Optimal Bike Pacing and Best Bike Split with Ryan Cooper | EP#131
Ryan Cooper, founder of Best Bike Split, chief scientist at Training Peaks and a world-leading expert on the physics of cycling joins us to teach optimal bike pacing in your triathlon bike leg.
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In this Episode you'll learn about:
- General and specific pacing advice for half and full distance triathlons.
- Pacing for draft legal racing - when is the right time to make a break?
- How should you adjust your power and effort for hills, headwinds and crosswinds?
- Aerodynamics vs. Power vs. Weight - how do they impact how fast we get around a bike course and which should be prioritise?
- How triathletes can use the Best Bike Split software to plan their ideal race in great detail.
About Ryan Cooper
- Ryan is the founder of Best Bike Split.
- He is the chief scientist at Training Peaks.
- Ryan is also a world leading expert on the physics of cycling, and how it translates into practical pacing advice.
About Best Bike Split
- Best Bike Split was originally conceived to help triathletes and time-triallists to plan and execute race strategy.
- We looked at a course, and the significant elevation or gradient changes, and direction changes.
- We then tried to see if we could incorporate information about the athlete, their bike and their aerodynamic profile together.
- We also try and include information about the wind and road conditions.
- Ultimately we try and plan a strategy for an athlete to get the biggest benefit for their power output.
- The idea was if you had a goal power, a goal time, we can show you how best to utilise your effort across the course.
- If you sign up and you have a race:
- We'd first walk you through setting up a profile.
- We ask for basic information such as height, weight, FTP, training altitude etc.
- We then drill into what kind of bike you have, the wheels, the tyres.
- This gives basic information about your drag.
- Then you can search for your course.
- We try and crowd source all the courses on the system.
- If yours doesn't exist, you can use a programme (e.g. Ride With GPS, Strava) to draw the course and upload it to the site.
- We'd first walk you through setting up a profile.
- Once we have that information, you can create a race plan:
- Select your bike, normalised power target or a goal time.
- If you use advanced metrics you can target a specific training stress score (TSS).
- From that we take in weather data, the course you selected and information about you to plan out your strategy.
- From there you can either download it onto a head unit to race with it, or pre-train on Zwift or Trainer Road using those power targets.
- We added TSS very early on because every Ironman or 70.3 course is very different.
- For example, Ironman Florida is very flat, so you may be able to break 5 hours on the bike.
- However if you look at Ironman France or Wisconsin, they're hilly so trying to break five hours there may not be wise.
- You can normalise the difficulty of the courses by using TSS as a target.
- You can explain to the athlete that while you may be able to do a 5 hour here, it might be better to do a 5:20 or 5:30 at another course for the same physiological impact.
- The plans are very detailed and specific, suggesting power for each part of the course etc.
Pacing the bike leg
- For the majority of people, on the vast majority of courses, you want to shrink your variability index.
- Variability index (VI): the difference between normalised power and average power.
- This means more of a steady state pace.
- There is a general rule of thumb of aiming for a VI of 1.05 or less.
- This means your normalised power is 5% higher than your average power.
- There's still quite a bit of flexibility in 5%.
- On some courses you may go higher, particularly if there's climbing.
- If your gearing isn't correctly thought through you may have to go higher than that.
- For the most part, your pacing should fluctuate in that range.
- We let the math work itself out, where for the most part you'll still be in the same VI range.
- That's not to say you should ride the flats and the hills at the same power.
- You'll want to vary that, maybe push a little bit harder up the hills or into the headwind.
- That little extra effort will give you more time than a completely steady state.
- E.g. if you did 210 watts on the uphill and 190 watts on the downhill they'll be a benefit to that compared to 200 watts for both.
- We have what we call a "cheat sheet".
- We break it down segment by segment.
- However if you want something more generalised we can say for this athlete on a 1-2 grade hill, this is the kind of power you should aim for.
- The steeper the hill, the more power you're going to have to output just to stay upright on the bike.
- What we find regardless of whether it's an amateur or professional is that athletes tend to push too hard on hills.
- You look at somebody and they're going along at 22 mph/36 kmph.
- They hit a hill and start to slow, and then feel the need to keep the speed going to keep pushing a little harder.
- You find that the power that they're outputting to keep their speed up is way over a steady state power level.
- Even if they should go 30-40 watts higher on a 6% grade - e.g. 240 watts.
- You'll often see that they're actually at 260-280 watts, and they'll feel that later in the ride.
70.3 vs Ironman pacing
- The pacing strategy isn't going to change too much across the two distances.
- Your nutrition strategy will change more for Ironman, as well as your percentage of FTP.
- For a lot of amateurs there isn't that much difference.
- They may do 75-80% of FTP for a 70.3 and 65-75% of FTP for an Ironman.
- Whereas a professional may do close to 90% of FTP for a 70.3 and 80-85% of FTP for an Ironman.
- Lionel Sanders will hold 90% of his FTP for a 70.3 no problem.
- For Ironman distance if you look at Jan Frodeno when he won Kona couple of years ago, he held 76% of his FTP, with a VI of 1.02.
- Even on a hilly, hard course he went right by the numbers and it played out well for him.
- It's race and condition dependent.
- In terms of pacing itself, for a 70.3 you're not going to go out and do a lot of punchy riding, with accelerations and decelerations.
- You should keep that same even keel.
- But since you're out there for 2-3 hours less than a full Ironman, your percentage of FTP can jump.
- Your nutrition may also be a little bit different.
- But generally your pacing shouldn't be too different, in the same VI range.
- Different athletes have different strengths.
- If your strength is the bike, and you know you can run well off it, you can push the percentages by 2-3%.
- If you know you're going to be struggling on the run, you want that TSS lower so the percentage of FTP may need to come down a little.
- In terms of TSS, I always go back to Joe Friel's blog post 'How to "cheat" by using a power meter in an Ironman'.
- It has the Ironman times and TSS broken down into strong runners based on times.
- I use this as the baseline.
- TSS will be different for males versus females just because you may spend a little bit more time out on the course.
- For males I go with a TSS of 280 as the cap on an Ironman.
- You can go higher than that and I've seen a lot of female racers go up to 300 and do really well.
- For 70.3, use a TSS of 165-170.
- You see amateurs and pros performing well off those numbers.
- Jim Vance's book: Triathlon 2.0 also has these kinds of numbers.
- He suggests 300-310 for and Ironman for more advanced athletes.
- We do see the spectrum from 275-310 TSS being a good range.
- I tend to go on the lower range because most people over-estimate how well they can run off the bike.
- A lot of times you see if they're shooting for the higher number at the high amateur, elite level they know their bodies well.
- As you get down to more general athletes, once they're on the course the thing you have in your head, and reality, can be different.
- I'd rather you had a smile on your face and were running well, but took an extra 2-3 minutes on the bike.
- You might lose 3 minutes, but gain 30 by not having to walk aid stations on the run.
- It's definitely an individual range, but as you get more elite you are more in tune with your numbers.
- You can then start pushing intensity factors and TSS up.
Pacing in draft legal racing
- Draft legal racing, much like pure road racing or crit racing, is quite a different beast.
- We use Best Bike Split for those, and we've done work with the US Olympic team and the draft legal triathlon team, as well as a few of the teams at the Tour.
- We look for places where it makes the most sense to sit in.
- You look for the places on the course where strategically you would not want to be taking a pull.
- Or where you may see somebody trying to make a break
- For example there could be a place where you have a crosswind to a tailwind.
- If you're looking for somebody to make a break, there's less advantage on the cross but when they make the turn to the tail the chase pack has to work harder to close the gap.
- Whereas if they turn into a headwind, the chase back can rotate at the front and pull you back in quickly.
- We have some tools we've worked on live on the site that allow you to do this.
- It's a very manual process, you have to go in and analyse it yourself.
- It basically gives you a strategic idea of what the course looks like, and allows you to do things like adjust your drag.
- If you adjust drag, say 40-50% lower, you can see the equivalent power that would be required sitting in the group on different sections.
- Obviously on the hills, if somebody goes you make a choice to either go after them or let them go.
- There is the strategy out on the race day but having a little bit better understanding of other factors may give you a bit of an advantage.
- For those who want pacing advice, you want to be sitting in whenever there is a headwind.
- It's tricky to make a break in a tailwind because everybody is going so fast.
- The extra power it takes to overcome at high speeds is much higher.
- If you already have a gap going into the tail wind it helps because the chase pack have to work that bit extra to drag in the people out front.
- If you are going to make a break, try getting the gap before you make the tailwind.
- Even it's a nice tail wind into a climb.
- In this situation, Best Bike Split is not so much for the pacing it's more trying to determine what the physiological load is going to be of the people you're racing against.
- The time analysis tool is where you can play around with these factors.
- Originally this tool was for goal setting and 'what if' scenarios.
- It basically has your race plan and then you can vary your aerodynamic drag, your power and your weight and see the impact of those changes on an individual section level.
- For example if you look at a race, and think for this course if I lose 2kg's, what's the impact of that?
- You can do any combination of changes and see how it impacts your race, and also see where specifically on the course it has the biggest impact.
- At the Tour de France two years ago, several teams reached out to us and they were using it specifically for different stages.
- They were assessing the power to weight impact of uping power on specific climbs.
Aerodynamics vs Power vs Weight
- For 95% of triathlon courses, at least in the US, they seem to be pretty vanilla.
- Not a lot of climbing and pretty straightforward.
- On these courses, aerodynamic drag is the biggest factor, then power.
- Because there's not a lot of climbing on the courses, weight isn't as big a factor.
- Time is better spent improving drag numbers.
- This can be done by getting a good bike fit and a good aerodynamic position.
- Clothing also has a big impact on drag.
- We see a lot of people using longer sleeve tri-suits now which does make a big difference in terms of drag.
- Physics wise, the faster you go the more impact drag has.
- Drag is exponential with speed while weight is linear with speed.
- Once you hit a little below 20km's per hour, weight takes a bigger priority on uphill sections.
- There's a speed and gradient where gravity is starting to play a much bigger role.
- Before 20km's per hour, you want to make sure your aerodynamic drag is the forefront of thinking.
- Worked example (using Best Bike Split), looking at the Kona bike course which has significant amounts of climbing.
- If you're looking at someone with normalised power of 195 - so they're doing 190 average power across the course.
- An average position triathlete would finish the bike in 5:15-5:20.
- That's a 72-73kg rider.
- If you drop 3% weight, so 2kg's, you're only looking at a benefit on that course of 1 minute 30 seconds.
- A lot of athletes couldn't drop 2kgs and still be in a healthy range.
- Conversely, if you optimise your aerodynamics assessed using CDA.
- CDA = coefficient of drag multiplied by your frontal area.
- What the wind see's versus the shape and how the wind reacts to the body.
- The range you see in triathletes is somewhere between 0.23 and 0.3.
- 0.3 is a high 'comfortable' position, mid-pack age grouper.
- 0.23 would be more the professionals, e.g. Jan Frodeno/Josh Amberger. Very low and tight on the bike, in a very aerodynamic position.
- Most athletes can get down to a 0.24 pretty easily.
- Assessing this on the Kona course, if you look at 0.26-0.245 you're looking at a 6:40-7 minute reduction on your bike split.
- It's really not that hard to get into those positions.
- It takes some work and you have to get used to riding in that position.
- There is a comfort versus aerodynamic trade off that you need to work on.
- I like to say do you look more like a bullet or more like a barn door?
- The more you look like a bullet the faster you're going to go.
- You need to get used to this position, and spending 95% of time there.
- Then you can use a tool like Best Bike Split to assess where might be best on the course to come out of the aero position to stretch.
- If your normalised power is 195, you would need to increase it by 5% to have the same gains as above.
- That would mean an increase of 10 watts over the 5 hours.
The aero analyser in Best Bike Split
- This is a beta feature that we rolled out in April 2017.
- Everyone knows their FTP and they know their weight, but CDA is so difficult to measure.
- We wanted to give athletes and coaches a good way to measure their CDA.
- We started off with drop downs about the type of athlete (elite, mid-packer etc).
- We then adjusted type of wheels etc.
- From there we went to a fit-based calculation where we used numbers from a bike fit.
- This gave a slightly better estimate of where drag was.
- We wanted to get more refined because it does impact your plan and estimated time so much.
- We came up with the aero analyser.
- It works by you uploading a race file.
- I suggest if you do a test run then make sure you have full race gear, do at least 15-20km and vary speed and power every couple of minutes.
- The programme breaks down your ride file and attempts to pick out what your race aerodynamic number would be, and what your relaxed aerodynamic number is.
- Your relaxed position would be when you're climbing or otherwise out of the aero position.
- We rolled it out in conjunction with a wind tunnel study we did with United Healthcare cycling team.
- We'd go to the wind tunnel, and go outside and do the rides, then compare the numbers.
- We found we could get within 1-2% when given good data from the riders.
- When we were off by significant amounts, we found that what they looked like in the tunnel and on the road was totally different.
- Similarly, a couple of riders wore a speedsuit in the tunnel, and then outside wore thermal suits.
- There was a significant difference between the speedsuit and something flapping in the wind.
Advice for using Best Bike Split
- What we see is that the more advanced you are and the more you've raced, you naturally find this rhythm.
- If we can pair a plan with an athlete that's been racing for a long time they naturally do a lot of these things.
- Someone that's been racing for 20 years, and you overlay their actuals and their plan, you see they follow it almost perfectly.
- Athletes that are newer to the sport see a huge benefit when using this system in terms of pacing strategy.
- It's great for anybody that wants to look at times and come up with a general race plan.
- It's nice to hear that if you plan the bike correctly you also then have a really great run.
- We found while doing this that bike manufacturers have a range of people that they're targeting.
- We found that lower power athletes can't follow a plan with a low VI because their gearing ratio doesn't exist.
- They either need to be on compact rings and they're not, or they need a much bigger cassette at the back.
- We're trying to look at how we can incorporate gear ratios into planning.
- We can then try to suggest gear ratios going into a race.
- We also want some input to put a minimum VI.
- If we know someone isn't going to be pedalling on the downhill, can we build that into the plan and subsequently show them the impact on that.
- E.g. if you get better at descending here's the time savers you can make on this course.
- We found that lower power athletes can't follow a plan with a low VI because their gearing ratio doesn't exist.
- The final piece of the puzzle is to enhance the post race analysis.
- Be able to take your race files and have that enhance your individual model.
- So next time you run a course it knows things like how well you take turns or how good you are at descending.
- It will know more about your aerodynamic drag, and when you tend to sit up or hold in,
- It will start to point out areas you may want to work on.
- We're shooting for a Q3 release of that before Kona.
- Best Bike Split does Kona predictions each year, which can be really fun to follow.
- We use Kona as our baseline test course for pretty much most things.
- That's because it's very difficult to predict things like weather due to the microclimates on the island.
- Last year the weather was unexpected and you saw a dramatic impact on the times.
- I don't think we'll see any more records falling there unless the wind can play nice again.
Rapid fire questions
- What is your favourite book, blog or resource related to triathlon or endurance sports?
- I go old school: Bicycling Science (third edition) by David Gordon Wilson.
- It's everything you've ever wanted to know in detail about the physics and the physiology of bicycling.
- What is your favourite piece of gear of equipment?
- It's got to be my aero helmet. It looks so cool.
- Who is somebody in cycling, triathlon or endurance sports that you look up to and admire?
- There's a coach who is a former pro cyclist called Ben Day.
- He said something to me last year that has stuck with me: 'as coaches or high performance people, our lives are spent swimming in numbers, but the performance so often is in between the ears and how we can react to it'.
- That stuck with me, you can get all these numbers but if you don't have it in your head there's no way you're going to perform up to your abilities.
- The big mistake that many age group athletes make in their racing is having too many occasions where power goes too high.
- Especially important for long distance, non-drafting races.
- The call to action is to go and sign up for a free Best Bike Split account, and see what your ideal pacing strategy would be after you've entered all the information.
- Also use the Time Analysis tool to see what impact changes to your power, aerodynamics and weight might have on the bike split.
- Changes in your power and aerodynamics trump changes in your weight.
Links, resources and contact
Links and resources mentioned
Connect with Ryan Cooper
Connect with host Mikael Eriksson
Hi! I'm your host Mikael,
I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.
I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show.
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