title: Effect of prolonged bed rest on the anterior hip muscles.
abstract: Prolonged bed rest and inactivity is known to cause muscular atrophy with previous research indicating that muscles involved in joint stabilisation are more susceptible. The anterior hip muscles are important for hip joint function and stability but little is known about the effects of prolonged inactivity on their function. This study investigated the effect of prolonged bed rest on the size of the anterior hip muscles and their pattern of recovery. The effect of resistive vibration exercise (RVE) as a countermeasure to muscle atrophy was also investigated. 12 male participants, randomly assigned to either a control or an exercise group, underwent 8 weeks of bed rest with 6 months follow-up. Changes in muscle cross-sectional area (CSA) of the iliacus, psoas, iliopsoas, sartorius and rectus femoris muscles were measured by magnetic resonance imaging at regular intervals during bed rest and recovery phases. CSAs of iliopsoas and sartorius decreased at the hip joint (p<0.05) during bed rest but iliacus, psoas, and rectus femoris CSAs were unchanged (p>0.05). No significant difference was found between the two groups for all muscles (all p>0.1), suggesting inefficacy of the countermeasure in this sample. These findings suggest that prolonged bed rest can result in the atrophy of specific muscles across the hip joint which may affect its stability and function.
authors.affiliation: The University of Queensland, School of Health and Rehabilitation Sciences, Division of Physiotherapy, St Lucia, Brisbane, Qld 4072, Australia. dilani.mendis@gmail.com
authors.forename: M
authors.initials: M
authors.lastname: Dilani Mendis
authors.forename: Julie A
authors.initials: JA
authors.lastname: Hides
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wilson
authors.forename: Alison
authors.initials: A
authors.lastname: Grimaldi
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Belavý
authors.forename: Warren
authors.initials: W
authors.lastname: Stanton
authors.forename: Dieter
authors.initials: D
authors.lastname: Felsenberg
authors.forename: Joern
authors.initials: J
authors.lastname: Rittweger
authors.forename: Carolyn
authors.initials: C
authors.lastname: Richardson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001510:Bed Rest / Q000009:adverse effects*; D006615:Hip / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009133:Muscular Atrophy / Q000503:physiopathology*