Swim-trained rats have greater bone mass, density, strength, and dynamics.
Hart, K. J., J. M. Shaw, E. Vajda, M. Hegsted, and S. C. Miller.
1Department of Exercise and Sport Science, 2Division of Radiobiology, and
3Department of Nutrition, University of Utah, Salt Lake City, Utah 84112; and 4School
of Human Ecology, Louisiana State University, Baton Rouge, Louisiana
APStracts 8:0338A, 2001.
Weight-bearing exercise is traditionally recommended for improving bone health in
postmenopausal women. Effects of swim exercise were studied as an alternative to
weight-bearing exercise in ovariectomized rats. Rats in a swim group (Sw, n = 8) swam
for 12 wk, 5 days/wk for 60 min per session. A control group (Con, n = 9) engaged in no
structured exercise. Femurs were analyzed for bone mineral density and for bone mineral
content by peripheral dual X-ray absorptiometry, biomechanical properties by three-point
bending (Instron), and bone structure and formation by histomorphometry. Food intake
did not differ among groups. Final body weights were significantly lower in Sw
compared with Con (P < 0.05). Swimmers had significantly greater femoral shaft bone
mineral density and content (P < 0.05) compared with Con. Femurs of the Sw group
had greater mechanical properties (P < 0.05) compared with Con. Histomorphometric
data was significantly better in the Sw group compared with Con after the 12-wk
intervention (P < 0.05). In conclusion, data from this study demonstrate some beneficial
effects of swim exercise on bone structure, turnover, and strength.
Received 17 November 2000; accepted in final form 1 June 2001
APS Manuscript Number A1115-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 29 June 2001