Fitness in Focus: What are the physicial demands of Enduro racing?

The Cannondale Alpine Bikes Enduro during the Tweedlove Festival was a massive test of the all round mountain biker. Steep technical stages, long days, big climbs and some intense pedalling were included. We look at what the physical demands of enduro really are — photograph from Trev Worsey

The Enduro World Series visited Scotland during Tweedlove and for the first time I was racing an Enduro of this level. I’ve raced a few enduros over the last 3 or 4 years with varying degrees of seriousness and success. The Enduro World Series is a real test of the all round mountain biker and without being over confident I consider myself to be a competent rider. In XC races, even on the World Cup, I’m a strong descender. However in comparison to the leading downhill and enduro racers my technical skill and downhill ability isn’t as strong, especially when things get steep, corners get tight and ruts get deep.

In terms of physiology and fitness however I felt like I would be one of the stronger riders in the race. Before the race there had been a lot of talk around the previous round in Ireland. The transitions between stages had been very tight and the stages had flat sections with lots of pedalling. This made me wonder what excatly are the physical demands of enduro racing? What kind of training should the aspiring enduro racer do?

Going into the race I fitted a Quarq power meter and rode with a Garmin Edge 500 GPS with heart rate. I also took a GoPro helmet cam to record selected stages. I recorded GPS, power, heart rate and video on day 1 and on day 2 I recorded GPS, Power and video.

Race day 1

A long day in the saddle but not too intense a race. A cross country race of this distance and elevation would be over in less than half the time. However the climbs would be attacked and the downhill sections would be used for recovery in an XC race. This isn’t the case in Enduro which is reflected in the intensity during the DH stages.

Race day 1 is considered a big day for an enduro race. With 4 significant climbs to reach the 4 timed downhill stages over nearly 60 kms, it is a long day on a long travel bike with bike tires. The stage liason times for Tweedlove this year turned out to be quite manageable. Often I was arriving at the stages with around 30–40 minutes to spare. Heart rate and power was relatively low during the liaisons and I was able to use prodominatly my base fitness or aerobic system which I have been training for nearly 15 years for XC racing. With this strong base fitness I was able to arrive at the start of each stage feeling comfortable and relaxed. What I did find in this instance was that it was difficult to get back to a racing mindset for the start of each stage. Something I need to work on as the psychology of Enduro is more similar to downhill racing than cross country.

The liaison climbs, although long and sustained, weren’t particularly taxing due to the long gaps between stage start times. I was able to climb to the top of stage 2 at an avergae heart rate of 115bpm — nearly a recovery pace for me due to a big aerobic base and a strong lactate threshold from XC racing.

Race stages

The race stages were physical though. What is interesting is that you only have a small window of opportunity to get the power down. You could have all the power in the world but if when it comes to deliver it you’re not in an appropriate gear, or you waste your power with wheel spin or poor line choice, you won’t be efficient or fast. Much of the physicality from the stages comes from dynamic movement on the bike through weighting, unweighting and pumping the bike on the trail and through corners. This isn’t measured through the power meter but is clear when looking at heart rate.

Stage 2 of the day was one of my stronger stages. The stage was mostly on the well known downhill tracks at Innerleithen, often used for downhill races. The stage featured some short climbs and a long fireroad sprint though. On average the window of opportunity to get the power down during pedalling was 5–10 seconds and there were only a handful of chances during the stage to do so.

During my race run I got the power down well and I didn’t fade towards the bottom. My technical riding can improve though which should maximise exit speed out of corners and technical sections. My dynamic movement, body position and stability when braking can improve through better upper body strength.
There were only a few moments to pedal on stage 2 yet you can see from the heart rate trace that the body is working hard from start to finish — 161 bpm is around the onset of my lactate threshold. My body is working hard to pump and move on the bike although I’m not pedalling. 996w is close to my peak power and I delivered this at the start of a long fireroad sprint to get up to speed. Many of the pedalling efforts in this stage were peak power sprint efforts. Imposible to read from heart rate but easy to see from the high spikes in power lasting a few seconds.

Race Day 2

Day two was a shortened race due to high winds and the weather warnings forcast. Two stages remained including two long climbs during the liaisons. These were once again quite manageable due to start times being spread out. The two stages were very different with one a nearly full downhill stage in deep mud. I had some technical problems during the stage and struggled to keep the bike moving in the deep mud and ruts. I have some work to do technically in this respect.

The final stage was one I was looking forward to. The longest stage of the race with a lot of pedalling and tight trails I know well. I was aiming to max out my effort on the pedalling sections. Unfortunately my heart rate reading is unavailable for this stage, but you can hear from the heavy breathing in the video that I’m working at maximum on the pedalling sections.

The final stage of the race was much longer than the rest of the stages with long sections of sustained pedalling. These efforts would see an increase in heart rate and are noticable from the burning feeling in my lungs and legs. These efforts prodiminantely use the anerobic system and last from 15–45 seconds. If you look at the two power graphs from the shared stages there are more spikes in the second and it’s clear to see that there is more intensity through the pedals on this stage, for much longer. The peak power is less but the average power is higher for longer. Good aerobic fitness should help a rider recover between these hard efforts during a stage.

What does this all mean?

Looking at the data of the race stages in the first instance it seems a high lactate threshold and aerobic conditioning might not be too important. Pedalling efforts during the race stages is as short at 5 seconds and probably only up to 30 seconds to 1 minute would suggest that these short, high intensity intervals are all an aspiring enduro racer should do. However, what it is easy to miss is that although I personally could cope with the distances and durations of the race my background as an XC/marathon racer helps me here. Not everyone has years of long, aerobic base conditioning to fall back on. Having a big aerobic base means that you are able to cope with the long stages and also recover between each race stage better. You will also last longer during a season if you are fitter, and should be able to cope with more races as well as be able to train harder between those races too.

If you are taking up Enduro racing with no experience of racing at all then you will need to build enough base fitness to ensure you can last not only the race distance but the practice as well. In the three days leading up to the race I rode for around 3 hours each day. Without sufficient aerobic conditioning simply surviving practice, and then recovering to be able to begin the race, would be difficult if not impossible. Aerobic fitness is important for all mountain bikers, even downhill racers, 4x racers and trials riders.

If you are coming into enduro from downhill racing your level of skill, upper body strength, core strength and peak power should be good. However your aerobic endurance and anaerobic power (especially for climbing) could be lacking. Spend some time riding longer distances and aim to cover your typical enduro race distance, including long, steady climbs.

If like me you are coming into enduro from a background in cross country racing it is likely that your aerobic conditioning is sufficient but your level of skill and peak power is lacking. Dynamic movement, body position, weighting and unweighting the bike as well as pumping will be very important. You will also need to develop upper body strength and core stability to be able to manage the higher speeds and forces on the body when cornering and braking. More downhill runs as well as pump track or BMX track sessions can help with this.

Stage 5 splashing — pic from Ian Linton photography

Conclusion

It is clear that enduro challenges you physically, mentally and technically. You need to be a smart rider with a good plan of attack for your racing — efficiency and adaptability is key. You need to identify your personal strengths and weaknesses and make a plan to improve. Ultimately without base aerobic fitness you won’t feel fresh enough to race each stage, recover between stages or be able to finish the race. Once your aerobic endurance is sufficient you can work on your peak power and anaerobic fitness. Aside from fitness, skill is a massive factor. To excel at enduro you really need to be a great all round mountain biker.

Good luck!

Dirt School

Rab’s race bike set up

Frame: Santa Cruz Bronson — large

Wheels: Reynolds Black Label 27.5 AM carbon wheels

Suspension: RockShox Pike RC 150 — 75 psi with 2 x tokens, Fox Float CTD Adjust Factory Kashima — 150 psi

Tyres: Schwalbe Magic Mary 2.3 front 24 psi, Maxxis High Roller 2.25 rear 25 psi

Brakes: Shimano SLX 180mm rotor front, 160mm rotor rear

Groupset: Sram X1 groypset with Quarq XX1 power meter (34t chainring)

Stem: Truvativ 50mm

Bar: Renthal Fatbar 760mm, Santa Cruz Palmdale grips

Seatpost: KS Lev Integra 125mm

Saddle: WTB Tweedlove