When I thought this chapter would be the most easiest to write due to my field experience, it ended up to be the most complicated as I feel I really can't mess up this one. Everyone is a runner. We all ran at some point in our life, and when you talk about running, most of your friends will at least get the broad line of your training or time in that discipline. Yet, it's an incredibly complex sport when it comes to becoming competitive, because nowadays it requires many factors to match other competitors with recent developments around that sport, including :

• Treadmill training
• Powermeter
• Shoes technology
• Running economy
• Heat conditions

In just a matter of 8 months, I managed to improve my marathon time from 3:30:00 to 2:57:16, joining the legendary #SUB3 club. More than that, that breakthrough helped me so much to believe in a #SUB10 performance. Yes, I didn't forgot to keep in sight the real prize. Running is the last part of a triathlon, and is of utter importance in an IronMan 140.6 when you have to deal with a 42-kilometre distance. I've read about so many triathletes ruining months and months of preparation by blowing up on the run and adding up one hour or more to their finish time by walking it down. It was never an option for me, before and during the marathon. Yes I could have faced an unexpected problem — we're not dealing with exact science there — but in normal conditions I knew it would indeed not be an option. Some are master at the walk / run strategy — and it's amazing to see actually when it's perfectly executed — but I will assume that most of us are just looking to be able to run it from A to Z.

If you read my #SUB10 journey chapter you should know that I will now focus on the run for a while, aiming in the long term for a 2:40:00 marathon time. Maybe one day I will dedicate another blog to that journey, who knows ? 

For now, I will try to summarize the most effective tips and tricks that helped me to improve and deliver on the pavement.

Get your own shoe insoles.

I'm not a lucky guy when it comes to my legs and foot “configuration”. I have indeed to deal with flat feet and valgus deformity of the knee, not really helping when it comes down to running on a frequent basis. When I started 2 years ago, it took me some time to realise that I would keep being injured again and again until I take the time to deal with that problem. What a surprise it was when I went to a chiropodist dedicated to sport athletes and learnt about my troubles. He created me two pairs of shoe insoles, one for the run obviously, but one also for the bike as my knees were somehow hitting the frame from time to time due to their distortion. The moment I started to wear them, I started a serious injury free period that is still lasting.

Without these custom insoles I would not have been able to keep up with the planned running volume training.

Actually, talking a bit with him about my case, he acknowledged that 70% of runners are affected by legs and foot problems requiring shoe insoles ! So if you are actually facing pain and / or injuries from time to time when you're running, I guess that the first thing you should do is to have a chiropodist appointment.

Deal with the heat

Global warming is a thing. Past years have seen surge of temperatures and heat waves impacting strongly some IronMan events. 2019 was no exception with IronMan France being shortened and IronMan Frankfürt striking a new DNF record of 26% ! This is a real deal and I think that in the short to mid term the organisers will have no other choice than to move and adapt race dates to that new paradigm shift. Until that time, dealing with heat is something you'll have to learn if you want to achieve your dream, run being the most impacted.

Much studies¹Impact of Environmental Parameters on Marathon Running Performance - Plos have been conducted over the past decade on the impact of temperature on the body during running, especially on the marathon. We're not entitled to a biology course, but I feel it's important to understand what's happening when we're ending up on a run course bathed by the heat. Whenever our body is facing high temperatures, the skin blood vessels will dilate, leading to increased blood flow to the skin so we're able to release heat. Problem is that — and it's the same for nutrition as we'll see later in the dedicated chapter — less blood is therefore available for the leg muscles. All things being equal, your heart rate will increase substantively and you won't be be able to run as fast as when it's cooler.

To define what a “high temperature” is for a marathon, consider that 10 degrees Celsius is the optimal target, while anything above 15 degrees Celsius will start to be at the expense of your performance. When the thermometer is raising to 25 degrees Celsius then you can expect your speed to be reduced by around 20% at that point. Yikes. So obviously when it comes to an IronMan marathon during the summer season straight in the middle of the day, we're all just pack animals trying to survive.

Yet some are doing better than others, and if you're struggling, maybe you're not ticking all those boxes :

• Train in the heat. Sometimes you have to fight fire with fire, and to get your body ready to face the beast you need to help it understand how it's done. I don't like high temperatures, I'm actually quite suffering when we go beyond 30 degrees Celsius. So what I did when the first heatwaves came to Europe early June was to go for my endurance run straight in the middle of the day during my lunch break. This could be dangerous, and you're right. So I went to the biggest park around Paris and ran in the forest, protected from the sun by the trees. I felt the heat, the humidity, but I wasn't directly exposed which makes a huge difference. Sessions still were pretty hard to deal with, but after 5 or 6 runs I could feel the job of adaptation my body has done.


Even if the temperature at Challenge Almere-Amsterdam was around 20 degrees Celsius, I always made sure to keep a sponge in my hands.

• Sponges, sponges everywhere. I guess all IronMan 140.6 — and Challenge Family — events are now offering sponges at aid stations. You would be plain stupid to not use them in all the ways possible. I made a point to never miss any aid station where I could grab some, always taking 3 sponges. The first one to squeeze on my head, the second and third in my triathlon suit straight against my chest. Again and again the same process every 5 kilometres or so. I can't stress how much it helps my body to regulate its temperature to the lowest possible.
• Hydrate all the way. For someone of my size, running at 20 degrees Celsius means losing 0.5 litres of water per hour through sweating, and it can go up to 1 litre of water per hour when the temperature is striking the 30 degrees Celsius. So let's say that if I would have done IronMan Frankfürt last June at 37 degrees Celsius — kudos to all the competitors, finishers or not — I would have roughly lost more than 3.5 litres just on the marathon. When you come to that number for my weight, we're clearly beyond the 5% of sweat loss meaning severe dehydration and close stroke. You must hydrate yourself at every aid station, even though you're not feeling thirsty. Not only with water, but also with electrolytes. No need to drink much — as a rule of thumb your body can't absorb more than around 0.6 litres per hour — but drink at least a glass.
• Omius. We're getting back to marginal gains there. This company is fairly new on the market and is promising to offer a revolutionary headband to help cool the body : « We are the first to use the same cooling techniques found in the heatsinks of your computer and the radiator in your car, to augment the efficiency of the human body. We have developed a new type of material that amplifies the body's cooling mechanisms, by increasing the skin surface area by 5x. » It was actually impressive to see so many professional triathletes using it at the 2019 World Championships in Kona. I'm lucky enough to be one of the beta testers, and all I can say is that it's really working. To what extent is impossible to say, I'm seeking some studies in the future there, but it's definitely like having a fridge on your head whatever the temperature.

Aim your IronMan marathon time right

Getting in a marathon after 3,800 metres of swim and 180 kilometres of bike is something very extreme, whatever the fitness level of any athlete. Putting on the shoes, we're all already very tired and at that point, and I can't stress how much your running technique can help to save the last gasp of energy you will need in the last part of the marathon.

Experienced runners should already have heard about that guy called Pete Riegel, former mechanical engineer and runner, who was the first one to theorize the relationship between exponential speed decline as a function of the distance.

For all the maths lovers around, the exact formula of the so called Riegel exponent being :

T2=T1×(D2÷D1)1.06

• T1 is the time achieved for D1.
• T2 is the time predicted for D2.
• D1 is the distance over which the initial time is achieved.
• D2 is the distance for which the time is to be predicted.

You're not that maths guy ? Me neither, so just keep in mind that as the distance increases by a factor of two, the speed decreases by 5%. This is pure physics, either for amateurs or world class runners.

But now comes the tricky part — wouldn't be fun otherwise — as the Riegel exponent is working fine for open running races, not really for triathlon. You just can't take your IronMan 70.3 half marathon time and use that formula for an IronMan 140.6 marathon, it's just pure utopia. A million variables can play a part after 7 hours or so of effort.

That's where your humble servant can play a part and give you some rule of thumb :

• Pros are good enough to stay within 15 minutes of their open marathon time
• Competitive age groupers — #SUB10 contenders sit there — must be able to stay within 25 minutes of their open marathon time
• Okay age groupers should be able to stay within 45 minutes of their open marathon time
• All others are just living their best popcorn life

Again, bike fitness, nutrition, weather, pacing are so many variables varying from one athlete to another, but yep... I guess this is close from reality if you don't mess up too much your training preparation ahead of the race.

If you're — already — running with power, then it should be more easier to pace yourself, like for the bike. You can use this chart from the Palladino Power Project hinting for a 75% to 80% FTP range, which ended up being relatively accurate for me with a 81% FTP effort on my #SUB10 marathon at Challenge Almere-Amsterdam.

Calling the drafting police

Research has shown²The Secret of Running - Hans Van Dijk & Ron Van Megen that world class runners — and what a demonstration of that did Eliud Kipchoge give at INEOS 1:59 Challenge — can reduce the air resistance due to their own wind by 20% with the use of pacemakers. That's something we don't have, clearly. Yet an average guy drafting on an open marathon can shave almost one minute of his time by running in a pack and overcoming slightly the 6% air resistance share of the total marathon effort.

We all at some point have gone through a run facing either a strong headwind or effective tailwind, or thinking we run faster on a treadmill due to the total lack of air resistance — we're going to discuss this soon enough. There is no reason it would be any different during any race.

Drafting is allowed on the IronMan 140.6 run, yet very hard to use effectively. On an open running race, you usually start within the gate of people close to your level, so from minute one you can just stick in the pack, or at least try. On a triathlon, people are not starting the run at the same time, and so it needs a little bit of time and / or luck to match with people running at your pace.

I can actually rely on that drafting effect as I did my best performance run at IronMan 70.3 Les Sables d'Olonne. The run course was on the waterfront, thus exposed to the wind. Getting on the first loop I got passed by pro triathlete female Anne Reischmann. Her pace was slightly better than mine by 5"/KM or around that, so I just offset that difference by sticking behind her and letting her deal with the pacing and the slight extra share of air resistance . We ran 14 kilometres together, until she turned to the finish line to claim a 1:29:47 half marathon and a second place on the pro women field ! I finished the last loop on my own, keeping the positive momentum, and clinched a 1:30:56 half marathon time !

Obviously this is something you can't get on demand, but if karma is good to you and you end up with that kind of situation, just don't let it slip it by !

No Vaporfly no party

People following me on my Instagram — free ad alright — are now used to my #NoVaporflyNoParty hashtag that I throw from time to time on my stories. The worldwide breakthrough that Eliud Kipchoge has done by beating the #SUB2 marathon mark in October 2019 has revealed what most experienced runners knew already : the Nike Vaporfly Next% confer an utterly big advantage compared to any other shoe on the market. Fact.

Proud creator of the #NoVaporflyNoParty !

I'm absolutely fascinated by the evolution of that model since its first release over 2 years ago — I got my first model the day it was released — and how the whole thing is exactly working with its fibre carbon plate and springy midsole foam. To keep it short, the shoe doesn't make you go faster, and it felt good to see Adidas athlete Rhonex Kipruto breaking the 10 Kilometre World Record with other shoes. No, the Vaporfly is the sole reigning queen on the king distance : the marathon. Its very own design and technology are offering a significant gain in term of running economy over long distances, allowing for runners using it to run the 42.195 kilometres 4% to 5% faster than with any other shoes ! For someone running a 3:30:00 marathon, it means shaving off 9 minutes off their final time ! That is not a marginal gain, that is a stratospheric one.

The New York Times has recently published a deep analysis about the Vaporfly and the relationship with increased marathoner performances over the past years, raising questions about whether World Athletic would ban the shoes in a near future. My opinion is that it will never happen — we're talking about Nike here — but they will eventually limit the drop height of the shoes to limit the number of components that can fit under the sole. In that sense the coming up AlphaFly Next% model should be the last unrestricted model coming from the Swoosh. Time will tell, but for now forget about the $275 price and grab your pair.

Treadmill, a friend who wishes you the best

Treadmill is for sure a good discussion topic among runners as it will not leave anybody indifferent. I actually truly hated it until a year or so ago; it was like torture to me every time I had to get on it. Then Zwift — I really should have bought shares in the company while it was cheap, damn — released a run version of the software, allowing you to run into in their virtual worlds while being on the treadmill. As a geek, I couldn't resist trying it for a while and it actually helped to at least give a chance to see the opportunity of running inside and its great advantages :

• Treadmill doesn't care. This is the first thing I realised after a few sessions. Once you're running on the belt, you're in a completely controlled environment. You decide the pace and incline; the treadmill is going to do what it’s going to do, and you’re just trying to keep up with it. This is absolutely fantastic especially for interval workouts as you don't have to worry about keeping a specific pace. Just set the speed and focus on your running technique. It helped me to break my fitness ceiling way faster than running outside, no question.
• Injury-free. Treadmills are now well known to reduce harmful shock to joints, muscles, and connective tissue. To what extent ? It obviously depends on the treadmill quality, the best in town being the Woodway where you feel like you are running outside without any shock. When you're dealing with 15+ hours of training, treadmill's cushioned belt is more than welcome.
• Efficient. Running on a treadmill is a lot like riding on a home trainer to me in the sense that it doesn't require you to bring a ton of stuff, worry about weather, traffic or clothes. You just prepare your bag before sleeping, you bring it to work and during your lunch break you go to the gym and run. You know exactly how much time it will take, no surprise. For someone with a tight schedule, this is luxury time management.

Treadmill using Stryd is the combination that helped the most to become a decent runner. Using data in a controlled environment was indeed the key.

That is for the pros, and I wouldn't be honest if I didn't talk about the stuff weigh against treadmills :

• Legs strength. Running on a treadmill is basically running in a totally linear pattern. When you're running outside, your body is dealing with tons of terrain irregularities like hills, curbs, etc... All of this is forcing you to make small movements to stabilize yourself, thus keeping your muscles and joints more balanced. If you plan to do a lot of your run training on your treadmill, core strength sessions are mandatory.
• Overstriding. When you set the speed of the treadmill at a fast pace you're not used to, your body will do its best to catch up as it just can't slow down. That can force you to overstride. That happens when your front foot lands too far in front of your centre mass. That can lead to injury especially for your hamstrings, so when you do intervals it's really important to try your best to not practice overstriding.
• Pace issues. This point is utterly complex to be fair, and as I will try to keep it short, I would advise you to do your own research if you plan to train a lot with the treadmill. First thing, easy to understand, is that on a treadmill you do not move, so you don't have to face any air resistance and use some extra power to overcome it. All things being equal, you can run faster on a treadmill. By what margins is very dependent on the athlete, but fairly by 5-6% ! To compensate this lack of air resistance, we have to play with treadmill incline, and a lot of studies have been conducted to define the right percentage. My lord Cody Beals has published a long article about that topic, but for the sake of clarity, I've always set my treadmill incline at 1% as it's usually mimics the best road imperfections and air resistance. That is for the first part of pacing issues, but there is another one : belt stretches. Treadmills are displaying the speed of the belt, but every time you land on it, your weight forces the belt to slow down. If you add up belt stretches and the mechanical components wear down, you can be pretty sure that a treadmill is never displaying your real effort. That's where — again — running with power is for me utterly mandatory on a treadmill as you can rely on that data with confidence, whatever the data displayed on treadmill screen.

Nowadays, I'm doing 70% of my training on the treadmill. And over time, I've learnt something else essential to be productive on it. When you run inside, most of the time in a gym I guess, you're already running in hot conditions for your body with most room temperatures around 23 degrees Celsius and humidity above 70%. We talked earlier of the impact of temperature on the run, but what I've not said yet is that in such conditions, your skin blood vessels will dilate, thus needing more blood flow to help the skin release some part of the heat produced. So when this happens, and as your amount of blood available is not infinitely available, less blood is available for the rest of the body, including what matters in our case : leg muscles. This is something you will definitely feel on a treadmill after a few minutes when you won't have any airflow to cool you down forcing your body to heat up.

There is actually a way to translate outside rate of perceived exertion to inside running, thanks to elite running endurance coach Steve Palladino and his Palladino Power Project. He wrote recently a meaningful article to sort this question; it's a must-read if you have some spare time. In case you don't, I've written below a formula that will most likely work in 90% of treadmill environment :

Treadmill FTP = Outside FTP X 0.96 (Air resistance) X 0.985 (Heat & Humidity)

Please note this is specifically working with power, and can't really being applied to speed for the pace issues already mentioned above.

Run with power

« Ah shit, here we go again. » That's what some of you may be thinking right now about my power obsession. « Fair enough » I would answer. Using running power for the past year and a half, I've seen its community and resources grow a lot. Groups like Stryd Community or Palladino Power Project, specifically address power training plans, books like the ones of Jim Vance³Run with power - Jim Vance or Hans van Dijk & Ron van Megen⁴The Secrets of Running - Hans van Dijk & Ron van Megen. It's absolutely fascinating to witness the birth of a tool that most runners will use in 10 years or less from now.

As discussed previously in the Data chapter, I'm working with Stryd, this one being the most advanced and accurate on the market right now, taking account also of the wind which is truly a game changer when it comes to pacing your effort. I've also been trying Garmin products, but even though a lover of the brand, I recognize that they are behind, no question for now. Stryd costs a fair amount of money with a displayed price of $270, but that's what it takes to get a premium product for outside and inside running that can dramatically help to track a lot of stuff :

• Running economy. « With great power comes great responsibility » once said Peter Parker's uncle. Two runners of the same weight and same power output on the same track can display a different pace by a wide margin depending on how economically they are running. This is called RE — Running Effectiveness — and can be calculated with the formula RE = (m/s) / (W/G). So it will rely on your running form including stride length, impact time, cadence, vertical oscillation, etc... If you're interested in that topic, please head to this Palladino Power Project article to learn more about.
• Fitness improvement. What's exactly is running faster ? It's hard to tell until your running in a race environment because it's dependant on many outside factors. With power, you have a constant and reliable output data to track your FTP and VO2 max without all that lab testing. Power is nothing other than your effort, whatever the conditions, and that makes all the difference with other factors like pace or heart rate. VO2 Max = (W/KG FTP*1,40)*10.
• Exact workout & planned race effort. This is a point directly linked with the one above, and I've already discussed power in the Data chapter. I won't write just to write, so refer to it if you forgot about it already.