title: Seven-year stability of physical activity and musculoskeletal fitness in the Canadian population.
abstract: BACKGROUND
  Knowledge of population patterns of physical activity levels and musculoskeletal fitness are important in the selection of appropriate target groups for public health interventions.
  
  
  OBJECTIVE
  To examine the stability of physical activity levels and musculoskeletal fitness in the Canadian population.
  
  
  METHODS
  The sample included 951 male and 958 female subjects, aged 11-69 yr, for whom the appropriate measurements were available in the 1981 Canada Fitness Survey and its 7-yr follow-up, the Campbell's Survey. Participants were divided into 2-yr age groups in childhood (11-18 yr) and 10-yr age groups in adulthood (19-69 yr). Measures of physical activity were estimated activity energy expenditure (AEE) and time spent on activity, whereas indicators of musculoskeletal fitness consisted of sit-ups, push-ups, grip strength, and sit-and-reach (trunk flexibility).
  
  
  RESULTS
  7-yr inter-age correlations ranged from -0.08 to 0.39 for AEE, -0.10 to 0.33 for time on activity, 0.42 to 0.80 for sit-ups, -0.07 to 0.73 for push-ups, 0.44 to 0.82 for grip strength, and 0.47 to 0.85 for sit-and-reach. In general, significant tracking correlations for physical activity levels were limited to adulthood, whereas significant tracking of musculoskeletal fitness was observed at all ages for all indicators except push-ups. Male subjects exhibited greater stability in push-ups than female subjects. The average percentage of participants remaining in the lower and upper quintiles of the distribution over 7 yr was greater for musculoskeletal fitness (36-68%) than for physical activity level (30-34%).
  
  
  CONCLUSIONS
  Physical activity level is not a very stable characteristic in the Canadian population; however, indicators of musculoskeletal fitness are moderately stable over 7 yr.
authors.affiliation: School of Kinesiology and Health Science, York University, North York, Ontario, Canada.
authors.forename: M D
authors.initials: MD
authors.lastname: Fortier
authors.forename: P T
authors.initials: PT
authors.lastname: Katzmarzyk
authors.forename: R M
authors.initials: RM
authors.lastname: Malina
authors.forename: C
authors.initials: C
authors.lastname: Bouchard
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002170:Canada / Q000453:epidemiology; D002648:Child; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D018737:Hand Strength; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D010807:Physical Endurance; D010809:Physical Fitness; D011159:Population Surveillance; D017678:Sex Distribution; D013223:Statistics as Topic; D013997:Time Factors