Jazz dance on isokinetic and isometric muscle strength in menopausal women: a randomized clinical trial with follow-up

Purpose To analyze the effect of a Jazz dance intervention on isokinetic and isometric muscle strength in the medium term (post-intervention and 16 weeks) and long term (6-month follow-up) in menopausal women. Methods In this randomized clinical trial (REBEC: RBR–87ndrv), 47 menopausal women were randomized into a Jazz dance (experimental) or control group. Strength was measured pre-, post-intervention, and after 6-month follow-up using the Biodex System 4 PRO isokinetic dynamometer. The experimental group engaged in 16 weeks of Jazz dance following a protocol, while the control group was instructed to continue their daily activities. Intention-to-treat (ITT) and per-protocol (PP) analyses were performed. Results ITT analysis showed no significant intergroup interactions for the primary outcome (peak extension torque; p = 0.077) or any variables between post-intervention and follow-up. However, ITT revealed intragroup improvements in total flexion work ( p = 0.027) and ratio ( p = 0.020) at post-intervention. In PP analysis, the experimental group showed significant intergroup improvements and higher peak extension torque than controls ( p < 0.001) at post-intervention. PP also indicated improved isokinetic strength ratio ( p = 0.045) and increased isometric peak flexion strength ( p = 0.045) following the intervention. No additional gain occurred at the 6-month follow-up, indicating a stabilization of results. Conversely, the control group showed strength increases only at follow-up for both isokinetic and isometric variables. Conclusion Jazz dance practice promotes medium-term increases in isokinetic and isometric strength in menopausal women. However, these benefits are not maintained after 6 months of detraining, highlighting the need for continued exercise practices to preserve strength gains in this population.