There are some very significant physiological differences between adults and children. Children are not shrunken down adults, with the same strength, endurance, cardiovascular, and temperature regulating systems. Fitness and exercise for children must be approached in a different way.
Children have immature temperature regulatory systems. They cannot sweat and shiver like adults. Due to their immature systems, the risk of injury from heat or cold climates, is increased. Children have a shorter tolerance time in these extreme climates. Children can adjust to the climate, but the rate of which they adjust is much longer than that of an adult. They do not sweat as much as adults do during exercise, making the risk for heat stroke or exhaustion, higher.
Because children generally like to do well and please their coaches, parents, friends, and in sporting events, an excited crowd, they can have the tendency to over exert themselves and do too much. For the safety of the child, and as the responsible adult, it would be highly recommended to postpone strenuous activity when heat and humidity is high. Also, it is very important to keep the child well hydrated. Thirst is not an accurate or safe way to gauge the need for fluids.
There are differences in the bone structure between a child and an adult. The skeleton of a child is mostly cartilage, which is softer than adult bone, and is pliable. Very early on, in specific growth areas, the cartilage becomes bone. These special areas are called growth plates. These growth areas are the weakest part of the bone. Injury can easily occur by sudden or repeated force. Mild force can be a positive thing and stimulate bone growth, but excessive force can cause damage and have a negative long term effect. When the body reaches full growth maturity, these areas become bone and are no longer weak.
There are several important cardiovascular differences that exist between adults and children. Children do not breathe as much air in during exercise as adults do. In children, their breathing frequency is greater during exercise, but their volume per breath or tidal volume is less. Children reach adult levels for ventilation at around 16-18 years of age. Younger children who train for endurance can develop adult-type ventilation patterns.
Children may sometimes have higher resting and maximal heart rates than adults do. A young child can have a maximum heart rate of 220 BPM (beats per minute). Adults rarely exceed a maximum of 205 BPM.
Children have less muscle mass, so their ability to develop as much power and strength as adults have, is less. Older children or teens can train with weights, which will lead to strength gain, and muscle size. However, most are not willing to commit 2-3 days worth of training a week, making the intermittent training not as effective. Furthermore, an understanding of exercise and growth requires a basic knowledge of the actual process, and the readiness for specific motor skills. The readiness for these motor skills are gradually developed. Specific factors like neurological, cardiovascular, and physiological areas play a role in this gradual process.
Clearly the differences between a child and an adult are significant. Children will develop physically, emotionally and mentally as they mature. Understanding this while training age appropriately can help the child advance, enjoy and continue a life full of fitness and optimal health.