The effect of swimming on bone modeling and composition in young adult rats

Abstract

The purpose of this study was to investigate the adaptability of long bones of young adult rats to the stress of chronic aquatic exercise. Twenty-eight female Sabra rats (12 weeks old) were randomly assigned to two groups and treatments: exercise (14 rats) and sedentary control (14 rats) matched for age and weight. Exercised animals were trained to swim in a water bath (35 degrees +/- 1 degree C, 1 hour daily 5 times a week) for 12 weeks loaded with lead weights on their tails (2% of their body weight) (BW). At the end of the training period following blood sampling for alkaline phosphatase, all rats were sacrificed and the humeri and tibiae bones were removed for the following measurements: bone morphometry, bone water compartmentalization, bone density (BD), bone mineral content (BMC), and bone ions content (Ca, Pi, Mg, Zn). The results indicate that exercise did not significantly affect the animals' body weight, bone volume, or length and diameters. However, bone hydration properties, BD, bone mass, and mineralization revealed significant differences between swim-trained rats and controls (P less than 0.05). Longitudinal (R1) measurement was higher by 43% for both humerus and tibia, and Transverse (R2) relaxation rates of hydrogen proton were higher by 117 and 76% for humerus and tibia, respectively; fraction of bound water was higher by 36 and 46% for humerus and tibia, respectively. BD, bone weight, and ash were higher by 13%. BMC and bone ions content were higher by 10%, and alkaline phosphatase was higher by 67%.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced Bone Mass Accrual in Swim-Trained Prepubertal Mice

“…In this study, bone properties were not different if the rats were loaded with an additional 1% body weight attached to the tail, or if they swam load-free (36). Adding 2% of body weight in a study by the same research group (35) resulted in similar increases in BMD and BMC at the humerus. Snyder et al (34) reported increased BMC and bone length at the humerus of rapidly growing rats that trained for 2 hId j1 , 5 dIwk j1 , for 10 wk with an added 2% body weight.…”

“…In contrast to the low BMD observed in human swimmers, there have been recent reports of improved bone properties for swimming female rats (33)(34)(35)(36)39). In a study by Swissa-Sivan et al (36), 5-wk-old rats swam for 1 hId j1 , 5 dIwk j1 , for 20 wk and reported increased bone length, volume, and bone mineral content (BMC) at the humerus.…”

High-Impact Drop Exercise Alters Mechanical Properties in Osteopenic Bone

“…Exercises can maintain and increase BMD [14][15][16][17][18] , bone material properties [19][20][21] , and bone formation, and reduce bone resorption [22][23][24][25] . Our investigation confirmed the osteogenic effects of high impact training, and its beneficial effect on bones in ovariectomized estrogen-deficient rats.…”

Skeletal site-specific effects of endurance running on structure and strength of tibia, lumbar vertebrae, and mandible in male Sprague–Dawley rats

“…Our rationale for investigating the potential systemic effects of exercise is based on the finding that non-weight-bearing swimming exercise has positive effects on bone (Swissa-Siva et al 1990;Synder et al 1992;Huang et al 2003) and that running exercise prevented not only tibia bone loss but also mandible bone loss in an ovariectomized rat model (Sakakura et al 2001). However, there are limited data on the systemic effects of exercise on bone.…”