-protocol analyses, compliance rate to exercise programme was considered.

RESULTS

No significant differences between control and intervention group were found for substantial injured orienteerers (OR 0.50, 95% CI 0.19-1.34), number of substantial injuries (OR 0.46, 95% CI 0.18-1.13) and incidence of ankle sprains (p = 0.775). In per-protocol analyses, significant differences in substantial injured orienteerers (difference -7.9%, OR 0.25, 95% CI 0.06-0.97) and number of substantial injuries (difference -8.5%, OR 0.26, 95% CI 0.07-0.92) in favour for the orienteers completing the exercises at least twice a week, compared to the control group, were found.

CONCLUSIONS

An exercise programme, consisting of balance and jump exercises, is suggested to be performed at least twice per week in order to reduce the risk of lower extremity injury in elite orienteerers.