title: A steps/minute value for moderate intensity physical activity in adolescent females.
abstract: The number of steps/minute (i.e., cadence) that equates to moderate intensity in adolescents is not known. To that end, 31 adolescent females walked on a treadmill at 5 different speeds while wearing an ActivPAL accelerometer and oxygen uptake was recorded by indirect calorimetry. The relationship between metabolic equivalents (METs) and cadence was explored using 3 different analytical approaches. Cadence was a significant predictor of METs (r = .70; p < .001). Moderate intensity (3 METs) corresponded to 94 or 114 steps/minute based on the mixed model and ROC analysis, respectively. These two values, and a practical value of 100 steps/minute, were cross-validated on an independent sample of 33 adolescent females during over-ground walking at 3 speeds. The sensitivity and specificity of each value correctly identifying 3 METs were 98.5% and 87.2% for 94 steps/minute, 72.9% and 98.8 for 114 steps/minute and 96.5% and 95.7% for 100 steps/minute. Compromising on a single cadence of 100 steps/minute would be a practical value that approximates moderate intensity in adolescent females and can be used for physical activity interpretation and promotion.
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA, USA.
authors.forename: Deirdre M
authors.initials: DM
authors.lastname: Harrington
authors.forename: Kieran P
authors.initials: KP
authors.lastname: Dowd
authors.forename: Catrine
authors.initials: C
authors.lastname: Tudor-Locke
authors.forename: Alan E
authors.initials: AE
authors.lastname: Donnelly
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D002153:Calorimetry, Indirect; D005080:Exercise Test; D005260:Female; D006801:Humans; D007590:Jogging / Q000502:physiology; D055686:Metabolic Equivalent; D010101:Oxygen Consumption; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D016138:Walking / Q000502:physiology*