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To investigate the effects of high-intensity contractions and low-intensity contractions with and without blood flow restriction on changes in blood pressure and hemodynamic parameters. A total of 179 participants (18–35 years) were randomly assigned to one of three training groups that exercised 3 times per week for six weeks or a non-exercise control group. The groups are as follows: 1) Control [CON, n = 44]; 2) completed 4 sets of two-minute isometric contractions at 30% maximal voluntary contraction [LI, n = 47]; 3) completed 4 sets of two-minute isometric contractions at 30% maximal voluntary contraction with a 12 cm cuff inflated to 50% of arterial occlusion pressure [LI+BFR, n = 41]; or 4) completed 4 maximal isometric contractions lasting 5 seconds [MAX, n = 47]. Blood pressure, vascular resistance, and reactive hyperemia were measured at pre and post. Data are presented as means (SD). There was no evidence that SBP (BF10: 0.066), DBP (BF10: 0.057), vascular resistance (BF10: 0.085), or peak reactive hyperemia changed (BF10: 0.044) or A.U.C. (BF10: 0.074). Change scores for SBP were 1.1 (6.7), 0.7 (5.8), −0.4 (6.5), and −0.9 (6.3) mmHg for CON, LI, LI+BFR, and MAX, respectively. DBP change scores were 1.5 (6.6), 1.5 (7), −0.7 (5.9), and 0.3 (6.3) mmHg for CON, LI, LI+BFR, and MAX, respectively. Although recommended as a non-pharmacological method of blood pressure control, isometric exercise with or without BFR did not lower blood pressure. Future work could examine the inclusion of a daily strength test prior to the low intensity protocol. [ABSTRACT FROM AUTHOR]

It was previously hypothesized that the cross-education of strength is asymmetrical, where a greater transfer of strength is observed from the dominant to the non-dominant limb. The purpose of this study was to examine if the magnitude of cross-education of strength differed between dominant and non-dominant limbs following unilateral high-load resistance training. One hundred and twenty-two participants were randomized to one of the three groups: 1) training on the dominant arm (D-Only), 2) training on the non-dominant arm (ND-Only) and 3) a time-matched non-exercise control (Control). The training groups completed 6 weeks (18 sessions) of unilateral elbow flexion exercise. Each training session started with one-repetition maximum (1RM) training (≤ five attempts), followed by four sets of high-load exercise (i.e. 8–12RM). Strength changes of the untrained arm were compared between groups. Changes in the strength of the untrained arm were greater in D-Only (1.5 kg) and ND-Only (1.3 kg) compared to Control (−0.2 kg), without differences between D-Only and ND-Only. Unilateral resistance training increased strength in the opposite untrained arm, and the magnitude of this effect was similar regardless of which arm was trained. However, there is still considerable uncertainty on this topic and additional research is warranted to confirm the current findings. [ABSTRACT FROM AUTHOR]

To determine (a) the impact of ischemic preconditioning pressures (applied as a % of arterial occlusion pressure [AOP]) on pressure pain threshold (PPT) and resistance exercise performance and (b) whether changes in performance could be explained by changes in PPT. Subjects (n539) completed 4 protocols in a randomized order: (a) ischemic preconditioning (IPC) at 110% AOP (IPC 110%), (b) IPC at 150% AOP (IPC 150%), (c) IPC at 10% AOP (Sham), and (d) time-matched control (CON). Each protocol included 4 cycles of 5 minutes of occlusion followed by 5 minutes of reperfusion. Pressure pain threshold was taken before and after. Discomfort ratings were given at the end of each cycle. Every visit finished with 2 sets of 75-second maximal isokinetic unilateral elbow flexion or extension. Overall, IPC 110% and IPC 150% resulted in similar increases in PPT relative to CON [110%: difference of 0.36 (0.18, 0.54) kg·m-2; 150%: difference of 0.377 (0.15, 0.59) kg·m-2] and Sham. Both resulted in greater discomfort than Sham and CON, with IPC 150% inducing greater discomfort than IPC 110% (BF10: 14.74). There were no differences between the conditions for total work (BF10: 0.23), peak torque (BF10: 0.035), or average power (BF10: 0.159). We did not find evidence that PPT mediated performance. We did not detect changes in performance with 2 different relative pressures greater than AOP. Our mean applied pressures were lower than those used previously. There might be a minimal level of pressure (e.g., >150% of AOP) that is required to induce ergogenic effects of ischemic preconditioning. [ABSTRACT FROM AUTHOR]

Purpose: To 1) examine whether blood flow restriction would provide an additional exercise-induced hypoalgesic response at an upper and lower limb when it is incorporated with low-load resistance exercise until failure, and 2) examine if increases in blood pressure and discomfort, with blood flow restricted exercise, would mediate the exercise-induced hypoalgesia over exercise without blood flow restriction. Methods: Forty healthy young participants completed two trials: four sets of unilateral knee extension exercise to failure at 30% of one-repetition maximum, with and without blood flow restriction. Pressure pain thresholds were assessed before (twice) and 5-min post exercise at an upper and lower limb. Blood pressure and discomfort ratings were recorded to examine mediating effects on exercise-induced hypoalgesia with blood flow restricted exercise. Results: Pressure pain threshold increased following both exercise conditions compared to a control, without any differences between exercise conditions at the upper (exercise conditions vs. control: ~0.37 kg/cm²) and lower (exercise conditions vs. control: ~0.60 kg/cm²) limb. The total number of repetitions was lower for exercise with blood flow restriction compared to exercise alone [median difference (95% credible interval) of -27.0 (-29.8, -24.4) repetitions]. There were no mediating effects of changes in blood pressure, nor changes in discomfort, for the changes in pressure pain threshold at either the upper or lower limb. Conclusion: The addition of blood flow restriction to low-load exercise induces a similar hypoalgesic response to that of non-blood flow restricted exercise, with a fewer number of repetitions. [ABSTRACT FROM AUTHOR]