title: Determination of step rate thresholds corresponding to physical activity intensity classifications in adults.
abstract: BACKGROUND
  Current recommendations call for adults to be physically active at moderate and/or vigorous intensities. Given the popularity of walking and running, the use of step rates may provide a practical and inexpensive means to evaluate ambulatory intensity. Thus, the purpose of this study was to identify step rate thresholds that correspond to various intensity classifications.
  
  
  METHODS
  Oxygen consumption was measured at rest and during 10 minute treadmill walking and running trials at 6 standardized speeds (54, 80, 107, 134, 161, and 188 m·min⁻¹) in 9 men and 10 women (28.8 ± 6.8 yrs). Two observers counted the participants' steps at each treadmill speed. Linear and nonlinear regression analyses were used to develop prediction equations to ascertain step rate thresholds at various intensities.
  
  
  RESULTS
  Nonlinear regression analysis of the metabolic cost versus step rates across all treadmill speeds yielded the highest R² values for men (R² = .91) and women (R² = .79). For men, the nonlinear analysis yielded 94 and 125 step·min⁻¹ for moderate and vigorous intensities, respectively. For women, 99 and 135 step·min⁻¹ corresponded with moderate and vigorous intensities, respectively.
  
  
  CONCLUSIONS
  Promoting a step rate of 100 step·min⁻¹ may serve as a practical public health recommendation to exercise at moderate intensity.
authors.affiliation: Dept of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Abel
authors.forename: James
authors.initials: J
authors.lastname: Hannon
authors.forename: David
authors.initials: D
authors.lastname: Mullineaux
authors.forename: Aaron
authors.initials: A
authors.lastname: Beighle
mesh_terms: D061725:Accelerometry; D000328:Adult; D001481:Basal Metabolism / Q000502:physiology*; D001823:Body Composition; D015992:Body Mass Index; D002153:Calorimetry, Indirect / Q000379:methods; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D055686:Metabolic Equivalent / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology*; D012044:Regression Analysis; D012420:Running / Q000502:physiology*; D016138:Walking / Q000502:physiology*