Reverse Two A Days
 

In HS and college sports the preseason practices used two practices a day to speed up the process of conditioning. I call this thread "Reverse" because my question is whether two a day rides can help avoid overtraining/repetitive use injuries. For example, if one is riding 20 miles a day normally, would two 10-mile rides, with a break in between, be less likely to lead to injury?

It probably depends on exactly what your goals are. Are you training for the TdF or a short track race?

I don't ride every day. Three usually, four sometimes and other weeks maybe one or none. But for short rides of 20 miles or even long rides, I'm not really warmed up and performing at my best until about mile 18.

Two 10 mile rides in a day is called commuting! It's a good way to build endurance, since in the beginning you have a work day to recover (assuming you're working a desk job). You have the opportunity to split rides such that one is an interval session with an extra recovery ride in the day. As your fitness develops, you may notice that you need to extend the ride home to continue to increase your stamina.

If there's a downside, it's that you'll want to include one or two longer rides every week, because a steady diet of only two 10-milers gets you ready for perhaps 15 mile long rides.