Even at the high school level, coaches for sports like football have noticed in the past 10-20 years that the fitness of incoming students has precipitously declined because so much of how children spend their time is less playing outside (e.g., running around, jumping, climbing, etc.) but playing inside (e.g., video games, doomscrolling, watching Youtube, etc.).

Suburbs around the country are quiet after school as all the kids are inside physically atrophying.