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Body Composition by DEXA and Its Association With Physical Fitness in 140 Conscripts


Medicine & Science in Sports & Exercise: December 2007 - Volume 39 - Issue 12 - p 2242-2247
doi: 10.1249/mss.0b013e318155a813
APPLIED SCIENCES: Physical Fitness and Performance

Purpose: The aim of the study was to determine the body composition of healthy young men and to investigate whether there exists an association between body composition and physical fitness.

Materials and Methods: A prospective cohort study of 140 healthy male conscripts (mean age 19.8yr, SD 1.0 yr) was conducted. We examined subject characteristics, aerobic performance, and muscle strength, and we assessed body composition using dual-energy x-ray absorptiometry (DEXA). The association between total body composition and lower-limb composition and physical performance was investigated by linear regression.

Results: The mean body mass index (BMI) of the subjects was 24.6 kg·m−2 (SD 4.7). Their mean bone mineral density (BMD) was 1.3 g·cm−2 (SD 0.1), fat percentage (fat%) 22.6 (SD 9.7), lean mass 57.6 kg (SD 7.0), and bone mass 3.2 kg (SD 0.4) at the beginning of the military service. Fat percentage was significantly associated with 12-min running performance (P < 0.001), and a significant relationship was found between muscle strength and fat% (P< 0.001), and increasing BMD (P < 0.001), in multivariate analysis. Lean mass was not associated with physical performance.

Conclusions: DEXA measurement of the proportion of body fat is a useful tool to indirectly assess running performance and muscle strength in Finnish male conscripts. Increased fat mass and fat percentage were strong predictors of poorer physical fitness. Moreover, the relationship between muscle strength and BMD was confirmed. However, muscle mass did not predict muscle strength in our sample.

1Centre for Military Medicine, Lahti, FINLAND; 2Department of Radiology, ORTON Orthopaedic Hospital, Helsinki, FINLAND; and 3Centre for Military Medicine, Helsinki, FINLAND

Address for correspondence: Ville Mattila, M.D., Ph.D., Tommilanraitti 1a, 36270 Kangasala, Finland; E-mail:

Submitted for publication March 2007.

Accepted for publication July 2007.

©2007The American College of Sports Medicine