Table 1.

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

			P0
Muscle	n	Diameter (μm)	(mN)	(kN m−2)	V0 (fl s−1)
15°C pH 7	44	72 ± 2	0.47 ± 0.02	120 ± 4	1.16 ± 0.04
15°C pH 6.2	44	72 ± 2	0.33 ± 0.01*	83 ± 3*	1.05 ± 0.02*
% change			−30	−31	−9
30°C pH 7	40	65 ± 2	0.50 ± 0.02	153 ± 5	9.97 ± 0.38
30°C pH 6.2	40	65 ± 2	0.44 ± 0.02*	135 ± 5*	7.47 ± 0.27*
% change			−12	−12	−25
30°C pH 7 w/CPK	7	60 ± 2	0.44 ± 0.03	158 ± 3	10.55 ± 0.37
30°C pH 6.2 w/CPK	7	60 ± 2	0.39 ± 0.02	139 ± 3*	7.60 ± 0.35*
% change			−11	−12	−28

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.