Table 2.

Values of tension and stiffness in the standard activating solution (ATP=5 mM, Pi=8 mM). n=10 for all experiments, except for those specified in ( ). The tension values are small, because of the presence of 8 mM Pi. For normalized tension, the data on each preparation were first normalized to the value at 200 mM IS, and then averaged. T₅₆ (force/cross-bridge) was deduced by fitting tension vs. [Pi] data to Eq. 4, and it represents force supported by cross-bridges (CB) in the states AM*DP and AM*D (major force-generating cross-bridges), and normalized to the value at 200 mM IS.

	150 IS	200 IS	250 IS	300 IS	Units
Tension	100 ± 11	87 ± 8	69 ± 7*	60 ± 6*	kPa
"	1.142 ± 0.032	1	0.786 ± 0.016*	0.691 ± 0.022*	Normalized
Stiffness	4.6 ± 0.4	4.2 ± 0.4	3.8 ± 0.4	3.6 ± 0.3	kPa
Tension/Stiffness	2.17 ± 0.05	2.07 ± 0.05	1.79 ± 0.04*	1.67 ± 0.07*	%L 0
Force/CB (T56)	1.10 ± 0.07(10)	1.00 ± 0.02(11)	0.95 ± 0.03 (12)	0.81 ± 0.03 (11)*	Normalized
App rate const 2πa	4.80 ± 0.31	4.77 ± 0.16	4.70 ± 0.21	4.98 ± 0.27	s−1
App rate const 2πb	132 ± 3	144 ± 2*	153 ± 2*	146 ± 6*	s−1
App rate const 2πc	191 ± 5	200 ± 3	222 ± 3*	235 ± 10*	s−1
Magnitude A	2.93 ± 0.29	2.87 ± 0.28	2.88 ± 0.31	2.82 ± 0.28	MPa
Magnitude B	15.6 ± 2.0	15.1 ± 1.6	13.5 ± 1.8	11.3 ± 1.7	MPa
Magnitude C	16.5 ± 2.1	15.8 ± 1.6	13.8 ± 1.8	11.6 ± 1.7	MPa
Magnitude H	0.79 ± 0.08	0.71 ± 0.08	0.58 ± 0.06	0.48 ± 0.06*	MPa

^*P<0.05 when compared to the corresponding value at 150 IS.