Sports Fitness Training

The number of walkers, joggers, bicyclists, step aerobics participants, and swimmers is tangible evidence of American’s increased awareness of the most important aspect of physical fitness: cardiorespiratory fitness, which refers to the ability of the circulatory and respiratory systems to supply oxygen during sustained physical activity.

The primary category of physical activity known to improve cardiorespiratory endurance is aerobic exercise. The term aerobic means “with oxygen” and describes any type of exercise, typically performed at moderate levels of intensity for extended periods of time, that increases your heart rate. Aerobic capacity(commonly written as VO₂ max) is defined as the maximum volume of oxygen consumed by the muscles during exercise.

To measure your maximal aerobic capacity, an exercise physiologist or physician will typically have you exercise on a treadmill. He or she will initially ask you to walk or run at an easy pace, and then, at set time intervals during this graded exercise test, will gradually increase the workload(i.e., a combination of running speed and the angle of incline of the treadmill) to the point of maximal exertion. Generally, the higher your cardiorespiratory endurance level, the more oxygen you can transport to exercising muscles and the longer you can maintain a high intensity of exercise prior to exhaustion.

According to the exercise testing guidelines of the American College of Sports Medicine, maximal aerobic capacity treadmill tests should not be conducted on men over 40 or women over 50 without a prior comprehensive physical examination and permission from their physicians.

Aerobic Fitness Programs

Researchers tell us that a physically active lifestyle is the key to improved cardiovascular health, but what level of activity is required to improve aerobic fitness? There are numerous variables in any particular aerobic activity, but for healthy young adults, aerobic activity that works your heart at a moderate intensity(approximately 70 percent of your maximum heart rate, or about 140 to 160 beats per minute) for prolonged periods of time(20 to 60 minutes of continuous activity) will improve your fitness level.

The most beneficial aerobic exercises are total body activities involving all the large muscle groups of your body, for example, swimming, cross-country skiing, or rowing. If you have been sedentary for quite a while, simply initiating a physical activity program may be the hardest task you’ll face. Don’t be put off by the next-day soreness you are likely to feel in your long-dormant muscles. The key is to begin your exercise program at a very low intensity, progress slowly … and stay with it. For example, if you choose an aerobic fitness program that involves jogging, you’ll need several weeks of workouts combining walking and jogging before you will reach a fitness level that enables you to jog continuously for 15 to 20 minutes.

You will need to adjust the frequency, intensity, and duration of your aerobic activity program to accommodate your initial level of cardiorespiratory fitness. As you progress, add to your exercise load by increasing exercise duration or intensity, but do not increase both at the same time.

• Determining Exercise Frequency If you are a newcomer to regular physical activity, the frequency of your aerobic exercise bouts should be at least three times per week. The surgeon general’s recommendation is for moderate amounts of daily physical activity. As your fitness level improves, your goal should be to exercise 20 to 30 minutes per day, five days a week.

• Determining Exercise Intensity Your aerobic exercise program should employ activities of moderate intensity that use large muscle groups and can be maintained for prolonged periods of time. The measure of such a workout is your target heart rate, which is a percentage of your maximum heart rate. To calculate target heart rate, subtract your age from 220 for females or from 226 for males. The result is your maximum heart rate. You determine your target heart rate by calculating a desired percentage of maximum heart rate, often 60 percent. If you are a 20-year-old woman, your maximum heart rate is 200(220 - 20). Your 60-percent target heart rate would be 120(200 x .60). People in poor physical condition should set a target heart rate between 40 and 50 percent of maximum. As your condition improves, you can gradually increase your target heart rate. Increases should be made in small increments: Increase from 40 to 45 percent; then from 45 to 50 percent. Because of the potential risks and adherence-to-exercise problems associated with high-intensity activity(> 80% of maximum heart rate), moderate-intensity activity of longer duration is suggested for adults who are not training for competitive athletics.

Once you know your target heart rate, you can determine how close you are to this value during your workout. You’ll need to stop exercising briefly in order to measure your heart rate. To take your pulse, lightly place your index and middle fingers(don’t use your thumb) over one of the carotid arteries in your neck (along either side of your Adam’s apple), or over one of the radial arteries (thumb side) of your wrist.

Be sure to start counting your pulse immediately after you stop exercising, as your heart rate will decrease quickly. Using a watch or clock, take your pulse for six seconds and multiply this number by 10(just add a zero to your count) to get the number of beats per minute(bpm). Your pulse should be within a range of about 5 bpm above or below your target heart rate. If necessary, increase or decrease the pace or intensity of your workout to achieve your target heart rate.

A target heart rate of 70 percent of maximum is sometimes called the “conversational level of exercise” because you are able to talk with a partner while exercising. If you are a novice and you are breathing so hard that talking is difficult. your intensity of exercise is too high. If you can sustain a conversational level of aerobic exercise for 20 to 30 minutes, you will improve your cardiorespiratory fitness.

The lower the intensity of the activity, the longer the duration you’ll need to get the same caloric expenditure. For example, a 180-pound man will expend 288 calories per hour of playing golf if he carries his clubs, but will burn 805 calories per hour if he is cross-country skiing. Your goal should be to expend 300 to 500 calories per exercise session, with an eventual weekly goal of 1,500 to 2,000 calories.

Since many of the health benefits associated with cardiorespiratory fitness activities take about one year of regular exercise to achieve, you shouldn’t expect an immediate reduction in your risk of cardiovascular disease when you start an exercise program. However, any low-to-moderate-intensity physical activity, even if it does not meet all the cardiorespiratory exercise.

Cardiorespiratory fitness The ability of the heart, lungs, and blood vessels to supply oxygen to skeletal muscles during sustained physical activity.

Aerobic exercise Any type of exercise, typically performed at moderate levels of intensity for extended periods of time (typically 20 to 30 minutes or longer), that increases heart rate.

Aerobic capacity The current functional status of a person’s cardiovascular system; measured as VO₂ max.

Graded exercise test A test of aerobic capacity administered by a physician, exercise physiologist, or other trained person; two common forms are the treadmill running test and the stationary bike test.