ABSTRACT
Objective To study effects of different types of high-impact exercises on the increment of bone mineral density (BMD) and bone mineral content (BMC) . Methods Thirty-nine male volunteers, including 13 hoopsters, 13 paratroopers, and 13 common college students as the control, were recruited and divided into two subgroups (subgroup 1:20-22 years old; subgroup 2:23-25 years old). Their BMDs and BMCs on calcaneus, first through fifth metatarsus, hip, and lumbar spine (L1-4) were evaluated. Results The BMC of calcaneus, the first and second metatarsals, total lumbar spine, and total hip in the hoopster group was significantly higher than that in the control group and paratrooper group. The hoopster group obtained statistically higher BMD at the lumbar spine, hip, and femoral neck than the other two groups. However, the BMCs and BMDs of the paratrooper group and control group had no significant differences at almost all measured anatomical locations. Conclusions BMC and BMD are not always in positive correlation with vertical ground reaction forces during normal exercises. Compared with parachuting training, playing basketball as a kind of variable load exercise can effectively increase BMC and BMD, and is more beneficial for reducing the risk of osteoporotic fracture.