title: Neuromuscular electrical stimulation prevents muscle disuse atrophy during leg immobilization in humans.
abstract: OBJECTIVE
  Short periods of muscle disuse, due to illness or injury, result in substantial skeletal muscle atrophy. Recently, we have shown that a single session of neuromuscular electrical stimulation (NMES) increases muscle protein synthesis rates. The aim was to investigate the capacity for daily NMES to attenuate muscle atrophy during short-term muscle disuse.
  
  
  METHODS
  Twenty-four healthy, young (23 ± 1 year) males participated in the present study. Volunteers were subjected to 5 days of one-legged knee immobilization with (NMES; n = 12) or without (CON; n = 12) supervised NMES sessions (40-min sessions, twice daily). Two days prior to and immediately after the immobilization period, CT scans and single-leg one-repetition maximum (1RM) strength tests were performed to assess quadriceps muscle cross-sectional area (CSA) and leg muscle strength respectively. Furthermore, muscle biopsies were taken to assess muscle fibre CSA, satellite cell content and mRNA and protein expression of selected genes.
  
  
  RESULTS
  In CON, immobilization reduced quadriceps CSA by 3.5 ± 0.5% (P < 0.0001) and muscle strength by 9 ± 2% (P < 0.05). In contrast, no significant muscle loss was detected following immobilization in NMES although strength declined by 7 ± 3% (P < 0.05). Muscle MAFbx and MuRF1 mRNA expression increased following immobilization in CON (P < 0.001 and P = 0.07 respectively), whereas levels either declined (P < 0.01) or did not change in NMES, respectively. Immobilization led to an increase in muscle myostatin mRNA expression in CON (P < 0.05), but remained unchanged in NMES.
  
  
  CONCLUSIONS
  During short-term disuse, NMES represents an effective interventional strategy to prevent the loss of muscle mass, but it does not allow preservation of muscle strength. NMES during disuse may be of important clinical relevance in both health and disease.
authors.affiliation: NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University, Maastricht, the Netherlands.
authors.forename: M L
authors.initials: ML
authors.lastname: Dirks
authors.forename: B T
authors.initials: BT
authors.lastname: Wall
authors.forename: T
authors.initials: T
authors.lastname: Snijders
authors.forename: C L P
authors.initials: CL
authors.lastname: Ottenbros
authors.forename: L B
authors.initials: LB
authors.lastname: Verdijk
authors.forename: L J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D004599:Electric Stimulation Therapy / Q000379:methods*; D006801:Humans; D007719:Knee Joint; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D009133:Muscular Atrophy / Q000517:prevention & control*; D052097:Quadriceps Muscle / Q000378:metabolism / Q000473:pathology*; D012149:Restraint, Physical / Q000009:adverse effects*; D055815:Young Adult
keywords: disuse atrophy; immobilization; neuromuscular electrical stimulation; skeletal muscle