Squat exercise biomechanics during short-radius centrifugation

Area of Science:

• Space Physiology
• Biomechanics
• Exercise Science

Background:

• Artificial gravity (AG) via centrifugation is a key countermeasure for physiological deconditioning during spaceflight.
• Centrifuge-based exercise must account for altered biomechanics due to gravity gradients and Coriolis forces.
• Understanding squat exercise biomechanics under AG is crucial for effective in-space training protocols.

Purpose of the Study:

• To investigate the biomechanical effects of centrifuge-induced artificial gravity on squat exercises.
• To quantify differences in squat biomechanics between normal gravity and AG conditions.
• To assess the safety and feasibility of exercise during centrifugation.

Main Methods:

• 28 participants performed supine squats on a 2m radius centrifuge at 0, 23, and 30 rpm, with upright squats in 1G as a control.
• Knee position, foot reaction forces, and motion sickness were recorded.
• Data were analyzed to compare biomechanical parameters between conditions.

Main Results:

• No participants experienced motion sickness or injuries.
• Mediolateral knee deflection increased by 1.0-2.0 cm under AG, with no adverse post-rotation effects.
• Peak foot reaction forces increased up to ~200% bodyweight with rotation rate.
• Foot force distribution became non-constant and sinusoidal under AG.
• Total foot reaction force relative to knee angles differed between upright and AG squats.

Conclusions:

• Brief exercise protocols during centrifugation are safe and well-tolerated.
• AG exercise does not cause significant after-effects in knee position or motion sickness.
• Findings inform the design of future centrifuge-based exercise countermeasures for space exploration.