Jumping on the moon as a potential exercise countermeasure.

Abstract

The Moon's gravitational field strength (17% Earth's gravity) may facilitate the use of bodyweight jumping as an exercise countermeasure against musculoskeletal and cardiovascular deconditioning in reduced gravity settings. The present study characterised the acute physiological and kinetic responses to bodyweight jumping in simulated Lunar gravity. Nineteen healthy adults (age: 25 ± 7 years, weight: 73 ± 11 kg; height: 1.81 ± 0.05 m, ${\dot{V}}_{O_2\max }$ : 50 ± 11 mL kg^-1 min^-1) performed an incremental jumping test in simulated Lunar gravity (9.5° head-up tilt suspension) comprising 4-min stages of jumping with 1-min rests, beginning at 30 cm and increasing 5 cm per stage up to 70 cm. A graded exercise test (GXT) to volitional exhaustion was subsequently performed using upright cycle ergometry. Cardiorespiratory outcomes ( ${\dot{V}}_{O_2}$ , ${\dot{V}}_{C{O}_2}$ , ${\dot{V}}_E$ , breathing frequency, respiratory exchange ratio and heart rate (HR)) and peak vertical ground reaction forces (vGRF) increased linearly (R² = 0.77-0.97) and blood lactate concentrations increased exponentially with jump height (R² = 0.98). Participants achieved HRs of 158 ± 17 beats min^-1 (88 ± 9% HR_max), metabolic rates of 35 ± 6 mL kg^-1 min^-1 (71 ± 9% ${\dot{V}}_{O_2\max }$ ), blood lactate concentrations of 5.8 ± 1.7 mmol L^-1 and peak vGRFs of 119 ± 17% bodyweight. Jumping at ∼20% bodyweight requires no equipment, allows for submaximal cardiovascular exercise intensities with and without blood lactate accumulation, and may have value as an exercise countermeasure in Lunar/Martian surface habitats.