An expanding explanation for the ascending limb of muscle’s active force-length relationship

Abstract

Many readers of this article will have taken, or perhaps taught, a systems-based physiology class. These often cover the material at a fast pace. As an example, at the University of Kentucky, I am allotted two hours to teach the medical students “all” of muscle physiology. We cover muscle’s length-tension relationship on slide seven. I explain that active force drops as filament overlap decreases on the descending limb, and that there is a plateau where the effective overlap does not change because of the thick filaments’ bare zones.