Intensity Monitoring for Adaptive Aerobics
Physiological effects of disabilities can affect the ability of
the athlete to self-monitor the intensity level of his/her exercise.
Several effects of the disability, depending on the nature of the
disability, can actually change the numerical basis of the
intensity charts that we have all learned to use, that we
probably have posted on the walls of our aerobics studio. Group
exercise leaders need to be aware of the constraints that
physical disabilities impose on monitoring exercise intensity and
you need to be able to inform the athletes in your class of the
proper way to interpret the intensity monitoring that you use.
Constraints in Monitoring Method
Athletes may not have the tactile sense to properly check their
own heart rate; if their disability is a spinal cord injury above
the upper thoracic area, their sense of touch may be impaired.
This means that the instructor or another athlete or a second
instructor must check the athlete's pulse at the proper time in
the class. For those of you who work at facilities that prohibit
you actually touching the athletes, this may cause administrative
problems; I would suggest that you discuss this with your
Some athletes in wheelchairs also wear gloves to protect their
hands while pushing their chair and these could impair checking a
pulse at the radial artery, which is the recommended heartrate
monitoring site. I would suggest in this case and for those
athletes who can't pick up an radial pulse, that they check their
heart rate at the brachial artery, since the carotid artery
location has started to be discouraged as a pulse check site.
Factors Affecting Heart Rate as Exercise Intensity Indicator
While heart rate monitoring has problems in application for some
disabled athletes, it is still the most widely used technique for
monitoring exercise intensity in all populations, and it should
be included in the programming for adaptive aerobics classes, as
well as for disabled athletes within mainstream studio aerobics.
Several limiting factors on the heart rate being used with
standard ranges must be acknowledged; the disabled athlete may
have a disability that limits the trainable, usable muscle mass,
the disabled athlete may have impaired cardiovascular or
autonomic function, the disabled athlete's anaerobic threshold
may differ from an athlete without disability and the athlete may
be influenced by drugs that alter physiologic responses to
Limited Trainable Mass
Many of the physical disabilities we described previously prevent
or partially limit the use of a large part of the skeletal muscle
mass during exercise due to impaired or absent motor control.
Spinal cord injury, Multiple Sclerosis, and head injury are three
examples of this absence of control. Cerebral Palsy and head
injury limit or impair movement coordination of large muscles. In
the case of amputees, the muscle mass is absent. Stroke, MS and
polio may cause paralysis that again limits the amount of muscle
that can be used in exercise.
Impaired Cardiovascular or Autonomic Function
Spinal cord injury above T-5 will limit the maximal heart rate to
between 110 and 130 beats per minute, which in most people using
standard heart rate monitoring methods or charts would be the low
end of the "fat-burning" aerobic range.
Anaerobic Threshold Difference
Again, due to reduced muscle mass, the threshold of lactic acid
production may be reduced; more lactic acid is produced for
exercise using a smaller muscle mass. This causes an increase in
heart rate, blood pressure and breathing rate for an absolute
work load. Exercise with spastic muscle contraction can also
induce greater increases in lactic acid accumulation, with
corresponding increases in blood pressure and heart rate.
Medicinal (Pharmacological) Agents
As with the general population, disabled athletes may be taking
prescription or over the counter drugs that affect the level of
intensity of their aerobics performance. Not being a pharmacist
or an M.D., I am not qualified to list what drugs produce what
effects. For instance, you don't have to be disabled
to have a prescription for beta blockers, which can effectively
limit exercise heart rate to well under the traditional "fat
End of the intensity monitoring section