In summary, the findings from cross-sectional studies
consistently report positive results regarding the
influence of various weight-bearing loading regimens
on bone mass, structure, and strength in athletes and
those who are physically active. Specifically, it is evident
from these studies that moderate- to high-impact loading
activities incorporating varied movement patterns,
as well as resistance training, are particularly beneficial
for the adult skeleton, as they provide high strain magnitudes
and strain rates, and varied strain distribution
patterns. However, it is important to recognize that such
studies only examine associations, are subject to selection
bias and confounding, and as such, cause and effect
cannot be inferred. To provide robust evidence-based
exercise prescription guidelines for optimizing bone
health and reducing fracture risk, well-designed, longterm
randomized controlled trials (RCTs) are required.
Importantly, given the length of the bone remodeling
cycle [126], at least 6 to 9 months is necessary to assess
a measurable and clinically meaningful change in bone
resulting from exercise intervention using current
imaging technologies.