It turns out that standing on one leg seems to be the first fitness marker ... And now, it seems there’s a “healthy” number of jumping jacks each age group should be able to bound through.

Salto-1P is a one-legged jumping robot at UC Berkeley ... We’ve even seen a wheeled robot prove that jumping doesn’t need legs.

Additionally, working one leg at a time allows for greater focus ... Sascha recommends using a jump rope as an ideal ...