Health After Tennis - BY PETER BRUNO, M.D

We play tennis because we enjoy it. Most of us like the competition, the feeling of being fit. But how does a sport like tennis relate to exercise and fitness ?
Research shows that there are two major components of fitness. Cardiorespiratory fitness results from any activity using large muscle groups that can be maintained for a prolonged period and is rhythmical and aerobic in nature. Examples are running, hiking, swimming, skating, biking, rowing, etc. Muscular strength training, or resistance, training, the second major component of fitness can be accomplished by lifting or holding weights or through calisthenics.

The amount of exercise we require to benefit from cardiorespiratory training is 20 to 60 minutes of continuous or discontinuous aerobic activity. The actual duration is dependent on the intensity of the activity. The lower the intensity, the longer the exercise period should be. Studies have also shown that two 10-minute sessions of aerobic exercise are almost as good as one 20-minute session. The most significant increases in conditioning will be noted in the first six to eight weeks, during which time the aerobic base is built.
Todetermine how hard to work Out, we should know our VO2 Max: Ventilation Oxygen Maximum. VO2 Max is the maximum amount of oxygen we can transport to our muscles regardless how fast our hearts are beating. It means finding a fitness lab and running on a treadmill at a graduated pace and incline, while breathing through an air tube that measures the amount of carbon dioxide generated. But for an easier route, our maximum heart rate (MHR) can be used as a guide-estimated by subtracting our age from 220. Our target heart I rate for training should be between 65 and 90 percent of this number. Those beginning aerobic training should start at the low end and work up as conditioning improves.

This formula is the most I frequently used, but it may underestimate the target heart rate by as much as 15 percent. A more accurate formula-although more complicated-is to take our maximum heart rate and subtract
our resting heart rate (our heart rate before we get out of bed, about 60 beats per minute). The number is then multiplied by the 65 to 90 percent figure we used before and then added back to our resting heart rate again. Now we have an average raining heart rate.

Ideal training gives the most benefit with the least risk. A beginner should work out at an intensity between 65 and 80 percent of the maximum heart rate, and even someone already in good shape should not exceed 90 percent of MHR. If we train at lower than 60 percent, we will not improve our cardiovascular fitness level. However, if we slowly increase our maximum heart rate, we will increase our fitness level. Gains made by training over 90 percent of MHR are minuscule compared to the risks of injury or overtraining. Aerobic exercise should be done three to four times per week, but we should always take one day off. here are two ways to approach resistance, or weight training. With proper supervision, we can find out our maximum weight for one repetition in a particular lift. Then we should use a weight that is about 60 to 80 percent of our max and do a number of repetitions, or sets. If our goal is to bulk up, use high weight and low repetitions (8 to 12). If we want strength and endurance for a sport like tennis, it's better to use less weight and do more repetitions ( 15 to 30). The goal in either case is to bring the muscle close to fatigue. At the end, we should barely be able to perform another repetition.

This type of exercise causes micro-tears, or ripping of the small myofibers of the muscles-tears that can only be seen under an electron microscope. Similarly, the bone is stressed and suffers micro-injuries. If we strain the same muscles and bones the next day, they will never get a chance to heal, and we will be damaging ourselves. On the other hand, if we give ourselves at least 48 hours to recover, the bone and muscle will heal. Not only that, but they will
be stronger, bigger and denser than before. That is the whole concept of strength training, and that is why we shouldn't work out more than three days a week with weights. How does tennis fit into an exercise program? Well, racquet sports include aerobic activity, but they are not purely aerobic. There is too much of a break in the action. Often, our heart rate will fall below the target range and not ! 'truly help our total aerobic base. The intensity must be such that it .keeps the heart rate high.