Relative dynamic muscular endurance of patients with neuromuscular disorders and of healthy matched control subjects.

Abstract

This study was undertaken to determine whether the relative muscular endurance of patients with paresis secondary to neuromuscular disorders was different from that of comparable healthy persons. Using an isokinetic dynamometer, I measured the peak knee extension torque of five patients with neuromuscular disorders and of five matched controls. Torque was measured during an initial and 40 subsequent maximal knee extensions at 180 degrees/sec. Gravity-corrected peak torques of the initial repetition and every fifth subsequent repetition were compared between groups, as were the percentages of decrease in torque (calculated relative to the initial torque) using two-way analysis of variance procedures. The results of these procedures demonstrated that the healthy subjects were significantly stronger than the patients with paresis (p less than .01) but that the patients had significantly better relative muscular endurance (ie, smaller percentages of decrease in torque) than the healthy subjects (p less than .05). These findings suggest that, for the patients tested, the relative muscular endurance of patients with paresis is not compromised. This finding does not preclude patients with paresis being unable to complete multiple repetitions of specific functional tasks requiring some critical level of muscular strength.