"You Take One Week Off Of Training..."
I hope that everyone is able to enjoy some vacation time this summer, and I look forwards to the inevitable laments of "Man, you take a little vacation and come back out of shape!" And while it's true that the first class back can be very strenuous, I don't think it's because you atrophied after a few days off; in fact I think it's quite the opposite. Training hard and often is very strenuous on your body. After weeks or months of class you are pretty worn down, even if you don't realize it. As a result two things happen. The first is that it becomes difficult to push yourself and train at 100% in class because you just don't have the energy. You may feel like you're going all out, and you probably are training as hard as you can, but it's a compromised 100%. The second effect of training long and hard without time off is that you become numb to the unpleasant sensations of class: you're tired and your body hurts all the time, so that becomes the new normal. When you take time off and recover, you're body heals and your energy replenishes, allowing you to go harder than ever when you return to training. But that also means you feel tired like it's the first time. Also, that week off has given your body a chance to remember what it's like to feel good, so when you're sprinting up and down the mat, stopping only to punch a pad for slightly too long, your body goes, "Hey! I don't like the way this feels!" So you may feel like you've lost your conditioning, but I think it's quite the opposite. The time off has let your body and mind recover so that you can train harder than before, and you're probably in better shape than ever.