Figure 7.

Force enhancement as a function of half-sarcomere length non-uniformities. (A) Force enhancement as a function of A-band displacements (equivalent to half sarcomere length non-uniformities) in single sarcomere preparations, and (B) in single myofibril preparations with multiple serial sarcomeres. Note that the small A-band shifts in the single sarcomere and the single myofibril only explain approximately 7 and 18% of the total force enhancement observed, assuming that the isometric reference contractions have perfectly identical half- and sarcomere length. However, since the isometric reference contractions have similar A-band shifts as the experimental active stretch contractions, none of the enhanced forces seems explained by stretch-induced half-sarcomere length non-uniformities from Rassier (2012) with permission.