PURPOSE: Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measu... more PURPOSE: Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measured during the Nordic hamstring exercise, risk factors for hamstring strain injury (HSI)?METHODS: 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.RESULTS: 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.CONCLUSION: 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.
ABSTRACT Hamstring strain injuries (HSI) are the most common injury within Australian football wi... more ABSTRACT Hamstring strain injuries (HSI) are the most common injury within Australian football with reports showing no decrease in incidence over two decades. To compare differences of HSIs and eccentric hamstring strength, using a field-based testing device, between elite and sub-elite Australian footballers. A prospective cohort study. 2 football teams were involved in the study with data collected at their respective club. The first team competes in the elite Australian Football League (AFL) whilst the other competes in the sub-elite North East Australian Football League (NEAFL). 82 Australian footballers, 41 footballers from a sub-elite NEAFL team and 41 footballers from an elite AFL team participated in the study. The teams were tested during their preseason, with each footballer performing 3 repetitions of the Nordic hamstring exercise on a field-based testing device. Between limb imbalance and absolute strength were the independent variables. The dependent variable was the HSI rates, each team was required to record all injuries for the subsequent 'home and away' season. Although not statistically significant, elite AFL players displayed slightly higher average peak torques for the left limb (+17.5N, P=.113) and right limb (+21.1N, P=.09). No difference was observed for between limb imbalance (P=.408) between elite and sub-elite players. However, elite players sustained 3 times more HSIs (9 vs. 3) and missed a greater number of games as a result (28 vs. 6). Minimal differences were observed between strength and between limb strength imbalances, however, a 60% increase in HSIs was observed in the elite group. We propose that the strength levels displayed within the AFL and additional study is required to assess whether the elite level has higher physical demands and thus requiring greater strength.
Hamstring strain injuries (HSIs) are common within the Australian Football League (AFL) with most... more Hamstring 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, session ratings of perceived exertion (s-RPE) and HSIs within AFL footballers. Global positioning system (GPS)-derived running distances and s-RPE for all matches and training sessions over two AFL seasons were obtained from one AFL team. All HSIs were documented and each player's running distances and s-RPE were standardised to their 2-yearly session average, then compared between injured and uninjured players in the 4 weeks (weeks -1, -2, -3 and -4) preceding each injury. Higher than 'typical' (ie, z=0) HSR session means were associated with a greater likelihood of HSI (week -1: OR=6.44, 95% CI=2.99 to 14.41, p<0.001; summed weeks -1 and -2: OR=3.06, 95% CI=2.03 to 4.75, p<0.001; summed weeks -1, -2 and -3: OR=2.22, 95% CI=1.66 ...
ABSTRACT The Nordic hamstring exercise (NHE) reduces the risk of hamstring strain injury (HSI). I... more ABSTRACT The 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 in elite Australian footballers. To determine if measures of eccentric hamstring strength during the NHE identify athletes at risk of future HSI. Prospective cohort study. Single competitive season in elite Australian football. Elite Australian footballers able to perform the NHE maximally at the time of testing. 210 athletes from 5 teams had their eccentric hamstring strength assessed. Eccentric hamstring strength was determined using a custom made device at the start and end of pre-season training. Reports of previous history of hamstring, quadriceps, groin and calf injury in the prior 12 months and any history of anterior cruciate ligament injury for all athletes were ascertained. Prospective occurrence of HSI. The hypotheses (a priori), were that athletes with lower levels of eccentric hamstring strength and greater between limb imbalances in strength would be at greater risk of HSI. Low levels of eccentric hamstring strength at the start and end of preseason training increased the risk of future HSI by 3.3 (P=.002) and 2.8 fold (P=.027) respectively. Prior HSI increased the risk of future HSI by 3.1 fold (P=.018). No measure of between limb imbalance or any other prior injury data increased the risk of future HSI. Multivariate logistic regression revealed an interaction between increasing age and eccentric hamstring weakness leading to an increased risk of HSI. Low levels of eccentric hamstring strength during the NHE increases the risk of future HSI in elite Australian footballers and this effect is magnified in older athletes.
Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measured durin... more 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.
Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the ... more Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the rate of recurrence has been consistently high for a number of years. Long-lasting neuromuscular inhibition has been noted in previously injured athletes, but it is not known if this influences the athlete's adaptive response to training. To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display less improvement in eccentric hamstring strength during preseason training compared with athletes without a history of HSIs (control group). Cohort study; Level of evidence, 2. A total of 99 elite Australian footballers (17 with a history of unilateral HSIs in the previous 12-month period) participated in this study. Eccentric hamstring strength was assessed at the start and end of preseason training using an instrumented Nordic hamstring device. The change in eccentric strength across the preseason was determined in absolute terms and normaliz...
PURPOSE: Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measu... more PURPOSE: Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measured during the Nordic hamstring exercise, risk factors for hamstring strain injury (HSI)?METHODS: 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.RESULTS: 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.CONCLUSION: 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.
ABSTRACT Hamstring strain injuries (HSI) are the most common injury within Australian football wi... more ABSTRACT Hamstring strain injuries (HSI) are the most common injury within Australian football with reports showing no decrease in incidence over two decades. To compare differences of HSIs and eccentric hamstring strength, using a field-based testing device, between elite and sub-elite Australian footballers. A prospective cohort study. 2 football teams were involved in the study with data collected at their respective club. The first team competes in the elite Australian Football League (AFL) whilst the other competes in the sub-elite North East Australian Football League (NEAFL). 82 Australian footballers, 41 footballers from a sub-elite NEAFL team and 41 footballers from an elite AFL team participated in the study. The teams were tested during their preseason, with each footballer performing 3 repetitions of the Nordic hamstring exercise on a field-based testing device. Between limb imbalance and absolute strength were the independent variables. The dependent variable was the HSI rates, each team was required to record all injuries for the subsequent &#39;home and away&#39; season. Although not statistically significant, elite AFL players displayed slightly higher average peak torques for the left limb (+17.5N, P=.113) and right limb (+21.1N, P=.09). No difference was observed for between limb imbalance (P=.408) between elite and sub-elite players. However, elite players sustained 3 times more HSIs (9 vs. 3) and missed a greater number of games as a result (28 vs. 6). Minimal differences were observed between strength and between limb strength imbalances, however, a 60% increase in HSIs was observed in the elite group. We propose that the strength levels displayed within the AFL and additional study is required to assess whether the elite level has higher physical demands and thus requiring greater strength.
Hamstring strain injuries (HSIs) are common within the Australian Football League (AFL) with most... more Hamstring 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, session ratings of perceived exertion (s-RPE) and HSIs within AFL footballers. Global positioning system (GPS)-derived running distances and s-RPE for all matches and training sessions over two AFL seasons were obtained from one AFL team. All HSIs were documented and each player's running distances and s-RPE were standardised to their 2-yearly session average, then compared between injured and uninjured players in the 4 weeks (weeks -1, -2, -3 and -4) preceding each injury. Higher than 'typical' (ie, z=0) HSR session means were associated with a greater likelihood of HSI (week -1: OR=6.44, 95% CI=2.99 to 14.41, p<0.001; summed weeks -1 and -2: OR=3.06, 95% CI=2.03 to 4.75, p<0.001; summed weeks -1, -2 and -3: OR=2.22, 95% CI=1.66 ...
ABSTRACT The Nordic hamstring exercise (NHE) reduces the risk of hamstring strain injury (HSI). I... more ABSTRACT The 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 in elite Australian footballers. To determine if measures of eccentric hamstring strength during the NHE identify athletes at risk of future HSI. Prospective cohort study. Single competitive season in elite Australian football. Elite Australian footballers able to perform the NHE maximally at the time of testing. 210 athletes from 5 teams had their eccentric hamstring strength assessed. Eccentric hamstring strength was determined using a custom made device at the start and end of pre-season training. Reports of previous history of hamstring, quadriceps, groin and calf injury in the prior 12 months and any history of anterior cruciate ligament injury for all athletes were ascertained. Prospective occurrence of HSI. The hypotheses (a priori), were that athletes with lower levels of eccentric hamstring strength and greater between limb imbalances in strength would be at greater risk of HSI. Low levels of eccentric hamstring strength at the start and end of preseason training increased the risk of future HSI by 3.3 (P=.002) and 2.8 fold (P=.027) respectively. Prior HSI increased the risk of future HSI by 3.1 fold (P=.018). No measure of between limb imbalance or any other prior injury data increased the risk of future HSI. Multivariate logistic regression revealed an interaction between increasing age and eccentric hamstring weakness leading to an increased risk of HSI. Low levels of eccentric hamstring strength during the NHE increases the risk of future HSI in elite Australian footballers and this effect is magnified in older athletes.
Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measured durin... more 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.
Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the ... more Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the rate of recurrence has been consistently high for a number of years. Long-lasting neuromuscular inhibition has been noted in previously injured athletes, but it is not known if this influences the athlete's adaptive response to training. To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display less improvement in eccentric hamstring strength during preseason training compared with athletes without a history of HSIs (control group). Cohort study; Level of evidence, 2. A total of 99 elite Australian footballers (17 with a history of unilateral HSIs in the previous 12-month period) participated in this study. Eccentric hamstring strength was assessed at the start and end of preseason training using an instrumented Nordic hamstring device. The change in eccentric strength across the preseason was determined in absolute terms and normaliz...
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