Does isokinetic muscle strength influence the functional performace of elderly people?

Abstract

Introduction: Aging is the natural course of human life and has repercussions on various structures and functions of body systems. Maintaining the muscle strength of the knee extensors and flexors becomes relevant for the performance of ADLs, and is often assessed using an isokinetic dynamometer. The a/agonist ratio is also given by this equipment, being a good indicator of muscle imbalances. Objectives: to analyze the influence of peak torque and power of the knee extensors and flexors on the functional performance of elderly people and to observe the interaction between the agonist/antagonist ratio and performance in functional tests. Methods: This is a cross-sectional study, in which elderly people from the community participated. The isokinetic variables analyzed were peak torque relative to body mass, mean power and agonist/antagonist ratio at speeds of 60º/s and 180º/s. The distribution frequency and descriptive analysis of the sample were used. To analyze the interaction between isokinetic variables and functional performance, Spearman's correlation test was used. A multivariate regression was performed considering isokinetic variables as independent variables, and functional performance variables as dependent. Results: 36 elderly people with a mean age of 60 years participated in the study, 29 women and 7 men. The agonist/antagonist ratio at 180º/s speed influenced the performance of the TUG test. The other variables showed no influence on the functional tests. Gait speed showed a significant positive correlation with the peak torque variable at 60º/s and 180º/s. Conclusion: isokinetic muscle strength can influence functional performance and the higher the agonist/antagonist ratio in elderly people, the better their performance in functional tests.

Keywords: elderly people; muscle strength; functionality.