Table 2.

Mechanical properties of TDT muscle expressing Tr-WT and EMB myosin isoforms

	Resting tension	Tmax	pCa50	Hill coefficient	Vslack
Tr-WT	0.9 ± 0.2 (mN/mm2)	37 ± 3 (mN/mm2)	5.62 ± 0.01	10.2 ± 2.1	6.1 ± 0.3 (ML/s)
EMB	2.1 ± 0.5	53 ± 5∗	5.67 ± 0.02∗	6.3 ± 0.9∗	3.1 ± 0.2∗

EMB, embryonic isoform; ML, muscle length; T_max, maximum calcium activated tension; Tr-WT, wild-type myosin isoform; V_slack, velocity determined using the slack test.

Tension values were measured at a SL = 3.6 μm. pCa₅₀ and the Hill coefficient were determined by fitting the tension-pCa response with the Hill equation (Fig. 2). Values are mean ± SE.

^∗Significantly different from Tr-WT, p < 0.05, Student's t-test. n = 7 and 8 for Tr-WT and EMB resting tension, respectively. n = 21 and 23 for Tr-WT and EMB active tension, respectively. n = 6 for pCa 50 and Hill coefficient, n = 10 for V_slack.