Table 3.

Effect of pH and temperature on type I fibre force–velocity–power parameters

					Peak power
Muscle	n	P0 (kN m−2)	Vmax (fl s−1)	a/P0	(μN fl s−1)	(W l−1)	Velocity at peak power (fl s−1)	Force at peak power (kN m−2)
15°C pH 7	43	118 ± 4	0.77 ± 0.04	0.07 ± 0.00	14.4 ± 0.7	3.5 ± 0.3	0.15 ± 0.01	24.0 ± 0.9
15°C pH 6.2	44	80 ± 3*	0.71 ± 0.03	0.10 ± 0.00*	11.1 ± 0.6*	2.9 ± 0.2*	0.16 ± 0.01	17.9 ± 0.7*
% Change		−32	−8	43	−23	−17	7	−25
30°C pH 7	39	147 ± 5	4.31 ± 0.15	0.33 ± 0.03	217.6 ± 13.4	65.5 ± 2.9	1.38 ± 0.04	47.3 ± 2.1
30°C pH 6.2	39	131 ± 5*	3.61 ± 0.16*	0.25 ± 0.02*	143.1 ± 9.8*	43.0 ± 2.3*	1.08 ± 0.04*	39.6 ± 1.8*
% Change		−11	−16	−24	−34	−34	−22	−16
30°C pH 7 w/CPK	7	155 ± 4	4.78 ± 0.22	0.50 ± 0.03	273.8 ± 15.1	98.7 ± 5.7	1.74 ± 0.07	56.5 ± 1.3
30°C pH 6.2 w/CPK	7	139 ± 4*	3.21 ± 0.19*	0.38 ± 0.02*	147.9 ± 14.2*	53.0 ± 4.1*	1.10 ± 0.05*	47.7 ± 1.6*
% Change		−10	−33	−24	−46	−46	−37	−16

Values are means ±s.e.m.; n, no. of fibres studied; V_max, maximal unloaded shortening velocity determined from the Hill plot test; w/CPK, solutions contained 140 U of creatine phosphokinase; a/P₀, unitless parameter describing curvature of the force–velocity relationship. The relative power unit of watts/litre (W l⁻¹) is equivalent of kN m⁻² fl s⁻¹.

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