Blood pressure response during resistance training of different work to rest ratio
Changes in the work to rest ratio (W:R) of resistance training protocols (RTP) (i.e. decreasing work and/or increasing rest) reduce the marked elevation in blood pressure (BP) that occurs during RTP execution. However, whether changes in RTP protocol structure without changing W:R can change BP responses to RTP is unknown. To investigate the effect of different structures of rest intervals and number of repetitions per set on BP response among RTP equated and nonequated for W:R, 20 normotensive participants (25±4 years) performed four different RTP of the leg extension exercise with the same work but different W:R structures. Two protocols followed the recommendations for cardiovascular disorders: I) HIGHW:R-3x15:44s - 3x15:44s (setxreps:rest between sets), which has high W:R (45reps:88s) and II) LOWW:R-3x15:88s - 3x15:88s, which has low W:R (45reps:176s). The other two protocols were W:R-equated to LOWW:R (45reps:176s): III) LOWW:R-9x5:22s and IV) LOWW:R-45x1:4s. Systolic BP (ΔSBP) and diastolic BP (ΔDBP) were assessed by finger photoplethysmography. There were significant main effects for ΔSBP following RTP (p<0.05): HIGHW:R-3x15:44s = LOWW:R-3x15:88s > LOWW:R-45x1:4s > LOWW:R-9x5:22s (+87±5 and +84±5 vs. +61±4 vs. 57±4 mmHg). For ΔDBP, there was a significant interaction between RTP and moment (p<0.05). Thus, HIGHW:R-3x15:44 > LOWW:R-3x15:88s > LOWW:R-45x1:4s > LOWW:R-9x5:22s (+53±5 vs. +49±5 vs. +44±4 vs. +38±3 mmHg). HIGHW:R-3x15:44s produced the highest increase in ΔDBP and LOWW:R-9x5:22s produced the lowest increase in ΔSBP and ΔDBP. Our findings may help the development of RT protocols that may mitigate pressure peaks without changing important exercise variables (i.e. volume or duration).