The Facts:
a. In this review of the literature, the authors note that exercise is often one of the things commonly recommended to patients in an effort to prevent and manage osteoporosis.
b. Bone densitometry is the most common method used to monitor the effect of these interventions. Although areal bone mineral density (Defined as “The bone mineral content, measured by dual-energy x-ray absorptiometry (DEXA), divided by the bone area in square-centimeters.”) is closely associated to fracture risk it “does not provide a reliable indication of bone geometry or morphological adaptation to stimuli.”
c. The effects of exercise on aBMD are often modest. But this “may not fully represent the benefit of exercise to the bone.”
d. “Ultimately, monitoring changes in bone geometry beyond DXA-derived
aBMD will provide further insight into the optimal therapeutic exercise program to enhance bone strength and reduce susceptibility to osteoporotic fracture.”
e. “Animal models suggest that mechanical loading indeed influences bone geometry and thus strength.”
f. Evidence exists that either in combination or alone resistance training and weight-bearing impact type exercise “will prevent postmenopausal bone loss at clinically relevant sites”
g. “In keeping with the basic rules of bone adaptation that mechanical strains above those habitually experienced are required, it is unsurprising that walking has been found to be essentially ineffective for enhancing aBMD .”
h. In one study of 164 postmenopausal women involving multidirectional jumping and bench stepping combined with antiresorptive drug therapy, “Exercise did not enhance the effect on bone mass, but increased the ratio of cortical bone to the total bone area at the distal tibia by 3.7% compared with the non-exercise group.”
i. “A meta-analysis examining the effects of progressive, “high-intensity” resistance training interventions (eight to twelve repetitions, corresponding to 60% to 70% of one repetition maximum) on changes in aBMD in postmenopausal women reported a significant training effect at the lumbar spine, a non-significant positive effect at the total hip, but no effect at the femoral neck.”
j. “…there is currently strong (Level A) evidence to support the positive effect of physical activity on bone mass, evidence supporting the effect of physical activity on the bone structure is less compelling (Level B).”
Take Home:
Physical activity can have a beneficial effect on bone mass and perhaps on bone structure.
Reviewer's Comments:
As in many articles, the results are complex and at times not straightforward. But overall the higher intensity exercises seem to be the most important for those seeking to retain their bone mass. I often opine on the geometry of spines and I predict that we will be hearing about more than just the bone mass in the future.
Reviewer: Roger Coleman DC
Editor: Mark R. Payne DC
Reference:Harding AT, Beck BR. Exercise, Osteoporosis, and Bone Geometry. Sports (Basel). 2017 May 12;5(2). pii: E29. doi: 10.3390/sports5020029.