Coaching, Training, Camps.

The art of pacing is critical and vital for race-day success, ensuring you expend your energy at the finish line and not beforehand. Approximately 50 percent of your Ironman will be spent on the bike. How you pace yourself will not only impact how fast you get complete the bike course, but also how well you run the marathon. Pacing is an acquired skill and, like all skills, it’s improved by  solid hard work. Hopefully I can clarify how to correctly complete the longest leg of the race – the bike.

When you exit the swim and start riding your bike, your body undergoes radical changes  because you’ve gone from a lying position – with most of your weight supported by the water and using your upper body for propulsion – to sitting more upright on a bike, using your legs to drive you forwards. This will result in an extreme transformation as blood flow has to be rapidly redirected and the demand for oxygen rises causing a physiological disruption  that can make snapping into a sustainable rhythm hard and difficult.

To help keep your level of effort under control as you leave T1, put the bike in a relatively low gear so that you have to spin your legs, rather than giving them a huge amount of resistance to push against.  The goal is to  pedal smoothly  and efficiently while you find your desired rhythm  as you build to optimal race pace. Also, try to stay low on the bike, except when climbing steeper hills, to maintain efficient aerodynamics and sleekness.

Hopefully  you should have spent time over the last few months developing a pedal cadence of between 80 and 100rpm – your natural and most efficient pedal cadence is likely to be somewhere in this range. Attempt to maintain this cadence   during your  race.

Don’t make the mistake of riding higher (or harder) gears and reducing your RPM to a rate that’s lower than the one at which you have trained your legs to work efficiently. Maintain the cadence rate you have trained for. Don’t ride harder gears at a slower cadence because your leg muscles will fatigue quicker and it’ll be harder to run off the bike.

Your cadence rate will also affect your heart rate – pedal slowly and your heart rate will probably drop, but you will consume too much muscle power. Pedal too fast and your heart rate will increase, but you’ll be wasting energy and not enhancing  your speed. Change your gears during a race to maintain an even cadence.

There are a lot more external factors that can influence bike pacing. The most common are wind and hills, and it’s prudent to be well informed about these, so check out the course profile and weather forecast in advance. Obviously, achieving even-pacing on a flat course on a calm day is much easier than on a rolling route with a brutal headwind.

When you’re riding into a headwind or ascending a hill, you’ll obviously need to exert more effort and power  to maintain a reasonable speed, but be careful not to fight the added resistance too aggressively. When climbing, aim to reach the highest point of a hill without your legs being completely thrashed and battered, so that you can maintain the pressure over the peak and immediately click up the gears to keep the effort going down the other side. If you really push yourself here you’ll raise your pulse rate above your lactate threshold, go anaerobic and accumulate lactate in your muscles. This will slow you down for the rest of the race, resulting in losing unnecessary time.

Furthermore, sprinting up a hill and coasting down the other side is definitely not efficient in terms of energy utilization and consumption of  average speed versus going moderately hard on the ascension  and keeping force on  the  way down without easing off  unless it’s dangerous. Any time spent riding at, or under, your lactate threshold heart rate will slow you down, so pedal downhill to keep your pulse rate up. Therefore, keep an eye on your heart rate monitor and control your effort, making sure that you don’t exceed your lactate threshold heart rate. You may feel that you should be riding harder, especially if other athletes are passing you on the hill, but don’t worry – if they’re pushing themselves too hard their bike split and overall race time will be adversely affected. Maintain a constant heart rate at, or just below, your lactate threshold.

With all this being said  why do so  many age groupers go out way too hard and then suffer the last 40 miles, which then seriously affects their run!

Because the bike makes up such a significant chunk of your race, overexerting yourself can lead to a disappointing run. If you train properly there’s no need to make any serious sacrifices. Instead, focus on the tactics that will help you successfully execute the bike without putting your body into overdrive, or tapping into important run energy reserves. Training to race an Ironman requires a lot of time on the bike. This isn’t just because you have to cover 112 miles, but because you have to cover this   distance and still feel fresh enough to complete a full marathon. Aiming for an average or above-average bike split without conserving some energy for the run is a mistake that usually leads to a sub- par performance. Instead of focusing  on bike split rankings , race according to your ability and training so you can finish strongly. If you pace yourself appropriately   on the bike, you can use the extra energy you reserved to shave critical time off the run. If you overdo it on the bike you increase the risk of bonking   and falling apart on the run and thus   adding minutes (if not hours) to your total time. Instead, dial your bike back a notch to ensure you’re able to stay strong through the entire 26.2 miles.  The ideal way to complete  112 miles is to evenly split or descend the second half. Ultimately,  the ride really starts at mile 80.  That’s when big time is either gained or lost.

To optimize your performance during a race it’s critical that you carefully control your effort. The Ironman bike needs to be a stable transition from swim to run. The goal is to keep perceived exertion, heart rate and power quite measured and controlled. As expected you’ll experience   fatigue and exhaustion, but with correct pacing there should be minimal negative impact.  Thus, try to evenly split or descend the second 56 miles and change gears often as   this changes how the muscles work and can spread out fatigue. Try to keep the RPM’s up (this must be a process of adaptation in training) but stay in the HR  zones set up based on past training and testing.  These zones are extremely critical on the bike and first half of the run.  Fuel and fluid intake is obviously very  imperative especially on the bike. The last 30-40 miles is when the bike leg really starts to hit you hard and it will take great focus and concentration to keep  your technique tight and finish the bike portion strong. Once your technique falls apart- you end up working harder to go slower.

In summation, the difference between a “good” swim   or “bad” swim is only about two to five minutes. The variance between  an “easy” bike or a “hard” bike is only about 10 to 20 minutes. But the difference between a “good” and “bad” run can be measured in hours.

The truth is, your likelihood of dramatically slowing down occur in the last 6-8 miles of the run. Therefore your focus all day is on creating conditions and circumstances for success in the final 6-8 miles of the run, NOT on laying down an awesome bike split. The Ironman run course is scattered with  walking  athletes who posted incredible bike splits.


Robert Haviland

M.S-Exercise Physiology/Rehab Science/Sports Performance

C.S.C.S, C.E.S. , C.N.C

Multiple USAT All-American  athlete