Fig. 4.

Contractile parameters of the first and the last (fatigue point) contractions during the repetitive contractile period in soleus muscle from WT (open bars) and Tg⁺ (crossed bars) mice. Time to reach 90% of the peak tension (T_90%) (A); peak contraction rate (+dP/dt) (B); half relaxation time (1/2RT) (C); peak relaxation rate (−dP/dt) (D). *P < 0.05, fatigue vs. the first contraction within the same group, paired t-test; ‡P < 0.05 low vs. high Po₂ within the same panel, two-way repeated-measures ANOVA. Data were averaged from 9 muscles of 5 mice for WT, and 7 muscles of 5 mice for Tg⁺.