Human skeletal muscle structure and function preserved by vibration muscle exerc

[Guest guest]

Eur J Appl Physiol. 2006 Mar 28

Human skeletal muscle structure and function preserved by vibration

muscle exercise following 55 days of bed rest.

Blottner D, Salanova M, Puttmann B, Schiffl G, Felsenberg D, Buehring

B, Rittweger J.

Department of Vegetative Anatomy, Center of Space Medicine Berlin,

Neuromuscular Group, Charite University Medicine Berlin, Campus

lin, Arnimallee 22, 14195, Berlin, Germany,

dieter.blottner@....

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.