Exercise is physical activity that is planned, structured, and repetitive for the purpose of conditioning the body. Exercise consists of cardiovascular conditioning, strength and resistance training, and flexibility.
Exercise is essential for improving overall health, maintaining fitness, and helping to prevent the development of obesity , hypertension , and cardiovascular disease. Surveys conducted by the Centers for Disease Control and Prevention (CDC) indicate that 61.5 percent of children aged nine to 13 years do not participate in any organized physical activity (for example, sports , dance classes) and 22.6 percent are not physically active during their free time. According to the American Obesity Association, approximately 30 percent of children and adolescents aged six to 19 years are overweight and 15 percent are obese.
A sedentary lifestyle and excess caloric consumption are the primary causes of this increase in overweight and obesity; regular exercise is considered an important factor in controlling weight. Overweight and obese children and adolescents are at higher risk of developing several medical conditions, including the following:
- orthopedic complications, such as hip and knee pain and limited range of motion
- cardiovascular disease
- high cholesterol
- sleep apnea
- psychosocial disorders, such as depression, negative body image, and eating disorders
Clinical studies have shown that regular exercise has numerous benefits, including the following:
- preventing weight gain and maintaining healthy weight
- reducing blood pressure and cholesterol
- improving coordination
- improving self-esteem and self-confidence
- decreasing the risk of developing diabetes, cardiovascular disease, and certain types of cancer
- increased life expectancy
Exercise consists of cardiovascular conditioning, strength and resistance training, and flexibility to improve and maintain the fitness of the body's heart, lungs, and muscles.
Cardiovascular conditioning involves moderate to vigorous physical activity that results in an elevated heart rate for a sustained period of time. Regular cardiovascular exercise improves the efficiency of the functioning of the heart, lungs, and circulatory system. For adults, aerobic exercise within a target heart rate range calculated based on a maximum heart rate by age is recommended. For healthy children, cardiovascular exercise that elevates the heart rate to no greater than a maximum heart rate of 200 beats per minute is recommended.
In general, the American Heart Association recommends at least 60 minutes of moderate to vigorous physical activity every day for children and adolescents. Cardiovascular conditioning activities should be appropriate for the age, gender, and emotional status of the child. Examples of exercise that elevates the heart rate are bicycle riding, running, swimming, jumping rope, brisk walking, dancing, soccer, and basketball.
Strength and resistance training
Strength and resistance training increases muscle strength and mass, bone strength, and the body's metabolism. Strengthening exercises increase muscle strength by putting more strain on a muscle than it is normally accustomed to receiving. Strength training can be performed with or without special equipment. Strength/resistance training equipment includes handheld dumbbells, resistance machines (Nautilus, Cybex), and elastic bands. Strength training can also be performed without equipment; exercises without equipment include pushups, abdominal crunches, and squats. Children as young as six years can participate in strength training with weights, provided they are supervised by a fitness professional trained in youth strength training. Child-sized resistance machines may be available at some fitness facilities. According to youth strength training guidelines, children and adolescents should perform strength training for approximately 20 minutes two or three times weekly on nonconsecutive days.
Flexibility is important to improve and maintain joint range of motion and reduce the likelihood of muscle strains . Most young children are naturally more flexible than older children and adults and will instinctively perform movements that promote flexibility. As children age, they should be encouraged to continue to stretch. Flexibility is especially important for children and adolescents engaged in vigorous exercise (running, competitive sports). Stretching is best performed following a warm-up and/or at the completion of an exercise session or sport. One activity that promotes flexibility that is increasing in popularity for children is yoga , in the form of children's yoga classes or exercise videos.
Before a child begins any exercise program, he or she should be evaluated by a physician in order to rule out any potential health risks. Children and adolescents with physical restrictions or certain medical conditions may require an exercise program supervised by a healthcare professional, such as a physical therapist or exercise physiologist. If dizziness , nausea , excessive shortness of breath, or chest pain occur during any exercise program, the activity should be stopped, and a physician should be consulted before the child resumes the activity. Children and adolescents who use any type of exercise equipment should be supervised by a knowledgeable fitness professional, such as a personal trainer.
A physical examination by a physician is important to determine if strenuous exercise is appropriate or detrimental. Prior to beginning exercise, a proper warm-up is necessary to help prevent the possibility of injury resulting from tight muscles, tendons, ligaments, and joints. Appropriate warm-up exercises include walking, light calisthenics, and stretching.
Proper cool-down after exercise is important and should include a gradual decrease in exercise intensity to slowly bring the heart rate back to the normal range, followed by stretches to increase flexibility and reduce the likelihood of muscle soreness. Following vigorous activities that involve sweating, lost fluids should be replaced by drinking water.
Improper warm-up and inappropriate use of weights can lead to muscle strains. Overexertion without enough time between exercise sessions to recuperate also can lead to muscle strains, resulting in inactivity due to pain. Some children and adolescents may be susceptible to exercise-induced asthma. For children and adolescents who perform high-impact activities, such as running, stress fractures may occur. Dehydration is a risk during longer activities that involve sweating; children and adolescents should be supplied with water during and after activity.
Significant health benefits are obtained by including at least a moderate amount of physical exercise for 30 to 60 minutes daily. Regular physical activity plays a positive role in preventing disease and improving overall health status. For children and adolescents just beginning an exercise program, results (including weight loss, increased muscle strength, and aerobic capacity) will be noticeable in four to six weeks.
Given the increasing prevalence of overweight and obesity in children and adolescents, it is important for parents to encourage regular exercise and also serve as role models by exercising themselves. Television, computers, and video games have replaced physical activity for playtime for the majority of children. Parents should make a commitment to replacing sedentary activities with active indoor and outdoor games. For busy families, exercise can be performed in multiple 10- to 15-minute sessions throughout the day.
For children aged two to five years, physical activities should emphasize basic movement skills, imagination, and play . Examples of appropriate activities for this age group include rolling and bouncing a ball, jumping, hopping, skipping, mimicking animal movements, and pedaling a tricycle.
For children aged five to eight years, physical activities should emphasize basic motor skills and more complex movements (eye-hand coordination). Non-competitive group sports or classes are appropriate for this age, and parents should focus on helping their children find an enjoyable physical activity.
Aerobic —An organism that grows and thrives only in environments containing oxygen.
Calisthenics —Exercise involving free movement without the aid of equipment.
For children aged eight to ten years, physical activities should emphasize the benefits of regular exercise. Team sports and group classes are appropriate for this age. Experts have found that physical activity decreases in this age group, so parents should focus on being
For children aged 11 to 14 years, physical activities should continue to emphasize the benefits of regular exercise. Participation in team sports, as well as individual activities, such as dance or martial arts, is appropriate for this age. Peer influence and hormonal changes can affect participation in group physical activities, so parents should consider encouraging exercise at home for children reluctant to participate with peers.
Community centers, local YMCAs, health clubs, and other organizations offer age-appropriate exercise programs for children and adolescents led by experienced and knowledgeable instructors. In addition, home exercise videos geared toward children are available in stores and from Web sites.
For children and adolescents with medical conditions that may limit exercise or place them at higher risk for exercise-related complications, supervised exercise programs may be available at hospital-based wellness centers.
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Jennifer E. Sisk, MA