The effects of eccentric hamstring strength training on dynamic jumping performance and isokinetic strength parameters: a pilot study on the implications for the prevention of hamstring injuries

Objectives: Although previous research shows that the hamstring length-tension relationship during eccentric contractions plays a role in hamstring injury, training methods to promote beneficial adaptations are still unclear. The purpose of this pilot study was to determine whether an eccentric hamstring specific training programme results in favourable adaptations. Design: Eccentric training consisting of the Nordic hamstring exercise performed twice a week for four weeks. Pre- and post-training concentric/concentric isokinetic testing of peak torque (PT) and position of peak torque (POS) was performed for both the quadriceps and hamstrings of both legs at 60 degrees s(-1). Vertical jump height was also assessed. Participants: Nine athletic, male subjects with no previous strength training experience. Results: There was a significant increase in vertical jump height (pre = 51.0 +/- 4.8 cm, post = 54.4 +/- 6.3 cm, p = 0.04), a significant reduction in quadriceps PT (pre = 204.6 +/- 21.9 N.m., post = 181.5 +/- 19.9 N.m., p = 0.01), a significant decrease in hamstring POS from full knee extension (pre = 32.5 +/- 7.4 degrees, post = 26.2 +/- 8.6 degrees, p = 0.01) and a significant hamstring POS difference between limbs (dominant = 33.8 +/- 9.5 degrees, non-dominant = 24.9 +/- 6.5 degrees, p = 0.01). Conclusion: Nordic hamstring exercise training may produce favourable neuromuscular adaptations for the possible prevention of hamstring injuries while enhancing performance in athletic, untrained males. (c) 2005 Elsevier Ltd. All rights reserved.