The effects of simultaneous isometric and eccentric- or concentric-biased exercise on cardiovascular and muscular health of young individuals

Isometric resistance training (IRT) and eccentric-biased training have both demonstrated improved cardiometabolic health. Consequently, simultaneous training has the potential to further enhance these improvements and overcome the commonly reported time-related barrier to exercise. Therefore, the effects of six-week simultaneous isometric and eccentric- (stair descent) or concentric-biased (stair ascent) exercise interventions were compared to a traditional isometric handgrip training protocol on cardiovascular and muscular health parameters in 54 normotensive and hypertensive young adults. Participants (33 males, age = 21 ± 1 yr; 21 females, age = 20 ± 1 yr) were randomly assigned to four groups: simultaneous isometric exercise and stair ascent (ISO-CONC, n = 13), simultaneous isometric exercise and stair descent (ISO-ECC, n = 14), isometric handgrip (IHG) exercise (ISO, n = 13), or a passive control (CTRL, n = 14). Participants undertook thrice-weekly supervised training for six weeks, with cardiovascular and muscular function (and structure) assessed at pre- and post-training. Significant reductions in resting systolic blood pressure (BP) were reported in all three training groups (d = 0.82–1.52), with a baseline-adjusted ANCOVA revealing that ISO-ECC diastolic BP was significantly lower than CTRL post-training. Gastrocnemius medialis muscle thickness (d = 0.79) and vastus lateralis fascicle angle only increased in ISO-CONC (r = 0.75). Whilst musculoskeletal improvements were only detected in the ISO-ECC group, large reductions in systolic BP were evident in all training groups, thus it may be more time-efficient to use the established isometric Handgrip intervention if reducing systolic BP is the primary therapeutic intention.