title: Reliability and Validity of Objective Measures of Physical Activity in Youth With Cerebral Palsy Who Are Ambulatory.
abstract: BACKGROUND
  Physical therapy for youth with cerebral palsy (CP) who are ambulatory includes interventions to increase functional mobility and participation in physical activity (PA). Thus, reliable and valid measures are needed to document PA in youth with CP.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the inter-instrument reliability and concurrent validity of 3 accelerometer-based motion sensors with indirect calorimetry as the criterion for measuring PA intensity in youth with CP.
  
  
  METHODS
  Fifty-seven youth with CP (mean age=12.5 years, SD=3.3; 51% female; 49.1% with spastic hemiplegia) participated. Inclusion criteria were: aged 6 to 20 years, ambulatory, Gross Motor Function Classification System (GMFCS) levels I through III, able to follow directions, and able to complete the full PA protocol. Protocol activities included standardized activity trials with increasing PA intensity (resting, writing, household chores, active video games, and walking at 3 self-selected speeds), as measured by weight-relative oxygen uptake (in mL/kg/min). During each trial, participants wore bilateral accelerometers on the upper arms, waist/hip, and ankle and a portable indirect calorimeter. Intraclass coefficient correlations (ICCs) were calculated to evaluate inter-instrument reliability (left-to-right accelerometer placement). Spearman correlations were used to examine concurrent validity between accelerometer output (activity and step counts) and indirect calorimetry. Friedman analyses of variance with post hoc pair-wise analyses were conducted to examine the validity of accelerometers to discriminate PA intensity across activity trials.
  
  
  RESULTS
  All accelerometers exhibited excellent inter-instrument reliability (ICC=.94-.99) and good concurrent validity (rho=.70-.85). All accelerometers discriminated PA intensity across most activity trials.
  
  
  CONCLUSIONS
  This PA protocol consisted of controlled activity trials.
  
  
  CONCLUSIONS
  Accelerometers provide valid and reliable measures of PA intensity among youth with CP.
authors.affiliation: M.E. O'Neil, PT, PhD, MPH, Department of Physical Therapy and Rehabilitation Sciences, Drexel University, 1601 Cherry St, Mail Stop 7502, Philadelphia, PA 19102 (USA). moneil@drexel.edu.
authors.forename: Margaret E
authors.initials: ME
authors.lastname: O'Neil
authors.affiliation: M. Fragala-Pinkham, PT, DPT, MS, Research Center, Franciscan Hospital for Children, Brighton, Massachusetts.
authors.forename: Maria
authors.initials: M
authors.lastname: Fragala-Pinkham
authors.affiliation: N. Lennon, MS, PT, Gait Analysis Laboratory, Alfred I. duPont Hospital for Children, Wilmington, Delaware.
authors.forename: Nancy
authors.initials: N
authors.lastname: Lennon
authors.affiliation: A. George, BS, Gait Analysis Laboratory, Alfred I. duPont Hospital for Children.
authors.forename: Ameeka
authors.initials: A
authors.lastname: George
authors.affiliation: J. Forman, MD, Department of Pediatric Rehabilitation Medicine, Franciscan Hospital for Children.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Forman
authors.affiliation: S.G. Trost, PhD, School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Australia.
authors.forename: Stewart G
authors.initials: SG
authors.lastname: Trost
mesh_terms: D061725:Accelerometry / Q000295:instrumentation*; D000203:Activities of Daily Living; D000293:Adolescent; D002547:Cerebral Palsy / Q000503:physiopathology* / Q000628:therapy*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D026741:Physical Therapy Modalities; D015203:Reproducibility of Results; D055815:Young Adult