
Whether you are toeing the starting line at the local 5k or anxiously awaiting the starting gun at the Boston Marathon, race morning is no time to be experimenting with new things. Running blogs and magazines are littered with horror stories of people making a last-minute switch to the cool new pair of socks their friend told them about, or the newest energy gel they read about in a magazine the night before.
A training partner of mine, who happens to be the fastest guy in the state at every distance 10k and longer, decided one morning a few months ago to take a caffeinated energy gel right before his 5000m race. He had forgotten his regular cup of coffee and tried to make up for it by taking a gel.
Eating anything that close to a race is never a good idea, but especially something you have never tried before. Half way into the race, he dropped out after having some stomach issues.
So whatever you do, don't change anything about your routine on race morning. You should be wearing the same top, shorts, shoes, socks, etc. on race morning that you have been training with the weeks leading up to the race.
In fact, it is recommended that you running your last few pre-race runs in exactly the clothes - head to toe - you plan on using on race day.