Effect of leg extension training on concentric and eccentric strength of quadriceps femoris muscles

Ten healthy male subjects carried out bilateral concentric leg extension training twice a week for 8 weeks. Before and after the training, maximal voluntary isometric and isokinetic strength and cross‐sectional areas of the quadriceps femoris were measured. Maximal bilateral leg extension power increased significantly after the training. Isometric and concentric unilateral strength did not change significantly before and after the training, while eccentric strength at 0.52 and 1.05 rad·s⁻¹ increased after the training with no changes in cross‐sectional area. The correlations between strength and cross‐sectional area increased significantly after the training. It was speculated that the increase in eccentric strength of knee extensors was due to modification of the neural inhibition during eccentric muscle actions.