Getting your children physically active is vital to the development of their growing bodies and plays a major influence in preventing or maintaining long-term chronic diseases. However, because the physiological makeup of children and adolescents is quite different from that of mature adults, children tend to fatigue rather quickly when performing such activities like biking or playing soccer. Understanding these differences can help make any sport activity more enjoyable for the child and help keep them motivated.
Physiological Response to Short-term Exercise
During a brief period of intense activity while biking or playing soccer, up to 90 seconds, the body responds by utilizing local reserves of oxygen and phosphate compounds, and breaking down energy reserves or glycogen. This inevitably creates an oxygen deficit and, as a result, shortness of breath occurs. Young children have smaller quantities of energy reserves, because the reserve available correlates with their muscle mass. As children grow, their muscle mass increases, which helps them build higher tolerance to anaerobic activities.
Physiological Response to Long-term Exercise
When a child is biking or playing soccer for periods of three minutes or more, his anaerobic system contributes less and his aerobic system begins to take over, only if the activity becomes less intense. The body increases heart and respiratory rates, cardiac output and oxygen uptake to deliver the oxygen needed for prolonged activities. Because children have a smaller cardiac output because of the relative size of their hearts and have lower concentrations of hemoglobin, they cannot exercise as long as adults, leading to shortness of breath or fatigue.
Maximal Oxygen Uptake
Children tend to have a lower tolerance for extended periods of exercise while biking or playing soccer than adults, ostensibly because of smaller glycogen stores and their limited ability to extract oxygen from the blood. A child's maximal oxygen uptake begins to improve gradually he ages. This improvement begins around the age 4 and, for boys, continues until they reach adolescence, and continues until the age of 12 or 13 for girls.
Considerations
There have been several studies performed to determine if there are any correlations between exercising regularly and a child's ability to uptake oxygen. According to one study, Kathleen Haywood states that when children between the ages of 14 and 17 trained regularly, they found a 15.8 percent increase in aerobic power. Whether or not training make a difference, a gradual approach is encouraged when engaging children in physical activity to keep them aerobically safe and to keep their spirits high when they play sports.
References
- "Essentials of Strength Training and Conditioning"; National Strength and Conditioning Association; 2008
- "Life Span Motor Development"; Kathleen Haywood, Nancy Getchell; 2004
