Fig. 9.

Examples of two separate rabbit psoas myofibrils that were repeatedly stretched to sarcomere lengths beyond actin myosin filament overlap. Note that in both cases repeat stretches did not result in a decrease in peak force or loading energy, thus indicating that even stretching to lengths up to 5.0 μm did not result in permanent damage and loss of force. a Myofibril stretched to an average sarcomere length of approximately 5.2 μm (stretch 1), then shortened and rested for 10 min at an average sarcomere length of 2.6 μm and re-stretched (stretch 2). Two sets of three stretch-shortening cycles were performed and the third stretch of the first set (stretch 1), and the first stretch of the second set (stretch 2) are shown b Myofibril stretched to an average sarcomere length of approximately 4.2 μm, then shortened and rested for 10 min at an average sarcomere length of approximately 1.8 μm. Two sets of three stretch-shortening cycles were performed (with a 10-min rest in between) and the first cycles (stretch 1) of the first and second set (stretch 2) are shown. Adapted from Herzog et al. (2014) with permission