The Time-Crunched Cyclist Podcast by CTS

Episode 200: How to Personalize Fueling and Training with Kilojoules

• CTS • Season 4 • Episode 200

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IN THIS EPISODE

  • Learn how to use kilojoules to quantify work rates and total work achieved, set fueling goals, and achieve weight loss goals. 
  • What is a kilojoule?
  • How kJs are used in training and racing
  • Fatigue resistance and durability
  • Basing energy intake during rides as a percentage of hourly kJ
  • Tracking kJ for weight management/loss goals 

LINKS
- Energy Expenditure: Calories, Kilojoules and Power in Cycling
- How Accurate is That Calorie Reading? 

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HOST
Adam Pulford has been a CTS Coach for nearly two decades and holds a B.S. in Exercise Physiology. He's participated in and coached hundreds of athletes for endurance events all around the world.

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Speaker 1:

From the team at CTS. This is the Time Crunch Cyclist podcast, our show dedicated to answering your training questions and providing actionable advice to help you improve your performance, even if you're strapped for time. I'm your host, coach Adam Pulford, and I'm one of the over 50 professional coaches who make up the team at CTS. In each episode, I draw on our team's collective knowledge, other coaches and experts in the field to provide you with the practical ways to get the most out of your training and ultimately become the best cyclist that you can be. Now on to our show. Now onto our show. Welcome back, time Crunch fans. I'm your host, coach Adam Pulford.

Speaker 1:

Today's podcast isn't answering any of your specific audience questions, but it is inspired by athletes that I coach ride with, and cyclists who want to maximize their training with stuff they have already. Most serious riders have a power meter on their bike, and they're pretty familiar with tracking average powers, peak powers, probably even normalized powers, even though that's going to be a podcast in the future. Now there's another thing that's super valuable, coming from your power meter too, and not too many people know about it, nor know how to track their progress with it. That valuable thing is called kilojoules of work. My goal for today is to teach you what a kilojoule is, how to measure it or access it from your power meter. Then learn how to apply it to training, racing and fueling strategies, as well as any weight loss goals, if that applies to you. So, without any further ado, let's get into it.

Speaker 1:

Okay, first things first. What is a kilojoule? There's a lot of science and stuff here. I'm going to keep it very basic. Kilojoule is a unit of work expressed as force times distance. Kilojoule is a unit of work expressed as force times distance. It's measured by your power meter. You don't have to do anything more other than pedal your bike and look at it and it's, ironically, an equal, one-to-one measurement of calories. So one kilojoule equals one calorie, okay, and it's burned while you're riding your bike.

Speaker 1:

The reason for that ironic one-to-one ratio is simply a fun kind of piece of ironic math combined with the fact that humans are only so efficient on a bicycle. Most of the calories that we eat gets used up and burned off as heat energy, and the other 20-25% of that energy goes into the pedals on our bicycle when we ride it. 25% of that energy goes into the pedals on our bicycle when we ride it, and because one calorie equals 4.186 kilojoules, the math back and forth for heat and efficiency workout to basicallya one-to-one. Now I'm not going to get into the math and walk you through the equations, but if that is of interest to you, I have linked to a really good article written by my good friend, daniel Matheny, who wrote an article for training peaks on this, so I've linked to it in the show notes have added for all you math nerds out there Uh, but really getting into the math of it doesn't really apply for what we're going to talk about on the podcast. All you need to know is that it's a one-to-one kilojoule to calorie ratio. So essentially, when you look at it and you see 800 kilojoules for the day for your ride, you burned 800 calories. Okay, so that's like point number one for you to take away from this podcast.

Speaker 1:

Now let's talk about how to use this for training and racing. Because it's measured by your power meter. It's an accurate, consistent unit that that we can rely upon from any bike over any terrain, indoors or out. Okay, one kilojoule today is one kilojoule tomorrow, just like one watt today is one watt tomorrow. Accuracy and consistency matters and that's why I, when I'm riding with people and in my athletes asking me which power meter to get, I always, I always choose for them the most accurate and consistent power meters out there. So how do you access this from your power meter? Okay, so, if you're using Wahoo, garmin, hammerhead or whatever device that you have as your cycling computer, just simply go into settings and search for kilojoules. Sometimes it's called Power KJ or just KJ, but look for it and put it on your dashboard. Put it on your kind of your main screen and just start looking at it. Get familiar with it while you're riding.

Speaker 1:

If you haven't used this to track how much work you're doing on training rise, I really suggest doing it, both on your cycling computer and wherever you house your data, such as training peaks, intervals to ICU, today's plan WKO5, wherever you put your stuff and look at it after the fact. Okay, in there you'll be able to search for kilojoules as well and, just like average power, normalized power, distance, speed, cadence, start looking at KJs. Once you start tracking kilojoules during training rides, group rides and races, you'll start to see patterns of your work rate. For example, if you go out and just start riding your bike on indoor trainers, so it's perfectly at 200 watts, for example. Watts for example, it'll come out to 720 kilojoules of work per hour. Okay, now, if we go kind of on the lighter side of that, for somebody who averages 120 watts for an hour, that'll be 430 kilojoules per hour. Now the reason I give you some of those examples is just to start to normalize or start to make you familiar with work rates. Okay, so let's just say you do a long ride, of that 430 kilojoules per hour, and your long ride's four hours long, it'll be a total work done of 1,720 kilojoules. But that again it comes down to the work rate, and I use both the absolutes of kilojoules as well as work rates in kilojoules, and I'll get into how I start to use this when coaching an athlete.

Speaker 1:

Now here's a good takeaway for everybody listening to this Do work if you want to perform. Don't just ride at zone two. You can't just ride your bike around in zone two, turn up to a race and think that you're going to win or perform well or do anything kind of noteworthy if you haven't done some intensity in your training. I would even argue that if you just did a bunch of zone two then did some intervals, I mean that is a better approach to it. Okay, then you jump into a long, grindy gravel race and think that you're going to hold up well in the long run Still not the best strategy, in my opinion. You need to. You need to do work on the bike, you need to work hard, need to know what working hard means and you need to be able to organize it in such a way that you can look at the work being done on your bike and point a finger at it and say I've improved the work that I've done. So here's how. If you want to perform well and hold up well at the end of some of those, like the long, grindy gravel race, for example, you need to do serious work.

Speaker 1:

Mixing all the intensities on a big ride with high aerobic focus Okay, high aerobic intensities, think zone three, low, zone four or and then kind of like splatters of zone five and six, okay, and you do that early on, you do that middle of the way through and you do that later on and you want to start to measure kilojoules of work throughout. Measuring the amount of work done in kilojoules at hours three, four and five, or however long your long rides are, will start to bring some context to this. Okay, because you can ride in zone two for a long time, because it's aerobic, you should be able to do that for hours and hours and hours. So long as you stay hydrated, you should just be able to go for a very long time. But if you're doing this and you get tired, heart rate may drift up, and coach Renee Eastman and I talked about this on our cardiac drift episode. Now, if you're going by heart rate only in your zone two rides, you will likely decrease the power in order to keep the heart rate where you want it to, based on your zone two endurance range for heart rate, and therefore kilojoules will start to decrease because your power is decreasing and you'll be doing less work later on in the ride.

Speaker 1:

We, in that episode where we talked about cardiac drift, we talked about the pros and cons of doing it like that. For me, I stick to the power and I use kilojoules of work to measure this versus heart rate alone. Okay, we talk about perceived effort, how that applies. So cardiac drift episode on the time crunch cyclist podcast. That's a good one to listen to if you want more about that. So I suggest to keep the work rate high or even throughout a long ride.

Speaker 1:

And here's how to do that. Let's just say you take a look at some of your long rides and you've been averaging right around 600 kilojoules per hour for your long rides and they're four hours long, so 2,400 kilojoules. But you notice that you start out more like 700 or 800 kilojoules per hour and then you fall off to 500 kilojoules per hour in the final hour. What I would suggest doing in that case is putting kilojoules on your dashboard or your display and restraining yourself in that first hour to only 600 kilojoules in the first hour, then hit another 600 kilojoules in the second hour. So you're up to 1200 total. Then you hit another 600, then you hit another 600. Okay, so the total is still coming up to 2,400 kilojoules, or 600 kilojoules per hour for the work rate, but what you're doing is you're adding more work later on in the ride, so you're training yourself to be more durable or do more work later on, and that is a very significant way, in a very impactful way, in a very efficient way of becoming more resistant to fatigue, becoming more durable, becoming more fit, however you want to talk about it, okay, and I'll mention this now but it's going to be a topic for a future episode.

Speaker 1:

But I do use kilojoule tracking for many of my cyclists doing races and events to improve their fatigue resistance or durability. Now these two terms are kind of synonymous with each other. I like to think of them a little bit differently. Durability specifically refers to can you produce the same or similar high power or force when you're fresh, for example, can you produce that same high power late in the game? Can you produce a similar high power, uh, after several hours of riding? So this is what we're talking about when we say are you durable for the long run? Are you holding up on your long rides, okay, producing some same high forces or same high powers late in the game, when you've already done a bunch of work earlier on?

Speaker 1:

How I measure this for my masters riders, for example, is to note their 20 minute peak power from a field test or when they're fresh, and then I test them when they're fatigued and basically I have them ride a mix of zone two to three until they hit about 1500 kilojoules of work. Then I have them do a 20 minute all out effort and I look at the differences between their fresh 20 minute power and their fatigued 20 minute power. Okay, I'll get into more of this into in a future episode and in the way of what those relationships can and should look like in general, we want to narrow them as much as possible, okay. So whatever that peak freshness is and whatever the fatigued 20 minute power is, I want to bring that fatigue 20 minute power up as high as I can, and that's going to be a very good indicator that we are increasing the fatigue resistance in an athlete. What I'm trying to tell you here is that if you're getting tired late in the game, or you're struggling to hit peak powers on a long ride, or maybe you're cramping when you hit a hill, climb after hour four, five and six and you're just falling apart, tracking kilojoules as a unit of work and developing a game plan to increase your work rate per hour or increase your work rate, especially for long rides, this will help you perform way better in all situations, especially for long endurance, races, events, fondos, whatever you're doing. So start tracking your kilojoules now and we'll get into fatigue resistance and durability more in a later episode.

Speaker 1:

I'm going to switch over to fueling here a little bit. You've heard various messages from me and my guests about fueling during rides on past episodes. Fueling with carbs is the hot topic right now and much of the messaging is more is better. But in one of my recent episodes with Alex Hutchinson we explored why more is not always better. The upper limit of absorption seems to be still right around that 90 grams of carbohydrate per hour. Now some pros are able to tolerate and take in more than that. You know, a hundred to 120 grams, maybe even more, with good results for time crunched athletes. We're not pros pros and I wouldn't give a blanket statement of more is better. A hundred grams is best for everyone. That's not what I'm saying For my athletes, I dial it in, okay.

Speaker 1:

I dial it in for their own individual needs. Specifically, I use percentages of kilojoules per hour to dial in their fueling strategies for them. So for long training rides and anytime, I call this like performance percentages, okay. So this is for long training rides with mixed intensities or races or fondos or just like long, hard, hilly group rides. This is what I recommend.

Speaker 1:

I suggest aiming for 40 to 50% intake of your output, based on the kilojoules that you're putting out from your power meter. So what this means is if you take your kilojoule per hour and multiply it by 40% or 50%, you'll then get a total calorie need range of what to consume per hour for that ride. Now if you want to do this in grams of carbohydrate versus just calories alone, all you need to do is divide by four and you'll get your grams of carbohydrate. So let's use some examples. Let's take that 200 watt average, 720 kilojoules per hour rider that I described above. 40% of that 720 kilojoule is going to be right around 290 calories or 72 grams of carbohydrate. If you take 50% of that 720, you're going to get 360 calories or 90 grams of carbohydrate. So you can see that those percentages they're hitting the current kind of prescribed 30 to 90 grams of carbohydrate per hour that many nutritionists, dieticians that have been on this podcast and stuff that you're reading out there. It's hitting the upper end of that. And so 40 to 50% applies very well for masters, riders, time crunched athletes, I would say 90% of the people out there.

Speaker 1:

Okay, you can use these performance percentages for hard training, rides, races, efforts where you want to maximize energy with fueling. You'll notice that on a very high level. Let's say, a thousand kilojoules per hour, you'll get 500 calories If you use that 50%, you'll get 500 calories from that and that comes out to 125 grams. Okay, so you can use these performance percentages and they'll scale up to before, to professional writers too, and they'll scale down to amateurs and weekend warriors. And again, these are performance percentages.

Speaker 1:

This is this is something that I use, my coaching practice. I want to give it to you all and this is something that I've seen and applied for almost 20 years of coaching in it. It works pretty much every time. So definitely try that. Okay. But I find that with all athlete types, these performance percentages, like I said, based on kilojoule outputs from your power meter, will have that realistic and very applicable scaling up and scaling down.

Speaker 1:

Well, let's scale it down for, for, uh, for example, okay, let's go back to that 120 watt average rider. That's going to be 430, uh, 430 kilojoules per hour, and if we take 50% of that, we get right around 213 calories or roughly 53 grams of carbohydrate per hour. And if we take 50% of that, we get right around 213 calories or roughly 53 grams of carbohydrate per hour. Now I'm just like hitting you with all these examples is because it's it's real life. You need to take these, you know these tools that I'm giving you and apply it to you. But on the very high side it works. On the very low side it works Okay. So use it for you, dial it in for your own individual needs, but I generally find that percentages based on kilojoule expenditure is the best um situation to start with your fueling needs, uh, for performance races in in events.

Speaker 1:

Now for your zone two training rides. I've talked about this too, but I'll mention it. I won't go as high on the on the percentages. Okay, I call those performance percentages Okay, um, but you're not burning as much glycogen on zone two rides. So for endurance rides that are lasting, let's just say two and a half hours, um or so, okay, uh, two and a half hours or so, two and a half hours or longer, I find that 25% to 33% intake of output is completely fine there. Less than two hours, I suggest drinking water and or electrolytes. As long as you come into those rides well-fed and topped off, you shouldn't need to eat a ton or consume a bunch of carbohydrate on that ride. So again on the low end of things, 25 to 30% of intake of your output, based on the kilojoules from the power meter, that's going to be good for the zone two rides.

Speaker 1:

Now let's talk briefly about weight loss. We can go pretty deep into this one, but I'm going to go kind of just like surface level. The main thing I want you to see is, with such an accurate measurement system of calories coming from your bike or from your power meter, you can use this as weight loss as well. Simply track your total kilojoule expenditure from the bike and use this as your calorie expenditure of exercise for the day. Now this, along with an accurate resting metabolic rate calculator, as well as a lifestyle factor, you'll be able to determine the caloric needs for the day and keep your weight in check. Keep your weight even for the day-to-day and week-to-week for energy expenditures.

Speaker 1:

If you need to lose weight, okay. If weight loss is part of your goal, simply have a net loss of 500 calories per day through exercise and diet and you'll be able to stay on track to lose roughly a pound of weight loss per week. I find that to be realistic without compromising performance for many masters and time crunched athletes, so I wouldn't go more aggressive than that. But weight loss? As long as you're a healthy person meaning like hormonally healthy, because hormones change everything Okay. But as long as you're metabolically healthy individual, it is a math game. If you eat less than you burn, you will lose weight.

Speaker 1:

If you want to do it intelligently and not lose performance, my suggestion is have a net loss of 500 calories per day, which should equate to about a pound per week. You do that for eight weeks or so and you'll see the weight come up. But you have to be disciplined. You're going to be a little hungry for the first couple of weeks and you just punch through it. Okay it's. It is as simple as that.

Speaker 1:

Now, if the resting metabolic rate and lifestyle factor is new to you, I'm not going to cover that here. Essentially, there's a ton of really good calculators online where you plug in information about yourself your height, your weight, your age and you plug it in. It gives you what you need to basically exist and then you describe your lifestyle. It'll give you a lifestyle factor of just moving around and then you use the calorie expenditure from your bicycle, from the kilojoule, and you get a game plan for weight loss or weight management. The main point here is using kilojoules to track calorie loss is the most accurate way to do that for cyclists. So now, in summary, what I really want everyone to take away from today's episode is that you have a measurement of work, called kilojoules, already on your bike. If you have a power meter which you can use to track total work done, you can track various work rates, calories burned and you can develop accurate fueling strategies for performance. You can also use these kilojoules to track calories burned each week and each month and if you have weight loss goals or weight management goals, you can use that super accurately to achieve those goals as well.

Speaker 1:

This is a metric that is oftentimes overlooked by many cyclists, gets confused. It's also kind of an older school approach is what I've heard from people I've been riding with and also some newer coaches, but I'm like, okay, I guess I'm old, old school, but like I've been using that this for years. Okay, so it's a great tool and if you don't know about it, start looking at it, start tracking it If you haven't already, and I think you'll find you'll be looking at your training and quantifying it in different ways for greater success, especially when it comes to durability and fatigue resistance. Like I said, we'll get into a lot more specifics of that in future episodes. So, in closing, thanks again for not only listening to our podcast but sharing your questions, your challenges and your curiosities by writing into us here at CTS. If you're new to the show, welcome. How you do this is by going to trainrightcom backslash podcast and click on ask a training question. Your submissions get sent directly to me and we'll do our best to answer it on upcoming episodes.

Speaker 1:

So that's it. That's our show for today. If you liked what you heard, please share it with your training partner or a friend, as this is the best way to grow the show and make sure you keep getting actual training advice to help you reach your goals. Be sure to come back next week for more and until then, keep getting out there and keep training right. Thanks for joining us on the Time Crunch Cyclist podcast. We hope you enjoyed the show. If you want even more actionable training advice, head over to trainrightcom backslash newsletter and subscribe to our free weekly publication. Each week you'll get in-depth training content that goes beyond what we cover here on the podcast. That'll help you take your training to the next level. That's all for now. Until next time, train hard, train smart, train right.

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