Increased muscle ultrastructural damage after eccentric contractions.

<p>Ultrastructural damage was evaluated based on Z-disk streaming as light damage or medium to severe damage in type I (light grey) and type II (dark grey) fibers. A) The percentage of sarcomeres showing medium to severe Z-disk damage. *: different from Pre (<i>P</i> = 0.02, Kruskal-Wallis test). (†): tendency to be different from type II fibers (<i>P</i> = 0.056, Kruskal-Wallis test). ‡: different from Con 48h (<i>P</i> = 0.008, Kruskal-Wallis test). B) The percentage of sarcomeres showing light Z-disk damage. *: different from Pre (<i>P</i> < 0.0001). #: different from type II fibers (<i>P</i> = 0.02). ‡: different from control 48 h (<i>P</i> = 0.0004). Values represent means and horizontal bars represent SEM. Representative transmission electron micrographs illustrates Z-disks (asterisk) with no streaming (C) and light (D), medium (D) and severe (E) Z-disk streaming. Scale bar = 0.5 μm.