Progressive iso-inertial resistance exercise promotes more favorable cardiovascular adaptations than traditional resistance exercise in young adults

Abstract

We compared the cardiovascular adaptations to resistance training (RT) using either traditional isotonic or iso-inertial resistance exercise in a randomized controlled study. Thirty-one healthy young adults (means ± SD, age ¼ 24 ± 3 yr) completed 10 wk of traditional isotonic RT (TRT; n ¼ 7 female/5 male), iso-inertial flywheel RT (FWRT; n ¼ 7 female/4 male), or a habitual activity control (Con; n ¼ 5 female/3 male). Before and following the intervention period, blood pressure, blood pressure reactivity, flow-mediated dilation (FMD), carotid-femoral pulse wave velocity (cfPWV), baroreflex sensitivity (BRS), and heart rate variability (RMSSD) were assessed. TRT and FWRT similarly improved isometric muscle strength. TRT significantly increased systolic blood pressure reactivity during isometric exercise compared with both FWRT (mean difference ± 95% CI, þ 10.8 ± 8.8 mmHg) and Con (þ 11.8 ± 9.1 mmHg). Cardiovagal BRS was significantly reduced in TRT versus FWRT (–6.82 ± 4.9 ms/mmHg; P ¼ 0.006) but not between TRT versus Con (P ¼ 0.12) or FWRT versus Con (P ¼ 0.43). Resting heart rate (RHR) and RMSSD worsened in TRT compared with FWRT (RHR, þ 8 ± 5.8 beats/min, P ¼ 0.006; RMSSD, –22.3 ± 15.6 ms, P ¼ 0.004). Changes in BRS and RMSSD were associated with changes in blood pressure reactivity in the RT groups (r ¼ –0.51 to –0.52). There were no significant changes in FMD or cfPWV in any group (P > 0.13). In conclusion, 10 wk of TRT and FWRT resulted in similar improvements in strength, but TRT caused impairments in blood pressure reactivity compared with FWRT and Con and parasympathetic nervous system activity compared with FWRT.