Running in Review

Eccentric Hamstrings Strength: Implications for Training

Title: Decrease in eccentric hamstring strength in runners in the Tirol Speed Marathon

Author(s): A Koller, G Sumann, W Schobersberger, H Hoertnagl, C Haid. Source: Br J Sports Med. 2006; 40: 850-852.

Purpose: To investigate the relationship between marathon distance overground running and hamstring eccentric strength. Design: Case-control study. Study Population: A total of 16 subjects participated in this study, 14 male and two female runners. The median age was 41.0 years (23.0-54.0) and median weight at the start of the race was 79.0 kg (61.1-89.1). Inclusion criteria included a history of running a minimum of six hours per week. Exclusion criteria included history of ligamentous knee trauma.

Intervention: Subjects underwent electrocardiographic, physical, and hematologic examination. Baseline isokinetic muscle testing data were collected prior to running and then again 18 hours after finishing the marathon. Results: No differences between peak torque before and after the race existed, except eccentric peak hamstring torque.

Review: The inferences of the current study are several and intriguing, reaching both those within the running community and those without. While case-control design and low participant number render these data statistically weak, valuable discussion points are yet available. Previous work has correlated hamstring injury directly with fatigue. Among footballers employed in English Premier Football League, for instance, the majority of hamstring related injuries are recorded at the end of the first and in the second half of play. More generally, the current study cites the hamstrings as the third most common location for injury in master runners (11.7%).

Fatigue and proprioception relate inversely, with the former predicting decreased neuromuscular control and perception of joint position in space. This study qualifies eccentric strength as a potential influence that precipitates hamstring injury. Eccentric muscle action is described as a lengthening contraction and produces greater force per unit area than its concentric counterpart, but is also more complex neurologically. In this way, injuries often occur during the eccentric phase of muscle action. As with any variety of contractile tissue deficit, proper diagnosis, precise resistance and proprioceptive training helps preempt first time and repeated injury. As the hamstrings are very active eccentrically during the late swing phase of gait, specific training would be of theoretical benefit at this time.