If you’re new to power data, have only used power “virtually” on a smart trainer or have just taken delivery of a brand new powermeter for your road bike, one of the first things you’ll want to do is set up new data fields on your Garmin or Wahoo GPS unit (other brands available, apparently). There are quite literally hundreds of data fields to choose from, some more useful than others. Here’s a quick run down on the most useful metrics to display.
3 Second Average: One of the first things you notice when using power on the road is just how variable your wattage numbers are. They jump up and down constantly. A change in road surface, minor gradient changes, shifting in the saddle, a change in wind speed, every variable will sway your numbers. Using a three second average (rather than instant power) will “smooth out” the number you see on screen. This keeps the displayed wattage more stable and in turn makes it easier to maintain a set wattage range if training to power zones.
Lap Average: The average power output for that lap, pretty self explanatory really! I have my Garmin set to auto-lap every 10km, but you can also use the lap button at any time. It’s VERY useful if you want to pace yourself over a segment or complete a climb to a set power range. Simply hit the lap button at the start and maintain your prescribed power for the duration. Note that lap average power includes zeros, so in some cases you may want to use…
Normalised Lap Average: This is arguably a more useful metric than Lap Average Power, as it takes out all the zeros (coasting) and just gives you the “normalised” power for that lap. It’s a better representative of the average power you could hold if the entire effort was steady. This is similar to Strava’s “weighted average power” number ( both are proprietary so use slightly different calculations). The difference between average and normalized power can also be a useful metric.
Max Power: I’ll admit, maximum power output is not exactly the most useful metric to display, but it’s an interesting number to know for café boasting. I tend to display Max Lap Power rather than the maximum power for the entire ride. That way, I can reset the data field by hitting the lap button. Useful if you’re out hitting some sprints!
Max 3 / 5 / 10 Second Power: If you’re a big sprinter, having an average for your max short duration power may be useful for you. Or if you’re training for crits where a 10-second burst to maintain position out of every corner comes in very handy. For the rest of us club riders, you’ll be able to see how many watts you needed to bag that five second town sign sprint! As a much lighter and far less powerful rider I am not that interested in this metric.
Left / Right Bower Balance: If you have a dual sided powermeter such as Favero Assioma Duo pedals, you can display your left-right power balance. While the usefulness of this data is up for debate, it can be quite interesting to know how balanced – or unbalanced – you are! It’s also interesting to track how your balance changes as you fatigue over a hard ride. There are a whole raft of other pedalling dynamics you can display too, but I find its best to dig into this stuff after the ride, rather than have it clog up your screen.
With the vast amount of data available to display, it’s important to remember to look up, pay attention and actually enjoy the ride! It’s no use knowing you’re doing 4.25 watts per kilo with a perfect 50/50 left-right pedalling balance when you crash into the rider in front. Don’t be a “stem-staring Froome” out there. The great thing about power data is the ability to analyse your performance AFTER the ride.
My advice? Keep your Garmin fields simple. Don’t overwhelm yourself with data during a ride. A minimalist approach of three second average power and lap average power works wonders. It’s more than enough.
One last tip: If you’re serious about using that fancy new powermeter to train and track your performance, I highly recommend this book: Training and Racing with a Power Meter. Read it cover to cover, then read it again. It’ll have you well on the way to using that powermeter effectively. Knowledge = power!