Intermittent short-arm centrifugation is a partially effective countermeasure against upright balance deterioration following 60-day head-down tilt bed rest

Abstract

This study investigated whether artificial gravity (AG), induced by short-radius centrifugation, mitigated deterioration in standing balance and anticipatory postural adjustments (APAs) of trunk muscles following 60-day head-down tilt bed rest. Twenty-four participants were allocated to one of three groups: control group (N=8); 30 minutes continuous AG daily (N=8); intermittent 6x5 minutes AG daily (N=8). Before and immediately after bed rest, standing balance was assessed in four conditions: eyes open and closed on both stable and foam surfaces. Measures including sway path, root-mean-square, and peak sway velocity, sway area, sway frequency power, and sway density curve were extracted from the centre of pressure displacement. APAs were assessed during rapid arm movements using intramuscular or surface electromyography electrodes of the rectus abdominis, obliquus externus and internus abdominis, transversus abdominis, erector spinae at L1, L2, L3, and L4 vertebral levels, and deep lumbar multifidus muscles. The relative latency between the EMG onset of the deltoid and each of the trunk muscles was calculated. All three groups had poorer balance performance in most of the parameters (all P<0.05) and delayed APAs of the trunk muscles following bed rest (all P<0.05). Sway path and sway velocity were deteriorated, and sway frequency power was less in those who received intermittent AG than in the control group (all P<0.05), particularly in conditions with reduced proprioceptive feedback. These data highlight the potential of intermittent AG to mitigate deterioration of some aspects of postural control induced by gravitational unloading, but no protective effects on trunk muscle responses were observed.

The Effects of 30 Minutes of Artificial Gravity on Cognitive and Sensorimotor Performance in a Spaceflight Analog Environment

“…While there was no statistically significant effect of 30 mins of daily AG on these balance and mobility measures, it is notable that the AG group’s decline in their SOT-5M equilibrium score with HDBR was 10.4 points less than that of control participants. Moreover, a recent study from the same campaign showed that some postural control measures declined less in bed rest for participants that received AG ( De Martino et al, 2021 ). Thus, a higher dose of AG (in terms of duration and/or magnitude) may prove beneficial.…”

Comparison of trunk muscle exercises in supine position during short arm centrifugation with 1 g at centre of mass and upright in 1 g

“…Recent findings suggest that passive exposure to intermittent centrifugation during 60 days head down tilt bed rest do not provide protective effects to maintain control and coordination of superficial and deep lumbar spinal muscles during anticipatory adjustments to quick arm movements (De Martino et al, 2021).…”

The Effects of Long Duration Spaceflight on Sensorimotor Control and Cognition

“…HDBR studies have examined the effects of artificial gravity applied via centrifugation as a potential countermeasure for spaceflight-associated brain and behavioral changes ( Frett et al, 2020 ). Recent data shows that artificial gravity does not prevent aerobic capacity declines during bed rest, although it does mitigate some muscular function decay ( Kramer et al, 2021 ) and partially counteract upright balance ( De Martino et al, 2021 ).…”