The amount of time children spend playing outside has
drastically decreased over the last generation:
Japanese people in their thirties, forties, and fifties used to play outdoors, on average, for more than hour and a half when they were kids.
Due to the growth of video games, and change in kids' lifestyle - such as increased participation in after-school activities, today's children in Japan spend, on average, less than an hour playing outside.
Simultaniously, the physical abilities of Japanese
children detoriated tremendously:
Yamanashi University conducted research comparing physical development of children of different generations by looking at performance in a variety of athletic disciplines including running, jumping, etc.
Shockingly, it was found that the average 5 year old child in 2007 had the athletic abilities of a 3 year old kid in 1985.
Similarly, the average third and fourth grader in 2007 was at the level of a 5 year old child in 1985.