Relationships among fitness, body composition, and physical activity

Timothy G. Lohman, Kimberly Ring, Karin Pfeiffer, Sarah Camhi, Elva Arredondo, Charlotte Pratt, Russ Pate, Larry S. Webber

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Purpose: This study was designed to examine the associations of physical activity and body composition with cardiorespiratory fitness in eighth grade girls. Methods: A random sample of 1440 eighth grade girls at 36 schools participated in this cross-sectional investigation, which represented an ethnically and geographically diverse group. Cardiorespiratory fitness was assessed using a modified physical work capacity test on a cycle ergometer that predicted workload at a heart rate of 170 beatsmin -1. Physical activity was assessed over 6 d in each girl using an accelerometer and body composition was estimated from body mass index and triceps skinfolds using a previously validated equation. Pearson correlations and multiple regression analyses were used to determine the relationships among fitness, physical activity, and body composition. Results: Significant linear relationships among cardiorespiratory fitness, body composition, and physical activity were found. The combination of fat and fat-free mass along with racial group and a race by fat-free-mass interaction accounted for 18% (R 2) of the variation in physical fitness. Adding moderate-to-vigorous physical activity to the regression model increased the R 2 to 22%. Black girls had somewhat lower fitness levels (P < 0.05) especially at higher levels of fat and fat-free mass than other racial/ethnic groups. Conclusions: Physical activity, fat-free mass, and the interaction between fat-free mass and racial group are significantly associated with cardiorespiratory fitness in adolescent girls.

Original languageEnglish (US)
Pages (from-to)1163-1170
Number of pages8
JournalMedicine and Science in Sports and Exercise
Issue number6
StatePublished - 2008


  • Accelerometry
  • Adolescent
  • Fatness
  • Physical fitness
  • Race/ethnicity

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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