1. Cool Down
It is recommended in all research I can find that a runner should not stop to stretch or lie down after a strenuous exercise. The cool down can be a simple walk or jog after the race. I walk for at least 10-15 minutes without sitting or stretching to ensure the muscles have time to cool down with a light stretch from regular motion. Sitting or lying down will allow cramping. Stretching may overstimulate the stretch mechanism in an exhausted muscle and produce cramping or even injury. Stretching can be done after the cool down and is a good idea if done at the right time. If the cool down is done effectively, it will alleviate some of the after marathon recovery.
Any amount of exercise utilizes the glycogen in muscles as an energy source, with blood glucose and free fatty acids. As the exercise level progresses to longer exercise or more strenuous exercise, these sources become depleted more quickly and "anaerobic" (without oxygen) mechanisms are utilized to produce lactate. The lactic acid in muscle fibers or even the muscle breakdown to obtain necessary energy can lead to muscle pain and stiffness. The speed of muscle recovery is determined by the amounts of lactic acid or protein (muscle) breakdown is required to repair the muscles (especially after an exercise is completed).
The University of Illinois did a study on rats in 1999 that showed quicker muscle recovery from this depletion with refuelling with foods containing Leucine (an amino acid) immediately after exercise. They showed muscle stiffness and soreness would subside more quickly. More recent studies have found 30 minutes to be the key time for muscle recovery. The foods eaten in the first 30 minutes after exercise help rebuild the muscles, while foods eaten later have less benefits for muscle repair.
Leucine is found in protein products such as meats and dairy products, as well as in protein bars and some sports drinks. It is not recommended, however, that pure amino acid supplements be taken, because the beneficial amount is not known. In the study, they made the following findings: "It [Leucine] stimulates muscle protein synthesis, provides fuel for the muscle and helps to maintain blood glucose. What really surprised us was that its activity is not seen when leucine or protein is consumed before or during exercise. Instead it has a dramatic impact on protein synthesis during the recovery period after exercise."
So how do I refuel after a race? After any run, and especially after this marathon, I drank a large glass of milk withing 30 minutes of completing the exercise. Fluids are also imperative as are some other carbohydrates to help further maintain blood glucose and reduce lightheadedness from low blood glucose. When I don't want to eat within 30 minutes after an exercise, I eat anyway, especially the large cup of milk and/or a yogurt to get the Leucine benefits.
3. Fluids, Fluids, Fluids...
An important part of refueling is fluid replacement to replenish the body. I have a tendancy to start sweating when I think about exercise. I therefore must replace a large amount of fluid after any form of exercise. This replacement is both for refueling and for providing the reservoir for flushing out waste products from the body and especially the muscles. It requires more fluid to carry all these waste products out of the muscles into the kidneys for excretion. Try to drink 6-8 ounces of water every 2-3 hours during the initial recovery period.
4. Hot or Cold?
Everything I have read recommends ice baths or ice massage after a strenuous exercise, and often they recommend avoiding the heat after exercise. I will say now that I aggressively treat my muscle soreness after an exercise (even after the marathon) with soaking in a warm bath or hot tub. Let me now discuss the science behind my actions. (Note that for me this works really well and decreases my muscle soreness significantly within the first 24 hours and reduces it nearly completely by 48 hours.)
The body reacts to hot and cold by dilation or contracture of blood vessels. Cold (ice) will reduce(vessel contracture) the blood flow into the area or cause the body to pull the blood from the area. Heat will increase (vessel dilation) the blood flow to the area and allow increased blood flow through the area. Since muscle pain is often due to lactic acid in the muscles or other waste products of "anaerobic" muscle metabolism (contracture), heat will allow blood flow through the muscles that can remove these waste products. Heat is only recommended by me during the first 12-24 hours. Ice can be utilized at anytime, but is rarely necessary if I undergo my usual exercise recovery regimen.
I have found through the use of these 4 simple techniques that I can continue to run, recover quickly and not suffer for days - weeks after a strenuous exercise. I plan to continue to train and run marathons and will evaluate the benefits of this regimen after any strenuous exercise. The proof will be in my recovery. Currently I am basically painfree the Monday after a Saturday 26.2 miles...I hope this helps.