The Change of Bone Mineral Content and Food Efficiency by Prolonged Swimming Exercise in Rats |
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Abstract |
This study was designed to clarify the change of bone mineral content (BMC) and food efficiency by prolonged swimming exercise in rats. Fourteen male Wister-Kyoto (WKY) rats at the age of 5-weeks old were randomly divided into two groups: control group (C group; n = 7) and swimming exercise group (S group; n = 7). All rats were allowed free access to food (AIN-93G, Ca content: 1.2495%) and tap water. After two weeks of adaptational period, the S group exercised in the pool with 60min/day, 5day/week for 12 weeks. Total body (t)-BMD and t-BMC were measured three times at initial, middle and end of the experimental period by dual energy X-ray absorptiometry (Lunar DPXL, USA). At the end of experimental period, rats were sacrificed and femur bones were removed for measure of femoral (f)-BMD and f-Ca content. f-weight, f-BMD, f-BMC and f-Ca content of S group were approximately 4.0% (p < .01) , 5.3% (p < .01), 12.3% (p < .001) and 5.7% (p < .001), respectively, higher than those of C group at the end of exercise period. t-BMD and t-BMC of S group were also approximately 1.8% (p < .05) and 16.1% (p < .05), respectively, higher than those of C group at the end of exercise period while body weight gain of S group were approximately 28.3% (p < .05) lower than that of C group during 6 weeks from 13 weeks to 19 weeks old. Ca efficiency to t-BMC and t-BMC gain of S group were approximately 26.3% (p < .01) and 43.8% (p < .05), respectively, higher than those of C group during 6 weeks from 7 weeks to 13 weeks old. These results suggest that swimming exercise might improve Ca efficiency to bone gain results in increase of BMD and BMC, and the swimming exercise in a growth period has more beneficial effects on improvement of bone mass with inhibition of gain in body weight. |
Key Words:
Swimming exercise, food efficiency, BMD, BMC, Rat |
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