Repeated Cycling Sprints with Different Restricted Blood Flow Levels

We examined the effect of different levels of blood flow restriction (BFR) during repeated sprint performance in leg cycling. The aim of this study was to evaluate the RSA leg cycling performance between various levels of blood flow restriction in well-trained athletes. Eleven athletes (6 men; 5 women) performed four sessions (familiarization, 0% BFR, 45% BFR, 60% BFR) of repeated sprint ability (10sec sprint, followed by 20sec recovery; RSA) to exhaustion or task failure. The number of sprints across conditions decreased with higher BFR (29.8±13.7, 13.1±6.5, 7.5±6.4, respectively, P < 0.05). Total work performed and maximal heart rate during the sprints were also reduced as the level of BFR increased. Mean power decreased across sprints as well as with increased occlusion (P < 0.001), and a faster decrease in power output was demonstrated as occlusion increased (e.g. significantly different than sprint 1 at sprint 3 in 0% BFR (P = 0.007), sprint 3 in 45% BFR (P < 0.001), and sprint 2 (P < 0.05) in 60% BFR, respectively). Results indicated, as expected, that RSA performance is decreased with higher levels of BFR. It is likely that other mechanisms related to central and peripheral systems differ between each condition as suggested by the increased discomfort in the legs versus decreased discomfort in breathing as well as lower maximal HR with higher BFR. It is of interest to investigate if the response elicited with BFR is similar to that of repeated sprinting in hypoxia (i.e., is a stimulus of localized hypoxia, BFR, similar or different than a stimulus of systemic hypoxia).