I have a copy of Fast After 50 on my nightstand. One of my main takeaways is that intensity is still important for older athletes, probably more important than volume, but recovery is a must. When I am in the middle of a heavy training cycle, I absolutely need to schedule in active recovery time. Some times that takes the form of a walk around the park with my wife or a super-easy ride. So easy that little kids on training wheels are dropping me.