June 28 — 29, 2007 Advisory Committee Meeting
Dr. Kohrt provided an overview of musculoskeletal health broken out in 3
distinct areas, bone health, joint health and muscle health.
Bone health should be addressed as a continuum across the life span. For
example, physical activity, or lack of physical activity, early in life may be a
determinant of bone health later in life. A second factor is things that
influence the rate of loss with aging.
An issue that will be a challenge to address is whether physical activity
influences bone strength. While one can see and measure favorable effects from
physical activity on the parameters of bone, one cannot actually measure bone
Another area to address is the non-skeletal effects of exercise on risk for
osteoporosis. An issue in this area is whether there is a dose-response effect
or how to evaluate dose response. The basic science seems to indicate intensity
as a key influencer on bone health. Intensity, however, is difficult to quantify
and easily explain to the lay person. An added layer of complexity is the fact
that we are really interested in the magnitude of loading force, which may be
unrelated to percentage of VO2 max or percentage of heart rate max.
It will be very important to get a better understanding of how we will weigh
evidence from randomized controlled trials versus observational cohort studies,
because it is only from the latter that we have information on fractures.
In terms of joint health, osteoarthritis is going to be very important to
address. On the other hand, it will be very difficult to address whether
physical activity is a benefit or a risk. This will need to be considered very
seriously in order to make recommendations for physical activity that should be
maintained throughout the lifespan if that does confer increased osteoarthritis
For muscle health there isn't necessarily a link between disease and physical
activity both in terms of impact on muscle quantity, muscle mass and muscle
quality. Presumably much of the work here will be linked with other groups.