Stiffness and force changes during the isometric force development.

<p>Simultaneous recordings of stiffness (upper records) and force (lower records) during the development of steady isometric force in contracting solution. The KCl concentration was 0 mM, 50 mM and 125 mM in records A, B and C, respectively. Upward and downward arrows indicate time of application and removal of contracting solution, respectively. The force increment on returning the fiber to relaxing solution is an artifact accompanying solution exchange procedure. The same explanation applies to force records shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063658#pone-0063658-g007" target="_blank">Figure 7</a>.