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

Condition A (low-volume, moderate-load, high-repetition) induced significantly greater increases in carotid-femoral pulse wave velocity compared to both high-load, low-repetition conditions.

• Condition A (2 × 10 repetitions) cfPWV increased from 6.2 ± 0.6 to 6.9 ± 0.8 m/s
• Condition B (2 × 4 repetitions) cfPWV changed from 6.5 ± 0.8 to 6.4 ± 0.7 m/s
• Condition C (5 × 4 repetitions) cfPWV changed from 6.3 ± 0.8 to 6.4 ± 0.6 m/s
• All pairwise comparisons between Condition A and Conditions B and C were statistically significant (all p < 0.05)
• Measurements were taken at baseline, immediately post, and 15 min post-training

No significant changes in muscle oxygenation variables were observed across the three resistance training conditions.

• Muscle oxygenation was monitored during performance of the hexagonal deadlift
• No significant differences were found across Conditions A, B, and C in muscle oxygenation variables
• Muscle oxygenation was assessed using near-infrared spectroscopy (pulse wave analysis methodology)

Three resistance training protocols matched for proximity to failure but differing in load and volume were examined for acute vascular responses.

• Eleven adults participated (6 males and 5 females)
• Exercises used were the hexagonal deadlift and bench pull
• Condition A: 2 × 10 repetitions (low-volume, moderate-load, high-repetition); Condition B: 2 × 4 repetitions (low-volume, high-load, low-repetition); Condition C: 5 × 4 repetitions (moderate-volume, high-load, low-repetition)
• Proximity to failure was standardized at 2 repetitions in reserve across all conditions
• Outcomes included carotid-femoral pulse wave velocity (cfPWV) and pulse wave analysis including augmentation index

Total time under tension and repetitions per set, rather than absolute load or set volume, were identified as the primary mediators of acute arterial stiffness responses to resistance training.

• Condition A, with the highest repetition count and longest time under tension per set, produced the greatest cfPWV increase despite using a lower absolute load than Conditions B and C
• Condition C had greater total set volume than Condition A (5 sets vs. 2 sets) but did not produce greater arterial stiffness increases
• The findings suggest the hemodynamic stimulus is driven by duration of muscular effort per set rather than loading magnitude or accumulated set volume