For adolescent girls, sports such as soccer—which combines weight-bearing exercise with repetitive impact from running and jumping—have the greatest effect in increasing bone density, thus reducing the lifelong risk of osteoporosis, reports a study in the current issue of the journal Pediatric Physical Therapy.
"Beyond the basic premise that kids need exercise, our study suggests that weight-bearing exercise with skeletal impact needs to be promoted during youth to preserve future bone health," comments James W. Bellew, P.T., Ed.D., of Louisiana State University, Shreveport.
Dr. Bellew and coauthor Laura Gehrig, M.D., compared bone mineral density (BMD) in three groups of adolescent female athletes: 29 swimmers, 16 soccer players, and 19 weightlifters. Bone mineral density is a standard measure of bone strength, used in the diagnosis and monitoring of osteoporosis.
Of the three groups, the soccer players had the highest BMD levels. Bone density was somewhat higher in weightlifters than in swimmers, although the difference was not significant.
The differences in BMD reflect differences in the characteristics of the three sports. Soccer and weightlifting are "weight-bearing" activities—the extra load placed on the skeleton promotes bone development. In contrast, swimming is a "non-weight-bearing" activity, because the body's weight is supported by the water.
In addition, soccer places repetitive impact on the skeleton, further promoting bone development. In association with this extra stimulus, the soccer players in the study had average BMD values higher than the normal values for adult women—even though the girls weren't yet fully mature. Weightlifters had BMD values similar to those of adult women, while BMD in swimmers was below adult norms.
Because there is no known cure for osteoporosis, effective approaches to prevention are critical. Previous studies have shown that sports and physical activity lead to increases in bone density. This is especially important in adolescence, when bone growth is most robust. "Especially with the explosion in passive, electronic home entertainment, efforts to promote physical activity in young people provide a unique opportunity to build bone strength now, thus reducing the risk of serious bone disease later in life," says Dr. Bellew.
The greatest gains in bone density—and the greatest reductions in osteoporosis risk—are likely to be produced by sports that combine weight-bearing with repetitive impact loading, according to Dr. Bellew. "Like other sports that involve a lot of running and jumping, soccer is definitely a good sport to consider for building bone strength. Lacrosse and field hockey are other good examples of sports that place a continuous load on the skeleton."
Although it does less to promote bone strength, "Swimming is still of tremendous cardiovascular benefit," adds Dr. Bellew. "Swimmers can add other forms of exercise that will promote bone development—for example, they can perform weight training in weight-bearing positions, or add running as a cross-training activity."
Pediatric Physical Therapy, published by Lippincott Williams & Wilkins, is the first and only peer-reviewed journal devoted exclusively to physical therapy for pediatric patients. It is the official voice of the Section on Pediatrics of the American Physical Therapy Association and is the winner of the Outstanding Peer Reviewed Journal APTA Component Award (2002, 2004 & 2005). Four times a year, Pediatric Physical Therapy delivers the latest research from the forefront of the field and is peer-reviewed to ensure validity and clinical applicability. Visit http://www.pedpt.com for more information.
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