Neuromuscular function in polio survivors at one-year follow-up

Many polio survivors complain of progressive loss of strength, work capacity, endurance, and ability to recover from fatiguing activity. These variables were measured initially and one year later in the quadriceps muscles of 28 symptomatic and 16 asymptomatic persons who had polio and 38 control individuals. Peak knee extension torque was measured isokinetically and isometrically. Endurance, or the amount of time the subject could maintain isometric torque at 40% of maximal torque, was measured. Work capacity was determined as the product of isometric torque and endurance time. Recovery of strength was measured at regular intervals for ten minutes after the endurance test. Statistical analysis was done by repeated measures ANOVA. Although the initial measures showed significant deficits in mean peak torque, work capacity, and recovery of strength in symptomatic postpolio subjects, no significant changes were found one year later in any of the variables. We conclude that symptomatic postpolio subjects do not lose significant neuromuscular function in one year.