Giving Child and Youth Development Knowledge Away, published by the Society for Research in Child Development, found that doing extra-curricular activities generally improves children's confidence and academic success.
'There is scant support for the over-scheduling hypothesis and considerable support for the positive youth development perspective,' it said.
Americans aged five to 18 spend on average five hours per week taking part in extra-curricular activities, though about 40 per cent do not participate in any activities at any one time.
The report concluded, 'Of greater concern than the over-scheduling of youth in organised activities is the fact that many youth do not participate at all. The well-being of youth who do not participate in organised activities is reliably less positive compared with youth who do.'
To view the report, visit www.srcd.org/press and create a log-in.