Cardiovascular responses to passive static flexibility exercises are influenced by the stretched muscle mass and the Valsalva maneuver

Abstract

Background: The respiratory pattern is often modified or even blocked during flexibility exercises, but little is known about the cardiovascular response to concomitant stretching and the Valsalva maneuver (VM) in healthy subjects.

Objectives: This study evaluated the heart rate (HR), systolic blood pressure (SBP), and rate-pressure product (RPP) during and after large and small muscle group flexibility exercises performed simultaneously with the VM.

Methods: Asymptomatic volunteers (N = 22) with the following characteristics were recruited: age, 22 ± 3 years; weight, 73 ± 6 kg; height, 175 ± 5 cm; HR at rest, 66 ± 9 BPM; and SBP at rest, 113 ± 10 mmHg. They performed two exercises: four sets of passive static stretching for 30 s of the dorsi-flexion (DF) of the gastrocnemius and the hip flexion (HF) of the ischio-tibialis. The exercises were performed with (V+) or without (V-) the VM in a counterbalanced order. The SBP and HR were measured, and the RPP was calculated before the exercise session, at the end of each set, and during a 30-min post-exercise recovery period.

Results: The within-group comparisons showed that only the SBP and RPP increased throughout the sets (p < 0.05), but no post-exercise hypotension was detected. The between-group comparisons showed that greater SBP increases were related to the VM and to a larger stretched muscle mass. Differences for a given set were identified for the HR (the HFV+ and HFV- values were higher than the DFV+ and DFV- values by approximately 12 BPM), SBP (the HFV+ value was higher than the DFV+ and DFV- values by approximately 12 to 15 mmHg), and RPP (the HFV+ value was higher than the HFV- value by approximately 2000 mmHGxBPM, and the HFV+ value was higher than the DFV+ and DFV- values by approximately 4000 mmHGxBPM).

Conclusion: Both the stretched muscle mass and the VM influence acute cardiovascular responses to multiple-set passive stretching exercise sessions.

Figure 1

Systolic blood pressure at rest, at the end of each stretching set and 30 min post-exercise. Within-group comparison, -. *, significant differences in all sets (a: HFV+, hip flexion with Valsalva; b: HFV-, hip flexion without Valsalva; c: DFV+, dorsiflexion with Valsalva; d: DFV-, dorsiflexion without Valsalva) (p<.05). The superscripted alpha-numeric codes indicate significant differences for the indicated set of exercise protocols specified by the letters (p<.05). Between-group comparison, -. **, significant differences for HFV+ as compared to DFV+ and DFV- (1^st through 4^th sets). ψ, a significant difference between HFV+ and HFV- (3^rd and 4^th sets). Δ:a significant difference between HFV- and DFV- (4^th set). The vertical bars denote 0.95 confidence intervals.

Figure 2

The heart rate at rest, at the end of each stretching set, and 30 min post-exercise. Within-group comparison, -. *, significant differences in all sets (a: HFV+, hip flexion with Valsalva; b: HFV-, hip flexion without Valsalva; c: DFV+, dorsiflexion with Valsalva; d: DFV-, dorsiflexion without Valsalva) (p<.05). Between-group comparison, -. **, significant differences for HFV+ and HFV- as compared to DFV+ and DF- across all sets. The vertical bars denote 0.95 confidence intervals.

Figure 3

The rate-pressure product at rest, at the end of each stretching set, and 30 min post-exercise. Within-group comparison, -. *, significant differences in all sets (a: HFV+, hip flexion with Valsalva; b: HFV-, hip flexion without Valsalva; c: DFV+, dorsiflexion with Valsalva; d: DFV-, dorsiflexion without Valsalva) (p<.05). The superscripted alpha-numeric codes indicate significant differences in the indicated set of exercise protocols specified by the letters (p<.05). Between-group comparison, -. **, significant differences for HFV+ and HFV- as compared to DFV+ and DFV- (1^st through 4^th sets). ψ, a significant difference between HFV+ and HFV- (2^nd through 4^th sets). The vertical bars denote 0.95 confidence intervals.