Effects of a 16-Week High-Speed Resistance Training Program on Isokinetic Muscle Strength Parameters and Health-Related Quality of Life in Independent Older Adults: A Clinical Trial

This study investigated the effects of a 16-week high-speed resistance training (HSRT) program on isokinetic muscle strength parameters and, secondarily, on health-related quality of life (HRQOL). Seventy-nine independent older adults were assigned to an intervention group (IG) and a control group (CG). The IG completed supervised HSRT three times per week, while the CG received no intervention. Each session lasted 60-70 minutes and included 5-6 exercises of 2-3 sets at maximal concentric speed and a controlled eccentric phase (≈2-3 seconds). Isokinetic muscle strength was assessed pre- and post-intervention using isokinetic testing of knee extensors (KE) and flexors (KF) at 60º/s and 180º/s on dominant (DS) and non-dominant sides (NDS). The HRQOL was measured using the SF-36 questionnaire. The IG demonstrated significant improvements in peak torque for KE-DS (∆change: 14.02 Nm; p < .001; η_p² = 0.215), KE-NDS (∆change: 16.19 Nm; p < .001; η_p² = 0.290), KF-DS (∆change: 8.06 Nm; p < .001; η_p² = 0.290), and KF-NDS (∆change: 8.33 Nm; p = .002; η_p² = 0.125), as well as in average muscle power for KE-DS (∆change: 15.51 W; p < .001; η_p² = 0.328), KE-NDS (∆change: 17.33 W; p < .001; η_p² = 0.298), KF-DS (∆change: 8.21 W; p < .001; η_p² = 0.284), and KF-NDS (∆change: 8.06 W; p = .005; η_p² = 0.100). HRQOL improvements were also observed. The present HSRT protocol effectively improves isokinetic muscle parameters and HRQOL measures in older adults.