We investigated the concurrent impact of HIIT and blood-flow restriction (BFR) as a novel approach to further enhance maximal aerobic and anaerobic physiology and performances in trained athletes. In a randomized controlled trial, eighteen endurance-trained males (V ̇O2peak 65.6±5.1 ml.min-1.kg-1) included three sessions of HIIT per week (sets of 15-s efforts at 100% maximal aerobic power, interspersed by 15-s recovery) into their usual training for three weeks, either with restriction imposed on both lower limbs at 50-70% of arterial occlusion pressure (BFR group, n=10) or without (CTL group, n=8), and were tested for sprint and endurance exercise performance. The total mechanical work developed during a 30-sec Wingate test increased only in BFR (3.6%, P=0.02). During the Wingate, changes in near-infrared spectroscopy-derived vastus lateralis muscle oxygenation (Δ(deoxy[Hb+Mb]), % arterial occlusion) were attenuated after BFR training (-8.8%, P=0.04). The maximal aerobic power measured during an incremental cycling test increased only in BFR (4.5%, P=0.0004), but there was no change in V ̇O2peak among groups. Both groups improved 5-km cycling time trial performance, but BFR displayed a concomitant greater elevation in [H+] (11%, P=0.02). Changes in other blood variables (e.g., pH, lactate, bicarbonate and potassium ion concentration, hemoglobin) were not different between groups. Combining short-duration HIIT performed at 100% aerobic power with BFR elicited greater changes in sprint performance and maximal aerobic power in endurance athletes, associated with locomotor muscle metabolic adaptations but no meaningful effect on cardiorespiratory fitness.
Read full abstract