Why do elite gymnasts usually start training as young children?

Answer: Mastery takes about a decade, best begun while flexible

Mastery takes about a decade, best begun while flexible ✓ — Elite gymnastics skills take roughly ten years of practice, and flexibility and body awareness are easiest to develop in childhood. Starting early lets athletes peak in their late teens, when a small, light body also helps in the air.

Competition rules require starting by age six — No rule forces an early start; the rules set a minimum age for senior competition, 16 at the Olympics, not a deadline for beginning. Early starts come from how long the skills take to build.

Young bones are too bendy to break in falls — Children's bones bend more, but they still break, and gymnastics injuries in kids are common. Their growth plates are especially vulnerable, which is why coaches limit training loads for young athletes.