Acute Physiological Responses to Resistance Exercise With Continuous Versus Intermittent Blood Flow Restriction: A Randomized Controlled Trial

Abstract

The primary goal of this investigation was to examine the physiological responses of blood flow restriction (BFR) resistance exercise (RE) performed with continuous or intermittent BFR and to compare these results to those from conventional high-and low-load RE without BFR. Fourteen men randomly completed the following experimental trials: (1) low-load RE with continuous BFR (cBFR), (2) low-load RE with intermittent BFR (iBFR), (3) low-load RE without BFR (LI), and (4) conventional high-load RE without BFR (HI). For the cBFR, iBFR, and LI exercise trials, participants performed four sets of 30-15-15-15 repetitions of the bilateral leg press (LP) and knee extension (KE) exercises, at an intensity of 20% of their one-repetition maximum (1-RM), at a 1.5s contraction speed, and with a 1-min rest period between sets. The only difference between the cBFR and iBFR protocols was that the pressure of the cuffs was released during the rest intervals between sets for the iBFR trial. For the HI trial, participants completed four sets of 10 repetitions of the same exercises, at 70% of 1-RM, with a 1-min rest period between sets, and at the same contraction speed. Muscle activity was assessed during each set using superficial electromyography, as well as changes in blood lactate concentration [La − ] from baseline at 5 min post exercise and in muscle swelling and plasma volume (% PV) at 5 and 15 min post exercise. There were no significant differences in muscle activity (p < 0.05) across the cBFR, iBFR, and LI protocols at any time point, whereas they were all significantly lower than HI. There were also no significant (p < 0.05) differences across the three low-load RE conditions for [La − ],% PV, or muscle swelling. HI elicited significantly (p < 0.05) greater responses than cBFR, iBFR, and LI for all the physiological markers measured. In conclusion, RE combined with cBFR or iBFR induce the same acute physiological responses. However, the largest physiological responses are observed with HI, probably because of the significantly greater exercise volumes. Therefore, releasing the pressure of the restrictive cuffs during the rest periods between sets will not hinder the acute physiological responses from BFR RE.

The Acute Physiological Responses to Traditional vs. Practical Blood Flow Restriction Resistance Exercise in Untrained Men and Women

“…Lastly, similar sEMG results were observed for the two BFR exercise conditions, although these were lower than those observed during HL. These results are supported by previous data from our research group that has also demonstrated that HL elicits greater myoelectrical activity compared to tBFR, utilizing the same exercises and muscle groups in a cohort of young adult males ( Freitas et al, 2020 ).…”

“…Lastly, similar sEMG results were observed for the two BFR exercise conditions, although these were lower than those observed during HL. These results are supported by previous data from our research group that has also demonstrated that HL elicits greater myoelectrical activity compared to tBFR, utilizing the same exercises and muscle groups in a cohort of young adult males (Freitas et al, 2020). Regarding the metabolic response to the exercise bouts expressed as WBL, our data suggest that males display greater metabolic response compared to females, regardless of the method of exercise performed.…”

“…Hence, once a certain level of metabolic stress is reached, a further increase in the metabolite accumulation will not necessarily result in a further increase in muscle swelling. This phenomenon has also been observed in previous research with tBFR and HL eliciting similar levels of muscle thickness post-exercise, despite much greater lactate levels measured following HL (Freitas et al, 2020).…”

Temporal Variability in Electrocardiographic Indices in Subjects With Brugada Patterns

“…Firstly, a comprehensive analysis of different ECG features has been performed, with 3-50 ECGs measured per patient, and a total of more than 1000 ECGs analyzed. This extended previous studies using only single ECG measurements at baseline (Tse et al, 2018b;Lee et al, 2020). Moreover, there is good inter and intraobserver variability, as reflected by the intra-class coefficient.…”

The physiological, morphological and functional responses to resistance exercise with blood flow restriction: an examination of protocol type and exercise load

“…However, when cuffs are released during inter-set rest periods (known as an intermittent BFR application), and consequently reperfusion occurs, PCr levels recover to baseline levels and therefore fail to reach those of HL-RE [312]. While these data suggest that metabolic stress is greater when a continuous BFR protocol is used (compared with intermittent application), studies using blood lactate as a measure of metabolic stress do not support this [97,232]. Such differences may arise from the systemic nature of the measurement, which reflects the concentrations of lactate within the circulation, as opposed to locally within skeletal muscle.…”