One way to begin strength training is to buy a set of dumbbells and start moving them around. Over time, bit by bit, we come to understand that we can get better benefits by being more precise: we start organizing our lifting into sets and reps, measuring the amount of weight lifted, planning out which days to train, and so on. What a good trainer understands though, is that there is a step missing here.
If we were to find ourselves in a weightless, gravity free environment balance practice would be meaningless. Balance of our bodies assumes a frame of reference within which we are blancing. I think for yoga this is one of the most interesting aspects of practicing balance. In yoga one of the first journeys we take is an inward journey.... learning to listen carefully to our bodies, to connect our bodies to our thoughts and our breath. But a journey only inward is inherently sterile.