title: Medial gastrocnemius specific force of adult men with spastic cerebral palsy.
abstract: Muscle weakness determines functional impairment in spastic cerebral palsy (SCP). Measurement of specific force (SF) allows for strength comparison with unimpaired populations (controls) accounting for neural (activation and coactivation), architectural (fascicle length and pennation angle), and structural differences (moment arm length).
  
  
  
  Medial gastrocnemius (MG) SF (and its determinants) was assessed in both paretic and non-paretic legs of 11 men with SCP and 11 age-matched controls during plantarflexion maximal voluntary isometric contraction (MVIC).
  
  
  
  SCP fascicles were 28% longer than control fascicles (P < 0.05). Pennation angle of SCP patients was 41% smaller than in controls. The physiological cross-sectional area of SCP MG patients was 47% smaller than in controls (P < 0.05). There was no difference in SF between controls and SCP patients.
  
  
  
  Weakness in SCP is primarily attributable to deficits in agonist activation and muscle size; consequently, SF measured in the MG is similar between SCP and controls. Muscle Nerve 56: 298-306, 2017.
authors.affiliation: Health Exercise and Active Living Research Centre, Department of Exercise and Sport Science, Manchester Metropolitan University, Crewe Green Road, Cheshire, CW1 5DU, UK.
authors.forename: Ayser W
authors.initials: AW
authors.lastname: Hussain
authors.affiliation: Health Exercise and Active Living Research Centre, Department of Exercise and Sport Science, Manchester Metropolitan University, Crewe Green Road, Cheshire, CW1 5DU, UK.
authors.forename: Gladys L
authors.initials: GL
authors.lastname: Onambélé
authors.affiliation: Health Exercise and Active Living Research Centre, Department of Exercise and Sport Science, Manchester Metropolitan University, Crewe Green Road, Cheshire, CW1 5DU, UK.
authors.forename: Alun G
authors.initials: AG
authors.lastname: Williams
authors.affiliation: Health Exercise and Active Living Research Centre, Department of Exercise and Sport Science, Manchester Metropolitan University, Crewe Green Road, Cheshire, CW1 5DU, UK.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Morse
mesh_terms: D000125:Achilles Tendon / Q000294:innervation / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D000843:Ankle Joint; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000150:complications* / Q000473:pathology; D004558:Electric Stimulation; D004576:Electromyography; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology; D018908:Muscle Weakness / Q000209:etiology* / Q000473:pathology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016059:Range of Motion, Articular; D018709:Statistics, Nonparametric; D019415:Torque; D055815:Young Adult
keywords: PCSA; cerebral palsy; medial gastrocnemius; muscle architecture; specific force; ultrasonography