The uncomfortable sensation in your muscles during a workout is caused by metabolic waste products that build up during exercise. Lactic acid is one waste product that has long been labeled the culprit of this burning sensation.
Lactic acid is also given a bad rap when trainers state that lactic acid causes the next-day soreness that sometimes occurs in the days after strength training. This is untrue. Lactic acid does not cause soreness. The soreness is likely caused by muscle damage and inflammation.
In fact, lactic acid is cleared from your muscles in minutes after exercise (and it is almost completely cleared within an hour at the most). After all, we know through experience that the burning sensation does not last beyond the post-workout shower. And if you spend a little extra time in your cool-down, you can even help remove the lactic acid faster.
Unfortunately there really is no way around the muscle soreness that will show up tomorrow or two days later (as is often the case for lower-body muscle soreness). If your training caused muscle damage (as strength workouts tend to do – but in a safe, strategic and effective manner), then you will probably have a little bit of muscle soreness tomorrow.
You just have to cut down the volume to avoid getting so sore. So don’t jump back into the weight room by doing 3 sets per exercise. Do 1 easy set, and you won’t be too sore.