The Irish Society of Chartered Physiotherapists (ISCP) offers expert advice to all athletes:
The week before:
By now you should be in your wind-down training phase in which you are reducing your number of miles. A lot of people are tempted to get an extra training session in before the big day. Don't. The wind-down stage is very important. It allows muscles to repair from months of hard training and prepare for the race day. Your hard work is done and you really need to conserve your energy. In the coming days make sure to get plenty of rest, drink lots of water and eat a good balanced diet rich in carbohydrates.
The night before:
Stick to your routine. Get enough sleep and avoid caffeine, tea and alcohol. Don't be tempted to over-eat in an attempt to build up energy stores. Doing so you run the risk of bloating and a bad night's sleep - not what you want the night before a 26-mile run.
Morning of marathon:
Eat a light carbohydrate-rich breakfast three hours before the race. Don't try anything new. Just go for what you normally would have, ie cereal, toast and jam, toast and a banana, scrambled eggs. Have your bags ready and know what you are going to wear. Rubbing Vaseline on your chest, under your armpits and on your nipples and groin area is a good idea to ward off chaffing and blisters. Wear properly fitting clothing that you have worn in already. Don't be tempted to wear new runners even if they are state-of-the-art trainers. Familiarise yourself with the race route.
Warm-up:
Always, always, always warm up and stretch before the event. A warm-up helps prepare your cardiovascular system for exercise and prepares your muscles for stretching. A warm-up should consist of light cardiovascular exercise until you feel warm and have a light sweat. When stretching hold each stretch (no jerking or bouncing) for at least 10 seconds to get the most benefit. Concentrate your stretching on the main muscle groups you are about to use. For runners, the main groups are the quads (at the front of the thigh), the hamstrings (at the back of the thigh) and the calves (stretch with the knee bent and straight to get both muscle groups here).
During the marathon:
During the race if you feel a cramp or strain slow down to a jog or walk for a bit. Stopping and doing some stretches can be a great help.
It's a good idea to bring a snack on the race. Glucose tablets don't take up time and dissolve under the tongue. Sports drinks give you carbohydrates as well as replace electrolytes lost through sweating. Otherwise, a cereal bar or Jaffa Cake can do the trick. Go with what you are used to. The day of the marathon is not the day to change things.
Make sure to take advantage of the water stations which are positioned every three miles along the race route. Having a marathon buddy is a great idea for when the going gets tough, otherwise make some friends along the way or draw inspiration from the crowd.
After the marathon:
After the race the most important thing is to drink water or an energy drink, eat some carbohydrates and keep warm. The idea is to bring the heart rate back to its resting state and to cool down slowly. Walking back to your car is an ideal way to cool down slowly. When you get home have a cold bath. This will help constrict the blood vessels, helping the return of blood flow to the heart and make way for fresh blood. During the race you will experience some micro tears and a little bit of bleeding. If you have a hot bath it will help increase the blood supply and make your injuries worse. A cold bath will help prevent muscle soreness and initiate the recovery process.