Yeah mug tennis, I have some experiences unfortunately of the matter.
I'm pretty frustrated with my forehand at the moment, it's my stronger and better baseline wing, but as of late it has been missing a bit. I tend to hit it too much with the arm and use the wrist too little. I'm working on it, and I get great shots when I concentrate but sometimes when I'm out of focus the problem resumes. Annoying.
Also I have this thing with my one-handed backhand that if I don't hit it properly or at least try to hit it properly, that's hard with good topspin, I won't be able to hit it the whole match. It's part mental and part physical, the shoulder and arm somehow don't warm up to the topspin shot and I have to slice most of the time. Frustrating.
At least my serve is working, I used to have a big problem with DFs for a few years because I had trouble figuring out the right motion to a proper spin and kick serve. Now I'm pretty much all over it. Also since I've been going to the gym for a half a year now, my first serve has cranked up nicely. Would be cool to serve to radar
The negative side of gaining mass however is that my fitness level has gone down a bit. I'm really fast and a good mover, but after a couple of hard points I'm sweating like Nalbandian
. When I hit top form some year ago I ran 3100 in the Cooper test, I'd be scared to find out what it is now...