HiiT vs Tempo

These days in cycling circles everyone’s obsession seems to be about what their maximal power is – as if cycling only consisted of maximal efforts up the hill on the local club ride. What they forget about is all the time it takes to get to the hill.

This focus on maximal power has come into fashion with the introduction of HiiT (high intensity interval training). The research shows that doing HiiT training can improve your maximal and endurance abilities, so now everyone thinks we should train this way all the time. While HiiT does play a part in a proper training program it is only a small one. Having a high capacity to do HiiT training, or an impressive maximal wattage, isn’t a good indicator of how you will perform outdoors.

Cycling events and weekend club rides tend to be multi-hour endeavours, often being in excess of three-hours or more. What becomes important in this scenario is what kind of work you can do in an aerobic capacity – what your tempo ability is.

To understand why this is the case we have to look at how much fuel – carbohydrate or fat – is available and which kind of fuel we burn when doing our rides. Important to understand is that the body can store about 2000 calories of carbohydrate (sugar), and that we have an almost limitless store of fat (even in the skinniest of riders) available to us.

When we are riding at or below our tempo heart rate, which is 80-83% of your maximal heart rate, your body is theoretically burning primarily fat, with a little bit of sugar, as its fuel source. Anything above this heart rate and the mix starts to change, with sugar becoming the primary fuel. The harder the effort the more sugar you need in order to do it – you need sugar to jam with the best when the time comes.

Now let’s consider what is happening when you are doing your club ride after a winter of “hard” training.

You have spent a lot of time over the winter training at threshold and doing HiiT training. Your maximal power has increased slightly. But what we want to know is how strong your tempo ability is relative to this maximal power. Typically, we would say that your tempo power needs to be at 75-80% of your maximal aerobic power (MAP) in order to be in balance. If your tempo ability isn’t very strong – even though you can push out a big maximal wattage number – when you are riding in the group your heart rate will likely be above the 83% ceiling for our fat burning, tempo zone. A high heart rate means that while riding in the group you are burning mainly sugar as a fuel source. The whole time you are getting to the point in the ride where everyone likes to jam you are using the fuel, sugar, that allows you to participate in that jam session. Ride long enough and you won’t have any sugar left to burn as a fuel source. If this happens, then you can’t keep up and are left wondering why the other riders are better.

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You can’t perform maximally without sugar. A good aerobic system will save your sugar for when it counts.

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A simple explanation is that in all likelihood the stronger rides have a better tempo ability as a percentage of their maximal power. This means that while riding in the group they can ride below the 83% heart rate ceiling for tempo, burning primarily fat as their fuel source and saving the sugar for when it matters. Interestingly, their maximal power may be lower than yours and yet when they get to the jam session, despite having a lower maximal power number, they are able to ride fast because they still have sugar left in their system.

It isn’t that HiiT isn’t important. This type of effort is what can determine making the split on the group ride or the race winning move. But you still need an aerobic system to get to the point in your ride to make this effort, and you need to get there with sugar to burn. Making sure that your aerobic system is adequately developed is the way to do this.

Determining maximal aerobic power (MAP)

There are many ways used to determine MAP. The best way in our experience is via a 3-minute step test - the test starts at a low wattage and every 3-minutes the watts go up. You can find ramp tests for various abilities in the Sans Chaine “Let’s get you some training zones” program.