Table 4.

Effect of pH and temperature on type II 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	19	141 ± 5	1.77 ± 0.06	0.19 ± 0.01	66.0 ± 5.2	20.0 ± 1.1	0.50 ± 0.01	38.9 ± 1.4
15°C pH 6.2	19	96 ± 4*	1.45 ± 0.06*	0.24 ± 0.02*	42.4 ± 4.1*	12.6 ± 0.8*	0.43 ± 0.02*	28.0 ± 1.0*
% Change		−32	−18	26	−36	−37	−14	−28
30°C pH 7	19	180 ± 5	7.14 ± 0.42	0.58 ± 0.07	512.1 ± 28.8	166.0 ± 8.9	2.53 ± 0.09	63.1 ± 3.1
30°C pH 6.2	18	161 ± 5*	5.99 ± 0.36*	0.65 ± 0.06	461.1 ± 38.8	135.3 ± 7.2*	2.24 ± 0.11*	58.0 ± 2.2
% Change		−11	−16	12	−10	−18	−11	−8
30°C pH 7 w/CPK	6	166 ± 7	7.09 ± 0.19	0.36 ± 0.02	337.3 ± 21.5	134.1 ± 2.2	2.40 ± 0.06	56.1 ± 1.9
30°C pH 6.2 w/CPK	6	145 ± 6*	5.76 ± 0.17*	0.33 ± 0.04	222.6 ± 14.7*	90.0 ± 3.5*	1.89 ± 0.04*	47.6 ± 1.8*
% Change		−13	−19	−8	−34	−33	−21	−15

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.