Fig. 2.

SA tension and kinetics of IFI and control jump muscle fibers. A: stretch-activated tension (F_SA) of IFI (red) and control fibers (black) plotted vs. Pi concentration. Error bars show SE. B: rate of SA tension generation, r₃ (rate of phase 3), of control (black) and IFI (red) fibers at three Pi concentations. Individual tension traces of SA responses following a 1% ML step over 0.5 ms were fitted to the sum of 3 exponential curves: a₃[1 − exp(−r₃t)] + a₂exp(−r₂t) + a₄exp(−r₄t) + offset. #P < 0.05 compared with control. *P < 0.05 compared with 0 mM Pi.