Table 2.

Effect of pH and temperature on type II fibre force and velocity

			P0
Muscle	n	Diameter (μm)	(mN)	(kN m−2)	V0 (fl s−1)
15°C pH 7	17	59 ± 2	0.39 ± 0.02	143 ± 5	3.70 ± 0.21
15°C pH 6.2	17	59 ± 2	0.26 ± 0.02*	98 ± 5*	2.71 ± 0.14*
% Change			−33	−31	−27
30°C pH 7	12	62 ± 2	0.55 ± 0.03	184 ± 10	19.93 ± 1.15
30°C pH 6.2	13	61 ± 2	0.52 ± 0.03	176 ± 8	13.46 ± 0.81*
% Change			−5	−4	−32
30°C pH 7 w/CPK	7	51 ± 4	0.36 ± 0.04	175 ± 5	18.86 ± 0.37
30°C pH 6.2 w/CPK	6	51 ± 4	0.32 ± 0.04	156 ± 7*	12.95 ± 0.27*
% Change			−11	−11	−31

Values are means ±s.e.m.; n, no. of fibres studied. P₀, peak isometric force; V₀, maximal shortening velocity; w/CPK, solutions contained 140 U of creatine phosphokinase.

^*Significantly different from pH 7, P < 0.05. At both pHs, the P₀ and V₀ values are significantly higher at 30°C, compared to 15°C.