title: Steps per day, peak cadence, body mass index, and age in community-dwelling older adults.
abstract: OBJECTIVE
  The relationships between demographic and anthropometric indices and older adults' quantity and quality of ambulatory activity are uncertain. We examined the relationship between accelerometer-determined steps per day (quantity) and peak 30-min cadence (quality; mean steps per minute recorded for the 30 highest, but not necessarily consecutive, minutes in a day) in community-dwelling older adults relative to sex, age, and body mass index (BMI).
  
  
  METHODS
  Minute-by-minute accelerometer-determined step data for 5.8 ± 0.9 d were available for 100 women and 43 men (58-92 yr, BMI = 26.6 ± 4.2 kg·m). Sex-specific Spearman correlations compared steps per day with peak 30-min cadence and both to age and BMI. Partial correlations were computed controlling for 1) age, 2) BMI, 3) steps per day and age, or 4) steps per day and BMI. Significance was set at P < 0.05.
  
  
  RESULTS
  Participants averaged 5605 ± 2588 steps per day with a peak 30-min cadence of 63.6 ± 24.6 steps per minute (mean ± SD). Correlations between these two variables were r = 0.883 (women) and r = 0.820 (men). Steps per day and peak 30-min cadence were significantly correlated with age (r = -0.442 and r = -0.327, respectively) and BMI (r = -0.248 and r = -0.286, respectively) in women. For men, steps per day and peak 30-min cadence were only significantly related to age (r = -0.665 and r = -0.381, respectively). Controlling for steps per day weakened all relationships with peak 30-min cadence to a point of nonsignificance with one exception: the partial correlation of age with peak 30-min cadence was weakened but remained significant (r = 0.335) after controlling for steps per day and BMI in men.
  
  
  CONCLUSIONS
  The usefulness of peak 30-min cadence beyond steps per day is not apparent, at least in terms of sex, age, and BMI, and needs to be evaluated in larger and more diverse samples and against other parameters of interest, including those more theoretically linked to intensity of effort.
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Schuna
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brouillette
authors.forename: Heather C
authors.initials: HC
authors.lastname: Foil
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Fontenot
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Keller
authors.forename: Catrine
authors.initials: C
authors.lastname: Tudor-Locke
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity