Just wondering if there is any good reads out there explaining why tennis skills seem to fluctuate. Or if anyone has some knowledge in the subject I'd like to hear it. For instance the past month or two I've been serving well. Hitting the lines, high first-serve percentages, etc. The last few days have been disappointing though (especially last night). I keep missing my first serves by 4 feet. I'm not hitting cleanly. Same thing has been happening to my volleys. I'm not hitting cleanly and they are floating too much. I'm also placing poorly and they are coming back more even when I have a good setup for an offensive shot. On the contrary, my backhand has been unbelievable recently. I always have big trouble returning serves with the backhand in my monday night block, but last night I was returning everything. Forehand has also been pretty reliable. EDIT: Whats interesting is that its not just that some days my shots go in and some days they don't, but that I feel less coordinated some days and that execution of the shot is more difficult. Why do I keep going through these ups and downs like this?