When Load Does not Tell the Whole Story: Acute Effects of Effort Matched Resistance Training Protocols on Arterial Stiffness.

This study examined acute vascular responses to three resistance training (RT) protocols differing in load and volume but matched for proximity to failure. Eleven adults (6 males and 5 females) performed three RT protocols consisting of the hexagonal deadlift and bench pull exercises with the following: (i). Low-volume, moderate-load, and high-repetition (Condition A: 2 × 10 repetitions), (ii). Low-volume, high-load, and low-repetition (Condition B: 2 × 4 repetitions), and (iii). Moderate-volume, high-load, and low-repetition (Condition C: 5 × 4 repetitions). Proximity to failure was set at 2 repetitions in reserve. Measurements of carotid-femoral pulse wave velocity (cfPWV) and pulse wave analysis (e.g., augmentation index) were collected at baseline, immediately post, and 15 min posttraining, whereas muscle oxygenation was monitored during performance the hexagonal deadlift. Condition A induced significantly greater increases in cfPWV (6.2 ± 0.6 to 6.9 ± 0.8 m/s) when compared to both Condition B (6.5 ± 0.8 to 6.4 ± 0.7 m/s) and Condition C (6.3 ± 0.8 to 6.4 ± 0.6 m/s), (all p < 0.05). No significant changes were observed in muscle oxygenation variables across conditions. These findings suggest that the number of repetitions per set and total time under tension (Condition A), rather than absolute load or set volume, play a more important role in mediating acute hemodynamic responses following RT.