Not tired, not sore ... must not be working hard enough. WRONG!
There are a few common myths we need to dispel. Soreness, fatigue and/or throwing up is NOT a measure of how hard you are working. I often ask, "Are you sore from the last workout? How do you feel today?" because I want to assess what muscles you have already worked and adjust that day's workout accordingly (even though some of you accuse me of taking some sort of sick pleasure in your pain).
Most hard-working individuals equate a good workout with being exhausted and sore. I can't tell you how many times I've had athletes say, "You didn't even make me puke" after a workout. My response is usually, "I didn't make you puke because I didn't want to make you puke. Making you puke would be easy. Getting you stronger, faster and more flexible actually takes some work."
Puking is one of the most catabolic things you can do to your body. If your goal is to increase muscular strength and/or muscular hypertrophy, you should do everything possible NOT to puke during your training!
Fatigue is another popular indicator people use to rate the productivity of their workouts. Remember that the aim of your training session should dictate how you feel after your workout. For example, if you're going to perform a plyometric workout to improve your vertical jump, you shouldn't be exhausted afterward. Actually, a properly designed plyometric workout should stimulate your neuromuscular system, and you should feel better afterward than when you started. On the other hand, is it good to be exhausted after a tough practice that was designed to get you in "game shape" for your given sport? YES!
Read more: http://www.defrancostraining.com/articles/38-articles/63-ten-training-myths-exposed.html