Like last year we had the opportunity to get an interview with Aslker Jeukendrup after finishing the IronMan World Championships.

Asker Jeukendrup is one of the leading sports nutritionists, he is the Director of the Human Performance lab at the University of Birmingham and in charge of one of the most active sport and exercise research groups. At the age of 35 he became the youngest professor at the University of Birmingham and has received several awards for his academic achievements and contributions to sport and exercise sciences, including a chair at the University of Brussels.
Asker is the author of several books (www.askerjeukendrup.com/2009/New_book.html) including High Performance Cycling and a Textbook on Sports Nutrition in collaboration with Prof Michael Gleeson. Asker has published over 150 peer reviewed journal articles and book chapters and has made it his mission to translate the science into practical applications that will benefit people who want to achieve their individual exercise goals, whether this is medals at Olympic Games or simply exercising for health reasons.

Over the last few years Asker has worked with some of the best athletes in the world, including several Olympic and World Champions; he has also worked with the Rabobank professional cycling team, Chelsea FC, UKAthletics, Ethiopian marathon runners, and some of the best swimmers and triathletes. Besides that, Asker is a 16 time Ironman finisher, including 3 times the Ironman World Championship in Hawaii, was National Champion duathlon in his age group, and won the San Francisco Golden Gate Headlands marathon amongst other sporting achievements.

Asker, congratulations finishing your fourth IronMan World Championships! Below 11 hours, with new personal best on swim and bike split, this is an awesome performance for somebody who is working as hard and successful in his job as you.
Can you tell us a little bit about your race?

I went to Hawaii 2 weeks before the race. I can still work even when I am not in the office but being in Hawaii allows me to focus a bit more on preparation for the race and to acclimate at the same time. I gave a talk at a sports medicine conference few days before the race, I participated in a PowerBar Sports Nutrition panel discussion at the expo, I even lectured from Hawaii to my students back in the UK through an online connection (despite an 11 hour time difference). So I was quite busy even the days leading up to the race. Even though this was my 4th Ironman Hawaii and I knew the course and the conditions well, I did not really know what to expect from my own body.

I started the swim a little nearer to the front than normal and had a good battle in the first 500meters of the swim. I was pleased to come out of the water faster than I had done in previous years. My transition was also a little faster and I felt better on the bike than I had done in previous years. I was at the turnaround point in Hawi almost 10 min faster than last year. However on the way back, even though I was feeling better than last year the strong winds were holding me back. Nevertheless I felt good on the bike and was significantly faster than previous years. It was extremely hot and humid, even hotter than last year. I started the run in good spirits. My plan was to start relatively slow and then pick up the pace a bit later if possible. However, already early on in the run I had some breathing problems a very tight chest almost like asthma. I had had this problem a couple of years ago in the hottest race I have ever done at Ironman Louisville in Kentucky. In that race I was reduced to walking and eventually I was taken in an ambulance and did not finish the race. I knew in Hawaii that I would finish the race but just had to give myself some time to recover and get my normal breathing back. I never panicked even though I had to go really slow till about halfway. Then I started to feel better and started to run a little faster. Towards the end (the last 6km) I was running normally and even finished on 7 min miles so I could finish under 11 hours. Without the tight chest I could have gone a lot faster so this just gives me even more reason to go back to try and have a really good race in Kona. It took Mark Allen a long time before he had a really good race, so I don't feel bad that I did not get it right even after my 4th attempt. Overall I am pleased with my result, especially considering the fact that I have to fit in my training around a 70 hour work week.

Do you have an explanation for the breathing problems in the run?

As I said I have had these problems before and they seem to happen especially in extremely hot and humid conditions. Although I never really got to the bottom of the problem I figured out a few things: it was not related to any heart issues or asthma.
They only happen in Ironman races and not so much in Ironman 70.3s. I am convinced that it is somehow related to my bike position since I have excluded most other options. So for next year I will change my position on the bike to maybe make it slightly less aero but more comfortable. I have been fortunate to be in a windtunnel and my position on the bike is very aerodynamic (even compared to most pro cyclists). However, I achieve this by having arm rests pretty close together which really constricts the breathing and puts pressures on upper back muscles. Hopefully by playing with the position a bit I can still be reasonably aero but be more comfortable. Hopefully I will get a chance next year to test these ideas in Kona. First I will do Ironman St George in Utah.

Did you take the next plane back to UK and how do you feel now - pretty much recovered or still exhausted?

I did take the next plane back to the UK, we did land after a 26 hour trip at 7AM in Birmingham and at 10AM I was lecturing at the University. I am recovered though, I had a couple of weeks off and now I am on my way to New York for the New York City Marathon. I am not expecting wonders but I got the opportunity to run and this is something I always wanted to do. (Editor: Asker finished the NYC Marathon in 3:38:40 h)

I think the answer to this is fairly simple. My swim was probably faster for a number of reasons. First of all, I swam a little more than pervious years, I may have swam shorter sessions but more of them. In the weeks before I left to Hawaii I was swimming better times in the pool than I had done before. The other factors are a better position at the start of the swim and I attribute a lot of the effect to my TYR Sayanaro swim suit!
For the bike I think the answer is even simpler. In previous years I focused a lot on running because my bike times were ok, but my runs in races sometimes let me down. Increasing running miles and/or intensity however did not make a lot of difference to my Ironman performances and thus I figured that I had to work on my bike so I could come off the bike fresher. This is what I did I increased the volume especially on the bike and did a lot of fairly hard and long rides. From my SRM files I could tell that my power output on the bike was higher than last year. The best example was a test ride 10 days before the Ironman on Maui. There is a road that goes up the Haleakala crater, one of the nicest bike rides in the world. It starts at sea level and goes all the way to the top 3000m. I was much quicker than last year even though I was not pushing harder. From an analysis of SRM files it becomes very clear that my sustainable power was better than last year. My peak power outputs for 30 seconds up to 10 min were similar, but the sustainable power output for 3 hours was 10-20W higher.

How do you use your SRM in training and competition? Did you follow a specific pacing strategy in the race and how do you prepare for that in training?

By always training and racing with SRM you get a very good idea of the power outputs you can sustain. In races is it sometimes easy to get too excited in the first part of the race and therefore I do look at my power meter to make sure I am not pushing power outputs that are impossible to sustain. So I guess I do use it for pacing especially at the beginning of a race. In training I have a number of courses that I ride and I record the average power outputs for those courses. I also have a number of climbs that I record from top to bottom. These benchmarks help me to monitor my progress. Of course a stopwatch would give a similar answer but SRM just adds a lot more accuracy and your measurement now is a lot less dependent on wind and other environmental factors. The ratio between heart rate and power output is another parameter I use to monitor progress. My heart rates seemed to be lower at a given power output in the weeks leading up to Hawaii. In the race itself I was also able to maintain a higher heart rate throughout meaning that the power output was significantly higher. There is so much more I would like to do with my SRM but the number of training session I can do on the bike are limited (usually to 2 a week) and this also limits my training options and my chances to play with my SRM.

In the "News" section on your webpage you mentioned before the race that you would "try to start the marathon better hydrated and fueled, even if this means that I have to slow down sometimes..." . Have you tried it?

I had less problems this year maintaining hydration on the bike and I drank on average just under a liter per hour. I was also able to eat something I had not done in previous years. I had no gastro-intestinal problems on the bike. I think mostly because I was better trained on the bike. I had more problems later on the run, I had a very severe stitch and I did actually get quite dehydrated towards the end and weighed in more than 4 kg lighter at the finish.

Are there any new developments in nutrition you tried before or during the race you could recommend to other athletes?

There is a developing theory that training with low glycogen in your muscles can help your training adaptation. We also conducted studies where we had people train twice a day. In between they would not eat much carbohydrate and therefore they would not replenish their energy stores the second training of the day would therefore be performed in a glycogen depleted state. The athletes who trained with this regimen showed better adaptations in their muscles. We took muscle biopsies and found that various enzymes, in particular those involved in fat metabolism increased in comparison to a group of athletes who did similar training but always in a glycogen loaded state. When we measured performance in these athletes we did not see much but the training program was only short and it is not unthinkable that training like this for a longer period of time would also result in significant performance improvements. I therefore incorporated one of these sessions with low glycogen into my training week.

You wrote about two students, Becca and Adrian, who joined you in Hawaii. Can you tell us a little about the study they are working on?

Yeah those poor students had to go all the way to Hawaii for a research project.... Becca and Adrian recruited triathletes of all levels and ages in Kona and asked them to complete two questionnaires: one before the race and one after. The purpose of the study is twofold: First we want to get an idea of what athletes take on board during their race. We have published certain recommendations but we actually have little knowledge of what athletes actually do. Secondly we want to get a good record of gastro-intestinal problems. Many athletes develop these problem but we have little understanding of the factors that cause it. We hope to find out a little bit more about who is more prone to develop the problems and which factors are likely to worsen the problems or increase the risks. We have targeted several other events as well such as the Tour of Spain, Ironman Frankfurt, Ironman 70.3 Wiesbaden, marathons etc etc. It will take a little while before all data is analyzed but it should help us to answer the two important questions I mentioned.

In 2010 a new edition of your textbook "Sport Nutrition" and a new book called "Sports Nutrition: from lab to kitchen" will be published. Can you tell us a little bit about both of them? "Sport Nutrition" set a benchmark on the textbooks concerning nutrition in sport. What changes, adds and news will be found in the 2nd edition?

The new Sport Nutrition book will come out in January 2010. The book will not only look better, it is updated in all chapters and there are new chapters on weight management and training adaptations. It discusses the science behind current recommendations and helps the reader understand why certain recommendations would help. The second book Sports Nutrition from lab to kitchen will come out in May 2010 and the goal of this book is to translate the latest science on key issues in sports nutrition and translate this science into practical application. It is an attempt to bridge the gap that often exists between science and practice. There are contributions in this book from world experts in various areas. Cutting edge information on methods to improve training adaptations, protein metabolism and muscle growth, new energy sources, special carbohydrate mixtures etc is provided in both books

Thank you very much Asker for taking your time giving us this really interesting interview.