Musculoskeletal research in human space flight – unmet needs for the success of crewed deep space exploration

Abstract

Based on the European Space Agency (ESA) Science in Space Environment (SciSpacE) community White Paper “Human Physiology – Musculoskeletal system”, this perspective highlights unmet needs and suggests new avenues for future studies in musculoskeletal research to enable crewed exploration missions. The musculoskeletal system is essential for sustaining physical function and energy metabolism, and the maintenance of health during exploration missions, and consequently mission success, will be tightly linked to musculoskeletal function. Data collection from current space missions from pre-, during-, and post-flight periods would provide important information to understand and ultimately offset musculoskeletal alterations during long-term spaceflight. In addition, understanding the kinetics of the different components of the musculoskeletal system in parallel with a detailed description of the molecular mechanisms driving these alterations appears to be the best approach to address potential musculoskeletal problems that future exploratory-mission crew will face. These research efforts should be accompanied by technical advances in molecular and phenotypic monitoring tools to provide in-flight real-time feedback.

Plyometric training increases thickness and volume of knee articular cartilage in mice

“…Composition and morphology of articular cartilage is optimized for load-bearing function and allows to sustain repetitive, high mechanical loads occurring during all load bearing activities. Mechanical load is essential for cartilage health, and immobilization -because of illness, injury or bed rest-changes tissue biology and structure [3,4,5,6,2,7]. Simple locomotion replacement training -including squats, heel raises and a small number of hops-, and resistive vibration exercise alone or combined with protein and bicarbonate supplementation does not provide sufficient countermeasures for bed rest induced changes in cartilage biology [8,9].…”

“…Space agencies support ISS crew with specific pre-and post-flight exercise programs and exercise routines while on board the ISS [7]. Pre-flight training prepares the astronauts to the challenges of space flight by strengthening the musculoskeletal system, and post-flight routines focus on comprehensive reconditioning.…”

Spaceflight Induces Strength Decline in Caenorhabditis elegans

“…As a species, we have been working and living in space for more than 60 years, with continuous occupation for the last 23 years via the International Space Station (ISS) [1]. During this time, we have discovered that spaceflight induces numerous physiologic alterations, including but not limited to muscle and bone loss, structural changes in the eyes and brain, altered cardiovascular function, and altered cognitive function [2][3][4][5][6][7][8][9]. In some cases, we have developed effective countermeasures for these undesirable outcomes, but in other cases, understanding and countering the causes of these outcomes remain active areas of investigation.…”

Cerebral Circulation and Brain Temperature during an Ultra-Short Session of Dry Immersion in Young Subjects

“…In turn, these physical effects provoke such physiological phenomena as redistribution of body fluids in bottom-up direction and “deafferentation”. Either real microgravity or its ground-based models exert a strong effect on the physiological systems of a human organism, primarily on the musculoskeletal, nervous, and cardiovascular systems [ 4 , 5 , 6 , 7 ].…”