How to train with a power meter – part six: how to use your power meter to pace a race or sportive
You're in red-hot form, but how can you make sure you produce your best performance on the day?
Back in my first piece in this series on how to use a power meter, I touched on the fact that having a power meter can help you put the gains you have made in training into practice in a race or sportive situation.
Now, let’s be clear, a power meter is, first and foremost, a training tool. However, there’s no point in making huge strides forward in training to then go too hard and blow up on the first drag during a 100 mile-sportive.
A power meter is the perfect tool to help you plan and then pace your effort on race day. Here’s how to ensure you produce your best performance when it really matters.
In order to decide upon the pace for a race or sportive, you first need to take a close look at the event in which you are participating and come up with a plan of attack.
As an example, I am going to use one of the most popular sportives in Europe: the Etape du Tour. The Etape will this year follow stage 18 of the Tour de France, from Briancon to the summit of the Col d’Izoard at 2,360m.
The route is 178km and opens with 120km of deceptively undulating roads and then two major climbs, the Col de Vars (9.3km at an average gradient of 7.5 per cent) and the Col d’Izoard (14.1km at an average of 7.3 per cent). Pacing the event correctly will be key in finishing in the fastest time possible.
For this example, I am going to use a fictitious rider weighing 70kg with an FTP of 300 watts, but exactly the same principles apply regardless of the rider – you need to tailor your plan based on your fitness, the length of the event, and its specific demands.
Now we need to break the route down into segments and decide on a pacing strategy.
The first 120km of the route is on very undulating roads – the type of rolling roads which can be deceptively hard to ride – and if a rider goes out of the blocks too quickly, they will soon pay the price. On this section of the route, the best bet will be to share the workload in a big group, maximising the rider’s speed while still keeping energy expenditure under control.
Even if we take a fast moving group riding at a sustained 40km/h, then this segment will take at least three hours to complete. Therefore, we need to find a power output that is sustainable for at least three hours.
A rider can be expected to ride in the ‘tempo’ zone for up to three hours, but this will mean burning an awful lot of glycogen – the primary source of energy in zone three. Glycogen stores are limited and, while they can be topped up during a ride, it makes a lot more sense to save that precious glycogen for the big climbs at the end of the Etape.
Therefore, a sensible option would be to aim for an average power output on the border of zone two, where the primary energy source is fat, and zone three – for our fictitious rider that would roughly be between 220 and 230 watts, striking a balance between speed and saving energy.
Of course, if you’re riding in a group then you may need to go above the suggested wattage to follow the wheels on climbs, so it’s important to keep an eye on your average power. Don’t be afraid to push on up the climb to stay with the group, but don’t go into the red and aim to keep the average power between 220 and 230 watts to ensure you aren’t doing the lion’s share of the work in the group.
Col de Vars (9.3km at 7.5 per cent)
When planning how to pace a climb, whether it’s in the Etape or not, you have to look at how long the climb is likely to take. From that, you can work out what power output is sustainable for that period. Of course, it’s not quite as simple as that because as the power goes up, the time it takes to climb comes down.
With that in mind, there are two ways to decide on pacing: one uses other people’s data on Strava, the other is purely a calculation. I tend to use both as the calculation is very specific to a rider while Strava times take into account things that can’t be factored in, such as prevalent wind conditions and the road surface.
Before you even login to Strava, go back into your training files and find the last hill efforts you did at threshold pace. Now make a note of the VAM score (look back on my article on how to analyse a training file for more on VAM) for the efforts. We’re going to use a VAM (rate of climbing) of 1,100m/h in this case.
Now take a look at the climb on Strava and find your weight category, in this case 65-74kg. Then find a rider for the segment with a very similar power to your FTP and similar VAM scores to those you have achieved when training – this helps match the weight more accurately. You now have a rough guide to your climbing speed. Going off this, I can find a rider who has ridden the Col de Vars with an average wattage of 307w and a VAM of 1,113.6m in 36.13mins.
The second method is to use the online calculator at www.bikecalculator.com – input all of your details and it will calculate an overall time. For this example, the calculator estimates a time of 35.54mins for a 70kg rider at 300 watts.
You now know the Col de Vars will take approximately 36 minutes, so you can go back to the peak power graph described in my article on analysing a training file and find your best ever power output for around 36 minutes. In this case, that delivers a value of 309 watts – now we know the target power out for the Col de Vars.
Col d’Izoard (14.1km at 7.3 per cent)
Repeat the method above for the remaining segments – working in a group on the drag up to the foot of the Col d’Izoard, then the target pace for the Izoard itself. Once again, using a combination of Strava and the online calculator, we can set a target pace of 302 watts for 52:45 minutes.
Riding with feel
Now, having set a pacing strategy, this may sound strange (particular when, as a coach, I am such an advocate on training with power), but it’s also important to learn to ride with feel.
We all will have experienced one of those rare days on the bike when everything feels easy – but it’s also very easy to go too hard in those situations and then pay the price later on. Learning to understand how your body feels, in combination with the numbers your power meter is producing, will stop you going too hard.
If everything has gone to plan in training and you have tapered correctly, then on the day of your main goal of the season you should ideally be on one of those days when it feels easy. So, to keep your effort under control, you need to ‘calibrate’ what you are feeling with what your power meter is telling you. You can work on this during training, learning to be in tune with your body and its reaction to the effort you’re producing.
When riding your event, you should regularly be glancing at your head unit to see your power meter readout, as this will allow you to equate how you feel with a wattage. If on a climb, you should take a quick look at your power meter reading every 30 seconds or so, and this will ensure you haven’t dropped off or pushed on too hard. Taking the above example for the Col de Vars, our fictitious Etape rider should be checking their power output every 30 second so they can be sure they are roughly on their target of 309 watts.
On top of this, if there are any change in external factors, such as drafting, wind, gradient, then it’s worth checking you power output again to see if you are riding at the correct intensity.
What about fatigue?
One important thing we haven’t factored into our pacing strategy is fatigue. The target pace represents the highest wattage you will be able to hold for the climb, however, you are obviously going to get tired throughout the day, so on the last climb the predicted pace may not be achievable.
That said, having a target will mean that you don’t start the climb too fast. I suggest you ride the first kilometre of that climb ten per cent under your target wattage. Then, based on how you are feeling, make an assessment of the target wattage and re-asses.
Having a plan that is based on your historical training data, combined with your power meter providing constant feedback, means that on race day you should be able to pace your effort perfectly and put your new-found form into practice.
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