title: Relationships between Isometric Muscle Strength, Gait Parameters, and Gross Motor Function Measure in Patients with Cerebral Palsy.
abstract: OBJECTIVE
  This study investigated the correlation between isometric muscle strength, gross motor function, and gait parameters in patients with spastic cerebral palsy and to find which muscle groups play an important role for gait pattern in a flexed knee gait.
  
  
  METHODS
  Twenty-four ambulatory patients (mean age, 10.0 years) with spastic cerebral palsy who were scheduled for single event multilevel surgery, including distal hamstring lengthening, were included. Preoperatively, peak isometric muscle strength was measured for the hip flexor, hip extensor, knee flexor, and knee extensor muscle groups using a handheld dynamometer, and three-dimensional (3D) gait analysis and gross motor function measure (GMFM) scoring were also performed. Correlations between peak isometric strength and GMFM, gait kinematics, and gait kinetics were analyzed.
  
  
  RESULTS
  Peak isometric muscle strength of all muscle groups was not related to the GMFM score and the gross motor function classification system level. Peak isometric strength of the hip extensor and knee extensor was significantly correlated with the mean pelvic tilt (r=-0.588, p=0.003 and r=-0.436, p=0.033) and maximum pelvic obliquity (r=-0.450, p=0.031 and r=-0.419, p=0.041). There were significant correlations between peak isometric strength of the knee extensor and peak knee extensor moment in early stance (r=0.467, p=0.021) and in terminal stance (r=0.416, p=0.043).
  
  
  CONCLUSIONS
  There is no correlation between muscle strength and gross motor function. However, this study showed that muscle strength, especially of the extensor muscle group of the hip and knee joints, might play a critical role in gait by stabilizing pelvic motion and decreasing energy consumption in a flexed knee gait.
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Hyung Ik
authors.initials: HI
authors.lastname: Shin
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ki Hyuk
authors.initials: KH
authors.lastname: Sung
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Chin Youb
authors.initials: CY
authors.lastname: Chung
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyoung Min
authors.initials: KM
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Ewha Womans University Mokdong Hospital, Seoul, Korea.
authors.forename: Seung Yeol
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Sungkyunkwan University Samsung Changwon Hospital, Changwon, Korea.
authors.forename: In Hyeok
authors.initials: IH
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea. pmsmed@gmail.com.
authors.forename: Moon Seok
authors.initials: MS
authors.lastname: Park
mesh_terms: D001696:Biomechanical Phenomena; D002547:Cerebral Palsy / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007717:Knee / Q000503:physiopathology; D007719:Knee Joint / Q000601:surgery; D008297:Male; D009128:Muscle Spasticity / Q000209:etiology / Q000503:physiopathology; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010388:Pelvis; D004856:Postural Balance / Q000502:physiology; D058971:Tenotomy
keywords: Muscle strength; cerebral palsy; gait parameter; gross motor function