Recurrent Hamstring Injuries Research Articles

The relationship between sustained hamstring pain and reorganisation of somatosensory representations: a randomised, controlled study.

Recurrent hamstring injuries are highly prevalent amongst sporting populations. It has been hypothesised that pain from an initial hamstring injury may induce reorganisation of somatosensory representations that could contribute to reinjury. However, because of the cross-sectional nature of existing research, it remains unknown whether somatosensory changes are a cause or effect of pain or if they are driven by other potentially confounding factors. Here, we explored the effect of experimentally induced sustained hamstring pain on tasks that interrogate somatosensory and spatial representations. Fifty healthy participants were randomly allocated to an experimental group that performed an eccentric exercise protocol on the right hamstring to induce delayed onset muscle soreness or a control group performing a repetition-matched concentric exercise protocol. The tactile cortical representation was assessed using two-point discrimination and tactile localisation, whereas the proprioceptive representation was assessed using a left-right judgement task. Peripersonal spatial representations were assessed using an auditory localisation task. Assessments were performed at baseline and day 2. No between-group differences in tactile acuity were observed. However, improvements in left-right judgments and worsening of auditory localisation occurred in the experimental group compared with the control group. This study provides preliminary evidence showing that somatosensory changes occur in response to sustained hamstring pain. Experimentally induced, sustained hamstring pain elicited enhancements in proprioceptive processing and deficits in peripersonal spatial processing, suggesting a shift in the allocation of attentional resources from the external (peripersonal) to internal (body) environment. These findings may hold important implications for reinjury risk and rehabilitation following hamstring pain.

Hamstring Activity Before and After Break-Point Angle Calculated By Smartphone Application During the Nordic Hamstring Exercise.

Previous studies have reported a gradual decrease in biceps femoris (BF) electromyography (EMG) activity after the break-point angle (BPA) during the Nordic hamstring exercise (NHE). However, no investigation has been conducted on BF EMG activity before and after BPA as calculated using a smartphone application (Nordic Angle app). The aim of this study was to investigate the BF EMG activity before and after BPA, as calculated using the Nordic Angle app. The hypotheses were that BF EMG activity would peak near the BPA and gradually diminish afterward. After a warm-up, participants performed three repetitions of prone leg curls to discern maximum voluntary isometric contraction (MVIC) of the hamstrings. The peak value of the BF EMG activity during the prone leg curl was used to convert BF EMG activity during NHE to %MVIC. BPA during NHE was calculated using the Nordic Angle app by analyzing a movie recorded with an iPhone camera. Additionally, the knee flexion angle during NHE was determined using two-dimensional motion analysis software based on video data. To compare EMG activity before and after BPA calculated by the Nordic Angle app, the knee flexion angle was divided into seven phases: 10-15° before BPA, 5-10° before BPA, BPA ± 5°, 5-10° after BPA, 10-15° after BPA, 15-20° after BPA, and 20-25° after BPA. There was no significant difference between the BPA of the Nordic angle and the knee flexion angle at peak BF EMG activity (d = 0.13, p = 0.678). The BF EMG activity at 20-25° after BPA was significantly lower than the BF EMG activity at BPA ± 5° (d = 0.87, p = 0.011). To prevent the recurrence of hamstring injuries, it is important to incorporate knee flexion exercises that enhance BF EMG activity at 15-35° of knee flexion (0° indicates a fully extended knee). Thus, it is recommended to keep the BPA of the Nordic Angle within 35° to effectively prevent recurrent hamstring injuries during NHE. 3b.

Investigating neural representations in response to posterior thigh pain – a potential risk factor for hamstring injury recurrence?

Background: Recurrent hamstring injuries are a major problem in sport. Despite extensive research regarding risk factors underlying hamstring injury, recurrence rates remain high, suggesting our current understanding may be overlooking important neurophysiological factors. Recent evidence demonstrates disruptions in tactile, proprioceptive, and spatial neural (cortical) representations in athletes who develop persistent posterior thigh pain following a hamstring injury. It is possible these disruptions may contribute to poor recovery and hamstring injury recurrence.

Risk Factors Associated With Recurrent Hamstring Injuries in Sports Athletes

Hamstring injuries are commonly strained and occur proximally around the muscle-tendon junction, injuring the biceps femoris laterally. Gashes, wounds, and strains are three different types of muscle damage depending on the event instrument. Objective is to assess recurrent hamstring injuries in sports athletes Methods: A cross-sectional research was observed in 183 participants .18 to 35 years were observed. Special informed consents were gathered from the participants before the study. Most of the participants were student athletes of the University of Lahore. Data was collected using a non-probability handy sampling strategy. SPSS statistics v. 25 was used to analyze the data. Results: Participants in the sample were on average 24.69 years old, the youngest is eighteen years old, while the oldest is thirty-four years old. In this study included both genders .102 were males (55.7%) and 81 female (44.3) participants, with 27 of the participants married and 4 divorced individuals. 35.% of the athletes play Football, 11.5% play Basketball, 14.8% play both Football and Basketball. While, 23.5% play Cricket and only 14.8% play Badminton. 36.6% of the participants had playing experience of 5 years or more. While others averaged between 1-4 years of experience. Only 75 of the 183 participants indicated that they stretched 5 minutes before any exercise or sports. 63 participants stretched 10 minutes before any exercise or sports. While, only 13 claimed they stretched for 20 minutes and 2 participants stretched for 25 minutes. A history of previous injury was noted in 48.6% of athletes, while 51.4% claimed to not have had any previous injury. Positive pain or tightness in the thighs was noted for 134 (73.2%) athletes. 48.6% of the dataset population had a recurrent hamstring injury. While, 51.4% did not. Conclusions: Notable associations were noted for hamstring injuries with stretching of muscles, muscle tightness, low back pains, inadequate warm-ups before playing and playing days after the occurrence of an injury. Results also shows that fatigue and old age is not a strong risk factor for the recurrence of hamstring strain.

Hamstring Injury Trends in Major and Minor League Baseball: Epidemiological Findings From the Major League Baseball Health and Injury Tracking System.

Background:Hamstring strains are the most common injury for professional baseball players and can result in significant time on the disabled list. To date, no study has reported the current trends in hamstring strains in professional baseball.Hypothesis:Professional baseball players would have an increased incidence of hamstring strains from 2011 through 2016.Study Design:Descriptive epidemiology study.Methods:Injury data were prospectively collected from 2011 through 2016 for every Major League Baseball (MLB) and Minor League Baseball (MiLB) team and was recorded in the MLB Health and Injury Tracking System. Data collected for this study included date of injury, activity during injury, time lost, primary injury or reinjury status, and imaging findings as well as player demographic information related to level of play, age, and position for all hamstring injury events. Injury rates were reported as hamstring injuries per number of games.Results:From 2011 to 2016, there were 2633 hamstring strains in professional baseball players. The rate of hamstring strains increased in MLB from a low of 1 injury every 39 games in 2011 to a high of 1 injury every 30 games in 2016. In MiLB, there were 2192 hamstring strains, with 1 injury every 35 games in 2011 compared with 1 injury every 30 games in 2016. The majority of injuries occurred in the infielder positions (37.5%) and resulted from base running (>50%), most commonly from home to first base. The most common hamstring injury was a grade 2 injury to the distal biceps femoris. The mean time missed after a hamstring injury was 14.5 days. Grade 3 and grade 2 hamstring strains resulted in significantly more days missed compared with grade 1 injuries (P = .005 and P = .002, respectively). The rate of recurrent hamstring injuries was 16.3% for MLB and 14.2% for MiLB. Recurrent hamstring injuries resulted in more time lost than primary injuries (mean, 16.4 vs 14.5 days, respectively; P = .02). A total of 42 injuries were treated with platelet-rich plasma, and 19 were treated with surgery. The number of injuries treated with platelet-rich plasma increased in successive years.Conclusion:The rate of hamstring strains in professional baseball players has increased over the past 6 years and has resulted in a significant loss of playing time. Study results indicated that these injuries are affected by injury characteristics, position played, running to first base, seasonal timing, and history of hamstring injuries.

Recurrent Hamstring Injuries in Elite Athletes - A Paradigm Shift to Mechanical Dysfunction of the Sacroiliac Joint as One Causation

Recurrent hamstring injuries are a significant and troubling issue in the elite athletic community. Reinjury may occur in up to 34% of patients in the kicking and running sports. We hypothesised that a proportion of these patients may have mechanical dysfunction of the sacroiliac joint as a causative mechanism. We recruited 23 elite athletes with recurrent hamstring injuries and lateralising lower back pain into the study after careful screening. Diagnosis was confirmed by scintigraphic SPECT/ CT imaging. Patients who failed directed physiotherapy were offered injection of the sacroiliac joint with platelet rich plasma (PRP). All 23 athletes (Av age 35 years, 19 M, 4F) had MRI evidence of hamstring tears (Av 4.2 tears) and met criteria for a diagnosis of sacroiliac joint dysfunction with mean clinical scores of 6.8 (Range: 7-9). Four patients returned to sport after physiotherapy and 19 underwent peri-articular PRP injection under ultrasound guidance. The baseline VAS was 80 (mean) and after treatment 9, indicating a significant response to treatment (p=0.002). All patients with SIJ dysfunction and recurrent hamstring tears responded to treatment. A plausible explanation for the relationship is the alteration in muscle sequencing around the pelvis following SIJ dysfunction.

Return to Play After Hamstring Injuries: A Qualitative Systematic Review of Definitions and Criteria.

BackgroundMore than half of the recurrent hamstring injuries occur within the first month after return-to-play (RTP). Although there are numerous studies on RTP, comparisons are hampered by the numerous definitions of RTP used. Moreover, there is no consensus on the criteria used to determine when a person can start playing again. These criteria need to be critically evaluated, in an attempt to reduce recurrence rates and optimize RTP.ObjectiveTo carry out a systematic review of the literature on (1) definitions of RTP used in hamstring research and (2) criteria for RTP after hamstring injuries.Study DesignSystematic review.MethodsSeven databases (PubMed, EMBASE/MEDLINE, CINAHL, PEDro, Cochrane, SPORTDiscus, Scopus) were searched for articles that provided a definition of, or criteria for, RTP after hamstring injury. There were no limitations on the methodological design or quality of articles. Content analysis was used to record and analyze definitions and criteria for RTP after hamstring injury.ResultsTwenty-five papers fulfilled inclusion criteria, of which 13 provided a definition of RTP and 23 described criteria to support the RTP decision. “Reaching the athlete’s pre-injury level” and “being able to perform full sport activities” were the primary content categories used to define RTP. “Absence of pain”, “similar strength”, “similar flexibility”, “medical staff clearance”, and “functional performance” were core themes to describe criteria to support the RTP decision after hamstring injury.ConclusionOnly half of the included studies provided some definition of RTP after hamstring injury, of which reaching the athlete’s pre-injury level and being able to perform full sport activities were the most important. A wide variety of criteria are used to support the RTP decision, none of which have been validated. More research is needed to reach a consensus on the definition of RTP and to provide validated RTP criteria to facilitate hamstring injury management and reduce hamstring injury recurrence.PROSPERO systematic review registration number: CRD42015016510.Electronic supplementary materialThe online version of this article (doi:10.1007/s40279-015-0468-7) contains supplementary material, which is available to authorized users.

Surgical Management of Recurrent Musculotendinous Hamstring Injury in Professional Athletes.

Background:Hamstring injury is the most common muscular lesion in athletes. The conservative treatment is well described, and surgical management is often indicated for proximal tendinous avulsions. To our knowledge, no surgical treatment has been proposed for failure of conservative treatment in musculotendinous hamstring lesions.Purpose:To describe the surgical management of proximal and distal hamstring musculotendinous junction lesions in professional athletes after failure of conservative treatment.Study Design:Case series; Level of evidence, 4.Methods:A consecutive series of 10 professional athletes, including 4 soccer players, 4 rugby players, and 2 handball players, underwent surgical intervention between October 2010 and June 2014 for the treatment of recurrent musculotendinous hamstring injuries. All athletes had failed at least 3 months of conservative treatment for a recurrent musculotendinous hamstring injury. Surgical resection of the musculotendinous scar tissue was performed using a longitudinal muscular suture. Lower Extremity Functional Scale (LEFS) and Marx scores were obtained at the 3-month follow-up, and a final phone interview was completed to determine recurrence of hamstring injury and return to previous level of play.Results:The mean age at surgery was 25.2 years (range, 19-35 years). The musculotendinous hamstring lesions involved 8 semitendinosus and 2 biceps femoris, with 6 injuries located proximally and 4 distally. Conservative treatment lasted a mean 5.1 months (range, 3-9 months) after last recurrence, and the patients had an average of 2.7 (range, 2-5) separate incidents of injury recurrence before surgical intervention was decided upon. At the 3-month follow-up, all patients had Marx activity scores of 16 and LEFS scores of 80. All 10 patients returned to the same level of play at a mean 3.4 months (range, 2-5 months). At a mean follow-up of 28.7 months, none of the athletes had suffered a recurrence. No surgical complication was encountered.Conclusion:In cases of failed conservative treatment of musculotendinous hamstring lesions, surgical intervention may be a viable treatment option in professional athletes and allows the patient to return to the same level of play.

THE PREVENTIVE EFFECT OF THE NORDIC HAMSTRING EXERCISE ON HAMSTRING INJURIES IN AMATEUR SOCCER PLAYERS: A RANDOMIZED CONTROLLED TRIAL

BackgroundHamstring injuries are the most common muscle injuries in male amateur soccer. Eccentric strength of the hamstrings is recognized as an important modifiable risk factor, leading to the development of...

The preventive effect of the Nordic hamstring exercise on hamstring injuries in amateur soccer players: study protocol for a randomised controlled trial

BackgroundHamstring injuries are the most common muscle injury in male amateur soccer players and have a high rate of recurrence, often despite extensive treatment and long rehabilitation periods. Eccentric strength...

Recurrent hamstring injuries—An overview of considerations

Recurrent hamstring injuries—An overview of considerations

Recurrent Hamstring Injuries—Risks and Prevention

Recurrent Hamstring Injuries—Risks and Prevention

Recurrent hamstring muscle injury: applying the limited evidence in the professional football setting with a seven-point programme

Recurrent hamstring injuries are a major problem in sports such as football. The aim of this paper was to use a clinical example to describe a treatment strategy for the...

Does Eccentric Training of Hamstring Muscles Reduce Acute Injuries in Soccer?

To investigate the effectiveness of a 10-week hamstring exercise training program in reducing the incidence and severity of new and recurrent hamstring injuries among male soccer players. Cluster-randomized (by team)controlled trial, stratified by level of play and geographic location. Sample size was calculated with 80% power to show a relative risk reduction for injury of 50% at P ≤ 0.05. Soccer community study in Denmark during the period January to December 2008. Teams in the top 5 soccer divisions (2 professional and 3 amateur)were invited to participate. The exclusion criterion for teams was that they already used eccentric hamstring exercises, and for participants was that they joined the teams after the beginning of the season. Of 116 teams, 54 were eligible and willing to be randomized and 50 were included in the analysis (942 players). Teams in both the intervention and control groups followed their normal training programs. At the beginning of the study period, the intervention teams added 27 sessions of the Nordicham string exercise (after warm-up) during the 10-week period of the mid-season break. The exercise begins with the player kneeling with the torso upright and rigid, and the feet held down to the ground by a partner. The player lowers his torso forwards toward the ground braking with his hamstring muscles until the chest reaches the ground (eccentric phase). He returns to the upright position, pushing with his hands to minimize the concentric phase load. Sessions per week and sets and repetitions per session increased to 3, 3, and 12, respectively. Team coaches supervised the sessions. A hamstring injury was defined as an acute occurrence of a “physical complaint in the region of the posterior thigh sustained during a soccer match or training, irrespective of the need for medical attention or time loss from soccer activities.” Injuries were recorded by the teams’ medical staff on standardized forms. Only first injuries during the season were included and recorded as first-time injuries or recurrences of injuries sustained before the season.Severity of injury was defined by number of days lost from full participation in games and practices. Injury rates per 100 player sessions were lower for the intervention group (3.8) than for the control group(13.1); thus, the rate ratio (RR) adjusted for age, level of competition, and previous injury was 0.293 (95% confidence interval[CI], 0.150-0.572). Both rates of new and recurrent injuries were lower for the intervention group than for the control group(new injuries: RR, 0.410; 95% CI, 0.180-0.933; recurrent injuries: RR, 0.137; 95% CI, 0.037-0.509). The 15 injuries in the intervention group resulted in absence of 454 days from soccer (mean, 30.3; SD, 18.3; range, 7-64 days per injury), whereas 51 injuries in the control group resulted in 1344 days absent (mean, 26.4; SD, 19.5; range, 4-89 days per injury). Mean severity of injuries (days absent) was not significantly different (P = 0.16) between groups. Delayed onset muscle soreness,but no other adverse effect, was reported by most members of the intervention group during the training period. An eccentric hamstring exercise program was associated with lower rates of new and recurrent hamstring injuries in Danish male soccer players.

Eccentric hamstring muscle training can prevent hamstring injuries in soccer players

Does eccentric muscle training of hamstring muscles reduce the rate of hamstring injuries in male soccer players? Cluster randomised, controlled trial with concealed allocation. The 5 top men's soccer divisions in Denmark. First team squad soccer players from teams in the top 5 national soccer divisions were included. Players who joined a team after the start of the trial were excluded. Randomisation of 54 teams allocated 26 to the intervention group and 28 to a control group. Both groups followed their usual training program. In addition, the intervention group completed 27 sessions of the eccentric hamstring muscle training in a 10-week period during the midseason break, and once a week in the second half of the season. The hamstring exercise (the Nordic curl) involves the player using hamstrings to resist forward falling of the trunk from a kneeling position. Players completed 2-3 sets of 5-12 repetitions of the exercise for 1-3 sessions per week. The primary outcome was the number of overall, new, and recurrent acute hamstring injuries during one full soccer season. A hamstring injury was defined as any acute physical complaint in the region of the posterior thigh sustained during a soccer match or training. Recurrence of an injury already reported in the trial period was not included to avoid recording the same injury more than once. 50 teams with 942 players completed the study. At the end of the season, there had been 15 hamstring injuries (12 new, 3 recurrent) in the eccentric hamstring exercise group and 52 injuries (32 new, 20 recurrent) in the control group. The number needed to treat (NNT) to prevent 1 hamstring injury (new or recurrent) was 13 (95% CI 9 to 23). The NNT to prevent 1 new injury was 25 (95% CI 15 to 72) and the NNT for recurrent injury was 3 (95% CI 2 to 6). Apart from short term muscle soreness no adverse events were reported in the exercise group. An eccentric strengthening exercise program for the hamstring muscles that can be performed during training can help prevent hamstring injuries in soccer players.

Risk factors of recurrent hamstring injuries: a systematic review

BackgroundAlthough recurrent hamstring injury is a frequent problem with a significant impact on athletes, data on factors determining the risk for a recurrent hamstring injury are scarce.ObjectiveTo systematically review the...

Preventive Effect of Eccentric Training on Acute Hamstring Injuries in Men’s Soccer

Background: The incidence of acute hamstring injuries is high in several sports, including the different forms of football. Purpose: The authors investigated the preventive effect of eccentric strengthening of the hamstring muscles using the Nordic hamstring exercise compared with no additional hamstring exercise on the rate of acute hamstring injuries in male soccer players. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Fifty Danish male professional and amateur soccer teams (942 players) were allocated to an intervention group (461 players) or a control group (481 players). Players in the intervention group conducted a 10-week progressive eccentric training program followed by a weekly seasonal program, whereas players in the control group followed their usual training program. The main outcome measures were numbers of overall, new, and recurrent acute hamstring injuries during 1 full soccer season. Results: Fifty-two acute hamstring injuries in the control group compared with 15 injuries in the intervention group were registered. Comparing intervention versus the control group, overall acute hamstring injury rates per 100 player seasons were 3.8 versus 13.1 (adjusted rate ratio [RR], 0.293; 95% confidence interval [CI], 0.150-0.572; P < .001). New injury rates per 100 player seasons were 3.1 versus 8.1 (RR, 0.410; 95% CI, 0.180-0.933; P = .034), whereas recurrent injury rates per 100 player seasons were 7.1 versus 45.8 (RR, 0.137; 95% CI, 0.037-0.509; P = .003). Number needed to treat [NNT] to prevent 1 acute hamstring injury (new or recurrent) is 13 (95% CI, 9-23) players. The NNT to prevent 1 new injury is 25 (95% CI, 15-72) players, and NNT to prevent 1 recurrent injury is 3 (95% CI, 2-6) players. Conclusion: In male professional and amateur soccer players, additional eccentric hamstring exercise decreased the rate of overall, new, and recurrent acute hamstring injuries.

Acute hamstring injuries in Danish elite football: A 12‐month prospective registration study among 374 players

The purpose of the present study was to examine the incidence rates of acute hamstring injuries in Danish elite football sustained during training or match play. Furthermore, it was our intention to document details about the recurrence, severity and the injury seasonal distribution. Hamstring injuries among 374 elite football players were registered prospectively during a 12-month period. A total of 46 first-time and eight recurrent hamstring injuries were registered. The incidence rates for incurring a first-time hamstring injury showed a significantly (P<0.01) greater incidence rate per 1000 h during match play compared with training. Of 32 players who reported a hamstring injury in the 12-month period before the study, eight (25%) incurred an injury that fulfilled the criteria for a recurrent injury. In 69% of the injuries, the severity of injury was categorized as moderate (8-28 days from injury to injury free) and 18% as severe (>28 days from injury to injury free). Each team sustained a mean of 3.4 hamstring injuries per season, with a mean of 21.5 days missed per injury (range 3-136; median 16 days per injury). The seasonal distribution showed an accumulation of injuries in the first 2 months after a 3.5-month mid-season winter break.

Application of eccentric exercise on an Australian Rules football player with recurrent hamstring injuries

Study Design Case report. Objective To assess an eccentric based intervention on an Australian Football player with recurrent hamstring injuries. Case description The athlete attempted several conventional rehabilitation programs in the past (e.g. physical therapy, manual therapy, acupuncture, active release, medial gluteal strengthening) with no sustained progress in regards to pain, soreness, or return to sport. Outcomes After the first three phases of the intervention (i.e. nine weeks), the optimum angle of peak torque during knee flexion decreased from 37.3 to 23.9 degrees in the injured leg, and from 24.3 to 20.3 degrees in the non-injured leg. After the first nine weeks, the optimum angles then remained constant for another 23 weeks. The optimum angle of peak torque was also shifted in the knee extensors by 3.9 degrees (injured leg) and 3.4 degrees (non-injured leg) after nine weeks and then remained constant for the remaining 23 weeks. Quadriceps to hamstring peak torque ratio's (Q/H ratios) and peak torque during knee flexion and extension remained constant throughout the intervention. Discussion An eccentric based intervention was shown to be safe and effective for altering the optimum angle of peak torque (i.e. shifting to longer muscle lengths) for this athlete with recurrent hamstring injuries.

Magnetic Resonance Imaging Parameters for Assessing Risk of Recurrent Hamstring Injuries in Elite Athletes

Background Magnetic resonance (MR) imaging has established its usefulness in diagnosing hamstring muscle strain and identifying features correlating with the duration of rehabilitation in athletes; however, data are currently lacking that may predict which imaging parameters may be predictive of a repeat strain. Purpose This study was conducted to identify whether any MR imaging-identifiable parameters are predictive of athletes at risk of sustaining a recurrent hamstring strain in the same playing season. Study Design Cohort study; Level of evidence, 3. Methods Forty-one players of the Australian Football League who sustained a hamstring injury underwent MR examination within 3 days of injury between February and August 2002. The imaging parameters measured were the length of injury, cross-sectional area, the specific muscle involved, and the location of the injury within the muscle-tendon unit. Players who suffered a repeat injury during the same season were reimaged, and baseline and repeat injury measurements were compared. Comparison was also made between this group and those who sustained a single strain. Results Forty-one players sustained hamstring strains that were positive on MR imaging, with 31 injured once and 10 suffering a second injury. The mean length of hamstring muscle injury for the isolated group was 83.4 mm, compared with 98.7 mm for the reinjury group (P = .35). In the reinjury group, the second strain was also of greater length than the original (mean, 107.5 mm; P = .07). Ninety percent of players sustaining a repeat injury demonstrated an injury length greater than 60 mm, compared with only 58% in the single strain group (P = .01). Only 7% of players (1 of 14) with a strain <60 mm suffered a repeat injury. Of the 27 players sustaining a hamstring strain >60 mm, 33% (9 of 27) suffered a repeat injury. Of all the parameters assessed, only a history of anterior cruciate ligament sprain was a statistically significant predictor for suffering a second strain during the same season of competition. Conclusion A history of anterior cruciate ligament injury was the only statistically significant risk factor for a recurrent hamstring strain in our study. Of the imaging parameters, the MR length of a strain had the strongest correlation association with a repeat hamstring strain and therefore may assist in identifying which athletes are more likely to suffer further reinjury.