Fig. 7.
In vitro isometric twitch characteristics of left costal diaphragm at 2 and 6 wk. Maximum twitch stress (Pmax), time to peak (TTP) twitch, and half-relaxation time (1/2RT) were significantly reduced at 6 wk (n = 10 control and 3 mdm), but not at 2 wk (n = 7 per genotype). Pmax, TTP, and 1/2RT in mdm diaphragms were reduced by 71%, 57%, and 52%, respectively. Rate of force development (dP/dt) was not different for either age group. *Significantly different from age-matched controls (P < 0.05).