Markers of isometric training intensity and reductions in resting blood pressure

Abstract

In this study, we examined the correlations between selected markers of isometric training intensity and subsequent reductions in resting blood pressure. Thirteen participants performed a discontinuous incremental isometric exercise test to volitional exhaustion at which point mean torque for the final 2-min stage (2min-torque(peak)) and peak heart rate peak (HR(peak)) were identified. Also, during 4 weeks of training (3 sessions per week, comprising 4 × 2 min bilateral leg isometric exercise at 95% HR(peak)), heart rate (HR(train)), torque (Torque(train)), and changes in EMG amplitude (ΔEMG(amp)) and frequency (ΔEMG(freq)) were determined. The markers of training intensity were: Torque(train) relative to the 2min-torque(peak) (%2min-torque(peak)), EMG relative to EMG(peak) (%EMG(peak)), HR(train) ΔEMG(amp), ΔEMG(freq), and %MVC. Mean systolic (-4.9 mmHg) and arterial blood pressure (-2.7mmHg) reductions correlated with %2min-torque(peak) (r = -0.65, P = 0.02 and r = -0.59, P = 0.03), ΔEMG(amp) (r = 0.66, P = 0.01 and r = 0.59, P = 0.03), ΔEMG(freq) (r = -0.67, P = 0.01 and r = -0.64, P = 0.02), and %EMG(peak) (systolic blood pressure only; r = -0.63, P = 0.02). These markers best reflect the association between isometric training intensity and reduction in resting blood pressure observed after bilateral leg isometric exercise training.

Reductions in Resting Blood Pressure in Young Adults When Isometric Exercise Is Performed Whilst Walking

“…Baross et al [32] reported significant reductions in SBP (−11 mmHg) and MAP (−5 mmHg) following isometric bilateral-leg training at relatively low intensities (approximately 14% MVC). However, the studies of Devereux et al [16] and Baross et al [32] used much longer periods of exercise, than we used in the present study; therefore the training stimulus is likely to have been much greater. In the present study training was performed 4 times per week, whereas most previous isometric training studies have used 3 times per week, and this may have contributed to our significant findings.…”

“…There is some evidence that brief, and low-intensity, isometric training programmes can induce reductions in resting blood pressure. For example, Devereux et al [16] reported significant reductions in SBP (−5 mmHg) and MAP (−3 mmHg) following only 4 weeks of isometric bilateral-leg training at an exercise intensity that equated to approximately 20% MVC. Baross et al [32] reported significant reductions in SBP (−11 mmHg) and MAP (−5 mmHg) following isometric bilateral-leg training at relatively low intensities (approximately 14% MVC).…”

“…One particular form of resistance training (isometric training) has been shown to be especially potent in reducing resting blood pressure (relative to the amount of training performed). Previous research has identified a significant decrease in resting SBP (−5 to −13 mmHg) and DBP (−3 to −9 mmHg) following either upper [13, 14] or lower body [15, 16] isometric training.…”

Isometric Exercise Training for Blood Pressure Management: A Systematic Review and Meta-analysis

“…Nine studies were included in our analysis, [16][17][18][19][20][21][22][23][24] with a total of 223 patients (Supplemental Table 1, available online at http://www.mayo clinicproceedings.org). Six studies used handgrip, and 3 studies used leg exercise.…”

Effects of the Intensity of Leg Isometric Training on the Vasculature of Trained and Untrained Limbs and Resting Blood Pressure in Middle-Aged Men

“…Isometric training was performed in the same way as detailed previously [4, 21]. Briefly, participants performed an MVC test and then an incremental isometric exercise test.…”