Premenarcheal gymnasts possess higher bone mineral density than controls.
OBJECTIVE
The purpose of this study was to examine bone mineral density (BMD), body composition, dietary intake, physical activity, and energy expenditure (EE) in premenarcheal gymnasts (N = 16; age = 10.5 +/- 1.5 yr) in comparison to age- (+/- 0.35 yr), height- (+/- 2.6 cm), and weight- (+/- 1.5 kg) matched controls (N = 16; age = 10.5 +/- 1.3 yr). It was hypothesized that premenarcheal gymnasts would have higher BMD, fat-free soft tissue (FFST) mass, physical activity, and EE, but lower fat mass, percent body fat, and dietary intake than controls.


METHODS
Dual energy x-ray absorptiometry was used to measure whole body, femur, and lumbar spine (L1-4) BMD, FFST, and fat mass. Three-day diet records were used to estimate mean daily dietary energy, macronutrient, and calcium intakes. Physical activity and EE were estimated by the Seven-Day Physical Activity Recall.


RESULTS
The BMD means of the gymnasts were significantly higher (P < 0.05) than controls at all sites, except whole body, as were lumbar spine and femoral neck bone mineral apparent densities, despite lower protein intake expressed per kg FFST mass. Fat mass was significantly lower in gymnasts versus controls (P < 0.01) as was percent body fat (P < 0.001). Very hard physical activity during weekdays (P < 0.0001) and estimated EE (P < 0.01) were significantly higher in gymnasts compared with controls.


CONCLUSIONS
Premenarcheal gymnasts have higher BMD than age-, height-, and weight-matched controls.
Nickols-Richardson
S M
SM
Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg 24061-0430, USA.
Modlesky
C M
CM
O'Connor
P J
PJ
Lewis
R D
RD
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D015519:Bone Density; D001842:Bone and Bones / Q000033:anatomy & histology; D002136:Calcium, Dietary / Q000008:administration & dosage; D016022:Case-Control Studies; D002648:Child; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005269:Femur / Q000033:anatomy & histology; D005272:Femur Neck / Q000033:anatomy & histology; D006173:Gymnastics / Q000502:physiology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology; D008572:Menarche / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology
D002136:Calcium, Dietary; D004044:Dietary Proteins