The Numbers Behind The West Highland Way FKT

To celebrate my West Highland Way Record Attempt film, in association with Wahoo and Santa Cruz Bicycles, breaking 100,000 views on Youtube, I thought I'd share a closer look at the data behind my ride with you. My Strava file has been public since the 3rd of December when the film was released, but I thought I'd delve deeper into the numbers. In this blog, I'll share my TrainingPeaks activity with you, as well as insight on the INSCYD test data on which I based my training and pacing strategy.

Ride Data

To get us started, let's have a look at the raw numbers from the ride. All of the data from the ride was recorded on my Wahoo ELEMNT ROAM, SRAM XX1 Eagle Quarq power meter, and Wahoo TICKR heart rate monitor.

If you're interested in my bike then check out my bike check blog.

Elapsed Time: 9:14:32

Distance: 153.37km / 95.3 miles

Total Elevation Gain: 3,628m / 11,903ft

Max Elevation: 570m / 1870ft

Min Elevation: 24m / 79ft

Speed: 16.9kph / 10.5mph

Heart Rate: 148bpm avg / 179bpm max

Power: 165watts avg / 237watts Normalised Power / 877watts max

Cadence: 80rpm avg / 157rpm max

Temperature: 15°C avg / 4°C low / 30°C high

Work: 5909kJ

Calories: 5806kCal

TrainingPeaks Training Stress Score: 424

TrainingPeaks Intensity Factor: 0.68

TrainingPeaks Variability Index: 1.44

Rider Information

Age: 35

Height: 178cm

Weight: 65.5kg

Body Fat Percentage: 7%

Resting Heart Rate: 38bpm

Maximum Heart Rate: 196bpm

Vo2 Max: 80 ml/min/kg

Anaerobic Threshold Power: 357 watts / 5.5 w/kg

Fat Max (maximum fat metabolism): 8.96 kcal/h/kg @ 236 watts (586kcal/hr)

Carb Max (sustainable steady state power @ 60-90g carbs per hour): 3.86 w/kg @ 253 watts

VlaMax (maximum production rate of lactate): 0.47 mmol/l/s

Functional Reserve Capacity: 13.9kJ

Peak Power: 1287 watts

This data was recorded using:

  • INSCYD PPD Metabolic Profiling

  • WKO5 Training and Analysis Software

  • Sram/Quarq power meter

  • Wahoo KICKR

  • Tanita BC-730 body composition monitor

So What Does This Really Mean?

If you were to look at the average speed alone, then these stats don't seem all that impressive. 16.9kph / 10.5mph for 95 miles? That's no big deal.

If you've never ridden or walked the West Highland Way, then I'll forgive you for thinking that. What is worth noting is that, for me, the West Highland Way is around about 90% (around 8 hours and 15 minutes) ridable, with 10% (around 55-60 minutes) walking and hike-a-bike.

One of the key sections of unrideable terrain is the northeastern section of Loch Lomond, where riders have to climb up, over, and back down rocky steps, boulders, and bridges for 10km / 6 miles.

There are also sustained sections of pushing and carrying when tackling Conic Hill and The Devil's Staircase. This is due to the sheer gradient of the climbs (the steepest section of Conic Hill is a brutal 43% gradient) and the loose, rocky surface is also difficult to find traction on.

So, taking this into account there is at least 1 hour of walking. This means there is at least 1 hour with no power to the pedals ie. zero watts. Add in the sustained sections of technical descending and singletrack where you don't pedal at all, then average power is a questionable metric.

Variability Index, Intensity Factor, and Normalised Power

So, if average power isn't a useful metric, why was I adamant I had a power meter fitted to my bike? Well, measuring power is still really useful when it comes to gauging physical output, energy use, and work done. This is where TrainingPeak's becomes really useful, quantifying how varied and how intense your ride was, and calculates normalised power.

"Normalised Power is calculated using an algorithm that is a little complex, but in a nutshell takes into account the variance between a steady workout and a fluctuating workout. The resulting value is an attempt to better quantify the physiological “cost” of the harder “feel” of the variable effort. For a highly variable workout, NP can be much higher than average power, where for a very steady workout, NP and average power are equivalent or very close together. A relatively high NP is showing that the workout had a lot of variation, and was harder physiologically than what average power may reveal" - TrainingPeaks / Coach George Ganoung

The difference between average power (165 watts) and normalised power (237 watts) is a whopping 43%. That is significant and indicates just how variable the effort of mountain biking the West Highland Way is, further demonstrated by the Variability Index of 1.44. For more info on Variability Index check out this article in the TrainingPeaks help center.

Power Data

Let's take a closer look at the power output breakdown into time in zones, as well as the power curve of peak power output for given durations. By doing this, we can begin to see the physiological demands of the ride in even more detail.

Time In Zones

Zone 1 (0-195w) : 4:23:32

Zone 2 (196-265w) : 1:56:16

Zone 3 (266-317w) : 1:30:03

Zone 4 (318-370w) : 48:16

Zone 5: (371-422w) : 20:30

Zone 6: (>423w) : 15:43

Peak Averages

Absolute Max: 877w

2 seconds: 787w

5 seconds: 705w

20 seconds: 523w

1 minute: 411w

5 minutes: 313w

20 minutes: 269w

60 minutes: 241w

90 minutes: 233w

So what can we take from looking at the numbers? We can see that there is a significant time spent at or above my lactate threshold power. In fact, there were around 85 minutes in total spent in zone 4, 5, and 6. We can also see that there are some significant power spikes, and with 15:43 total time in zone 6, we can assume that these spikes happened regularly.

What is also notable is that there are a massive 4 hours and 23 minutes spent in the lowest zone 1, less than 56% of my FTP. Does this mean that there were a lot of easy sections to recover during the ride?

What about heart rate?

If we look at power alone then some would assume that half of the ride was spent riding at a low intensity, giving lots of opportunities to recover. However, looking at the heart rate data would suggest far from that. In fact, if you were to look at heart rate data alone then you could assume the ride was a constant, steady-state tempo, medio, or threshold effort.

Something that needs to be considered is that due to the technical and rough nature of mountain biking, heart rate very rarely drops when you stop pedalling. In fact, some of the most demanding sections of a ride can be when you aren't pedaling, including hike-a-bike, gnarly descending, and flat technical sections.

Time In Zones

Recovery Zone (<116bpm) : 0:04:59

Zone 1 (117-126bpm) : 0:19:33

Zone 2 (127-146bpm) : 3:19:54

Zone 3 (147-159bpm) : 4:03:42

Zone 4 (160-173bpm) : 1:23:40

Zone 5 (174-183bpm) : 0:02:44

Zone 6 (183-196bpm) : 0:00:00

Peak Averages

Absolute Max: 179bpm

2 seconds: 179bpm

5 seconds: 179bpm

20 seconds: 178bpm

1 minute: 176bpm

5 minutes: 172bpm

20 minutes: 162bpm

60 minutes: 154bpm

90 minutes: 154bpm

It is worth noting that when you make efforts while cycling there is a delay, or lag, in heart rate response. This lag happens when responding to efforts and during recovery. For example, if a rider sprints for 20 seconds you won't see the full extent of the heart rate reaction until after the effort has ended, and heart rate will continue to climb after the effort has finished. It will take time for the heart rate to begin to drop once it has peaked from the effort too. If you make another hard effort soon after (20-60 seconds for example) then the heart rate will remain elevated.

This screenshot takes a closer look at the climb and descent of Conic Hill on TrainingPeaks. I set my peak heart rate for the whole ride while climbing Conic Hill, and it was actually set while pushing and carrying my bike. Looking at the power and heart rate traces on Conic Hill gives a great example of how heart rate remains elevated while power spikes aggressively. You can also see that on the long descent to Loch Lomond that power equals zero yet heart rate remains elevated above 140bpm for the duration of the descent.

Energy Demands

We're hopefully beginning to see that mountain biking the West Highland Way isn't just a long, slow endurance ride. Over a 9 hours+ period there are repeated power spikes, and when forced to dismount and hike-a-bike is when we actually see some of the highest heart rate readings. What does that mean in terms of energy demands?

In a nutshell, the energy demands are very high. TrainingPeaks has a hierarchy of how to calculate work done in kJ and energy expenditure in kCals (calories). Power sits at the top of the hierarchy with an accuracy rate of within 5%, above heart rate (10-20% accuracy rate) with time and distance at the bottom. However, we know that using power as a metric alone isn't ideal, as there are long sections of descending and freewheeling where energy is still being used.

TrainingPeaks calculated my energy expenditure for the entire ride to be 5,806kCal based on power meter readings. My Whoop heart rate tracker calculated my energy expenditure as 7,179kCal based on my heart rate alone. I won't ever actually know with certainty which is correct, but this is some serious energy expenditure. Now, where do these calories come from?

Using INSCYD testing I know with laboratory accuracy my energy expenditure at given power outputs. For example, up to 236 watts energy consumption comes primarily from fat stores (65% fat to 35% carbs = 558kCal fat / 308kCal carb per hour). At 7% body fat, I have 4.5kg of fat stores equalling over 40,000kcals to call on.

However, as soon as I cross the FatMax threshold, carbohydrate demand increases rapidly. At zone 3, Tempo or Medio pace (around 293 watts) energy consumption equals 1108kcals per hour at 43% fat to 57% carbohydrate (476kCal fat / 632kCal carb per hour). When riding at my anaerobic threshold (commonly referred to as FTP) energy consumption comes 100% from carbohydrates at 1281kcals per hour or 21kcals per minute.

Looking at the duration of the ride and the high power demands it's clear that carbohydrates were going to be in high demand from start to finish. Studies show most people can store a maximum of 15 grams of glycogen per kilogram of body mass, which would suggest that I could have 3,930kCal energy stored as glycogen when beginning the ride.

If my pacing and nutrition strategy wasn't carefully planned then after 4-5 hours I'd likely be fully glycogen depleted. This meant that my pacing strategy and nutrition plan was of top priority, and was also the reason I chose Secret-Training nutrition products.


Thankfully, I had done my research and was aware of the likely demands of mountain biking the West Highland Way. So how did I train for it?

A lot of riders and coaches talk about specificity when it comes to training, so you may expect that I would spend a great deal of time doing long, hard mountain bike rides with lots of zone 3, zone 4, and 'Sweetspot' efforts. You may also think that due to the power spiked erratic nature of the ride that I would include anaerobic sprints as part of my training. This was not the case.

The way that I approached my training was to breakdown the demands of the ride and work on them in isolation. By using my INSCYD test results I was able to plan my training so that I could consolidate my strengths and improve my weaknesses. The main goals of my training plan were:

  • Increase Vo2max

  • Increase my maximum fat metabolism

  • Improve lactate buffering capacity, lactate exchange, and lactate combustion

  • Reduce VlaMax to optimise carbohydrate efficiency

  • Reduce body fat percentage

The majority of my training was completed either on my road bike or indoors on my Wahoo Kickr. I chose this over mountain biking as it allowed me to control my training to target specific energy systems. The strength and conditioning training I completed was unloaded and focussed on mobility and addressing any imbalances.

When I got closer to the record attempt, and I was confident I could sustain the duration of the ride, I began to spend more time on the trails and put all of the pieces of the puzzle together. It is worth noting that my technical riding skills are one of my main strengths, so I felt I was able to sacrifice some mountain bike time in the pursuit of physiological gains.

Wrap Up

So there you have it, the numbers behind my West Highland Way FKT. I'm really happy with how I approached this record attempt ride, and my only disappointment is that the weather conditions weren't as good as they could have been. I'm really excited to see what other riders can achieve, especially with better conditions, and I'm sure we'll see the WHW FKT drop below 9 hours in the not too distant future.

It's been one hell of a ride and I can't believe that we all managed to pull this off! Thanks so much to all of the fantastic people who got behind my idea.

If you haven't seen the film yet then settle down in a comfy chair and press play on the film below,

'til next time,

Over and out


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