... contractions. Force and stiffness following active shortening were decreased by 10.0±1.8% and 11.0±2.2%, respectively, compared with the isometric reference contractions. Similarly, ATPase activity per second (not normalized to the force) showed a decrease of 15.6±3.0% in the force-depressed state compared...

... or a maximally closed position. Thus, the two muscles could be compared when both maximally stretched or shortened. In both states, the sarcomeres in the opener muscle were always shorter than those of comparable fibre groups in the closer. Table 1. Comparison of myofibrillar ATPase activity (mATPase...