However, the loss of muscular strength in Fbn2-null mice is more extreme than the reduction in the maximum force produced by the muscle itself, suggesting an extra-muscular involvement.
The apparatus was used in the peak mode, the recorded value corresponding to the maximum force produced by the animal.
AIL did not differ in the percent of maximum force produced at any frequency between T+ and T0 males.
Values obtained during the rising phase of the phase-plots represented the maximum force produced by a trabecula at a particular [Ca2+]i value.
The percent of maximum force produced by T+ and T0 males at increasing frequencies in both AIL and FCR was similar within muscle comparisons (Fig. 4).
Isometric force measurements showed that, at early stages of disease (22 and 24 weeks of age), the maximum force produced by these muscles is not significantly different from that produced by the equivalent muscles in wild-type littermates (Fig. 3).
The maximum force produced by the tibialis anterior (TA), extensor digitorum longus (EDL) and soleus muscles was established in both of the hindlimbs of male SOD1 G93Adl B6 mice at early and late stages of disease, as defined by our longitudinal SHIRPA and grip-strength measurements.
These reductions in fibrotic deposition were not associated with improvements in maximum force-producing capacity, but we did observe small but significant improvements in the resistance to fatigue in both the diaphragm and TA muscles of mdx mice treated with tranilast.
Nine-week treatment with tranilast did not improve whole-body strength or mobility and did not improve maximum force-producing capacity in the TA or diaphragm muscles of control or mdx mice (i.e., for TA muscle: C57BL/10 control 1,825 ± 35 mN vs. C57Bl/10 tranilast 1,743 ± 55 mN; mdx control 1,456 ± 88 mN vs. mdx tranilast 1,177 ± 139 mN).
Oxypurinol decreased the maximum tetanic force produced by EDL and soleus muscles, and polyethylene glycol-tagged Cu,Zn-SOD decreased the maximum force production by the EDL muscles.
The relative tight correlation between maximum thrust force produced and the amplitude of the distance moved by flippers during the downstroke suggest that this is the major mechanism by which thrust force is modulated.
