Ever wondered why children never seem to get tired as they move from one hectic physical activity to another during a day? New research published in the open-access journal ‘Frontiers in Physiology’ says that this is because children not only have fatigue-resistant muscles, but also recover very quickly from high-intensity exercise – even faster than well-trained adult endurance athletes!
Says Sebastien Ratel, Associate Professor in Exercise Physiology at the Université Clermont Auvergne, France, “During many physical tasks, children might tire earlier than adults because they have limited cardiovascular capability, tend to adopt less-efficient movement patterns and need to take more steps to move a given distance. Our research shows that children have overcome some of these limitations through the development of fatigue-resistant muscles and the ability to recover very quickly from high-intensity exercise.” Previous research has shown that children do not tire as quickly as untrained adults during physical tasks but there was no evidence to prove this until now.
The researchers asked three different groups – 8-12 year-old boys and adults of two different fitness levels – to perform cycling tasks. The boys and untrained adults were not participants in regular vigorous physical activity. In contrast the last group, the endurance athletes, were national-level competitors at triathlons or long-distance running and cycling.
Each group was assessed for the body’s two different ways of producing energy: The first, aerobic, uses oxygen from the blood. The second, anaerobic, doesn’t use oxygen and produces acidosis and lactate (lactic acid), which may cause muscle fatigue. The participants’ heart rate, oxygen levels and lactate-removal rates were checked after the cycling tasks to see how quickly they recovered. In all tests, the children outperformed the untrained adults.
“We found the children used more of their aerobic metabolism and were therefore less tired during the high-intensity physical activities,” says Ratel. “They also recovered very quickly, even faster than the well-trained adult endurance athletes, as demonstrated by their faster heart-rate recovery and ability to remove blood lactate. This may explain why children seem to have the ability to play and play and play, long after adults have become tired.”
Adds co-author Anthony Blazevich, “Many parents ask about the best way to develop their child’s athletic potential. Our study shows that muscle endurance is often very good in children, so it might be better to focus on other areas of fitness such as their sports technique, sprint speed or muscle strength. This may help to optimise physical training in children, so that they perform better and enjoy sports more.”
The study can be used to develop athletic potential in children and improve our knowledge of how disease risk, such as diabetes, increases as our bodies change from childhood to adulthood. Concludes Ratel, “It seems that being a child might be healthy for us.”