Sign up for our newsletter

Data, data everywhere: understanding the world of training data

29 Sep 2021

It’s not the data itself that’s valuable, it’s the insight you extract from it

The increased availability and affordability of technology such as heart rate monitors and power meters means that most modern cyclists generate, track and log a huge amount of data on each ride. Gone are the days when you had to make do with an elapsed time and distance, measuring efforts on ‘feel’. Now, you have access to real-time, lab-level analysis at your fingertips, while it’s possible to drill down into the minutiae of any data field as soon as you walk back through your front door.

It’s all very well creating all of this data, but it’s meaningless unless you can understand it. Seeing that you spent 10% of your ride in zone 4 of your heart rate or that your hour-long session’s training stress score was 85 is useless if you don’t go on to use this information to inform future training sessions or riding intensity.

Here, we’ll run you through various fields you’re likely to look at post-ride, what they’re showing you and how you can use this insight to help you reach your training goals. 

Functional Threshold Power

Functional Threshold Power (or FTP) is the maximum number of watts you can average for 60 minutes. In theory, you shouldn’t be able to ride above your FTP for a sustained period, as it would lead to faster fatiguing or, in the worst case, the dreaded bonk.

Your FTP is a good marker of your overall fitness and is something that can go up or down depending on your training – all you have to do to find out if you’ve improved is put yourself through a somewhat unpleasant FTP test.

Once you know your FTP, you can use that figure to determine your power zones (more on these below), which can be very handy when it comes to targeted training sessions. In general riding, knowing and understanding your FTP is a great way of being able to manage your efforts on climbs or sprints.

It’s worth noting that having a higher FTP than another rider doesn’t necessarily make you a better cyclist (or vice versa). The key figure here is watts per kg, where you divide your FTP by your weight. This is a more appropriate figure to compare and determines how your power translates on the road – it takes more power to move a heavier rider, after all.

Training Stress Score

Each ride or workout generates a Training Stress Score (TSS), which is calculated by multiplying the intensity of the activity with its duration to give you an idea of how much it has taken out of you.

While it’s great to have a figure confirming that, yes, that session really was as hard physiologically as it felt, TSS comes into its own when planning recovery, rest and what future training loads should be. For example, if you had a recommended TSS for the week of 350 and were already at 300 with one ride in your training block to go, it would be a good idea to keep that final session at a low intensity.

Your cumulative TSS is a great way of increasing your training load in a measured and sustainable way too. For example, if you had a cumulative TSS of 350 for the week, you can plan on increasing that to between 371-399 the following week – any more and you’re likely to be overtraining and pushing yourself to do too much too soon.

Power distribution

When you train using a power meter, the data will be broken down post-ride into zones. That data generally comprises seven zones, each covers a range of a percentage of your FTP. For example, zone 2 would be time spent riding at 56-75% of your FTP and is general endurance riding, while zone 5 is your VO2 Max – roughly 106-120% of FTP.

Analysing your ride’s power distribution is beneficial if completing a drill or session where you’re tasked with riding at a specific intensity for a set amount of time. The graph shows you how successful you were at achieving the predetermined goal, or if there were points where you went too hard or not hard enough.

Over time, if your power distribution graph shows that you’re consistently not able to ride at a particular intensity during training, it could be time to add some specific drills into your schedule, targeting your weakness to make you a better all-round cyclist.

Heart rate zones

Like power, your heart rate can also be broken down into zones. Instead of being based on a functional threshold, though, the zones are determined on a percentage of your maximum heart rate – you can’t go above 100%, after all.

Although there are some flaws in looking solely at heart rate data – short, sharp, intense efforts sometimes don’t have a corresponding increase in beats per minute because of the slowness of heart rate response – it helps to give you an overall idea of your fitness and your body’s adaptation to a training plan.

For example, if over time your heart rate zone distribution starts to skew left but your power output remains the same, it shows that your body is able to produce the same amount of power for less effort. An irregularly fast heartbest can also be a sign that your body is trying to tell you something – whether that be you’re overtraining or that you might be getting ill.

Even clearer insight

While it’s useful to be able to have an understanding of the data your rides generate and what your body is potentially telling you about its physiological adaptation to training loads, the best way to get the most out of your results is by getting the insight of a specialist. Traditionally, this has meant securing the services of a coach, who would spend time poring over your TSS, power distribution and heart rate readings to create or amend the next stage of your training programme.

Now, that feedback can be instant with the new Wahoo SYSTM training app built on Four Dimensional Power® developed by the Wahoo Sports Science Division.

Once you’ve built your training plan using the training plan builder, SYSTM delves into your data after each workout – whether that’s on the bike, turbo trainer or cross-training – to see if you’re on the right track, exceeding expectations or at risk of overtraining. It provides feedback on how to improve your weaknesses and focus on your strengths, helping you gain an even greater understanding of your own rider profile. If you want to turn your post-ride scrolling from imperceptive to insightful, it might be time to delve a bit deeper into your data.

• To find out more about how Wahoo SYSTM can boost your training, try it free for 14 days