I've read here before that age 42 is about when you start to really see declines in speed/performance. So in early July I ran a 17:20 5k. I was pretty encouraged since I had only done a couple of quality workouts. I had visions of going sub-17 for the first time in years. Well, I turned 42 in late July. Nothing else has changed. My running has been consistent, and I have felt no change in my pace/effort. I've done some decent speedwork and felt good. I have run 2 5k's in the last month, and failed to break 18:00 both times. Each time I can come up with excuses (one was XC, so hard to judge time, the other was very hot and windy and a small race with little competition), but no way I should be running over 18 if I am in the shape I feel I am in. So let me just say: turning 42 sucks.