Using a power meter to measure performance and train effectively

Over the last 8 weeks I’ve been really focusing my training and learning to properly utilise a power meter to quantify my gains.

I wanted to share my experience on here with everyone in case others are interested in how and when to do the same.

Let’s start a little further back. This year was my first year racing, I jumped in with both feet back in November ’15 doing Winter Track League at Lee Valley and beginning to road race through the Winter Series. I very much raced myself fit, with very little out of race training. I commuted and rode steady quite a bit, but racing twice a week with maybe one other training session was enough for me. Come March time and the opportunity to come and train with RPR came and I joined around the beginning of April. At this point I was flying, feeling very confident on the bike and felt I could push myself hard and often.

I had a few early races with RPR with some fairly good performances, nothing ground breaking but all was well. It was around this point things started turning south. I started to see a decline in my numbers and couldn’t hit what I could before. I wasn’t too sure why but became quite hung up on a number of elements. Am I over-training? Is my diet wrong? Am I not getting enough rest?

It seemed the more I strived to work everything out the worse it got. I put myself in a bit of a hole over it and started to get tired, grouchy etc. When I look back now, perhaps the signs of overtraining.

At this point life off of the bike meant my training volume dropped quite a bit. I still maintained the same intensity by doing RPR sessions and my usual riding but less often. I actually wasn’t aware at the time but when I looked through my Performance Management Charts on Training Peaks the negative trend was there. It was around this point that Yoda offered to lend me an SRM for a few weeks sighting that my power data in RPR rides seemed low in comparison to others.

Straight away some burningly obvious patterns appeared. Without going too much into it, over ranges from 2/5/10/20/60 minutes my vector pedals were reading roughly 20% down on the SRM. At this point I decided to cut the racing, take a step back, evaluate where I am and plan to build back up.

Finding out that my power meter was under reading gave me the confidence boost I really needed and gave me confidence that I could in fact hit the numbers I was used to seeing earlier in the season. This was where I decided to spend a block of time getting strong again.

I spent some time reading and learning about how to effectively use power to schedule and monitor training. Solely based on the Performance Management Chart (PMC). For those who may not know the metrics it uses are:

  • CTL
  • ATL
  • TSB

The prerequisites to use the performance management chart are FTP and an understanding of TSS.

I’ll explain what all these mean and although this info is widely available online it makes for easier reading to have it all here. Some online sources may go into far more detail which isn’t entirely necessary to grasp the concepts at first. I’ll leave out explaining what an FTP is, if you’re unsure this may be too much for you!

By briefly explaining these areas I’ll be able to talk you through my 8 weeks of training better!

TSS – Training Stress Score

Training Stress Score is a metric which allows you to monitor training load. Every time you ride with a power meter a TSS value is calculated based on the length and intensity of your ride. A TSS of 100 is the equivalent of riding at your functional threshold for one hour. Riding at high power will accumulate TSS more quickly. You can however accumulate the same TSS value by riding at lower power for long durations. Balancing duration and intensity is a whole other subject I’ll leave for another post.

CTL – Chronic Training Load (Fitness)

Chronic Training Load is a 42 day rolling average of your daily TSS. Essentially it is a value which represents your daily volume of training over the past 6 weeks.

ATL – Acute Training Load (Fatigue)

Acute Training Load is a 7 day rolling average of your daily TSS. Calculated in the same manner as CTL but over a much short period it represents your daily training volume over the past week.

TSB – Training Stress Balance (Form)

Training Street Balance or form is your CTL minus ATL. Essentially your long term fitness, minus your recent training volume. This allows you to see how fresh you should be. For example, if your average daily TSS over 42 days is 100 (CTL), but your average daily TSS this week is 130 (ATL) then your form will be -30. This is because over 6 weeks you adjusted your body to deal with 100 TSS per day, so if you’ve averaged 130 TSS for the most recent week, you’re going to feel fatigued. As such your form is down.

So with that in mind. Come the beginning of July my CTL was at 40. A pretty low value, typically a well-trained cyclist, your average Rouleur perhaps, should be able to maintain around 80-100. For some disciplines a higher CTL isn’t a good measure, but as someone who wants to road race and ride RPR sessions 40 is very low.

For example, in one group 1 session I tend to accumulate around 150TSS, so if I did 2 sessions a week and nothing else that’s 300TSS. Doing that every week gives a CTL of 42 (300TSS / 7 Days). So if I want to ride multiple RPR sessions a week, commute and ride or race at the weekend more CTL (fitness) is needed.

My goal therefore was to build my CTL. Arlen aptly used the metaphor or ‘filling the bucket’. Essentially you train up your CTL so your body has a higher reserve of fitness which you can make use of. The more you do, the more your body becomes used to higher training volumes, thus you can ride again sooner. Some riders in the club are very developed at this hence they manage some mental miles, we all know who they are!

I looked into the effective ways to build fitness and how quickly the body can manage it. This is known as ‘Ramp Rate’. Generally, as a well-trained cyclist who has previously managed high volume training, the lower your CTL the faster you will initially be able to ramp it. For this reason it isn’t usually a linear gain, simply trying to ramp by 8pts a week won’t work. As your CTL gets higher your ramp rate will slow down.

One of the guideline boundaries to watch out for during all this is fatigue and not letting it build up too much. I mentioned the calculation of form being fitness – fatigue. Basically you don’t want to let your form drop below -30 too often and for too long. Everybody handles it differently and some riders may be able to handle it, but typical the majority of people wind up injured or ill if they drop below -30 regularly or for extended periods.

The challenge then is how to plan in how much you can do. Thankfully training peaks allows you to plan in future workouts and by filling in a TSS value it will predict your future PMC chart and subsequently the CTL, ATL and TSB values.

I looked at my typical training pattern and decided on what I wanted. Loosely for me it was:

Monday Nothing / Commute only 20TSS
Tuesday RPR Chaingang Session 150TSS
Wednesday Light 60-90mins 70TSS
Thursday RPR Session 150TSS
Friday Chat Laps / Easy Rising 60TSS
Saturday Easy / Social 50TSS
Sunday Long Ride 3+ Hours 200TSS
Weekly Total ~15 hours 700TSS

This sort of volume gave me a daily average TSS of 100, meaning if I maintained this schedule for 6 weeks I would have a CTL of around 100.

The problem there is with a current CTL of 40 my typical week was around 280TSS. Jumping straight to 700TSS and holding it would inevitably cause me problems. For this reason I decided to use training periodization and the concept of ramping volume for 3 weeks, then having a light week to recover somewhat. Then go again.

My 8 weeks in Summary:

I managed to follow the principle of 2 build phases of 4 weeks, 3 ascending weeks and the 4th week reduced to recover. The table and graphs below show my volume in both duration and distance. You can see that I allowed it to steadily climb for 3 weeks then tapered it off for the 4th/8th week.

Duration (Hours:Mins) Distance (Miles)
Week 1 12:31 216.9
Week 2 16:32 279.1
Week 3 17:50 319.7
Week 4 09:24 151.7
Week 5 15:48 260.1
Week 6 17:19 290.8
Week 7 18:10 316.6
Week 8 11:48 216.3


Very happy with the progression and ability to follow the plan I saw similar trends with my Performance Management Chart. So let’s have a look at those.

PMC Charts.

With all the chat of PMC I’ll take you through what mine looked like with some summarisation.

Here is the last 6 months of my PMC chart. The blue filled in line denotes CTL (Fitness). The pink is ATL (Fatigue) and the yellow is TSB (Form).

We can see that in March my CTL was around 45. I managed to increase it over a couple of months until May when I went to New York for Red Hook Crit. Here is where it begins to descend as my training volume reduces. Subsequently fatigue was way down and form was way up. You may think that lots of form is good. Actually anything over +20 begins to suffer your fitness. This is because the only way your form ascends is to rest. If you rest for 8 weeks your fitness disappears.

The second steeper and more prolonged rise is the 8 week training block. This is exactly what I wanted the chart to look like! Let’s go into the 8 weeks with a little more detail and explain some of the key points.


Day 1 – Monday 11th July

On day one of the 8 week training block my CTL was 41.3 and fitness/form pretty much balance.


End of Week 3 – Ride London

As I built training volume over the next 3 weeks we see a good increase in CTL. The last ride of the 3 weeks was the Ride London Surrey 100. I’ve highlighted Monday 1st August, the day after. You can see that 3 weeks of hard training, finishing with a big/hard ride has pushed my TSB (form) to -46.1. Remember that -30 is a guideline of going too deep? Thankfully for me I now have the 4th week of my training block where I reduce volume in order to recover. It’s not all bad, those with a keen eye for detail will see that CTL (fitness) is now 60.2.


End of Week 4 – Taper Week

So moving on to the end of week 4 where I’ve halved my distance / time cycling you can see that my fatigue has dropped and my form is now -2.3. Generally anything above -10 has me feeling fresh. A positive figure is rarely achieved and you would perhaps only taper all the way into a positive figure for a major race. At -2.3 I feel ready to tear legs off. If we take a step back and look at the fitness it has increased in 4 weeks from 41.3 to 60.6.

Remember I mentioned that fitness was at 60.2 at the end of week 3. Whilst that is true fatigue was also 101.5, meaning form of -46.1. This shows the importance of dropping it back for a week. I haven’t lost fitness, I’ve maintained it but at the same time I’ve shed a huge amount of fatigue. That’s set me up to start another 4 week block and go again.


Sunday 4th September – Surrey League Road Race

So the end of the 8 weeks was the day of the Surrey League race Tom and I attended. We can see I built a further 20 points of fitness with a CTL of 80.8. The pattern was very similar to the first block, I built up to the high 70’s after 3 weeks then maintained in week 4 to shed fatigue. This is what we commonly call a taper when there is an event we want the form for. I went into the Surrey League race with a form of -13.3. You may know that was a race Tom won and I finished 5th. I felt strong, laid down some big attacks, covered attacks and solo’d for 20 minutes at 373w for the final lap. I finished the race happy that I could continue. This backs up the theory that you don’t necessarily need to go into a positive figure. If I did just how hard could I race? Well actually some people perform worse when too fresh. This is something you have to try and test over time.


So in conclusion my goal was to build my CTL. Over 8 weeks I took it from 41.3 to 80.8. A big success in my eyes. I’m now reaping the results and feel much more tuned in fast club sessions and races.

My FTP when starting the 8 week block was 353w. I tested on Tuesday and my result was 369w. That is another benchmark to show my body has absorbed the training and adapted well.

I am completely sold on following the numbers and I’m a big believer that it has allowed me to improve in the most efficient way I can. I’m sure over time I will learn more and eek out even more ways to fine tune extra gains.

Happy to answer all and any questions. Also a big thank you to Tom P and Arlen who put up with countless questions from me regarding this stuff and really helped me solidify some of the theory and practice. I’m sure it’s no coincidence that those two follow these principles too and have seen equally great results out (collarbone excluded Arlen! Bummer).

Using a power meter to measure performance and train effectively