High-Impact Exercise Promotes Bone Gain in Well-Trained Female Athletes

Abstract

Maximizing peak bone mass, as well as reducing its loss after menopause, is important for the prevention of osteoporosis. One mode of activity, gymnastics training, invokes high impact loading strains on the skeleton which may have powerful osteogenic effects. To examine the role of athletic activity, specifically gymnastics, on bone mineral density (BMD) accretion, we monitored longitudinal changes in regional and whole body BMD in collegiate women gymnasts and competitive athletes whose skeletons are exposed to differential loading patterns: runners and swimmers. Two cohorts were studied. Cohort I ‫؍‬ 26 gymnasts (19.7 ؎ 1.2 years), 36 runners (21.1 ؎ 2.7 years) and 14 nonathletic women (19.3 ؎ 1.7 years) followed over an 8-month period. Cohort II ‫؍‬ 8 gymnasts (18.9 ؎ 1.1 years), 11 swimmers (20.0 ؎ 2.3 years) and 11 nonathletic women (19.0 ؎ 1.2 years) followed over a 12-month period. Lumbar spine (L2-4), femoral neck, and whole body BMD (g/cm 2 ) were assessed by dual-energy X-ray absorptiometry. For cohort I, the percent change in lumbar spine BMD after 8 months was significantly greater ( p ‫؍‬ 0.0001) in the gymnasts (2.8 ؎ 2.4%) than in the runners (؊0.2 ؎ 2.0%) or controls (0.7 ؎ 1.3%). An increase in femoral neck BMD of 1.6 ؎ 3.6% in gymnasts was also greater ( p < 0.05) than runners (؊1.2 ؎ 3.0%) and approached significance compared with controls (؊0.9 ؎ 2.2%, p ‫؍‬ 0.06). For cohort II, gymnasts gained 2.3 ؎ 1.6% at the lumbar spine which differed significantly ( p < 0.01) from changes in swimmers (؊0.3 ؎ 1.5%) and controls (؊0.4 ؎ 1.7%). Similarly, the change at the femoral neck was greater ( p < 0.001) in gymnasts (5.0 ؎ 3.4%) than swimmers (؊0.6 ؎ 2.8%) or controls (2.0 ؎ 2.3%). The percent change in BMD at any site did not differ between eumenorrheic and irregularly menstruating athletes. These results indicate that bone mineral at clinically relevant sites, the lumbar spine and femoral neck, can respond dramatically to mechanical loading characteristic of gymnastics training in college-aged women. This occurred despite high initial BMD values and was independent of reproductive hormone status. The results provide evidence to support the view that high impact loading, rather than selection bias, underlies high BMD values characteristic of women gymnasts. Because all athletes underwent resistance training throughout the year of study, muscle strengthening activity did not appear to be a significant factor in the skeletal response observed in gymnasts. We conclude that activities resulting in high skeletal impacts may be particularly osteotropic for young women. (J Bone Miner Res 1997;12:255-260)

Relationship between physical activity and bone mineral status in young adults: the Northern Ireland young hearts project

“…16 Some sports, for example those involving high-intensity weight-bearing exercise, or high peak strains, appear to provide better opportunities for maximizing bone than others. 5,11,27 However, previous reports have been constrained by routinely used methods for estimating peak strains. In the present study, we have been able to account for both the frequency with which subjects undertook peak strain activities, and the usual length of time spent at the activity.…”

“…8,30 In addition, activities involving considerable impact or strain have been shown to stimulate osteogenic responses. 12,16,27 However, of the studies to date, many have been carried out with athletes 11,18 and older age groups, 12 or have used small sample sizes, 2,7 and are not representative of young adult populations. Furthermore, many studies do not discriminate between different types of physical activity (e.g., work, leisure, sports, and peak strain activities) and do not account for intensity, frequency, and duration of physical activity in their analyses.…”

Interlimb Differences in Lower Extremity Bone Mineral Density Following Anterior Cruciate Ligament Reconstruction

“…3 High skeletal impact loading training has been suggested to optimize bone health, specifically at the pelvis and proximal femur. 3,10,19,33,34 Walking alone had a significant positive effect on BMD for the lumbar spine, but not on the femur or calcaneus. 25 The higher impact level of activity may be necessary for promotion of bone mineral accretion and minimizing bone mineral losses following ACL reconstruction.…”

Whole Body Vibration Training Effects on Bone Mineral Density in Postmenopausal Osteoporosis: A Review

“…Some authors [65,66] suggest that highly intensive training has positive effects on bone mineral density even in well-trained athletes, but however, it is questionable whether people with diagnosed osteoporosis should be exposed to high intensity load. (Table 1) Apparently, the skeletal system's answer to whole body vibration training, or the mechanotransduction which it activates, is osteogenesis [67,68], respectively, increased bone density after mechanical stimulus indicates that skeletal system adapts to the type of physical activity [30,69].…”