I've been physically active all my life. Over 30 years ago I started running for my health. I'd quit smoking and knew I needed something to keep me from going back to it, so I took up running. I've added cycling and yoga to my routines to keep in shape.
Things happen though, we get used to our routines, the body adapts. In October of 07 I fell off my bike and cracked my pelvis. I'm back on the bike, back walking, working on my stamina for running and all in all in good shape. Yet, I recognize my balance could be better.
Yoga helps but keeping our balance is as important as keeping our flexibility. Our balance, like so many other things, tends to diminish as we age. Working to improve is a constant. So with any and all of your exercising, make balance exercises a part of your routine too. It may just help you stay on the bike!