European Journal of Applied Physiology

, Volume 93, Issue 4, pp 463–468

Effects of 17-day spaceflight on knee extensor muscle function and size

Authors

    • Section for Exercise Physiology, Department of Physiology and PharmacologyKarolinska Institutet
  • Hans E. Berg
    • Section for Exercise Physiology, Department of Physiology and PharmacologyKarolinska Institutet
  • Daniel Bring
    • Section for Exercise Physiology, Department of Physiology and PharmacologyKarolinska Institutet
  • Harlan J. Evans
    • Life Sciences, Systems and ServicesWyle Laboratories
  • Adrian D. LeBlanc
    • Department of MedicineBaylor College of Medicine
Original Article

DOI: 10.1007/s00421-004-1236-9

Cite this article as:
Tesch, P.A., Berg, H.E., Bring, D. et al. Eur J Appl Physiol (2005) 93: 463. doi:10.1007/s00421-004-1236-9

Abstract

It is generally held that space travelers experience muscle dysfunction and atrophy during exposure to microgravity. However, observations are scarce and reports somewhat inconsistent with regard to the time course, specificity and magnitude of such changes. Hence, we examined four male astronauts (group mean ~43 years, 86 kg and 183 cm) before and after a 17-day spaceflight (Space Transport System-78). Knee extensor muscle function was measured during maximal bilateral voluntary isometric and iso-inertial concentric, and eccentric actions. Cross-sectional area (CSA) of the knee extensor and flexor, and gluteal muscle groups was assessed by means of magnetic resonance imaging. The decrease in strength (P<0.05) across different muscle actions after spaceflight amounted to 10%. Eight ambulatory men, examined on two occasions 20 days apart, showed unchanged (P>0.05) muscle strength. CSA of the knee extensor and gluteal muscles, each decreased (P<0.05) by 8%. Knee flexor muscle CSA showed no significant (P>0.05) change. The magnitude of these changes concord with earlier results from ground-based studies of similar duration. The results of this study, however, do contrast with the findings of no decrease in maximal voluntary ankle plantar flexor force previously reported in the same crew.

Keywords

AstronautsIso-inertial concentric and eccentric actionsMagnetic resonance imagingMuscle atrophyMuscle strength

Copyright information

© Springer-Verlag 2004