Human skeletal muscle structure and function preserved by vibration muscle exercise following 55 days of bed rest.
Prolonged immobilization of the human body results in functional impairments and musculoskeletal system deconditioning that may be attenuated by adequate muscle exercise. In a 56-day horizontal bed rest campaign involving voluntary males we investigated the effects of vibration muscle exercise (RVE, 2x6 min daily) on the lower limb skeletal muscles using a newly designed foot plantar trainer (Galileo Space) for use at supine position during bed rest. The maximally voluntary isometric plantar flexion force was maintained following regular RVE bouts during bed rest (controls -18.6 %, P<0.05). At the start (BR2) and end of bed rest (BR55) muscle biopsies were taken from both mixed fast/slow-type vastus lateralis (VL) and mainly slow-type soleus muscle (SOL), each having n=10. RVE group: the size of myofiber types I and II was largely unchanged in VL, and increased in SOL. Ctrl group: the SOL depicted a disrupted pattern of myofibers I/II profiles (i.e., type II>140 % vs. preBR) suggesting a slow-to-fast muscle phenotype shift. In RVE-trained SOL, however, an overall conserved myofiber I/II pattern was documented. RVE training increased the activity-dependent expression of nitric oxide synthase type 1 immunofluorescence at SOL and VL myofiber membranes. These data provide evidence for the beneficial effects of RVE training on the deconditioned structure and function of the lower limb skeletal muscle. Daily short RVE should be employed as an effective atrophy countermeasure co-protocol preferentially addressing postural calf muscles during prolonged clinical immobilization or long-term human space missions.
Department of Vegetative Anatomy, Center of Space Medicine Berlin, Neuromuscular Group, Charité University Medicine Berlin, Campus Benjamin Franklin, Arnimallee 22, 14195, Berlin, Germany. dieter.blottner@charite.de
Dieter
D
Blottner
Michele
M
Salanova
Britta
B
Püttmann
Gudrun
G
Schiffl
Dieter
D
Felsenberg
Björn
B
Buehring
Jörn
J
Rittweger
D000328:Adult; D001510:Bed Rest / Q000009:adverse effects; D001706:Biopsy; D005081:Exercise Therapy / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007537:Isometric Contraction; D035002:Lower Extremity; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism / Q000473:pathology; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology*; D009133:Muscular Atrophy / Q000209:etiology / Q000517:prevention & control*; D052248:Nitric Oxide Synthase Type I / Q000032:analysis / Q000378:metabolism; D013026:Space Flight; D013997:Time Factors; D014732:Vibration / Q000627:therapeutic use*
C496320:NOS1 protein, human; D052248:Nitric Oxide Synthase Type I