COACH’S CORNER - Carb Periodisation & Ultra Running by Joshua Duff

March 27, 2024

hear it first from smurf endurance sports' director and coach joshua duff, all about carb periodisation

Over the past 10-15 years, debate has raged in the endurance sports space about how to best fuel training and racing. Most recently, there are reports of elite ultrarunners consuming up to 120g of carbohydrate (CHO) per hour to fuel races, which is counter to other elite runners who have taken on a more low CHO approach. However, there is a developing area of research regarding CHO periodisation and how this may be the optimal strategy for fuelling endurance training and racing.

Let’s dive in to what this means and could look like for both amateur and elite ultrarunners.

FUEL TYPES

During prolonged exercise, such as ultrarunning, our body utilises two fuel types, those being carbohydrate (CHO) and dietary fat, to support our metabolism and keep us moving forward. CHO is stored as glycogen in the muscles and liver, and fat in fat cells and muscle. The rate at which we use these two fuel substrates is dependent upon our exercise intensity and duration, heat stress and our recent diet (1). Our body has a finite storage capacity of CHO, whereas our fat stores (even for very lean athletes) are effectively unlimited.

What this could mean is that having a robust capacity to utilise fat as a fuel source during exercise may reduce the burden placed on our limited CHO stores, therefore maintaining CHO availability and delaying fatigue (2, 6, 7). In relation to ultrarunning which is (except for elite and high performing amateurs) mainly completed at a low intensity below the aerobic threshold, fat is likely to be the major fuel source for exercise. This is in contrast to high intensity exercise which relies mainly on CHO for fuel. Therefore, it makes sense to become better at oxidising fat for fuel to improve your ultrarunning training and racing performance.

WHAT IS CHO PERIODISATION?

If developing our capacity for oxidising fat for fuel may assist our training and racing, how do we do it? Recent studied in 2018 and 2022 out of New Zealand examined endurance athletes and CHO intake around training sessions. This study found that periodising CHO around training to maximise fat oxidation while also enabling high performance at higher intensities led to increases in fat oxidation at low intensities while also maintaining high performance at higher intensities (3, 4).

What this looks like in practice is very similar to training periodisation where, instead of manipulating the training program to best achieve our training objectives, we are manipulating our CHO intake around training to best achieve our metabolic and training objectives for individual sessions (5). For example, prior to a high intensity V02 Max session, you may want to consume some CHO to support the quality of that training session. In contrast, a lower intensity session may be completed fasted and on no CHO (up to 1-3 hours depending upon your current capacity for fat oxidation) to upregulate fat oxidation. Therefore, not only are you maximising the training effect, but also the metabolic conditioning required for high performance in ultrarunning.

There is also recent research to suggest that ‘training the gut’ may reduce gastrointestinal distress associated with high rates of CHO ingestion during exercise, particularly runners (8, 9, 10). Therefore, there is also worth in taking on this approach particularly in race specific sessions and long sessions closer to race day to maximise your capacity for digesting exogenous CHO during exercise. It is important to note here that for racing, aiming to ingest most of your fuel from CHO is the best strategy for optimal performance.

WHAT IS IT NOT?

There are some points to make very clear with the CHO periodisation approach as to what it is not:

· CHO periodisation isn’t necessarily low carb high fat (LCHF) – but it can be. Adopting a LCHF lifestyle may heighten the upregulation of fat oxidisation, but is not essential to the approach

· It is not keto. The reality is that we require CHO to perform at our best and a keto approach (except possibly for short periods of time or those with metabolic diseases) is not optimal for ultrarunning performance

· It is not limiting fuel intake or calorie restriction. You still need to ensure you take on sufficient calories before, during and after exercise when appropriate via CHO, dietary fats and protein. It simply the manipulation of what source and when we take on this fuel

· It is not limiting CHO during racing. For these big efforts, CHO is essential to optimal performance

WHAT DOES THIS ALL MEAN?

If you were to apply a periodised CHO approach to maximise your physiological and metabolic conditioning for ultrarunning, there is adequate evidence and research to suggest that this may work towards optimising your performance. What this looks like is:

· Restricting carbohydrate intake around and during lower intensity activity with low glycolytic demand

· Beginning very long duration training sessions fasted and with no CHO for the first 1-3h to improve fat oxidation, then ingesting carbohydrates to help extend the duration of those sessions

· Fuel more intense sessions with CHO to support training quality and maximise the stimulus for adaptation

· Ensure adequate overall calories are always ingested to fuel your training, racing and general day-to-day life

· Fuel your races with CHO at a level that suits you and your race day needs

But is also means ensuring you have discussions around fuelling training and racing with your coach or a sports nutritionist to ensure you get the best possibly advice for you. Because as we know, everyone is different and will have different energy demands.

Joshua duff is the director and head coach of smurf endurance sports based in cairns, far north queensland. if you would like more information on being trained by joshua, click through here to our aura endorsed coaches page.

References

1. Plews, D. July 31, 2023. Unveiling the Potential: New Research on Fat Oxidation at Higher Exercise Intensities.

2. Plews, D. December 21, 2022. Maximal fat oxidation rates: What does it mean, what does it tell you?

3. Maunder E, Kilding AE, Plews DJ. Substrate metabolism during Ironman Triathlon: Different horses on the same courses. Sports Med 48: 2219–2226, 2018.

4. Rothschild JA, Morton JP, Stewart T, Kilding AE, Plews DJ. The quantification of daily carbohydrate periodization among endurance athletes during 12 weeks of self-selected training: presentation of a novel Carbohydrate Periodization Index. doi: https://doi.org/10.1101/2022.06.21.22276725.

5. Plews, D. August 31, 2022. Right Fuel, Right Time – Carbohydrate Manipulation to Make Every Session Count!

6. Frandsen J, Vest S, Larsen S, Dela F, Helge JW. Maximal fat oxidation is related to performance in an Ironman triathlon. Int J Sports Med 38: 975–982, 2017.

7. Maunder E, Plews DJ, Wallis GA, Brick MJ, Leigh WB, Chang WL, Stewart T, Watkins CM, Kilding AE. Peak fat oxidation is positively associated with vastus lateralis CD36 content, fed‑state exercise fat oxidation, and endurance performance in trained males. Eur J Appl Physiol 122: 93–102, 2022.

8. Costa RJS, Miall A, Khoo A, Rauch C, Snipe R, Camões-Costa V, Gibson P. Gut-training: the impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance. Appl Physiol Nutr Metab 42: 547–557, 2017.

9. Cox GR, Clark SA, Cox AJ, Halson SL, Hargreaves M, Hawley JA, Jeacocke N, Snow RJ, Yeo WK, Burke LM. Daily training with high carbohydrate availability increases exogenous carbohydrate oxidation during endurance cycling. J Appl Physiol 109: 126–134, 2010.

10. Miall A, Khoo A, Rauch C, Snipe RMJ, Camões-Costa VL, Gibson PR, Costa RJS. Two weeks of repetitive gut-challenge reduce exercise- associated gastrointestinal symptoms and malabsorption. Scand J Med Sci Sport 28: 630–640, 2018.

< Older Post

Newer Post >

AUTRA News Report 19-02-2025

By Kate Dzienis • February 19, 2025

The latest in race results, covering Cradle Mountain Run, City Run, Oscars 100 Hut 2 Hut and Yaberoo Trail Ultra.

Final 2024 Points Competition Results

By Alexis Oosterhoff • January 30, 2025

Results for the 2024 AUTRA Points Competition have been finalised, and are available on our Points Competition page. Full details of the top 10 (as shared on Facebook during January) are detailed below, and results for all participating AUTRA members can be found in the documents at the above link. It was a real battle throughout the year between our top two finishers, Phil Gore & Kevin "BK" Matthews, with both giving it their it their all at events, and through contributions to the community - volunteering at multiple events, and submitting articles to our monthly newsletter, Ultramag. They finished within 2km of total distance for the year (Phil on 1203.087km, and Kevin on 1205.510km), and it was only Phil's final volunteering effort on 6 Inch Trail Marathon in December that gave him the that very narrow victory. As you'd be aware from previous communications, this marks the end of the Points Competition. With trail running (of all distances) now incorporated into AU T RA's constitution, and after careful consideration of the costs of the competition payouts in it's current form, the committee felt it was time for it's retirement. This marks my seventh and final year of delivering the points competition to membership (2018-2024), after taking on the role from Cheryl Symons. It has brought me great joy in doing so, and I feel like I've had an opportunity to get to know so many of our members through seeing their race (and volunteering) performances over the years! I'm continuing in my role as the AUS/NZL statistician for DUV (from whom we shared the data for the points comp), and you can expect to continue to find your ultra-race result on their site. 1st Place - Phil Gore (WA) - 86 points Phil's achievements this year have included a massive 265.653km (and 2nd place) at the IAU 24h Asia & Oceania Championships, wins at the Red Dirt Backyard Ultra (33 laps), the Australian leg of Big Dog's Backyard World Team Championship (96 laps), and the Soochow/Taipei 24h Ultramarathon (270.826km). He also knocked out an easy (!) 72km at the Light Horse Ultra 24h in between supporting his amazing wife Gemma. Those two 24h wins netted Phil new Oceania 24h Open Male records, IAU Level 1 qualifiers, and pushed him to the top of Australia's 24h trophy board (with only the great Yiannis Kouros having run further). Phil topped-up his points by contributing one article to Ultramag, worked as an Event Director at Herdy's Frontyard Ultra, and volunteered at a further five events through the year. He finished on 86 points. 2nd Place - Kevin Matthews (WA) - 84 points Finishing in 2nd place in the AUTRA 2024 Points Competition is WA's Kevin Matthews. He monstered his way through the year with finishes at Australia Day Ultra 100km, Delirious WEST 200mi, 24 laps at Herdy's Frontyard Ultra, 190km at Light Horse Ultra 24h, 23 laps at Birdy's Backyard Ultra, and also completed Feral Pig 100 miler, Sandman 50km and Six Inch 47km. And to top things off, he contributed five articles to Ultramag, and volunteered at five events. BK ran 1205km in Ultramarathon races this year, all of them AUTRA-listed, and surpassed 100 marathon finishes (including 51 Ultramarathons!) Kevin finished the year on 84 points, a massive 34 points ahead of our 3rd place finisher Sue Robertson. 3rd Place - Sue Robertson (WA) - 50 points Finishing in 3rd place in the AUTRA 2024 Points Competition is WA's Sue Robertson. Sue completed the Ultra Series 100 miler trilogy of Delirious WEST, Irrational SOUTH and Unreasonable EAST, and rounded out her year with the Sandman 50km and Six Inch 47km races. She received 30 points from the racing at AUTRA-listed events, and was awarded a further 20 points by volunteering across eight events and contributing two articles to Ultramag, for a total of 50 points for the year. Thank you Sue! 4th Place - Margie Hadley (WA) - 47 points Finishing in 4th place in the AUTRA 2024 Points Competition is WA's Margie Hadley . She was the top-female finisher at both the No Time to Die Frontyard Ultra & Wild Dog Backyard Ultra, 2nd at Birdy's Backyard Ultra, ran 182km at the Australian 24h Track Invitational and placed 3rd at Coast to Kosci. Margie received 47 points in the competition 5th Place - Melissa Robertson (NSW) - 44 points Finishing in 5th place in the AUTRA 2024 Points Competition is NSW's Melissa Robertson. Melissa took out 1st place at Irrational SOUTH 200 miler, 2nd place at Lakes Trail Festival 100km, 1st place at Hume & Hovell 100 miler, 3rd place at Rumble in the Jungle and 6th place at Ultra-Trail Kosciuszko 100 miler! She also volunteered at the GNW 50km event, receiving 44 points in the competition! 6th Place - Aaron Young (WA) - 42 points Finishing in 6th place in the AUTRA 2024 Points Competition is WA's Aaron Young . Aaron finished in 1st place at each of the Ultra Series "Triple Crown" of 200 milers (Delirious WEST, Irrational SOUTH and Unreasonable EAST), 55 laps at Big Dog's Backyard World Team Championship, and rounded his year out with Feral Pig 100 miler. Aaron receives 42 points, just nudging ahead of Maree Connor (who also finished on 42 points) on a count-back 7th Place - Maree Connor (NSW) - 42 points Finishing in 7th place in the AUTRA 2024 Points Competition is NSW's Maree Connor. Maree had an outstanding year, achieving 2nd place with 221km (and an IAU Level 1 qualifier) at the IAU 24th Asian and Oceania Championships, 1st place at the Lakes Trail Festival 100km, 1st place with 67km at the Southern Sydney 6h race, and 1st place with 116km at the Narrabeen Allnighter 12h. Maree also competed at Spartathlon race this year (for which she contributed an article to the September Ultramag on her experience), receiving 42 points in the competition. 8th Place - Darren Linney (SA) - 41 points Finishing in 8th place in the AUTRA 2024 Points Competition is SA's Darren Linney . Darren completed 34 laps at No Time to Die BYU, 199km at the Adelaide 24h race, and 814km at the Australian 6 Day race, for a total of 1241km raced and 41 points . 9th Place - Tristan Cameron (WA) - 40 points Finishing in 9th place in the AUTRA 2024 Points Competition is WA's Tristan Cameron. Tristan completed the Ultra Series Triple Crown of 200 mile races (Delirious WEST, Irrational SOUTH and Unreasonable EAST), along with Feral Pig 100 miler, for a total of 1154km raced and 40 points. 10th Place - Jen Millum (WA) - 39 points Finishing in 10th place in the AUTRA 2024 Points Competition is WA's Jen Millum . Jen finished 1st at all three of the Ultra Series Trilogy of 100 milers (Delirious WEST, Irrational SOUTH and Unreasonable EAST), and was 2nd female with 35 laps at the Wild Dog Backyard Ultra. With a volunteer stint at the Yaberoo Trail Ultra, Jen finished the year with 39 points in the competition. To view the complete list of members who secured points in 2024 click here and then follow through to Points Summary under the 2024 tab. All winners have already been contacted, with cash prizes distributed for 1st - 7th places, and AUTRA Store vouchers sent for 8th, 9th & 10th.