国际英语新闻：Children born in autumn, winter may be more sporty

Children born in the autumn and winter months are more likely to be sporty, according to one of the largest studies into childhood ever undertaken.

The findings are the latest to emerge from "Children of the 90s", which has followed the health and development of 14,000 children since before their births in the early 1990s.

Researchers at Bristol University in England, where the study is based, found that children born in the spring were the most sluggish, according to a paper published in the British Medical Journal.

Those born in the summer were 4.5 percent more active, while those delivered in the autumn and winter were 9 percent more active.

The researchers asked 5,451 children aged 11 and 12 to wear devices around their waists that recorded, minute by minute, their levels of activity for a week. The gadgets also logged the intensity and frequency of physical activity.

Researchers then compared the children's activity levels with an array of other factors such as their birth dates, how active their mothers were during and after pregnancy and whether they had siblings.

Calum Mattocks, who is leading the study, said a biological explanation was unlikely. He suspected a link to when children begin school.

"If you're born later in the school year, you're likely to be smaller than your peers and that could disadvantage you in sports and other activities, such as playing," he said.

Older children are likely to be bigger and stronger than their classmates and more likely to do better in sports, perhaps motivating them to stay interested in exercise as they grew up, he added.

The findings could help schools develop activity classes that encourage smaller, younger children, and help them improve their fitness.

"Previous studies have indicated that children born late in the school year might be at a disadvantage academically. Our findings show this might also be true of physical activity, which could impact on future health," Mattocks said.

"If teachers are aware of this, they can try to make it possible for younger children to achieve at an appropriate level. This could help them stay motivated, before they decide they're 'no good at games'," he said.

Having at least one physically active parent led to children being on average 4 percent more active; an older sibling improved activity levels by a similar amount.

A weak link was found between watching television and activity levels later in life. Children who watched a lot of TV between the ages of three and four were less than 1 percent less active than others by the time they reached 11.

The Guardian