Fig. 6.

The force-frequency relationship and eccentric contraction profile in normal and affected ECU muscle. (A) The absolute isometric force of the ECU muscle at 5, 20, 40, 60, 80, 100 and 120 Hz from normal and affected dogs. (B) The specific isometric force of the ECU muscle at 5, 20, 40, 60, 80, 100 and 120 Hz from normal and affected dogs. (C) The relative muscle force at the indicated stimulation frequency. Sample size for the force-frequency relationship: normal (n=15) and affected (n=14). (D) Relative changes of the tetanic force during ten cycles of eccentric contraction. The tetanic force at the beginning of the first cycle of eccentric contraction was designated as 100%. Sample size: normal (n=15) and affected (n=15). Data are mean±s.d. *P<0.05 (the statistical difference between normal and affected dogs at a fixed stimulation frequency in A-C was analyzed by multiple unpaired t-tests; the statistical difference of the same group of dogs (normal dogs as a group, affected dogs as another group) at different stimulation frequencies in A and B was analyzed by one-way ANOVA with Tukey’s post hoc test; the statistical difference between normal and affected dogs at each eccentric contraction cycle was analyzed by multiple unpaired t-tests). #, significantly different from each other between two indicated frequencies in dogs of the same category (normal versus normal, affected versus affected).