RELIABILITY OF A HANDGRIP TEST FOR EVALUATING HEART-RATE AND PRESSOR-RESPONSES IN MULTIPLE-SCLEROSIS

Purpose: The purpose of this study was to determine the test-retest re liability of an isometric handgrip exercise protocol designed to evalu ate heart rate and arterial pressure responses in individuals with mul tiple sclerosis (MS). Methods: Three males and eleven females, aged 24 through 51, performed isometric handgrip contractions at 30% of maxim al voluntary contraction (MVC) to the point of fatigue (defined as ina bility to maintain the target force for three consecutive seconds). Du ring this exercise, rate of perceived exertion (RPE) was recorded ever y 30 s. Heart rate and beat-to-beat systolic, diastolic, and mean arte rial pressures were recorded continuously throughout the duration of e xercise. Surface EMG was monitored continuously via loudspeaker to pro vide feedback on extraneous muscular activity. Each subject performed three trials. A repeated measures ANOVA was used to calculate intercla ss reliability estimates for each dependent variable. Results: Reliabi lity estimates for MVC and time to fatigue were 0.98 and 0.84, respect ively. Reliability estimates for the following dependent variables at the point of fatigue were: RPE, 0.90; Delta HR, 0.97; Delta systolic p ressure, 0.92; Delta diastolic pressure, 0.87; and Delta MAP, 0.88. Co nclusions: We conclude that this isometric handgrip protocol is a reli able method for evaluating heart rate and blood pressure responses in MS patients.