Ironman Swim Fitness: Is It Critical?

by Kevin Purcell, D.C.

Is it a good use of time to pursue deep swim fitness prior to your ironman? The answer may depend on how much time you have available to train outside of work and family obligations. But be honest, it is a safe bet that most Kona types are swimming quite a bit.

If you have the opportunity, I think it is worthwhile to develop deep swim fitness so that steady efforts keep you competitive out of the water at ironman. It is common to see athletes with lesser swim fitness over-swimming for 60-75 minutes and that can be the start of a cascade of problems later in the day.

Consider this: if you have good cycling fitness, the time needed to increase your bike fitness and drop 15 minutes from your bike split may be more than what is needed to drop your IM finish time 15 minutes through increased swim fitness. How?

Over-swimming will likely lead to decreased ability to fuel and hydrate the bike and run. Being very fit in the water affords us the opportunity to stay competitive on the swim while protecting bike performance (power), the ability to fuel and run fitness. Developing swim strength will save you more than the five minutes you drop from your swim split. Our ability to swim long and strong without generating fatigue is critical in ironman. As stated above, we don't want the swim to materially impact your bike or run splits. You want to come out of the water absent fatigue, seeing appropriate heart rates in transition.

Some athletes feel that they can skimp on swimming because with less effort at the pool they can turn in nearly the same swim split logging 10,000 meters a week as they would on 16,000 to 20,000 meters a week. However, with limited swim fitness they are probably using too much effort over 2.4 miles. To make a desired time, they may raise heart rates beyond what is advisable, compromising the body's ability to assimilate calories on the bike. The remaining 90% of an IM becomes more challenging.

I believe coming out of the water in 57 minutes as opposed to 1:03 will provide the opportunity to ride with superior athletes. The minutes saved in the water through superior swim fitness take on more meaning. The athlete fuels better, is fresher, rides with faster athletes and is likely get to the run much earlier than the six minutes the faster swim split would indicate.

Swim volume adds aerobic fitness without adding risk. For most athletes seeking to lower race finish times, swimming more volume carries very little risk of over-training or injury. If you are focused on lowering race times by 15 minutes consider getting into the pool more often.

I recommend high maintenance swim volume to athletes who are not time constrained because it matters and makes a difference. If an athlete desires to be near the front of his or her race category, everything matters. We can earn minutes in the pool, minutes through better sleep and minutes through improved nutrition. Find time to swim by eliminating things in your day that are unnecessary -- this is the way your competition is thinking and training.

Dr. Kevin Purcell, D.C. works with long course triathletes; from elite to those new to endurance sport. Coach KP has guided over 30 athletes to qualification in Kona, including 10 IM age group championships and two AG podiums. Dr. Kevin is certified in Active Release Technique (ART) and recently did a two week medical rotation at the Olympic Training Center in Chula Vista. Coach KP retired from competition in 2006.