A. Heinonen et al., RANDOMIZED CONTROLLED TRIAL OF EFFECT OF HIGH-IMPACT EXERCISE ON SELECTED RISK-FACTORS FOR OSTEOPOROTIC FRACTURES, Lancet, 348(9038), 1996, pp. 1343-1347
Background Osteoporotic fractures among the elderly are common, and wi
thout preventive measures the burden of these fractures on health-care
systems will increase further. The purpose of this randomised control
led study was to evaluate, in premenopausal women, the effects of high
-impact loading on several determinants of osteoporotic fractures. Met
hods 98 healthy, sedentary female volunteers aged 35-45 years were ran
domly assigned to either a training (n=49) or a control group (n=49).
Progressive high-impact exercises were done three times per week for 1
8 months. We measured bone mineral density (BMD) in specific axial and
lower-limb sites, by dual-energy X-ray absorptiometry, at baseline an
d after 12 and 18 months. Maximum isometric strength, muscular and car
diovascular performance, and dynamic balance were also assessed. Findi
ngs BMD at the femoral neck, a weightbearing site, increased significa
ntly more in the training group (mean 1 . 6% [95% CI 0 . 8-2 . 4]) tha
n in the control group (0 . 6% [-0 . 2 to 1 . 4], p=0 . 006). By contr
ast, at non-weightbearing sites, such as the distal radius, there was
no significant difference between the training and control groups (-1
. 5% [-2 . 7 to -0 . 3] vs -0 . 7% [-1 . 9 to -0 . 5], p=0 . 60). In t
he training group there was a significant improvement in vertical jump
and predicted oxygen consumption per min at maximum exercise compared
with controls. Interpretation High-impact exercises that load bones w
ith a rapidly rising force profile in versatile movements improve inte
grity, muscular performance, and dynamic in premenopausal women. If do
ne on a regular basis, this type of exercise may help decrease the ris
k of osteoporotic fractures in later life. Long-term studies are requi
red to show whether these 18-month results can be translated into long
-term benefit.