Lumbopelvic Muscle Changes Following Long-Duration Spaceflight

Area of Science:

• Space medicine
• Human physiology
• Musculoskeletal health

Background:

• Long-duration spaceflight poses risks to astronaut health, particularly affecting lumbopelvic muscles.
• Previous research indicated muscle deterioration, but recent data on current exercise interventions is needed.

Purpose of the Study:

• To assess the impact of long-duration spaceflight on specific lumbopelvic muscles (psoas, quadratus lumborum, paraspinals).
• To determine if muscle volume and attenuation changes persist with current exercise devices.

Main Methods:

• Computed tomography (CT) scans of 16 astronauts before and after 4-6 month missions were analyzed.
• Muscle volume and attenuation at the L2 vertebral level were measured to assess structural changes and myosteatosis.
• One-sample t-tests were used to evaluate changes in muscle parameters.

Main Results:

• Significant decreases in quadratus lumborum muscle volume (9.5%) and attenuation (6.0%) were observed.
• Paraspinal muscles showed significant decreases in volume (5.3%) and attenuation (5.3%).
• No significant changes were found in psoas muscle volume, attenuation, or intermuscular adipose tissue.

Conclusions:

• Long-duration spaceflight leads to significant structural deterioration in quadratus lumborum and paraspinal muscles.
• The psoas muscle appears more resilient to spaceflight effects with current exercise protocols.
• Astronauts experience muscle loss despite using the interim resistive exercise device, highlighting the need for further countermeasures.