Fig. 4.

Steady-state isometric forces obtained in single, mechanically isolated sarcomeres (rabbit psoas) at sarcomere lengths of 2.4 μm [optimal length = 100% force (filled brown circle)] and 3.4 μm [approximately 50% of maximal isometric force at the plateau length (filled blue diamonds and filled black square = mean force). Also shown are the isometric steady-state forces of these isolated sarcomeres following a stretch from 2.4 to 3.4 μm (filled green triangles and filled black circle). FE Mean force enhancement observed in these sarcomeres, OFE the mean force above the maximal, isometric plateau forces for these sarcomeres. Note the enormous force enhancement and the consistently greater forces in the enhanced state compared to the plateau force. Adapted from Leonard et al. (2010) with permission