Differences in delayed onset muscle soreness, lactate levels, perceived exertion and pain between two bouts of blood flow restriction training in young, trained, men and women

Abstract: Background Resistance training with high intensity has multiple health benefits but high intensity (>60% 1 repetition maximum) resistance training is sometimes contraindicated, thus exercise modalities that utilize lower intensity (≤60% 1 repetition maximum) could be used. Low intensity exercise does not normally yield the same benefits as high intensity but when combined with blood flow restriction (BFR) it has been shown to yield similar results to that of high intensity resistance training. However, previous research has had mostly homogenous groups and often used harder BFR protocols, usually in the lower extremities, leaving gaps in the BFR literature. Thus less strenuous BFR protocols, on the upper extremities and on a more heterogenous group could be used to fill those gaps. Aim In this experimental and non-randomized study, the aim was to evaluate the effects of blood flow restriction on delayed onset muscle soreness, blood lactate, ratings of perceived exertion (RPE, 6-20), and self-reported pain (Borg category ratio scale, CR10, 0-10) between two bouts of BFR training in young, trained, men and women. And whether higher blood lactate correlated with higher perceived exertion. Methods Thirteen participants (7 men and 6 women) between the ages 22 and 32 were recruited for this study. The participants were healthy and regularly participated in strength training (2x per week or more) but were unfamiliar with BFR training. BFR training was performed on two occasions, separated by one week. Blood lactate was collected pre and post-training on each occasion. RPE and CR10 were collected immediately post-training, and delayed onset muscle soreness was collected at 24, 48, and 72 hours post-training after both occasions. Results Eleven participants completed the entire study. Delayed onset muscle soreness was significantly lower (p < 0.05) at 24h (an effect size of cohen’s d = 0.75) and 48h (d = 0.88) after the second bout of blood flow restriction training. Blood lactate increased between bouts (d = -0.62) but did not reach significance. RPE and CR10 were lower after the second bout (15.4 vs 14.5 and 5.1 vs 4.0 respectively) however reduction did not reach statistical 1significance. Blood lactate and ratings of perceived exertion had a low positive correlation (r = 0.34) after the second bout of blood flow restriction training but the result was not statistically significant. Conclusion One bout of blood flow restriction training was enough to induce a protective effect to further bouts, which was shown as a reduction in the magnitude of the delayed onset muscle soreness after the second bout of exercise.