Concerns that a busy schedule of activities is leaving a generation of children pressurised and stressed have been challenged by a research review.
The researchers say extra-curricular activities are highly beneficial
Academics in the United States found that taking part in extra-curricular activities could boost children's self-esteem and academic performance.
And few youngsters said they joined groups because of parental pressure.
The study argues for the continued expansion of organised activities such as sports and after-school clubs.
The researchers said there was little evidence to back up what they called the "over-scheduling hypothesis" for children aged five to 18.
In an analysis of a national study and review of three scientific studies, they concluded that "organised activities did not dominate American-based young people's free time" and that activities such as watching the television and playing games took up as much or "considerably more" time.
The study found young people in the US spent an average of five hours a week taking part in organised activities such as sports, music and the arts, although a small proportion (between 3% and 6%) spent 20 or more hours participating in such pasttimes.
And, at any given time, 40% of young people were not engaged in these activities, the study found.
"Written and televised media reports and popular parenting books suggest that the lives of many young people are now replete with hurry, stress and pressure brought on, in part, because of their involvement in too many organised activities," the report said.
"Youth are seen as taking part in a variety of activities because of the perceived pressure from parents and other adults to achieve and attain long-term educational and career goals."
But the study, as well as dismissing this notion, said youngsters who participated in out-of-school activities had lowered rates of smoking and drug use, improved educational attainment and better relationships with their parents.
Dr Joseph Mahoney of Yale University, who led the research, said the real issue was those young people who did not participate in extra-curricular activities.
"Of greater concern than the over-scheduling of youth in organised activities is the fact that many youth do not participate at all," he said.
"The well-being of youth who do not participate in organised activities is reliably less positive compared to youth who do participate."
The research calls for the opportunities for young people to participate in activities such as sports, music and the arts to be increased.
"For the vast majority of young people, participation is associated with positive developmental outcomes."
The findings are published in Social Policy Report, a publication of the Society for the Research in Child Development.