ok, heres the situation. I’m 18 and headed to college this fall. I’ve been doing tri’s for 3 years, mainly oly with a few sprint. I am considering, a half IM, but its not set in stone. I want to do an IM by 2007, and i want to do several marathons first. Should i do one this fall or wait one more year. i know many people say they can do some damage under a certain age.
Bob
As someone who started tris before college like yourself, I’d focus on the shorter faster stuff for now and worry about the longer stuff in several years. Just as you have planned. If you putting in enough volume the half will be no problem. You can always go longer and slower but as you get older it becomes harder to develop and maintain that high end top speed. Develop your leg speed then worry about the IM. I’m about 2min off my road 10k and about 2:25 off my track 10k pr from college. I’m in my early 30’s for reference.
I kinda agree with Desert Dude. But really it depends on your specific goals. Are you doing the marathon because you want to say you finished one? Or because you think it would be good training for triathlons? Or because you want to race the marathon? The answers to these questions would help you decide if a marathon is a good thing now.
At age 18, with an athletic background, you’re not too young to go for a marathon.
I’m 40 years older. At age 58, am I too old for a marathon? Some say yes, including my wife! But I’ve done 3 marathons in the last two years and just recently completed the Utah Half IM Duathlon (swim was cancelled). Sure, my marathon times are down from when I was in my 30s (2:58 was my PR back then, 3:53 is my best time of the 3 recent ones), but I’m enjoying the experience more than ever.
Definitely wait a few years and you’ll run much better. I would recommend running with your university cross-country team (most coaches love walk-ons if you’re in good shape 
) Do this for a few seasons and build up more strength … I ran competitively for age 11 until 25 when I did my first marathon off 35-40 miles/week and only 3 runs longer than 10 miles (I did the race really last minute without any planning). The fact that I had trained for so many years and had put in lots of 70-80 mile weeks when I ran university cross-country definitely enabled a much better result (2:32) than if I had jumped into one at 18 without the years of base… same theory goes for ironman so waiting a few years there like you plan will pay off. My $0.02 …
i am purely doing the marathon to get ready for IM. I am positive i can finish the distance. I ran cc for my high school and our longest runs were around 10-13 miles, which i felt fine for. Once i get past mile 5 or 6 i get into a comfortable pace. I am not interested in racing to win my age group, but i want to finish in no more than 3:20.
Bob
Bob,
Okay then, follow your heart. I say, if you want to run a marathon, go for it. But run it conservatively. Start out much slower than you think your should, and much, much slower than you feel like you could. It seems that no matter how many time or how many people tell young (and sometimes old) runners to start off slowly, the new marathoner just can’t seem to hold back. If you don’t have the discipline to hold back, i.e., know the pace at which you’re supposed to run the first few miles and stick to that pace no matter how slow it feels, don’t run marathon.
–Scott