LOW-INTENSITY, ALTERNATE-DAY EXERCISE IMPROVES MUSCLE PERFORMANCE WITHOUT APPARENT ADVERSE AFFECT IN POSTPOLIO PATIENTS

The purpose of this study was to examine the effect of a low-intensity , alternate-day, 12-wk quadriceps muscle-strengthening exercise progra m on muscle strength and muscle and motor unit integrity in 12 postpol io patients. Patients performed six to ten repetitions of a 5-s durati on knee extension exercise with ankle weights. After completing six re petitions, patients rated the perceived exertion (RPE) in the exercise d muscle. The patient continued repetitions until RPE was greater than or equal to 17 or ten repetitions were performed. The weight was incr eased the next exercise day whenever the RPE was < 17 after ten repeti tions. Before and after the training program, median macroamplitude as well as jitter and blocking were determined electromyographically (EM C), serum creatine kinase (CK) was measured, and quadriceps muscle str ength was assessed. The ankle weight lifted after 2 wk of training and at the end of the program were also recorded. Although the ankle weig ht lifted at the end of the program significantly (P < 0.05) increased from a mean +/- SD of 7.1 +/- 2.7 to 11.2 +/- 4.7 kg, the dynametrica lly determined muscle strength measures did not significantly (P > 0.0 5) increase. The EMC and the serum CK variables also did not significa ntly (P > 0.05) change as a result of the exercise program. We conclud e that performance was improved, as demonstrated by an increase in the amount of weight the patients lifted in the exercise program. No evid ence was found to show that this program adversely affected the motor units or the muscle as the EMG and CK did not change.