[wtallis]

> When I started riding again, I definitely felt unsteady for the first few days or weeks compared to my previous riding ability.

This can happen to frequent riders simply as a result of switching to a different bike with different geometry from what you're used to. Eg. if you normally ride a mountain bike with a fairly upright posture and suddenly switch to a road bike with a low and narrow handlebars and toe overlap, or if you raise your seat after being accustomed to keeping it very low.

[fatnoah]

I had a similar experience, but with cross-country skiing. I was an avid skier from age 2 to 22. I raced in high school, spent every weekend out skiing (skating and traditional), had no problems on any trail, no matter how steep or difficult, etc.

In college, I took up downhill skiing. Twenty years later, I tried cross-country skiing again and could barely stay upright! I went in with full confidence and ended up shuffling around like a zombie on ice.