When we push our body outside it’s comfort zone, you cause your muscle tissue to tear, and in order to recover, you need water, protein, rest and STRETCHING. So if we do all that after a workout, why do we get second day soreness? Well…there are lots of theories. One says that lactic acid continues to build up in your muscles for days (??) after your workout. This is false. 
Lactic acid DOES build up in your muslces during your workouts, AND causes SAME DAY soreness. When you rehydrate and get a good stretch, the pain usually subsides. Okay…another theory is that SDS (technical term: Delayed Onset Muscle Soreness…but I like SDS better. So there.) occurs while your muscle fibers are repairing themselves. Basically, you’ve done so much damage that to fix it is painful. Not so much.
Here’s the deal: no one really knows why you can’t walk 2 days after that killer leg workout. But you can do something to help. Drinking LOTS of water (more than your standard 64 oz.) is a good start. So is stretching (both dynamic and static) BEFORE and AFTER your workouts. Basically, we’re all stuck with it at some point. Thankfully, as we get stronger, SDS will go away. Our muscles will adapt to the new exercise and we’ll feel great on day 2. Until then, take a few days to rest if you’re hurting (I mean really hurting…can’t walk up the stairs kinda stuff) and then get back into it. If you’re mildly sore, it’s probably fine to workout again. Just listen to your body and if it says “stop”, then stop.
