title: Energy demands of walking in persons with postpoliomyelitis syndrome: relationship with muscle strength and reproducibility.
abstract: OBJECTIVE
  To describe the energy demands of walking in subjects with postpoliomyelitis syndrome (PPS) in comparison with the demands in healthy subjects, and to assess the reproducibility of walking energy measurements.
  
  
  METHODS
  Four repeated measurements with a 1-week interval between each measurement.
  
  
  METHODS
  Outpatient clinic of a university hospital.
  
  
  METHODS
  Fourteen subjects with PPS and 14 age- and sex-matched healthy subjects.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Walking speed and energy cost of walking. The correlation parameter was lower-extremity muscle strength sum (MSS). The reproducibility parameters were standard error (SE) of measurement and smallest detectable difference (SDD).
  
  
  RESULTS
  Walking speed in subjects with PPS (61.8 m/min) was significantly lower (-28%) and energy cost (4.8 J.kg(-1).m(-1)) was significantly higher (40%) than in healthy subjects. MSS correlated strongly with energy cost (r=-.84, P=.000), explaining 71% of the variance. The SE of measurement of energy cost measurements ranged between 1.7% and 3.4% for PPS subjects and between 1.2% and 2.4% for healthy subjects. The SDD ranged between 4.6% and 9.4% for PPS subjects and between 3.3% and 6.6% for healthy subjects, depending on the number of repeated measurements that were considered.
  
  
  CONCLUSIONS
  Energy cost of walking in subjects with PPS is strongly related to the extent of muscle weakness in the lower extremities. Although variability was greater for PPS subjects than for healthy subjects, reproducibility of energy cost measurements was high. Therefore, metabolic assessment of energy cost of walking is a sensitive tool that can reveal clinically relevant changes even in the condition of a person with PPS.
authors.affiliation: Department of Rehabilitation Medicine, VU University Medical Center, Amsterdam, The Netherlands. m.brehm@vumc.nl
authors.forename: Merel-Anne
authors.initials: MA
authors.lastname: Brehm
authors.forename: Frans
authors.initials: F
authors.lastname: Nollet
authors.forename: Jaap
authors.initials: J
authors.lastname: Harlaar
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D001784:Blood Gas Analysis; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D026741:Physical Therapy Modalities; D016262:Postpoliomyelitis Syndrome / Q000175:diagnosis* / Q000534:rehabilitation*; D011336:Probability; D012016:Reference Values; D015203:Reproducibility of Results; D018570:Risk Assessment; D012720:Severity of Illness Index; D016138:Walking / Q000502:physiology*