Fig. 4. Intracellular pH values during the critical swimming speed test (left; speed as % U_crit) and the first 150 min of recovery [right; time after U_crit (min)]. The right broken vertical line indicates the traditional U_crit value; the left broken vertical line at 89% represents the mean time when kicking was initiated. Values are means ± s.d., N=3–6. Horizontal error bars represent s.d. of the mean speed. Asterisks indicated significant difference from control values.