H-13K Free Communication/Poster Exercise Training
Hamstring strains are common in sports characterized by acceleration and high-speed running. It is assumed that muscle injuries occur during forceful eccentric muscle action, and that low hamstring strength or a low hamstring to quadriceps strength ratio are risk factors for strains.
To compare the effects of a 10-week training program with two different exercises. Nordic hamstrings (NH) and hamstring curl (HC) on maximal hamstring muscle strength among male soccer players.
The subjects were 21 well-trained soccer players who were randomized to NH-training (n = 11) or HC-training (n = 10). The programs were similar in both groups, starting with 2 sets of 6 reps, then gradually increasing to 3 sets of 8–12 reps over 4 weeks. HC was done in a traditional hamstring curl machine. NH was done with subjects on their knees with a partner supporting the ankles, then resisting a forward fall with their hamstrings. Both exercises have eccentric and concentric components, but focusing on the eccentric phase in NH and the concentric in HC. Hamstring strength was measured as maximal moment on a Cybex dynamometer before and after the training period.
In the NH-group we observed an increase in eccentric hamstring strength at 60°/s from 240±40 Nm to 266±43 Nm (p = 0.001, 11%), as well as in isometric hamstring strength at 90° knee flexion (107±17 Nm to 115±23 Nm, p = 0.027, 7%), 60° knee flexion (186±20 Nm to 199±26 Nm, p = 0.004, 7%), and 30° knee flexion (218±22 Nm to 233±30 Nm, p = 0.007, 7%), but no effect on concentric quadriceps strength. Consequently there was a significant increase in the hamstring: quadriceps ratio from 0.89±0.12 to 0.98±0.17 (p = 0.005, 11%). In the HC-group there were no changes, and for all strength variables there was a significant difference in the training response between groups.
NH-training for 10 weeks is more effective to develop maximal eccentric hamstring strength in well-trained soccer players than a comparable program based on traditional hamstring curls.