Background: Previous meta-analyses based on aggregate group-level data report antihypertensive effects of isometric resistance training (IRT). However, individual participant data meta-analyses provide more robust effect size estimates and permit examination of demographic and clinical variables on IRT effectiveness. Methods: We conducted a systematic search and individual participant data (IPD) analysis, using both a one-step and two-step approach, of controlled trials investigating at least 3 weeks of IRT on resting systolic, diastolic and mean arterial blood pressure. Results: Anonymized individual participant data were provided from 12 studies (14 intervention group comparisons) involving 326 participants (52.7% medicated for hypertension); 191 assigned to IRT and 135 controls, 25.2% of participants had diagnosed coronary artery disease. IRT intensity varied (8–30% MVC) and training duration ranged from 3 to 12 weeks. The IPD (one-step) meta-analysis showed a significant treatment effect for the exercise group participants experiencing a reduction in resting SBP of −6.22 mmHg (95% CI −7.75 to −4.68; P < 0.00001); DBP of −2.78 mmHg (95% CI −3.92 to −1.65; P = 0.002); and mean arterial blood pressure (MAP) of −4.12 mmHg (95% CI −5.39 to −2.85; P < 0.00001). The two-step approach yielded similar results for change in SBP −7.35 mmHg (−8.95 to −5.75; P < 0.00001), DBP MD −3.29 mmHg (95% CI −5.12 to −1.46; P = 0.0004) and MAP MD −4.63 mmHg (95% CI −6.18 to −3.09: P < 0.00001). Sub-analysis revealed that neither clinical, medication, nor demographic participant characteristics, or exercise program features, modified the IRT treatment effect. Conclusion: This individual patient analysis confirms a clinically meaningful and statistically significant effect of IRT on resting SBP, DBP and mean arterial blood pressure.

The purpose of this study was to establish whether changes in resting blood pressure and the vasculature of trained and untrained limbs are dependent on training intensity, following isometric-leg training. Thirty middle-aged males undertook an 8 week training programme (4 × 2 min bilateral-leg isometric contractions 3 times per week). Two groups trained at either high (HI; 14%MVC) or low (LO; 8%MVC) intensity a third group (CON) acted as controls. All parameters were measured at baseline, 4-weeks and post-training. Resting SBP (−10.8 ± 7.9 mmHg), MAP (−4.7 ± 6.8 mmHg) and HR (−4.8 ± 5.9 b·min−1) fell significantly in the HI group post-training with concomitant significant increases in resting femoral mean artery diameter (FMAD; 1.0 ± 0.4 mm), femoral mean blood velocity (FMBV; 0.68 ± 0.83 cm·s−1), resting femoral artery blood flow (FABF; 82.06 ± 31.92 ml·min−1) and resting femoral vascular conductance (FVC, 45%). No significant changes occurred in any brachial artery measure nor in any parameters measured in the LO or CON groups. These findings show that training-induced reductions in resting blood pressure after isometric-leg training in healthy middle-aged men are associated with concomitant adaptations in the local vasculature, that appear to be dependent on training intensity and take place in the later stages of training.

The substantial positive adaptation in multiple functional and physiological variables that are cited within the primary etiology of muscle strain injury, including strength, ROM, muscle stiffness, and maximal energy storage, indicate that the stretching of active muscle might influence injury risk in addition to muscle function. The lack of change in muscle-tendon stiffness simultaneous with significant increases in tendon stiffness and decreases in passive muscle stiffness indicates that tissue-specific effects were elicited.