Relationship of strength, weight, age, and function in ambulatory children with cerebral palsy

Jon Davids, Donna J. Oeffinger, Anita M. Bagley, Mitell Sison-Williamson, George Gorton

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Background: The natural history of ambulatory function in individuals with cerebral palsy (CP) consists of deterioration over time. This is thought to be due, in part, to the relationship between strength and weight, which is postulated to become less favorable for ambulation with age. Methods: The study design was prospective, case series of 255 subjects, aged 8 to 19 years, with diplegic type of CP. The data analyzed for the study were cross-sectional. Linear regression was used to predict the rate of change in lower extremity muscle strength, body weight, and strength normalized to weight (STRN) with age. The cohort was analyzed as a whole and in groups based on functional impairment as reflected by Gross Motor Function Classification System (GMFCS) level. Results: Strength increased significantly over time for the entire cohort at a rate of 20.83 N/y (P=0.01). Weight increased significantly over time for the entire cohort at a rate of 3.5 kg/y (P<0.0001). Lower extremity STR-N decreased significantly over time for the entire cohort at a rate of 0.84 N/kg/y (P<0.0001). The rate of decline in STR-N (N/kg/y) was comparable among age groups of the children in the study group. There were no significant differences in the rate of decline of STR-N (N/kg/y) among GMFCS levels. There was a 90% chance of independent ambulation (GMFCS levels I and II) when STR-N was 21 N/kg (49% predicted relative to typically developing children). Discussion: The results of this study support the longstanding clinically based observation that STR-N decreases with age in children with CP. This decrease occurs throughout the growing years, and across GMFCS levels I to III. Independent ambulation becomes less likely as STR-N decreases. This information can be used to support the rationale, and provide guidelines, for a range of interventions designed to promote ambulation in children with CP.

Original languageEnglish (US)
Pages (from-to)523-529
Number of pages7
JournalJournal of Pediatric Orthopaedics
Volume35
Issue number5
StatePublished - 2015
Externally publishedYes

Keywords

  • Age
  • Ambulation
  • Cerebral palsy
  • Strength
  • Weight

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Orthopedics and Sports Medicine

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    Davids, J., Oeffinger, D. J., Bagley, A. M., Sison-Williamson, M., & Gorton, G. (2015). Relationship of strength, weight, age, and function in ambulatory children with cerebral palsy. Journal of Pediatric Orthopaedics, 35(5), 523-529.