I would define a foundation, as training and racing at shorter distances to build strength and power. This will translate to a faster triathlon at the shorter distances and ultimately preparing you to go faster at the 70.3 or Ironman distance. I will teach you how your body reacts to extreme torture; what works best for you; how to train; what races would be best for you; etc. There are so many things you will learn about yourself during this journey.
I have often thought that almost anyone can complete an Ironman distance race. As I look back over my career and many that I have coached I see a common theme for those that have been incredibly successful. Almost everyone, including myself, had years of training and racing at the Sprint and Olympic distances and all have had an athletic background of some sort. This doesn’t mean that you can’t complete an Ironman 70.3 or full Ironman with minimal training. All it means as that these athletes have a large foundation to build upon.
I will use myself as a case study. I started running in the military. After about 10 years of military service I discovered that I enjoyed it and it was nothing for me to go do a 10-mile run for the fun of it. Eventually someone asked me to run a half-marathon. From there I was hooked and started doing marathons for the next 3-years. It took me 3-years to get to a point where I could run fast enough to qualify for Boston. It didn’t happen overnight, it took years to build my speed and endurance. After about 4-years of running marathons, I was told I needed to stop running. At that point I bought a bike to cross train and continued to run.
At some point, a buddy talked me into doing a triathlon. With no training in the pool and no bike, I decided to join him for a sprint triathlon with a borrowed bike. I had an absolute blast even though I thought I was going to drown in the pool. Two years later, I bought a bike and did my first real triathlon with some training the following summer with little training in the pool and minimal on the bike. I was hooked.
I spent the next 3-years doing local races at the Sprint and Olympic distances. I didn’t know it at the time, but this was when I developed my speed for Ironman 70.3 and Ironman distance races. I remember doing my first 70.3 distance race hoping I could finish the bike in 3-hours which works out to be 18.6 mph. I continued racing Sprint and Olympic distances bringing my speed up more. I got to the point that I was now racing the short distances at 22+ mph. Which easily translated into 20+ for Ironman 70.3 and Ironman distance (pending weather and terrain).
It took years of training to get that fast. I have a good friend that easily ran a 1:10 half marathon. When he started riding and training for triathlons he had no speed on the bike, yet he could run all his competitors down. Years later, he now rides at 21+ mph for an Ironman. The point is it took a coach and many Sprint and Olympic distance races to build his speed and endurance.
If you are interested in completing an Ironman 70.3 or Ironman race, I would recommend you spend 3 to 4 seasons racing at the Sprint and Olympic distances. Take the $3,000 you would spend on an Ironman weekend and apply it toward a coach. Learn the sport, build speed and endurance first. Can you do it in 6-months with minimal experience? Absolutely. However, your experience will be a whole lot different and it won’t be as memorable as if you were to train up to it an learns the sport.