Effects of stretch/shortening magnitude on force depression of the quadriceps femoris after pure shortening and stretch-shortening contractions

It is well known that the force production of the muscle is history-dependent. The steady-state isometric force following an active shortening or lengthening contraction is smaller (force depression) or greater (residual force enhancement) compared to an isometric reference contraction. However, it remains unclear which parameters can contribute to increased performance during stretch-shortening cycles (SSC). The present work disputes the influence of stretch/shortening magnitudes and initial muscle length on the contraction performance of the quadriceps femoris. To examine these parameters eleven subjects have been tested at an isokinetic dynamometer during maximal voluntary contraction.