NEW YORK (Reuters Health), Dec 31 - Women who participated in weight-bearing sports during their teens, the formative years for bone growth, have stronger bones after menopause than women who participated in lighter activities during their youth. Those findings, from investigators in Japan, are published in the December 23 Online First edition of the British Journal of Sports Medicine. Dr. Takeru Kato at Suzuka University and colleagues assessed bone health among 46 postmenopausal women between 52 and 73 years of age. The women were grouped according to what types of activities they had participated in between the ages of 12 and 18 years. There were 16 women who participated in high-impact, weight-bearing activities, such as running and jumping, and 30 who participated in low-impact, nonweight-bearing exercises, such as swimming, or very little exercise. The investigators measured bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine and femur on dual energy x-ray absorptiometry (DEXA). They used magnetic resonance imaging (MRI) to measure bone size, shape, and characteristics, including the mid-diaphyseal cross-sectional area of the femur, periosteal and endosteal perimeters, and maximum and minimum second moment of area. Women who had participated in high-impact, weight-bearing activities during their teen years had significantly greater BMC in both the lumbar spine and femoral neck than their less active counterparts. They also had significantly greater femoral mid-diaphyseal bone cross-sectional area, periosteal perimeters, and maximum and minimum second moment of area than the nonweight-bearing groups. BMD did not differ significantly between the two groups. "Adolescent weight-bearing exercise exerts preservational effects on femoral mid-diaphyseal size and shape, while DXA-measured BMC effectively identified the same tendency," Dr. Kato and colleagues conclude. Weight-bearing activity during the formative years shows positive effective on bone health, "even after 40 years." Br J Sports Med 2008.