Table 2.

Contractile parameters of skinned fibres

	Tpre (kPa)	Po/Tpre	Vmax (μm (h.s.)−1s−1)	β (μm (h.s.)−1 s−1)	α/Po	Stiffness (Tpre h.s. nm−1)	Power (mW g−1)
ATP	189 ± 39	0.96 ± 0.016	1.29 ± 0.18	0.187 ± 0.014	0.147 ± 0.016	0.275 ± 0.028	16.2 ± 4.0
UTP/ATP	0.65 ± 0.07	0.91 ± 0.013	0.44 ± 0.062	0.925 ± 0.041	2.12 ± 0.080	0.798 ± 0.057	0.403 ± 0.10

The values in the upper row are absolute values ±s.d. in the presence of ATP in the units given. The values in the lower row are the ratios of the values in UTP to those in ATP ±s.e.m. h.s., half-sarcomere. Number of fibres = 12.