BackgroundThe relationship between muscle injury and strength disorders remains a matter of controversy.PurposeProfessional soccer players performed a preseason isokinetic testing aimed at determining whether (1) strength variables could be predictors of subsequent hamstring strain and (2) normalization of strength imbalances could reduce the incidence of hamstring injury.Study DesignCohort study (prognosis); Level of evidence, 1.MethodsA standardized concentric and eccentric isokinetic assessment was used to identify soccer players with strength imbalances. Subjects were classified among 4 subsets according to the imbalance management content. Recording subsequent hamstring injuries allowed us to define injury frequencies and relative risks between groups.ResultsOf 687 players isokinetically tested in preseason, a complete follow-up was obtained in 462 players, for whom 35 hamstring injuries were recorded. The rate of muscle injury was significantly increased in subjects with untreated strength imbalance...

/pdf/strength-imbalances-and-prevention-of-hamstring-injury-in-jh9l6bnrtd.pdf

Strength Imbalances and Prevention of Hamstring Injury in Professional Soccer Players: A Prospective Study

BackgroundThe incidence of hamstring muscle injuries in professional rugby union is high, but evidence-based information on risk factors and injury-prevention strategies in this sport is limited.PurposeTo define the incidence, severity, and risk factors associated with hamstring muscle injuries in professional rugby union and to determine whether the use of hamstring strengthening and stretching exercises reduces the incidence and severity of these injuries.Study DesignCohort study (prevention); Level of evidence, 3.MethodsTeam clinicians reported all hamstring muscle injuries on a weekly basis and provided details of the location, diagnosis, severity, and mechanism of each injury; loss of time from training and match play was used as the definition of an injury. Players’ match and training exposures were recorded on a weekly basis.ResultsThe incidence of hamstring muscle injuries was 0.27 per 1000 player training hours and 5.6 per 1000 player match hours. Injuries, on average, resulted in 17 days of lost...

Incidence, Risk, and Prevention of Hamstring Muscle Injuries in Professional Rugby Union:

who did not [relative risk (RR) 5 1.53, P 5 0.22], nor was there a difference compared with the baseline data (RR 5 0.89, P 5 0.75). The incidence of hamstring strains was lower in teams who used the eccentric training program compared with teams that did not use the program (RR 5 0.43, P 5 0.01), as well as compared with baseline data for the same intervention teams (RR 5 0.42, P 5 0.009). Eccentric strength training with Nordic hamstring lowers combined with warm-up stretching appears to reduce the risk of hamstring strains, while no effect was detected from flexibility training alone. These results should be verified in randomized clinical trials.

/pdf/prevention-of-hamstring-strains-in-elite-soccer-an-1xiu5vnxh7.pdf

Prevention of hamstring strains in elite soccer: an intervention study.

Hamstring strain injuries (HSIs) are common in a number of sports and incidence rates have not declined in recent times. Additionally, the high rate of recurrent injuries suggests that our current understanding of HSI and re-injury risk is incomplete. Whilst the multifactoral nature of HSIs is agreed upon by many, often individual risk factors and/or causes of injury are examined in isolation. This review aims to bring together the causes, risk factors and interventions associated with HSIs to better understand why HSIs are so prevalent. Running is often identified as the primary activity type for HSIs and given the high eccentric forces and moderate muscle strain placed on the hamstrings during running these factors are considered to be part of the aetiology of HSIs. However, the exact causes of HSIs remain unknown and whilst eccentric contraction and muscle strain purportedly play a role, accumulated muscle damage and/or a single injurious event may also contribute. Potentially, all of these factors interact to varying degrees depending on the injurious activity type (i.e. running, kicking). Furthermore, anatomical factors, such as the biarticular organization, the dual innervations of biceps femoris (BF), fibre type distribution, muscle architecture and the degree of anterior pelvic tilt, have all been implicated. Each of these variables impact upon HSI risk via a number of different mechanisms that include increasing hamstring muscle strain and altering the susceptibility of the hamstrings to muscle damage. Reported risk factors for HSIs include age, previous injury, ethnicity, strength imbalances, flexibility and fatigue. Of these, little is known, definitively, about why previous injury increases the risk of future HSIs. Nevertheless, interventions put in place to reduce the incidence of HSIs by addressing modifiable risk factors have focused primarily on increasing eccentric strength, correcting strength imbalances and improving flexibility. The response to these intervention programmes has been mixed with varied levels of success reported. A conceptual framework is presented suggesting that neuromuscular inhibition following HSIs may impede the rehabilitation process and subsequently lead to maladaptation of hamstring muscle structure and function, including preferentially eccentric weakness, atrophy of the previously injured muscles and alterations in the angle of peak knee flexor torque. This remains an area for future research and practitioners need to remain aware of the multifactoral nature of HSIs if injury rates are to decline.

/pdf/hamstring-strain-injuries-factors-that-lead-to-injury-and-re-4r3n0c406v.pdf

Hamstring strain injuries: Factors that Lead to injury and re-Injury

Objective To provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies. Methods Thirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to complete a questionnaire on muscle injuries to evaluate the currently used terminology of athletic muscle injury. In addition, a consensus meeting of international sports medicine experts was established to develop practical and scientifi cd efinitions of muscle injuries as well as a new and comprehensive classification system. Results The response rate of the survey was 63%. The responses confirmed the marked variability in the use of the terminology relating to muscle injury, with the most obvious inconsistencies for the term strain. In the consensus meeting, practical and systematic terms were defined and established. In addition, a new comprehensive classification system was developed, which differentiates between four types: functional muscle disorders (type 1: overexertion-related and type 2: neuromuscular muscle disorders) describing disorders without macroscopic evidence of fibre tear and structural muscle injuries (type 3: partial tears and type 4: (sub) total tears/tendinous avulsions) with macroscopic evidence of fibre tear, that is, structural damage. Subclassifications are presented for each type. Conclusions A consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. This will help to improve clarity of communication for diagnostic and therapeutic purposes and can serve as the basis for future comparative studies to address the continued lack of systematic information on muscle injuries in the literature. What are the new things Consensus definitions of the terminology which is used in the field of muscle injuries as well as a new comprehensive classification system which clearly defines types of athletic muscle injuries. Level of evidence Expert opinion, Level V.

https://bjsm.bmj.com/content/bjsports/47/6/342.full.pdf

Terminology and classification of muscle injuries in sport: The Munich consensus statement

Background: Muscular tightness is frequently postulated as an intrinsic risk factor for the development of a muscle injury. However, very little prospective data exist to prove this.Hypothesis: Increased muscle tightness identifies a soccer player at risk for a subsequent musculoskeletal lesion.Study Design: Prospective cohort study.Methods: We examined 146 male professional soccer players before the 1999—2000 Belgian soccer competition. None of the players had a history of muscle injury in the lower extremities in the previous 2 years. The flexibility of the hamstring, quadriceps, adductor, and calf muscles of these players was measured goniometrically before the start of the season. All of the examined players were monitored throughout the season to register subsequent injuries.Results: Players with a hamstring (N = 31) or quadriceps (N = 13) muscle injury were found to have significantly lower flexibility in these muscles before their injury compared with the uninjured group. No significant differences...

Thomas D'Have

Papers

Muscle Flexibility as a Risk Factor for Developing Muscle Injuries in Male Professional Soccer Players A Prospective Study