Thursday, March 18, 2021

My 100 mile Ultra Marathon: On the Concept2 Ski Erg

Why an Ultra Marathon?

Typically an ultra marathon is considered any distance over 26 miles (ie more than a convertional marathon distance).  One year ago (14th March 2020) I ran the Borneo 100mile Ultra, through the jungle and mountains.  It-was-horrendous!  It took me approximately 38 hours to complete, without sleep and carrying an injury (Achilles tendonitis).  The weather was scorching and the terrain was unforgiving (especially in the jungle sections).  

On Wednesday 10th March 2021 I had felt particularly good training wise and smashed out an hour the Concept 2 Ski Erg.  I did over 12km, that was the longest time I'd spent on this bit of kit (the longest distance having previously been 5km) and felt I could keep going.  So I did another 30 mins.  

I thought, 'I could do with a challenge, so I'll do 100 miles on this. Oh and this weekend is the one year anniversary of the Borneo 100 miler', so it seemed apt-although a bit last minute.  That's my kind of thinking...not really thinking too much and just getting on with it.

On Thursday 11th I did some testing with Stu Bauld, the 'Science guy' at Ufit Personal Training Studio.  He loves a bit of sports science and was keen to test my lactate threshold and VO2 max.  With the data we could look at different fineness markers and predict some outcomes.  

I'll hand over the next bit to my man Stu...


VO2max is the maximum amount of oxygen an individual can take in and use during high intensity exercise. The trend is that a higher VO2max allows an individual to produce more energy therefore perform more work. However, there are other metrics (arguably more important) that can be measured during this test to help optimise endurance performance.

Measuring gas exchange (the amount of oxygen taken in versus the amount of carbon dioxide produced) allows us to measure how much fats and carbohydrates are being used at different exercise intensities. A RAMP test is performed to measure the total oxygen consumption at different work intensities until exhaustion. The test is initiated at a very low intensity and then increases every 60 seconds until exhaustion is reached.

Most people only have enough stored carbohydrates in their body to supply the energy for about two hours of moderate intensity exercise. The depletion of these stores will ultimately lead to the rapid onset of fatigue. In contrast, fat can supply almost twice as much energy as carbohydrate or protein (9 calories per gram versus 4 calories per gram for carbohydrate and protein) therefore can supply energy for hours and hours as the body has an almost unlimited fat storage capacity. Consequently, it makes sense that when embarking on an ultra-endurance event, maximising the use of fat stores and minimising the use of carbohydrate stores would be an optimal strategy. 

The graph below shows the crossover point from Phil’s VO2max test which reflects the intensity at which the body transitions from predominantly fat usage to more carbohydrates. This means that exercise intensity above this point is too high for fat to be the main supplier of energy. The crossover point occurs at 155W which means that when working at an intensity above this point, carbohydrate stores will begin to reduce at a much faster rate which could lead to the early onset of fatigue. Therefore, it was advised that for the duration of this challenge exercise intensity remained below the power output of 155W.

Fig.1 Graph shows the carbohydrate (light green line) and fat use (dark green line) at different working intensities (purple step) during a RAMP VO2max test on a SkiErg.

Breath analysis is the most accurate/accessible method of determining how many calories you expend during exercise. The rationale behind this is that virtually every bioenergetic process in the body is oxygen dependent. As previously mentioned, from calculating the amount of carbon dioxide produced relative to the amount of oxygen consumed we can establish the contribution of fat and carbohydrate to total energy metabolism. This then allows us to verify the total number of calories being used at each working intensity. The graph below shows the metabolic cost from Phil’s SkiErg VO2max test at each power output.

Fig.2 Graph shows the total calories per minute expended at each working intensity.  This is further divided into the amount of calories supplied from fat and carbohydrate.

This information could then be used to advise on re-fuelling strategies in order to prevent the onset of fatigue.  For example:

  • The energetic cost at 124W is 12.6kcal/min. 
  • One hour would result in 756kcal expended; 
  • With a contribution of 600kcal (66.6g) from fat and 156kcal (39g) from carbohydrate. 

Additionally, identifying the intensity at which fat is maximally being used can also help inform on pacing strategies for the actual event; therefore ensuring that as much carbohydrate is spared as possible with the majority of energy being supplied from the limitless fat stores.

The availability of this information is not only useful for endurance performance, but can also allow us to take a much more informed approach when working with weight loss clients. For example weight loss is driven by energy balance; whereby an individual must expend more calories than they consume leading to a calorie deficit. Having this data on an individuals’ physiology means that we accurately know how many calories they expend during different exercise intensities which can then allow a highly individualised program to be assembled that can optimise their weight loss goals.

'Race day'

I had already had clients booked in on Saturday morning of 13th, so was I already committed to work until 1430 in the afternoon.  But it was still a good start time, as the gym would be quiet and I and like that to get into 'the zone'.  I set up my make shift kitchen (microwave oven) downstairs, so I wouldn't take up valuable rest time going up and down stairs to the staff room, to cook food.  I also taped up the areas I thought were going to need it and got nutrition supplies close to hand.

Nutritionally, I learned a valuable lesson from the Borneo Ultra and the 60 hour prowler push I did in December.  You can't beat real food.   In Borneo, on the first day I was downing all sorts of artificial nutrition crap, trail wind, gels and sweats.  It fucked with my performance and I felt shite.  
As soon as I swapped that out for proper food at the rest stations, like fruit, noodles, rice coffee and even biscuits, my performance on the second day improved noticeably, even though it should've decreased relative to the fatigue.

On the prowler push I noticed the same.  Although I was eating 'real' food from the start, from Fitthree, on the first day I was still eating crap in-between.  As soon as I stopped that, digestively and performance wise, I noticed an improvement.  So off the back of that, I only ate proper food throughout the Ski.  

At 1430 I set off.  I predicted a total completion time of 20 hours, so started pacing myself for 10km per hour.  I couldn't keep to the Wattage recommended, but stuck around 91-95Watts (up until around midnight).  I also set up the monitor to hourly intervals i.e. 1 hour on and up to 10 minutes off for rest. 

To be honest and quite surprisingly, it was all going pretty well.  I managed to maintain and average 11km+/per hour pace up until midnight, without any pain or niggels, just muscle fatigue.  

From 0100ish, I started to slow down.  I went down to around 10km/hr and in the dark hours of the 'graveyard' shift (0300 onwards) is slowed right down.  Some hours I was just under 10km/hr and each pull felt like immense effort.  

It's at 0400, when the mind starts to fuck with you and you start asking yourself 'why am I doing this' and 'just fucking stop'.  'You're not doing this for anyone, or anything.  Just stop before you get injured'. To the rational mind that makes complete sense.  I wasn't going to let anyone down, if I didn't finish.  I wasn't committed to anything. I wasn't going to lose money.  Not that many people knew I was doing it, so I had nothing to prove.  So why the fuck continue?

The only reason I could tell you was, I was doing this for myself.  I would know that I quit.  I would let myself down and the thought of telling my son I quit something, just doesn't 'sit with me'.

All done and dusted 

This wasn't the hardest physical challenge I've ever done.  I've run a 250km Ultra Marathon through the Arctic on two shins with stress fractures in -27℃, which was excruciating pain.  I'd ridden 12 hours on a Watt bike which felt like my quads were being shredded with a rusty rake.  I'd ran 100 miles without sleep, through a jungle, in 33℃+ temperatures.  Rowed for 24 hours and pushed a 90kg sled for 26 miles over 60 hours.  Basically, I've been through a bit of shit to prepare me for this, so I found this 'relatively easy' in comparison.  

I finished the the challenge in 17 hours 32 sec (15 hours total Ski time) and a complete distance of 163km (the way the monitor worked, I had finish on a full hour).  My shoulders were fucked, but that was about it.  I was surprised I had no real injuries, I was expecting Rhabdomyolysis (Rhabdo), but all good.  I have to be honest though, I was fatigued for two days after and needed lots of naps in the afternoons to catch up on sleep and rest the nervous system. 

What makes a 'Ultra Athlete'?  

The argument I present is, I've run, rode, skied, rowed and pushed a sled for hours and distances over the conventional marathon distance.  So does that make me a 'Ultra Athlete', compared to say a 'Ultra athlete' who just runs, or an 'Ultra athlete' that just cycles etc?  

Loved to know what you think?  

You can follow the stories on my Instagram handle here.  For  more information on booking in for some sports testing, speak to Stu Bauld on LinkedIn.

Keep it real folks 

The Fat Loss & Performance Coach


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