Jumping in simulated lunar gravity with blood flow restriction as a potential exercise countermeasure: The acute...

The present study examined the cardiovascular, metabolic, neuromuscular and perceptual effects of low-intensity jumping in simulated lunar gravity (∼20% bodyweight) with blood flow restriction (BFR). Fourteen healthy adults (24 ± 4 years; 1.81 ± 0.06 m; 75 ± 12 kg) completed an incremental jumping test in simulated lunar gravity (9.5° head-up tilt suspension) followed by a graded exercise test to determine maximal oxygen uptake ( ${\stackrel{.}{V}}_{O_2\mathrm{peak}}$ ). Two exercise visits (with and without BFR) were completed on separate days comprising 6 × 2 min of low-intensity (40% ${\stackrel{.}{V}}_{O_2\mathrm{peak}}$ ) continuous jumping at ∼20% bodyweight, with 1-min passive rest periods. Blood flow restriction was applied at 60% limb occlusion pressure to the lower limbs during the exercise periods and removed during the rest periods. Jumping in simulated lunar gravity with BFR, compared to without BFR, significantly decreased muscle tissue oxygenation within the vastus lateralis (∼20%) and gastrocnemius medialis (∼5%), and increased heart rate (10-23 beats min^-1), carbon dioxide output (2-4 mL kg^-1 min^-1) and minute ventilation (7-16 L min^-1). Oxygen consumption was either unaffected or slightly elevated up to 3 mL kg^-1 min^-1. Blood lactate concentration was significantly greater during BFR jumping by ∼1-2 mmol L^-1. Pre-post exercise knee extension peak force declined in both conditions to similar extents. Perceived exertion, discomfort and body instability significantly increased with BFR. Jumping in simulated lunar gravity with BFR requires little equipment and elicits similar metabolic, cardiovascular and perceptual responses to BFR aerobic exercise in terrestrial settings (e.g., BFR walking/cycling), and therefore may have value as a musculoskeletal and cardiovascular exercise countermeasure during planetary exploration missions.