Watching toddlers' movement can be really instructive. Toddlers are unstable and actually rely not on strength or righting reactions (both of which develop and integrate with time) but on the softness of their bones and the fluidity of their joints. They can make great errors in stepping and stumbling because they have a large range of motion in their joints. They easily recover from falls. Their bodies are buoyant and adaptable. Their joints acutually pulse, or open and close, as they walk or reach out for something they want and draw it back toward their center (or their mouth.)
"...it's bones are soft, it's muscles are weak, and yet it's grip is very strong,"
(Daode jing Chapter 55, Liu ming)
Qi gong and internal martial arts combine these two approaches to movement, that of the very young and that of the very old. Both approaches can be considered weak.
From doing these practices, as we age, our joints have more space and we use the space that we have more efficiently. We return to balance without much strain or effort.
Somewhere I picked up the saying: "Walk with your feet on the ground and your head in the clouds."