Post AXTRI Bike Leg Analysis: Why did it go wrong?

I’ll do this post in English as well, as it is a sort of follow up analysis of the AXTRI Race Report.

As mentioned in my AXTRI race report, I suffered from extreme emptiness and lack of energy on the run leg. I have spent some time afterwards trying to find out what went wrong, and have landed on a preliminary conclusion combining pacing and nutrition factors. This is merely an analysis of my race nutrition, and not a scientific article, so analysis of the different components of the various energy products can be done another time 🙂  Let me break down the different pieces.

Heart rate and effort: Make no mistake about it, this bike leg is very hard and demanding. On a cold day with some rain (as during the competition), it put’s an even bigger strain on the system. Another challenge I faced before this competition was that I had onlye done long bike legs like this in standalone bike races, and in a couple of AXTRI specific «race simulation» workouts. I know approximately how much effort I can handle when in a standalone 4h race, but where to draw the line with a demanding half-marathon looming after T2 to avoid emptying the tank too soon? In addition, I have not had any accurate testing of my lactate threshold (basically I am not exactly aware of my heart rate threshold for lactate accumulation), so I would undertake the AXTRI bike leg based on a mixture of perceived exertion and my heart rate monitor.

My immediate feeling is that this part of the race went as I had planned, the big questions is if  the plan was good enough? Most of the time I was in zone 3 (which should be a safe zone with regards to lactate accumulation, at lest in the low end of the zone), with some short sections in zone 4 (medium lactate accumulation) early on the first climb. My legs felt good, with no stiffness (some fatigue is expected of course, given the tough climb), and I felt energy restored on the downhills.  I was not «pushing it», and it felt like there was always a couple of more gears to go.

Graph of my heart rate (red line), with a rough zone indication.  The grey graph indicates altitude scaled time (why the downhills are so steep compared to the climbs). One can see that the red graph is mostly in the grenn (zone 3) area on the climbs.

Energy consumption: Another very important factor in ultra-endurance events is the energy intake (food and liquids.). This has been my achilles heel for years, and although I had specific long sessions to drill inn the food and drink scheme, I had only a marginal improvement over previous competitions. First things first: The race plan said 2-3 packs of gel/hour with some supplements of energy bars to break the monotony. I would also target one 0.75 bottle with sports drink per hour, with 6 Crampfix salt tablets total. This would give an energy intake of around 1200kcal with the different products I had + 900kcal from the energy drink, for a total of 2100kcal of 525kcal/hour.  This should be more than enough judging by different litterature I had studied on the subject, and I felt confident about keeping this scheme.

When I reaced T2 I had consumed 2 Liquid gels (150mlx2), 1  regular gel (25ml), and 0.5 sports bar, which gave me about 750kcal + 550 from the sports drink. Total: 1300kcal (325kcal/hour).  As I started the run I did not take anything other than sports drink the first 25min before the «wall» hit.

Some key factors influencing nutrition was that I missed the drink station on the way down to Erdal, and ran empty before the middle of the climb back. I did not dare to take gels in this period, and could feel this affecting the perceived effort (it felt harder to keep a steady pace).  But ultimately I was not eating enough on any of the climbs, or on the flats on top.

Conclusion: It appears to me that a combination of reducing the heart rate by about 2% , along with forcing myself to empty my food stores (basically means sticking to the race plan), I am sure that I would have had a much better total performance. I would have lost approx 5mins on the bike, but would have gained an estimated 25mins on the run by avoiding the «hammer».  In total I would have expected a total time decrease in the range of 20-25 minutes. Maybe I could have kept the same pace on the bike, AND gained time on the run by sticking to the race plan?  These are speculations of course, but I will adopt a more modest approach to the bike before IM Kalmar (zone 2 effort), and hopefully be able to run to my potential instead 🙂 I will also try an do more race nutrition simulations, including experimenting with different products, to counter this reoccurring problem of the tank running empty too soon.  After all, triathlon is about performing consistently in all three sports, AND be smart on the nutrition side, which after all is the fourth discipline.


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Det viktigste er å delta, men det er lov å komme først.

Marthe Katrine

Trening, erfaringer og opplevelser mot min første Ironman

Cathrines triatlon

Trening, erfaringer og opplevelser mot min første Ironman

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