title: Low-volume resistance exercise attenuates the decline in strength and muscle mass associated with immobilization.
abstract: We determined the effectiveness of low-volume resistance exercise (EX) for the attenuation of loss of muscle mass and strength during leg immobilization. Men (N = 5) and women (N = 12, age 24 ± 5 years, body mass index 25.4 ± 3.6 kg/m(2)) were divided into two groups: exercise (EX; n = 12) and control (CON; n = 5). Subjects wore a knee brace on one leg that prevented weight bearing for 14 days. Resistance exercise (EX; 80% of maximal) was performed by the immobilized limb every other day. Immobilization induced a significant reduction (P < 0.05) in muscle fiber and thigh cross-sectional area (CSA), isometric knee extensor, and plantarflexor strength in the CON (P < 0.01) but not in the EX group. There were significant losses in triceps surae CSA in the CON and EX groups (P < 0.05), but the losses were greater in CON subjects (P < 0.01). A minimal volume (140 contractions in 14 days) of resistive exercise is an effective countermeasure against immobilization-induced atrophy of the quadriceps femoris but is only partially effective for the triceps surae.
authors.affiliation: Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada.
authors.forename: Bryan R
authors.initials: BR
authors.lastname: Oates
authors.forename: Elisa I
authors.initials: EI
authors.lastname: Glover
authors.forename: Daniel W
authors.initials: DW
authors.lastname: West
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Fry
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tarnopolsky
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Phillips
mesh_terms: D019412:Anatomy, Cross-Sectional; D001284:Atrophy; D004032:Diet; D004576:Electromyography; D005260:Female; D006801:Humans; D007103:Immobilization / Q000009:adverse effects*; D007866:Leg; D008279:Magnetic Resonance Imaging; D008297:Male; D009046:Motor Neurons; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology*; D013848:Thigh; D013997:Time Factors; D019415:Torque; D014891:Weight Lifting