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Life in Space for Life on Earth, ESA, Triest, 2010;

Lower-limb muscle atrophy and effect of resistive vibration exercise during 56-day bed-rest

Jahr: 2010

Belavy D, Miokovic T, Armbrecht G, Rittweger J, Felsenberg D
Charité Universitätsmedizin Berlin, GERMANY; German Aerospace Center, GERMANY

Abstract

Objectives:
Developing more efficient countermeasures for the maintenance of muscle and muscle function in spaceflight is a priority for space agencies. In this work, we examine changes in muscle volume of the lower-limb during prolonged bed-rest and the impact of a high-intensity resistive vibration exercise (RVE) countermeasure as part of the 1st Berlin Bed-Rest Study (2003 and 2004).

Methods:
20 male subjects underwent 56-days of bed- and were assigned to either an inactive control, or a countermeasure group which performed high-load resistive exercises with whole-body vibration. 11 exercise sessions were performed per week, with exercises including including squats, heel raises, toe raises and "kicks" against a vibrating platform. Magnetic resonance imaging of the lower-limbs was performed at two-weekly intervals and the volumes of individual muscles were measured.

Results:
In the control group, rate of muscle atrophy differed between muscles (F=8.81, p<0.0001) and was greatest in the triceps surae (gastrocnemius medialis: -22.3[1.5]%, soleus: -16.5[1.8]%, gastrocnemius lateralis: -14.4[2.8]% after 56-days bed-rest), followed by the vastii (-15.9[3.7]%), and hamstrings (semimembranosus: -12.3[1.3]%, biceps femoris long head: -12.5[5.5]%). The adductor longus, sartiorius, gracilis, rectus femoris and anterior tibial muscles showed limited loss of muscle volume (=5.1%) during bed-rest. Countermeasure exercise reduced atrophy (F>3.0, p<.025) in the triceps surae (-6.6 [1.8]% vs. -18.3 [2.0]%) and the vastii (-4.6[1.6]% vs. -15.9[3.7]%) muscles, but did not impact upon atrophy of the hamstring muscles (-10.9[2.2]% vs. -11.3[3.1]%).

Conclusions:
Understanding which muscles are most affected by bed-rest helps to design more time efficient training programmes to target these particular muscle groups. The limited effect of RVE on the hamstrings was possibly due to insufficient hip flexion/extension during squat exercises. Consideration of the results of the current and other works suggests that (resistive) exercise needs to be performed at high-loads to maintain muscle mass during prolonged bed-rest.

Schlagworte: Galileo Space, Counter Measure, BBR 1
GID: 2299; Letzte Änderung: 18.06.2010
Weitere Informationen: Original Article