Sports Medicine Handbook - NCAA

40
Assessment of Body Composition
invasiveness and speed of
measurement, but results from this
technique are influenced by
hydration state. Since studentathletes
have hydration states that
are in constant flux, BIA results
may be misleading unless strict
hydration protocols are followed.
In general, all of the commonly
used techniques should be viewed
as providing only estimates of body
composition, and since these
techniques use different theoretical
assumptions in their prediction of
body composition, values obtained
from one technique should not be
compared with values obtained
from another technique.
Concerns with
Body Composition
Assessment
1. Using Weight as a Marker of
Body Composition—While the
collection of weight data is a
necessary adjunct to body
composition assessment, by itself
weight may be a misleading value.
For instance, young studentathletes
have the expectation of
growth and increasing weight, so
gradual increases in weight should
not be interpreted as a body
composition problem. A studentathlete
who has increased
resistance training to improve
strength may also have a higher
weight, but since this increased
weight is likely to result from more
muscle, this should be viewed as a
positive change. The important
consideration for weight is that it
can be (and often is) misused as a
measure of body composition, and
this misuse can detract from the
purpose of body composition
assessment.
2. Comparing Body Composition
Values with Other Athletes—
Student-athletes often compare
body composition values with other
student-athletes, but this
comparison is not meaningful and
it may drive a student-athlete to
change body composition in a way
that negatively impacts both
performance and health. Health
professionals involved in obtaining
body composition data should be
sensitive to the confidentiality of
this information, and explain to
each student-athlete that
differences in height, age and
gender are likely to result in
differences in body composition,
without necessarily any differences
in performance. Strategies for
achieving this include:
• Obtaining body composition
values with only one
student-athlete at a time, to
limit the chance that the data
will be shared.
• Giving student-athletes
information on body
composition using phrases
such as “within the desirable
range” rather than a raw
value, such as saying “your
body fat level is 18 percent.”
• Providing athletes with
information on how they
have changed between
assessments, rather than
offering the current value.
• Increasing the focus on
muscle mass, and decreasing
the focus on body fat.
• Using body composition
values as a means of helping
to explain changes in
objectively measured
performance outcomes.
3. Seeking an Arbitrarily Low
Level of Body Fat—Most studentathletes
would like their body fat
level to be as low as possible.
However, student-athletes often try
to seek a body fat level that is
arbitrarily low and this can increase
the frequency of illness, increase
the risk of injury, lengthen the time
the student-athlete can return to
training after an injury, reduce
performance and increase the risk
of an eating disorder. Body
composition values should be
thought of as numbers on a
continuum that are usual for a
sport. If a student-athlete falls
anywhere on that continuum, it is
likely that factors other than body
composition (training, skills
acquisition, etc.) will be the major
predictors of performance success.
4. Frequency of Body
Composition Assessment—
Student-athletes who have frequent
weight and/or skinfolds taken are
fearful of the outcome, since the
results are often (inappropriately)
used punitively. Real changes in
body composition occur slowly, so
there is little need to assess
student-athletes weekly, biweekly
or even monthly. If body
composition measurements are
sufficient and agreed upon by all
parties, measurement frequency of
twice a year should be sufficient.
In some isolated circumstances in
which a student-athlete has been
injured or is suffering from a
disease state, it is reasonable for a
physician to recommend a more
frequent assessment rate to control
for changes in lean mass. Studentathletes
and/or coaches who desire
more frequent body composition or
weight measurement should shift
their focus to assessments of
objective performance-related
measurers.
Summary
The assessment of body
composition can be a useful tool in
helping the student-athlete and
coach understand the changes that
are occurring as a result of training
and nutritional factors. However,
the body composition measurement