Riding a fast triathlon is not all about going as hard as you can. Here are three ways to ride smarter.

When you race a triathlon you cannot expect to go at 100 percent intensity for the entire thing. Pace judgement is critical if you want to execute the best swim, bike and run possible. However, it’s hard to accurately measure your intensity on the bike without a power meter.

Here are three common mistakes triathletes make on the bike, causing fatigue without any overall benefit, and how to fix them using a power meter.

1) Pacing

The problem: Attempting to ride at a constant power output that is too high.

Sort it: The best way to race a triathlon is to spread your energy out appropriately between the three disciplines so that you stay strong throughout. You can use a power meter to help you gauge your race pace with far more accuracy. To do this, you’ll need to know your current best power output for a 20 minute time trial, known as a CP20 test (see previous page) Once you know your CP20 power output you can work out your Functional Threshold Power or FTP.

Your FTP is an estimation of your best average power output for a one hour time trial. It is a common measure of cycling ability and it’s really easy to estimate. Just multiply your CP20 power by 95 percent to get your FTP.

2) Variability

The problem: Riding in bursts ranging from easy to super hard.

Sort it: We’ve talked about the importance of maintaining average power output, but it’s also important to realise that not all averages are the same.


For example, let’s say you did a triathlon where your power constantly fluctuated between 100 and 300 watts. This might give you an average of 200 watts for the entire ride. Then a week later you did another triathlon where your power fluctuated less between 175 and 225 watts.power-meter-4-300x200

The average power would still be the same, at 200 watts. The first example, where your bike power fluctuated a lot, would likely result in a slower run split. This is because big fluctuations in power cause more muscle fatigue and micro-trauma.

Whereas in the second triathlon, where your bike power was smoother, you would probably record a similar bike split and run better afterwards.


This is sometimes known as the variability index (VI). Essentially it’s a score that reflects how much your power output fluctuates around the mean average for a given ride. Ironman winners typically ride at a VI of 1.04, fluctuating their power by only a small amount throughout the race.

3) Gearing

The problem: Riding hard on the hills with inappropriate gearing.

Sort it: In order to ride at an even pace and reduce your variability index, you need to make sure you have the right gearing for your races. If you don’t have appropriate gears you’ll end up riding too hard up the hills or riding at a very low cadence just to maintain forward motion.

This will cause unnecessary fatigue and will make it harder to run afterwards. Suggesting you have the right gearing may sound obvious but not many people get this right. There is a certain amount of bravado about the subject, for example: “I’m so tough, I only need a 23 tooth sprocket for any course.”

But in reality the more you can reduce your variability index and avoid churning a big gear, the less fatigue you’ll experience for a given bike split. If your race route is hilly, you should consider using an 11-28 or 11-32 rear cassette and a compact chainset.