title: Swim-trained rats have greater bone mass, density, strength, and dynamics.
abstract: 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 dual energy 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 were 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.
authors.affiliation: Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Hart
authors.forename: J M
authors.initials: JM
authors.lastname: Shaw
authors.forename: E
authors.initials: E
authors.lastname: Vajda
authors.forename: M
authors.initials: M
authors.lastname: Hegsted
authors.forename: S C
authors.initials: SC
authors.lastname: Miller
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001696:Biomechanical Phenomena; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D001846:Bone Development / Q000502:physiology*; D004435:Eating / Q000502:physiology; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010052:Ovariectomy; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013550:Swimming / Q000502:physiology*