I'm 29 years old, 6 feet tall, 175 pounds. I think I'm in pretty good shape, and the only exercise I get is tennis. I'm wearing Wilson ProStaff 500 shoes. Somewhere between a 4.0-4.5 player.
I just played today after not playing for 3 days and I didn't notice the "heaviness" this time - not a match though, just a 2-hour hitting session. I'm going to continue with this new relaxed pace and see what happens. And oh yeah, I'll try some new shoes next time out, maximize my chances