The nature of force depression and force enhancement in skeletal muscle contraction

Abstract

Here, we review the history-dependent phenomena associated with muscle force production. Specifically, the depression of the steady-state isometric force following muscle shortening, and the enhancement of the steady-state isometric force following muscle stretching are discussed. First, we describe the observations that have been made experimentally, then we introduce the primary proposed mechanisms for force depression and force enhancement. Next, in view of the available results, we critically evaluate specific hypotheses based on these mechanisms. Finally, we recommend further discussion about some of the proposed mechanisms.

Keywords:

• mechanisms of contraction
• history-dependent properties
• sarcomere length non-uniformities
• actin-myosin interaction
• cross-bridge theory