Predictive value of the elbow flexion isokinetic strength from functional fitness tests in elderly.

Abstract

INTRODUCTION: Elbow flexion strength can improve functional performance in older adults,especially in daily activities (1), allowing for correct prescription of the training programs. Isokineticdynamometry allows for the precise measurement of muscle strength (2). However, its high costhas led to an increased reliance on functional fitness tests instead (3). Therefore, this study aimsto investigate the predictive value of functional fitness tests for elbow flexion isokinetic strength atdifferent angular velocities in elderly.METHODS: The sample size of this cross-sectional study consisted of 320 participants (241 femalesand 76 males; age: 69.26±5.62 years). Participants attended the laboratory once. Isokinetic strengthwas measured using a calibrated Biodex® Multi-Joint System V.4X isokinetic dynamometer. Peaktorque (N·m) was recorded for seated-elbow flexion at angular velocities of 180º/s and 60º/s. Inline with the study objectives, four of the seven tests of the Senior Fitness Test battery, designedby Riki & Jones, were selected. The tests were performed in the same order and strictly adheredto the guidelines of the Senior Fitness Test manual (4). The tests performed were the following: (I)Up-and-Go Test (UGT); (II) 30-Second Arm Curl Test (30AC); (III) 30-Second Chair Stand Test (30CST);and (IV) 6-Minute Walk Test (6MWT).RESULTS: Small yet significant correlations were found between all functional tests and isokineticelbow flexion strength. The strongest correlations were observed between the 30AC and elbowflexion at 180º/s (r=0,29; p<0,01), and the 6MWT at 180º/s (r=0,27; p<0,01) and at 60º/s (r=0,26;p<0,01). There was a significant negative correlation between isokinetic elbow flexion and UGT at180º/s and at 60º/s (r=-0,19, and r=-0,15, respectively). Significant regression equations includingthe 30AC, the 30CST, age and sex were found for isokinetic elbow flexion, with similar values forelbow flexion at 180º/s and at 60º/s (R2=0,55 and R2=0,54, respectively).CONCLUSION: The present study revealed significant, small correlations between elbow flexionisokinetic strength and functional fitness in older adults. An inverse relationship between agilityand dynamic balance, as measured by the UGT, and elbow flexion isokinetic strength suggeststhat higher agility does not correspond to greater elbow flexion isokinetic strength. Additionally,positive correlations between 30AC and 6MWT indicate that these tests may serve as accessibletools for assessing elbow flexion isokinetic strength in older adults when isokinetic devices areunavailable.