title: Gait propulsion in patients with facioscapulohumeral muscular dystrophy and ankle plantarflexor weakness.
abstract: Facioscapulohumeral muscular dystrophy is a slowly progressive hereditary disorder resulting in fatty infiltration of eventually most skeletal muscles. Weakness of trunk and leg muscles causes problems with postural balance and gait, and is associated with an increased fall risk. Although drop foot and related tripping are common problems in FSHD, gait impairments are poorly documented. The effect of ankle plantarflexor involvement on gait propulsion has never been addressed. In addition to ankle plantarflexion, gait propulsion is generated through hip flexion and hip extension. Compensatory shifts between these propulsion sources occur when specific muscles are affected. Such a shift may be expected in patients with FSHD since the calves may show early fatty infiltration, whereas iliopsoas and gluteus maximus muscles are often spared for a longer time. In the current study, magnetic resonance imaging was used to assess the percentage of unaffected calf, iliopsoas and gluteus maximus muscles. Joint powers were analyzed in 10 patients with FSHD at comfortable and maximum walking speed to determine the contribution of ankle plantarflexor, hip flexor and hip extensor power to propulsion. Associations between muscle morphology, power generation and gait speed were assessed. Based on multivariate regression analysis, ankle plantarflexor power was the only factor that uniquely contributed to the explained variance of comfortable (R(2)=80%) and maximum (R(2)=86%) walking speed. Although the iliopsoas muscles were largely unaffected, they appeared to be sub-maximally recruited. This submaximal recruitment may be related to poor trunk stability, resulting in a disproportionate effect of calf muscle affliction on gait speed in patients with FSHD.
authors: Department of Rehabilitation, Radboud University Medical Centre, Dept. 898, P.O. Box 1901, 6500 HB Nijmegen, The Netherlands.
authors: N H M
authors: NH
authors: Rijken
authors: Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors: B G M
authors: BG
authors: van Engelen
authors: Department of Radiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors: J W J
authors: JW
authors: de Rooy
authors: Department of Rehabilitation, Radboud University Medical Centre, Dept. 898, P.O. Box 1901, 6500 HB Nijmegen, The Netherlands.
authors: V
authors: V
authors: Weerdesteyn
authors: Department of Rehabilitation, Radboud University Medical Centre, Dept. 898, P.O. Box 1901, 6500 HB Nijmegen, The Netherlands. Electronic address: Sander.Geurts@radboudumc.nl.
authors: A C H
authors: AC
authors: Geurts
mesh_terms: D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000503:physiopathology*; D004856:Postural Balance; D016059:Range of Motion, Articular / Q000502:physiology; D013639:Tarsal Bones / Q000503:physiopathology; D016138:Walking / Q000502:physiology
keywords: Gait; Kinetics; Neuromuscular disorders