Ice And Heat For Sore Muscles: Is It Heat, Then Ice? Or Ice, Then Heat?

Use ICE primarily to soothe ACUTE pain in one specific area that strikes out of the blue (like your back, knee, etc.) reduce swelling & inflammation

When To Apply:  Ideally, you should always apply ice within 1 hour of the ache, pain and soreness setting in (like after a workout).

A Good Regimine: Ice for 15 minutes max, then 30 minutes without. Do this up to 4 times a day, as needed. For up to 2 days max. (If you still need pain relief, then switch to HEAT (below).

How It Works: Cold temperatures reduces nerve-cell activity while constricting blood vessels to ease swelling.
 

Tips For Using Ice On Sore Spots:

Help to eliminate a bad bruise by applying ice directly to the sore spot. The ice decreases blood flow to the area. Since a bruise is basically a build-up of blood under the skin, you'll effectively be making the bruised area smaller. 

Use an ice pack or a bag of frozen vegetables wrapped in a towel. Don't put ice directly on the skin.
 

If the pain is in one of your limbs (hand, finger, toe, etc.), you should elevate the limb higher than your heart if possible for 24 hours after the injury to reduce swelling and pain.

 

Use HEAT primarily to soothe CHRONIC pain that comes & goes over time (like lower back, neck, hamstrings, etc.) relax tight muscles

When To Apply:  Ideally, you should always apply heat after the any acute pain associated with the area has passed. Otherwise, you could worsen the swelling in that area.

A Good Regimine:  Heat (in the form of a heating pad or soak in a hot bath) for 20 minutes. Do this up to 3 times a day, as needed.

How It Works:  Heat increases circulation and loosens the muscles. Heat helps calm muscle spasms and relieves soreness.

Tips For Using Heat On Sore Spots:

Make a moist heat wrap by filling a sock with dry (uncooked) rice, stopping 2 inches from the top. Close tightly with a string, then microwave for 2 minutes. Lay this over your neck and reheat when it cools.

Apply a warm washcloth to your neck, then very slowly move your neck through its full range of motion -- forward, side to side, and back -- until the neck feels less tense.
  

For a heated soak in the tub, add 2 cups of Epsom salt to warm (not hot) water. The magnesium in the salt reduces inflammation and helps to ease the pain. It's also an electrolyte that helps to ensure proper muscle, nerve, and enzyme function in your body.

 

And, on a related note...

Use ANTI-INFLAMMATORY medicines to reduce pain

When To Take:  You can take anti-inflammatories before you think you'll experience pain, or right after you experience pain.

Some examples:  Ibuprofen (Advil) or Naproxen (Aleve)


Sources:
All You, December 2007
Good Housekeeping, March 2006
Family Circle, September 2007
Good Housekeeping, June 2006