Risk Of Hamstring Strain Injury Research Articles

Running exposure is associated with the risk of hamstring strain injury in elite Australian footballers

BackgroundTo investigate the association between running exposure and the risk of hamstring strain injury (HSI) in elite Australian footballers.MethodsElite Australian footballers (n=220) from 5 different teams participated. Global positioning system...

Lack of Effect of Ankle Position During the Nordic Curl on Muscle Activity of the Biceps Femoris and Medial Gastrocnemius.

Regular performance (~2×/wk) of Nordic curls has been shown to increase hamstring strength and reduce the risk of hamstring strain injury, although no consensus on ankle position has been provided. To compare the effects of performing Nordic curls, with the ankle in a dorsiflexed (DF) or plantar-flexed (PF) position, on muscle activity of the biceps femoris (BF) and medial gastrocnemius (MG). 15 male college athletes (age 22.6 ± 2.1 y, height 1.78 ± 0.06 m, body mass 88.75 ± 8.95 kg). A repeated-measures design was used, with participants performing 2 sets of 3 repetitions of both variations of Nordic curls, while muscle activity was assessed via surface electromyography (EMG) of the BF and MG. Comparisons of muscle activity were made by examining the normalized EMG data as the percentage of their maximum voluntary isometric contraction. Paired-samples t test revealed no significant difference in normalized muscle activity of the BF (124.5% ± 6.2% vs 128.1 ± 5.0%, P > .05, Cohen d = 0.64, power = .996) or MG (82.1% ± 3.9% vs 83.5 ± 4.8%, P > .05, Cohen d = 0.32, power = .947) during the Nordic curls in a PF or DF position, respectively. Ankle position does not influence muscle activity during the Nordic curl; however, performance of Nordic curls with the ankle in a DF position may be preferential, as this replicates the ankle position during terminal leg swing during running, which tends to be the point at which hamstring strains have been reported.

Effect of high-speed running on hamstring strain injury risk

BackgroundHamstring strain injuries (HSIs) are common within the Australian Football League (AFL) with most occurring during high-speed running (HSR). Therefore, this study investigated possible relationships between mean session running distances,...

Are Laboratory And Field-based Hamstring Strength Tests Correlated?

Laboratory based isometric and isokinetic (concentric and eccentric) dynamometry is negatively associated with Hamstring strain injury (HSI) risk. A field-based posterior lower limb strength test assessing maximal isometric hamstring contraction via a portable force platform is sensitive to fatigue induced changes in hamstring strength following a soccer match, but it is not known if the posterior lower limb strength test reflects the more robust dynamometry strength measures. PURPOSE: To investigate laboratory isometric (ISOdyno), concentric (CONdyno) and eccentric (ECCdyno) dynamometry strength measures relative to the field-based isometric posterior lower limb (ISOplat) test using a portable force platform. METHODS: 21 amateur soccer players (Male, 24 ± 3.1 yrs, 75.5 ± 9.5 Kg, 178.2 ± 6.3 cm) were recruited and familiarised with ISOdyno, CONdyno,/ECCdyno and ISOplat at least one week prior to experimental testing. The test order was standardised as part of a larger project. In week one players performed two maximum ISOplat tests (supine, 30° Knee flexion, 5 sec), and ≥7 days later performed two maximum ISOdyno (prone, 30° Knee flexion, 5 sec), followed by two CONdyno/ECCdyno (prone, 0-135° Knee Flexion 60°.S-1) tests using the dominant limb. At least 2-minutes rest between contractions was provided during each assessment. Pearsons correlations (r) between measures were performed with significance set at p<0.05. RESULTS: Average force measured 224.4 N (ISOplat), 125.5 Nm (ISOdyno) 131.1 N.m (ECCdyno) and 96.4 N.m (CONdyno). ISODyno was positively associated with both CONdyno (r2= 0.57, p= <0.0001, 95% CI 0.485-0.896), and ECCdyno (r2= 0.53, p = 0.0002, 95% CI 0.430-0.882) but no other significant correlations were observed. CONCLUSION: Evidence has shown isometric and isokinetic dynamometry is related to HSI risk. The absence of any correlation between the isometric posterior lower limb hamstring test with these dynamometer strength measurers suggests this test may not have a similar predicative capacity. These results could be explained by the anatomical position of the subject, or activation of hip extensor muscles that may have influenced the maximal force produced during ISOplat.

Hamstring and Quadriceps Isokinetic Strength Deficits Are Weak Risk Factors for Hamstring Strain Injuries

Background: A hamstring strain injury (HSI) has become the most common noncontact injury in soccer. Isokinetic muscle strength deficits are considered a risk factor for HSIs. However, underpowered studies with small sample sizes unable to determine small associations have led to inconclusive results regarding the role of isokinetic strength and strength testing in HSIs. Purpose: To examine whether differences in isokinetic strength measures of knee flexion and extension represent risk factors for hamstring injuries in a large cohort of professional soccer players in an adequately powered study design. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 614 professional soccer players from 14 teams underwent isokinetic strength testing during preseason screening. Testing consisted of concentric knee flexion and extension at 60 deg/s and 300 deg/s and eccentric knee extension at 60 deg/s. A clustered multiple logistic regression analysis was used to identify variables associated with the risk of HSIs. Receiver operating characteristic (ROC) curves were calculated to determine sensitivity and specificity. Results: Of the 614 players, 190 suffered an HSI during the 4 seasons. Quadriceps concentric strength at 60 deg/s (odds ratio [OR], 1.41; 95% CI, 1.03-1.92; P = .03) and hamstring eccentric strength at 60 deg/s (OR, 1.37; 95% CI, 1.01-1.85; P = .04) adjusted for bodyweight were independently associated with the risk of injuries. The absolute differences between the injured and uninjured players were 6.9 N·m and 9.1 N·m, with small effect sizes (d < 0.2). The ROC analyses showed an area under the curve of 0.54 and 0.56 for quadriceps concentric strength and hamstring eccentric strength, respectively, indicating a failed combined sensitivity and specificity of the 2 strength variables identified in the logistic regression models. Conclusion: This study identified small absolute strength differences and a wide overlap of the absolute strength measurements at the group level. The small associations between lower hamstring eccentric strength and lower quadriceps concentric strength with HSIs can only be considered as weak risk factors. The identification of these risk factors still does not allow the identification of individual players at risk. The use of isokinetic testing to determine the association between strength differences and HSIs is not supported.

Short biceps femoris fascicles and eccentric knee flexor weakness increase the risk of hamstring injury in elite football (soccer): a prospective cohort study

Background/aimTo investigate the role of eccentric knee flexor strength, between-limb imbalance and biceps femoris long head (BFlh) fascicle length on the risk of future hamstring strain injury (HSI).MethodsElite soccer players...

High intensity running increases risk of hamstring strain injury in elite Australian rules footballers

High intensity running increases risk of hamstring strain injury in elite Australian rules footballers

Is There Evidence to Support the Use of the Angle of Peak Torque as a Marker of Hamstring Injury and Re-Injury Risk?

Hamstring strain injuries are the predominant injury in many sports, costing athletes and clubs a significant financial and performance burden; therefore, the ability to identify and intervene with individuals who are considered at high risk of injury is important. One measure that has grown in popularity as an outcome variable following hamstring intervention/prevention studies and rehabilitation is the angle of peak knee flexor torque. This current opinion article will firstly introduce the measure and the processes behind it. Second, the article will summarise how the angle of peak knee flexor torque has been suggested to measure hamstring strain injury risk. Finally, the numerous limitations will be presented and the article will outline how these limitations may influence the usefulness of the angle of peak knee flexor torque measure. These include the lack of muscle specificity, the common concentric contraction mode of assessment, reliability of the measure, various neural contributions (such as rate of force development and neuromuscular inhibition), as well as the lack of prospective data showing any predictive value in the measure.

Biceps Femoris Aponeurosis Size: A Potential Risk Factor for Strain Injury?

A disproportionately small biceps femoris long head (BFlh) proximal aponeurosis has been suggested as a risk factor for hamstring strain injury by concentrating mechanical strain on the surrounding muscle tissue. However, the size of the BFlh aponeurosis relative to BFlh muscle size, or overall knee flexor strength, has not been investigated. This study aimed to examine the relationship of BFlh proximal aponeurosis area with muscle size (maximal anatomical cross-sectional area (ACSAmax)) and knee flexor strength (isometric and eccentric). Magnetic resonance images of the dominant thigh of 30 healthy young males were analyzed to measure BFlh proximal aponeurosis area and muscle ACSAmax. Participants performed maximum voluntary contractions to assess knee flexion maximal isometric and eccentric torque (at 50° s and 350° s). BFlh proximal aponeurosis area varied considerably between participants (more than fourfold, range = 7.5-33.5 cm, mean = 20.4 ± 5.4 cm, coefficient of variation = 26.6%) and was not related to BFlh ACSAmax (r = 0.04, P = 0.83). Consequently, the aponeurosis/muscle area ratio (defined as BFlh proximal aponeurosis area divided by BFlh ACSAmax) exhibited sixfold variability, being 83% smaller in one individual than another (0.53 to 3.09, coefficient of variation = 32.5%). Moreover, aponeurosis size was not related to isometric (r = 0.28, P = 0.13) or eccentric knee flexion strength (r = 0.24, P ≥ 0.20). BFlh proximal aponeurosis size exhibits high variability between healthy young men, and it was not related to BFlh muscle size or knee flexor strength. Individuals with a relatively small aponeurosis may be at increased risk of hamstring strain injury.

Eccentric hamstring strength and hamstring injury risk in Australian footballers.

Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measured during the Nordic hamstring exercise, risk factors for hamstring strain injury (HSI)? Elite Australian footballers (n = 210) from five different teams participated. Eccentric hamstring strength during the Nordic exercise was obtained at the commencement and conclusion of preseason training and at the midpoint of the season. Injury history and demographic data were also collected. Reports on prospectively occurring HSI were completed by the team medical staff. Relative risk (RR) was determined for univariate data, and logistic regression was employed for multivariate data. Twenty-eight new HSI were recorded. Eccentric hamstring strength below 256 N at the start of the preseason and 279 N at the end of the preseason increased the risk of future HSI 2.7-fold (RR, 2.7; 95% confidence interval, 1.3 to 5.5; P = 0.006) and 4.3-fold (RR, 4.3; 95% confidence interval, 1.7 to 11.0; P = 0.002), respectively. Between-limb imbalance in strength of greater than 10% did not increase the risk of future HSI. Univariate analysis did not reveal a significantly greater RR for future HSI in athletes who had sustained a lower limb injury of any kind within the last 12 months. Logistic regression revealed interactions between both athlete age and history of HSI with eccentric hamstring strength, whereby the likelihood of future HSI in older athletes or athletes with a history of HSI was reduced if an athlete had high levels of eccentric strength. Low levels of eccentric hamstring strength increased the risk of future HSI. Interaction effects suggest that the additional risk of future HSI associated with advancing age or previous injury was mitigated by higher levels of eccentric hamstring strength.

ECCENTRIC HAMSTRING STRENGTH DURING THE NORDIC HAMSTRING EXERCISES IS A RISK FACTOR FOR HAMSTRING STRAIN INJURY IN ELITE AUSTRALIAN FOOTBALL: A PROSPECTIVE COHORT STUDY

BackgroundThe Nordic hamstring exercise (NHE) reduces the risk of hamstring strain injury (HSI). It is unknown if measuring eccentric hamstring strength during the NHE can predict risk of future HSI...

A NOVEL MOBILE DEVICE BASED HAMSTRING STRENGTH TEST RESULT CAN PREDICT ISOKINETIC HAMSTRING STRENGTH IN PROFESSIONAL FOOTBALL PLAYERS: A STUDY OF RELIABILITY AND VALIDITY

BackgroundIsokinetic hamstring strength test is considered as a golden standard for identifying players with increased risk of hamstring strain injuries. However, those testing protocols were time consuming and inconvenient.ObjectiveThe aim...

Acute hamstring strain injury in track‐and‐field athletes: A 3‐year observational study at the Penn Relay Carnival

This study aimed to observe the incidence rates of hamstring strain injuries (HSIs) across different competition levels and ages during the Penn Relays Carnival. Over a 3-year period, all injuries treated by the medical staff were recorded. The type of injury, anatomic location, event in which the injury occurred, competition level, and demographic data were documented. Absolute and relative HSI (per 1000 participants) were determined, and odds ratios (ORs) were calculated between sexes, competition levels, and events. Throughout the study period 48,473 athletes registered to participate in the Penn Relays Carnival, with 118 HSIs treated by the medical team. High school girls displayed lesser risk of HSI than high school boys (OR = 0.55, P = 0.021), and masters athletes were more likely than high school- (OR = 4.26, P < 0.001) and college-level (OR = 3.55, P = 0.001) athletes to suffer HSI. The 4 × 400-m relay displayed a greater likelihood of HSI compared with the 4 × 100-m relay (OR = 1.77, P = 0.008). High school boys and masters-level athletes are most likely to suffer HSI, and there is higher risk in 400-m events compared with 100-m events.

Is There a Potential Relationship Between Prior Hamstring Strain Injury and Increased Risk for Future Anterior Cruciate Ligament Injury?

Hamstring strain injuries (HSIs) are the most prevalent injury in a number of sports, and while anterior cruciate ligament (ACL) injuries are less common, they are far more severe and have long-term implications, such as an increased risk of developing osteoarthritis later in life. Given the high incidence and severity of these injuries, they are key targets of injury preventive programs in elite sport. Evidence has shown that a previous severe knee injury (including ACL injury) increases the risk of HSI; however, whether the functional deficits that occur after HSI result in an increased risk of ACL injury has yet to be considered. In this clinical commentary, we present evidence that suggests that the link between previous HSI and increased risk of ACL injury requires further investigation by drawing parallels between deficits in hamstring function after HSI and in women athletes, who are more prone to ACL injury than men athletes. Comparisons between the neuromuscular function of the male and female hamstring has shown that women display lower hamstring-to-quadriceps strength ratios during isokinetic knee flexion and extension, increased activation of the quadriceps compared with the hamstrings during a stop-jump landing task, a greater time required to reach maximal isokinetic hamstring torque, and lower integrated myoelectrical hamstring activity during a sidestep cutting maneuver. Somewhat similarly, in athletes with a history of HSI, the previously injured limb, compared with the uninjured limb, displays lower eccentric knee flexor strength, a lower hamstrings-to-quadriceps strength ratio, lower voluntary myoelectrical activity during maximal knee flexor eccentric contraction, a lower knee flexor eccentric rate of torque development, and lower voluntary myoelectrical activity during the initial portion of eccentric contraction. Given that the medial and lateral hamstrings have different actions at the knee joint in the coronal plane, which hamstring head is previously injured might also be expected to influence the likelihood of future ACL. Whether the deficits in function after HSI, as seen in laboratory-based studies, translate to deficits in hamstring function during typical injurious tasks for ACL injury has yet to be determined but should be a consideration for future work.

Validez y fiabilidad de los ratios de fuerza isocinética para la estimación de desequilibrios musculares

Several isokinetic strength ratios (bilateral and unilateral) of the knee have been extensively used: (i) to identify possible anterior cruciate ligament (ACL) and hamstring strain injury risk factors; (ii) to monitor the effectiveness of rehabilitation programs; and (iii) to determine if an athlete is able to return safely to training and competition sessions after finishing a specific rehabilitation program. However, the precision of these isokinetic strength ratios to evaluate muscle imbalances has been accepted based on theoretical and empirical knowledge, and less based on the scientific evidence regarding their validity and reliability. The purposes of this literature review were: (1) to analyse and compare the validity and reliability of unilateral and bilateral isokinetic strength ratios of the knee for estimating and monitoring possible muscle imbalances; as well as (2) to report cut-off values to categorize the muscle function as normal or with significantly high injury risk. A total of 13 scientific studies fulfilled all the previously established inclusion and exclusion criteria. After analysing all the studies, it was possible to conclude that: (i) very few studies have analysed the validity and reliability of bilateral and unilateral (conventional and functional) isokinetic strength ratios of the knee to identify muscle imbalances; (ii) a bilateral imbalance lower than 10-15% and unilateral imbalances lower than 20-40% could be an appropriate cut-off score to reduce the likelihood of developing hamstring strains and ACL injuries; (iii) the isokinetic strength ratios of the knee appear to present moderate absolute reliability scores (standard error of the measurement <15%); and (iv) more studies are needed to determine the validity and reliability of the isokinetic strength ratios of the knee in different sport modalities.

An Evidence-Based Approach to Hamstring Strain Injury: A Systematic Review of the Literature

Background:Hamstring strain injury is a common problem within sport. Despite research interest, knowledge of risks for and management of hamstring strain is limited, as evidenced by high injury rates.Objective:To present the current best evidence for hamstring strain injury risk factors and the management of hamstring strain injury.Methods:MEDLINE, AMED, SportDiscus, and AUSPORT databases were searched (key terms “hamstring” and “strain,” “injury,” “pull,” or “tear”) to identify relevant literature published between 1982 and 2007 in the English language. Studies of adult athlete populations (older than 18 years) pertaining to hamstring strain incidence, prevalence, and/or intervening management of hamstring strain injury were included. Articles were limited to full-text randomized, controlled studies or cohort studies. Twenty-four articles were included. Articles were critically appraised using the McMaster Quantitative Review Guidelines instrument. Data pertaining to injury rates and return to sport outcomes were extracted. Each author undertook independent appraisal of a random selection of articles after establishing inter-rater agreement of appraisal.Results:Previous strain, older age, and ethnicity were consistently reported as significant risks for injury, as was competing in higher levels of competition. Associations with strength and flexibility were conflicting. Functional rehabilitation interventions had preventive effects and resulted in significantly earlier return to sport. Additionally, weak evidence existed for other interventions.Conclusion:Current evidence is inconclusive regarding most interventions for hamstring strain injury, while the effect of potentially modifiable risks is unclear. Further high-quality prospective studies into potential risks and management are required to provide a better framework within which to target interventions.