I've seen dozens of runners from 

the  cross-country team at Boulder High  grimace,  shiver and squeal as  they sit in an ice bath, hoping to stop muscle soreness after a particularly grueling workout. 

All that pain for nothing. Too bad they don't know it won't h elp. There are some things you can do for delayed onset muscle soreness (DOMS), but a 15-minute ice b ath isn't one of them. 

Keep reading.

First, if your muscles are sore after a workout, should you worry?

Timing is important. Muscle soreness is only worrisome if it happens during or shortly after the workout. Ea rly soreness means you have an injured joint or a muscle strain that should be evaluated. But, if you experience muscle soreness 1 or 2 days afterwards, that's part of getting stronger. You may start to feel sore at 12 hours and by the second day, those muscles may be even sorer. The muscle is weakest one day after the workout, but then after 4 days, you are stronger than before.

  

What is a muscle strain versus just a sore muscle from a workout?

  

A muscle strain means you've torn the muscle all the way across the fiber. Not good. When you do a lot of new exercise, especially eccentric exercise, instead of a big tear, you have what looks like Swiss cheese - lots of small tears as you break down the muscle. Those micro-tears cause local inflammation. When the soreness disappears, what broke down builds up and you end up with a stronger muscle.

  

In DOMS, soreness is a sign you've done something different. The exercise is either more intense, a different type, such as eccentric, or you've used a muscle you aren't accustomed to working. So, if you run faster, for example, you are using more fast-twitch fibers, perhaps your stride is longer so the muscle is working in a different range of motion - something has changed. That creates soreness and eventually strength.