December 2, 2014
“Chapter 7 summary”
A comprehensive exercise prescription for an individual is based upon an objective evaluation of that individual's response to exercise, including observations of heart rate (HR), blood pressure (BP), ratings of perceived exertion (RPE) and a subjective response to exercise. The fundamental objective of an exercise prescription is to create a significant change in personal health behavior to incorporate habit physical activity. Therefore, the most appropriate exercise prescription for a particular person is the one that is most helpful in achieving this behavioral change. According to ACSM emphasizes that, "The art of exercise prescription is the successful integration of exercise science with behavioral techniques that results in long-term program compliance and attainment of that individual's goals." The guidelines for aerobic conditioning talks about the essentials of a systematic, individualized exercise prescription are based on the following components Mode, Intensity, Duration, Frequency and Progression.
Mode: The first step we talk about is the Mode of exercise and the Mode of Activity so any activity that uses large muscle groups, performing rhythmic exercise which can be sustained for 15-60 minutes of continuous exercise, and which is aerobic in nature becomes an appropriate mode of exercise activity for most patients. Activities such as walking, or walking in water, jogging when moving the arms rapidly forward and backward, running, skating, bicycling, rowing and cross country skiing (Nordic Tracking) are considered to be highly aerobic activities. Some of these activities are inappropriate for cardiac patients but walking, bicycling, walk-jogging, and light rowing are usually considered appropriate for the uncomplicated cardiac patient and the non-cardiac patient. No matter what is wrong with the patient, each session of exercise should be started with a 10-15 minute warm-up period of low intensity exercise, an exercise intensity that is lower that the steady state exercise at which the patient will be training. Cool down should be as long as warm-up and should include a gradually declining exercise intensity than that at which the patient exercised during steady state. It is advantageous to add stretching and flexibility exercises prior to the warm-up period and following the cool-down period.
Intensity: the second step is Intensity of Exercise and the intensity of exercise for an apparently healthy individual is usually between 40 % - 85 % of their VO2max or its equivalent in heart rate which is 55 % - 90 % of maximal heart rate. For the cardiac patient, the ideal heart rate training zone will be between 40% - 75% of the maximum symptom limited heart rate as determined from a graded exercise treadmill test. Determining the exercise intensity for any patient is always adjusted in light of the patient's physical work capacity. For females above the age of 50 and for males above the age of 40, it is highly recommended that they undergo a graded exercise stress test (GXT). This test is most often performed on a treadmill although GXT's can be done on an ergometer. When a GXT is performed, a thorough physician will provide the following pieces of information like the resting heart rate, maximum symptom limited heart rate, resting systolic and diastolic blood pressures, maximum symptom limited systolic and diastolic blood pressures, maximum MET's attained - preferably at the onset of symptoms. . The formula looks like this: Target Heart Rate=[(Max HR Achieved - HR @ rest) x (Activity Fraction)] + HR @ rest, The Activity Fraction is defined as : [(.6 - .8) + (Max METs Achieved/100)] An example of how to calculate an activity fraction is :Activity Fraction = (.6 + (12 METs/100)) = .72, The value of .72 would be the multiplier that you would insert into the formula. This will be performed more than once sometimes up to three cases to make sure