For the first time in many years I had the opportunity to watch the race from the sidelines.  It is surely a different perspective, but it also reminded me how many mistakes we make when so caught up in the world of racing.  Standing on the sidelines gives you a perspective of what we overlook when it the midst of the race.

I was able to narrow the race in Kona down to four key factors that great determine the race outcome and the individual results.

All about the run

Kona is all about the right pacing on the bike.  Whether a Pro or Elite Age Grouper (aren’t they all in Kona?), your ability to effectively run off the bike is the entire goal.  It is a delicate balance between biking strong, but not too hard.  It is an understanding that the bike leg is tiring, demanding, but there is an extra tank of fitness awaiting you in T2 in order to run an effective marathon.  It is your maturity and confidence to allow others to push harder than you, knowing that you are looking to race the full 140.6, not just 130-135 miles of it.  Many in the pro field as well as the AG field can bike faster/stronger, but they choose not to since they know their patience on the bike allows them to shine on the run.  Besides the demoralizing effect of going backwards in your placing off the bike, you are also feeding your competitors ability to run better since they recognize your struggles.

This year had an extreme example of this.  Look at 3^rd place Patrick Lange running himself from 23^rd with a 2:39 marathon.  What kind of confidence must he have had in his run while seeing the gap and his placing grow on the bike?  What kind of math was he doing while seeing the 12 minute deficit coming out of T2?   It was not just a few racers ahead of him, it was 20+ each one he passed he grew more confident and his competitors more nervous about him approaching.  Could he have ridden faster?  I am quite certain he could have.  But instead, in his first full IM race, he chose the humility to have the best possible 140.6 result, and that meant running to his potential.  How confident is he now going into any IM in the world?  Knowing that against the best in the world he can run himself to the front.  He swims well (48) and runs faster than anyone has ever in Kona (!), so now he can gradually, strategically work on his bike strength, approach and pacing.  A textbook approach to joining the world’s best in Kona in your first IM ever!

Even this past weekend in IM 70.3 Hefei China: once again both winners ran themselves to victory.  It is all about the run…

Take a look at the Age Group results:  all show a similar approach.  They could all run.  Despite many of the frustrations in the sport regarding drafting, the best runners still win.  And if you think its that much easier to draft a 112 miles, then try it some time in training: almost always are you riding faster than your fitness, hence the draft is needed, and that effect still drains you, leaves you fatigued etc.  While drafting might save you watts here and there, it is mentally draining, still requires a fair amount of work, and has you pushing at times way harder than you would usually ride on a steady, controlled, efficient 112 miles.  So, you are back to needing to have the best possible run.

Which brings me back to the overall triathlon training & coaching principle:  until you teach yourself in racing how fast you can run, there is no point in riding the bike fast, or nearly as fast as you can.  Until you are seeing the run pacing and splits you see in training, the ones you know you are capable of holding, then any faster AG bike split is a waste of your IM racing progression.  Knowing what you can run, whether a 3:30, 3:15 or even 3:00, is well worth it when it comes to the next IM:  riding the bike with that confidence in your mind.  The performance benefits of moving well at the end of a race are significant – most importantly in your ability to tolerate pain and displaying mental toughness.

How does this apply to your training and racing?  Knowing it is all about the run, means…you need to run… a lot. But this is also a big misconception in the sport:  the need to run a lot of miles or the need to run fast miles.  No – the key to successful IM and Half IM running is:

• Frequency: gradually, safely and it might take a few seasons to get there. But each season you get faster.  And more importantly:  focus on the running frequency vs. biking and swimming.  If you can only do one, run.
• Nutritional quality: high quality food = superior performance. There is no other way, especially for handling the running volume.
• Hills: perform the bulk of your runs in rolling hills to build all around leg strength, especially at this time of year (trails!)
• Steady State flat running – 1-2x a week we insert steady paced flat running. Leg turnover, economy of motion, technique and mental focus.
• The proper fatigue:  remember the keys to a superior run leg: we want the majority of our fatigue to come from sessions that directly impact overall race performance. This means outstanding race specific cycling muscular endurance.  You want to access your existing run fitness.

Since most athlete are running so far below their existing run fitness, our goal is to improve overall endurance (best trained on the bike) and durability (best trained with run frequency)…

Know your strategy

It’s your 140.6, so don’t let anyone take your strategy from you.  In Kona you can see the best athletes are focused on their own race.  Frodeno?  Never sniffed too much wind on the bike, he knew what the others can do, what he needs to do, and stuck with it.  Rinny?  No panic – just run when the time comes – get to T2 well, and then go!  Elite AGers? Race your splits/wattages/paces/efforts and then see what needs to be done with 10 miles to go on the run.  “If I stick my plan until 130.6, I’ll be having a great day.  Then, I will evaluate the situation and see placing vs. effort vs. current body scan”.  You are almost guaranteed success at this point.

Drafting and others racing should not influence your race strategy.  The strongest emotions of the day come within seconds of crossing the finish line.  How did I race?  Did I give it my all?  Did I execute my plan?  Did I race to the best of my ability today, given my fitness, the circumstances etc.?  If yes to all this, then you are most always happy with your race result and the progression you are making as an athlete.

Focusing on others, getting sucked into another’s race or being distracted from yours, means you are risking months of training for a race with people you don’t know.  You don’t know what they are capable of, how they race, what their fitness is as well as the mistakes they are currently making.

Training Principle:  Focus on your training plan.  A long training day on the weekends is filled with distractions:  Friends and other riders.  Multiple places to stop.  The terrain might not be ideal.  Training days are great for executing your plan despite adversity & distractions.  Let others come along on your day.  Let others ride along your intervals.  Eat your fuel and drink your hydration on your schedule.  Execute your training on the terrain for your day.  It’s your training day.  Own it.

Control the chaos

In Kona there a so many inputs.  Despite having the best intentions to race your own race, execute your plan, and run well off the bike, it’s a long day of chaos.  Incredibly fast racers, hot temperatures, constantly shifting winds and then throw in nerves, the finality of the race and intentions to do well.

When watching the best in Kona, those with the best results all controlled the chaos around them on the day.  Control the chaos.  Understand things will go wrong.  Brace for things being more difficult than planned.  Realize the your fellow competitors are capable of racing well too, as they are just as focused and prepared as you.  Use temperatures and environment to your advantage since it creates challenges and difficulties for all.  The best in Kona also deconstruct their race prior:  whether via visualization of the race, detachment exercises and segmenting their day in to multiple stages of successful results.

Training principles:  create chaos in your training and simulation days.  Ride too hard, run too hard early off the bike, ride with others that ride too hard for you, have others draft off you & properly annoy you, choose a harder course and then run off the bike, ride into windy conditions on purpose.  Start early when its too cold; start midday when its too hot; practice getting flats; practice being stuck in one gear; race Olympic and half IMs with the intent to blow up yet continue on; create high stakes around a local race so that you can simulate nerves (i.e. post your desired best outcome on social media PRIOR to the race or bet someone a big dinner, wine etc. regarding the result).  Create chaos – internally as well as externally.

The only thing I would avoid practicing chaos?  Nutrition and hydration.  That is not something to create chaos around.  This is something to narrow the focus and perfect.

There are many ways to train chaos.

Bike Setup

This might seem like a no brainer but it is ridiculously clear in Kona.  Not only have I learned from my own mistakes and understanding with this, but the front of the field in Kona has a glaring lesson:  bike setup is critical.

We all know the basic principles of being aero, but it becomes so much more exposed in Kona.  Not only can one observe hundreds (!) of athletes sitting up on their $12,000 aero bike, completely exposed to the wind, but the most important lesson was how relaxed, efficient and focused the best athletes in Kona were on the bike.  Their ability to not only cut through the wind in a superior position & setup, but remaining aero for 95% of the course despite its difficulties, remaining relaxed while still pushing significant wattages at the front, staying focused in their cadence, race positioning all while conserving as much energy as they can.  The ability to ride fast, while conserving energy is the key to a good run.  Only a bike setup that allows you to stay COMFORTABLY in the aero position for 5+ hours, WHILE still maintaining the wattage range you intended will allow you to achieve this.

A good aero position with allow you to ride lower watts but with the same bike split (or faster) in mind.  A good set up will allow you to save even more time/watts as you integrate wheels, clothing, helmet and bottle placement.

The key lesson from Kona here?  The front of the pack is focused meticulously on their set up.

Training Principle:  A great bike fit helps, but you must must must be relaxed and efficient in it.  It might be great in the wind tunnel, but if you can’t hold it for 105 of the 112 miles, fuhgetaboutit. So therefore – we must train it – every so gradually.  It might be frustrating seeing some lower wattage numbers, but without starting aero, relaxed and efficient in your pedal stroke, you will not see the gains of being in an aero position.  Every minute in an IM bike leg where you are not aero costs you 2 minutes vs. had you been aero for that minute.  2 minutes!  String that together over 5 hours, think how many times you sit up.  This takes into account not only the drag by not being aero, but how long it takes to get back to an efficient, relaxed aero position; how sitting up effects cadence, motivation, as well as many times athletes stand up and sort of stretch out their back and legs.  The later in the bike leg this happens, the longer the transition time is to going back to an aero, relaxed, efficient position…

Therefore seeing lower wattage numbers is no big deal since you are staying in the aero position.  Imagine now if you train relaxed, efficient and focused, seeing the wattages gradually increase over your training phase, that is pure speed AND time savings.

This is a great time of year to work on this.  Outside staying aero.  On the trainer indoors staying aero.  Turn off the lights and feel yourself relaxing into your aero position without focusing on watts, only feel and clean, efficient pedaling.

If you can remember these four factors as you go into the next Ironman season, you are certain to have significant race day improvements.  How can you not?  A better run, a better focus on your own race strategy, a better ability to deal with the chaos and adversity of the day and a better bike set up…each one will buy you time.  Put them all together and they might buy you a PR.

Racing well, racing fast & executing a set race day plan is fun.  We just observed 17 days of it in Rio.  Its what athletes worked hard for – so it should feel great and we surely saw those emotions on display!

But as we all know – beyond all the joy of the Olympics and the incredible athletic achievements, there are plenty of challenges.  Many athletes struggle to break through to that next level.  Whether you have now graduated to racing your event vs. just finishing, all the way to qualifying for something like the Olympics, Kona or Boston – it is always about progress and moving forward – to that next level.  Often just executing a successful day with all the little details (like no walking aid stations, avoiding too many calories, controlling the pace during the first half of the race or faster transitions) is a struggle for many come ‘the day’.  What does it take?  How can you take that next big step forward?  What will it take to get that next big break through?

For many endurance athletes its all about the mental approach they bring to their sport.  Whether triathlete, ultra-runner/swimmer, or any ultra endurance endeavors:  the mental approach is a huge untapped potential.  Key word here is approach.  It’s a mindset.  It is a set approach to how you, as an elite athlete, go about your day of training (Please remember: being an elite athlete does not require elite results.  Being an elite athlete is about how you approach your sport: you can match the focus, diligence, consistency and daily awareness that World Champions bring to their sport despite being a complete beginner. It’s a mindset!).

Some of the best athletes in the world have a few things in common – whether sprinters that race for a whopping 9-ish seconds or solo sailors out alone on the oceans for weeks on end.  We have all seen great athletes this week and so it is a good refresher what they all – across all playing fields – seem to have in common.

1. All great athletes understand that ‘greatness’ is something that has to happen daily.  It means taking small definitive steps daily in their focus on excellence or diligence.  John Wooden used to teach even the best basketball players coming in to his program on Day 1 how to tie their laces.  It sounds ridiculous, but attention to detail and doing it right, by habit/routine is a common trait all great athletes have.  It’s the little details that add up to a great result.  So many weekend warriors have a great occasional workout.  But in order to achieve their best, a great athlete understands the great workout needs to be a daily norm, not the exception.  Focused training equals focused racing.  And focused racing means executing a successful day.  (The hidden benefit here is progression as well: what was a great workout now becomes the norm and elevates your definition of a great workout to an even higher standard!)
2. All great athletes have a deep connectivity and purpose as to why they are doing their sport.  While many athletes focus and repeat good habits (recovery, nutrition, body work and technique), the best of the best have a deeper reason for being so engaged in the sport.  It’s a sense of mission, its that little extra when the days are tough, when the workouts suck.  Its a deep conviction that there is no quit, no matter what the consequences.  This doesn’t mean your training is dedicated to you grandmother or that you are raising awareness to a cause.  It’s a deep down set of values and reason as to why they will see it through.  ‘It might not be today or this year but I will succeed’…
3. Patience – Great athletes – in all sports – are in it for the long haul.  It is a common thing in endurance sports for participants to do one or two events and then check it off their list of cool things to do. I have found this is indicative in many cases how they always did sports or in other aspects of their lives.  Great athletes understand that hard work today (while valuable) doesn’t necessarily mean results tomorrow – or next month etc.  Every year I coach busy working athletes that bust out 5-6 weeks of great workouts and then are discouraged when they don’t suddenly PR their next event.  Especially in ultra endurance events: there is no such thing as overnight success.  It’s a gradual, slow progress.  It requires discipline, diligence, humility and perseverance.  And luckily it does as it is what makes a great result even more rewarding a deeply satisfying.  The long haul approach is also what will separate you from the rest of your competition/peers.
4. All great athletes seem to also understand the simple beauty in what it takes to be fast/successful/achieve the desired result: that hard work, consistency and focus can’t be faked, there is no short cut through this.  Daily deliberate training sounds so easy to say/write, but we all know its not.  It’s actually quite funny how simple their approach is.  We all know athletes that try the quick approach to success, try to hack the system, but we also don’t see them at the top, especially not in ultra endurance sports.  The sports in the ultra world are hard, and for anyone looking for a shortcut to success is quickly exposed over the long distances.  Nothing, absolutely nothing can hack into fitness: true, deep, aerobic fitness…Pay your dues every day, and your ROI will not only be results but satisfaction in knowing you did it the right way: Daily deliberate training.
5. Failure.  All great athletes have failed.  It’s a part of every path that leads to the top.  Those stumbles, those DNFs, those races where walking was the majority of the ‘run’, those injuries, those bad workouts all help great athletes stay on track.  Failure reminds us what we are working for, why we are working for it.  Overcoming obstacles makes us stronger – helps us realize that the path is littered with challenges.  The path to great results must be hard, hence why it is such a rewarding, valuable, delicate path!  It brings out our true emotions to why sport is important to us.  Failure narrows our focus again on what our goals are.  Failure also motivates great athletes:  the “come back stronger” sensations are incredibly powerful.  If it were easy to achieve our desired results, then all this work is not very inspiring.  If it just took a little focus, a little desire, a little extra push to reach our goals, that would make the result less valuable.  Embrace the suck as someone has been know to say.  Understand that overcoming the obstacle is the entire point of it all.

I wanted to share some solid insight from this power file from the Paris Roubaix winner this year. First – click here to take a look at the file yourself in a more raw format. But below is also how I look at the data with regards to fitness and aerobic capacity.

What I wanted to highlight was a few points:

1. Power to HR ratio (1st graph below). As many of you have heard me say – a great indicator of our fitness is your ability to maintain watts/HR ratio for most of your rides. That means the range of your watts and of your HR stay consistent throughout a 4-6 hrs ride. If early on your averaged X watts for 30 min and late in the ride you avg similar watts at the same HR…awesome. Very little fatigue and drift. Most of us do not have this fitness. Late in the ride our watts may be the same – but the HR is way higher. OR if riding on HR – the watts later in the ride are way lower. Given that Mathew Hayman is racing, and trying to win, it is really amazing to see how ‘in control’ he was of effort to HR throughout his ride. Early on you can see he was riding within the groups as his wattage and HR are quite choppy. But once he settles in to racing and his strategy/group – it stays quite steady in ratio to each other.
2. Please notice his cadence (2nd graph below). Not only does he average 87 for 160 miles….! But it says in very close relationship to his HR. Another sign of control and fitness. Also please notice how Normalized Power (347) and avg power (302) are quite far off. This means there was a) a lot of coasting b) some incredibly high wattage spikes (1100+ watts a few times…!) Peak 1 min is 660w, Peak 20 sec is almost 1000w! Despite these efforts, he still maintain HR control and still averaged 87 cadence…
3. Notice that these are just the last 110 miles of 160. The first 50 are chill roll out miles in the peloton. But it is still 50 miles (2 hrs) of cycling prior…so fuel, and hydration and conserving energy are key.
4. 6700 kj in 6 hrs…he needs to eat about 2000 calories…just in this back end…so his first 50 miles were truly that…fueling and prepping. In pro cycling you can’t just grab a bar from the bento box during an attack..or breakaway..!

Graph 1: Power to HR Ratio

Graph 2: Cadence

What does this mean for your training? We want to be able to maintain this type of aerobic balance between solid power and HR control. Especially when racing, and needing to run off the bike, if we ride in a ratio that maintains balance between HR and watts, the running energy levels and speed will still be available.

As we head out on long rides and the weather turns to summer, be aware of this ratio. Ask yourself if there is a wattage that you can ride whereby your HR stays steady throughout. Or, how far do the two drift apart. Most of you cannot, and why I want you to start easier, or ride on feel more often!

For those of you without power: notice how your cadence and HR stay in line. Since we know that power = force x speed (cadence), keeping your cadence steady, relatively high, means your watts will most likely be showing higher. The great part about good cadence control for all of us is: because higher cadence early on in the ride nets lower watts, it keeps us in good balance throughout – late in the ride that wattage will stay somewhat in range…Try it!

As always – please let me know of questions. I hope this helps you see some interesting power/cadence/HR ratios.

Although the heart of the racing season is approaching, it still seems quite far off.  It is these weeks in March and April that truly set you up for the summer.  It is also during these weeks, since you did a better job through the winter, that you can propel ahead of where you were last year – or in years prior. But too often, despite the days getting longer and the weather gradually turning, athletes often lose their perspective and motivation for the season that lies just ahead.

I receive daily workout updates and emails from athletes that either missed workouts, couldn’t stay motivated, have too much going on, or are even a little burnt out from pushing themselves mentally too early in the season.  Where once the athlete was filled with inspiration and pumped (!) to train for the next season, there is now lack of perspective regarding improvement, the doubt on how to get it all done, even frustration with the training plan.  The common theme in all these emails & updates is the difficulty to sustain motivation.

Somehow, when the event is right around the corner, life doesn’t get in the way, schedules clear up and the excuses fade from the training logs.  The athlete is filled with inspiration and focused to execute each session effectively.  Yet it is those events, the ‘A’ races, which end up also being the problem.  As we try to remain focused on the big event, our season highlight, we end up feeling overwhelmed. The amount of work between now and then is so large that it leaves us paralyzed.

Consistent, daily motivation & inspiration isn’t about the final result though.  True motivation, the kind that replenishes itself daily, lies in that simple concept I repeat so often: progression.  Of course your long-term goals are important, and they act like a North Star as you navigate through a season of competing and training, but the daily jolt you need comes in the form of progression.

Be a little better, just a tiny bit, than yesterday:

If you can focus on just one thing (in life actually…), it is being a bit better today, than yesterday.  When you get on your bike today, lace up the running shoes, or dive into the pool today, don’t think about your ‘A’ race.  Think about how you will be just a bit better than yesterday.  That’s all.  If you achieve this, you are not only a better athlete, but also one step closer to your goals for the ‘A’ race.  But the beauty in focusing only on being a better YOU, not a better athlete, faster, stronger etc., is that it simplifies the daily fun & motivation into it being just about you.  Just being a better you than yesterday.  You warmed up better, your prepped better for the workout, you fueled better, you hydrated better, you focused on recovery better, you were more engaged during the workout, you understood the workout better, you filled out your log better for your coach (!?) etc.  All and any of these things make you a better athlete than yesterday.  Not always a new personal best in the pool, highest avg. wattage or best running pace…but instead a better YOU.

Why?  Small, easily digestible improvements work so well.  Being better than yesterday allows for many little improvements to be made and allowing yourself to be successful.  How you are going to drop the avg. pace on your run by x:xx seems daunting, but being a second here or there faster than yesterday is doable.  This will help you move forward with positive momentum vs. the overwhelming feeling of how far you still need to go.  Better than yesterday…

Better than yesterday also allows you to focus on the process, it forces you to be in the present.  It requires you to pay attention in your workouts: “what am I doing now, today, that is better than yesterday?”  You never want to miss the opportunity, even if oh so small, to do things better.  Being a process-oriented athlete will inevitably create an environment for you to be an even better athlete.  In many ways, you are now behaving and approaching your training like an elite athlete: being better than yesterday…that is often all they focus on.

Better than yesterday also peaks our curiosity (and therefore motivation).  Can I?  How will I be better than yesterday?  Think ahead and prepare for that improvement.  And repeat the next day…can I be better?  Yes!  Only a little bit, but I AM BETTER.  Repeat.

Be creative with your daily dose of improvement too.  Eat better, arrive earlier, practice the mental game for your workout, maybe push one set harder than ever before, try warming down.  Any and all of these things can help answer the simple question:  Am I better today than yesterday?

As I was riding the Coast last week I had plenty of time to myself, to think. I was riding sweep for a group of 28 cyclists, 495 miles down the CA coast from SF to Santa Monica.  In past years I used this ride for many different approaches to my training.  Last year it was my last prep aerobically for my 100 mile running race 12 days later – less pounding on the legs, but still 8 hrs a day of time in a HR zone.  Other years I have used it to go from out-of-shape cycling to in-shape cycling – BAM – in a matter of a week!  And, of course, there are the years where I have been fit and hammer with the front groups….key words being “already fit”…so I had my base miles in me.  After 17 years of riding a January Coast Ride, I figured it out pretty well on how it works best for me, and, I’d like to say for my athletes.  And, it keeps coming back to the same concepts…you can’t escape the base miles…

This year I finally made the decision to depart a day ahead of a bigger Coast Ride group that comes together every year.  That ride has gone from what the original Coast Ride was back in the early 90s to a mini race down the Coast.  Roadies and weekend warriors putting their fitness on the line to thump their chest that they had a solid Coast Ride….in January…!   Originally a bunch of very accomplished pro and elite triathletes started this in order to force themselves into 600 miles of easy aerobic riding back to San Diego.  It was on the Monday after SuperBowl Sunday every year, and since the 49ers seemed to be in it a lot back then, San Francisco was a fun place to be.  Besides many injuries, broken collar bones and road rash, the faster Coast Ride accomplishes very little other than going deeply anaerobic repeatedly for a couple of hours every day for 3 days (they only go to Santa Barbara, 370 miles).  That’s great when I’m preparing to race. In the winter, however, my training purpose is not race fitness; it’s base fitness. You don’t establish base fitness by going deeply anaerobic repeatedly for a couple of hours.

My notion of a base ride is a long, steady workout with heart rate mostly in zone 2. This is roughly a well-conditioned athlete’s aerobic threshold. Riding two or more hours at this effort challenges the body to make some improvements. One is to become better at using fat for fuel while sparing muscle glycogen stores. The longer your races are, the more important this shift is. The other critical shift has to do with increasing the capillary bed in the working muscles. The more capillaries you have the easier it is to get fuel and oxygen to the muscle. There are other benefits also, but for now we’ll focus on these.

The problem with this base workout is that it seems too easy at first so the athlete is tempted to abandon zone 2 and start riding variably paced with hard and easy efforts – fartlek intervals, essentially. And by so doing reduces the aerobic benefits of the day’s workout.

The aerobic threshold ride is sort of like Chinese water torture. What at first seems easily manageable eventually becomes challenging. One has to have the patience to hang in there to see what I mean. (This is one of the numerous reasons why I so often say that patience is necessary to be a good endurance athlete.) Ride for three, four, five, six hours at this effort and you soon learn what the aerobic system is all about.

Doing such a workout with a group presents problems, however. The greatest is that not everyone’s Zone 2 HR produces the same power or speed. The highly fit, usually young riders are talking easily while riding in zone 2 – as they should be. The slower, usually older riders who try to keep up are often well out of zone 2 but determined to hang on. While this workout is best done alone, if in a group the best option is for the group to split up into smaller groups of like ability – which I noticed many did during the Coast Ride – but not well enough I suspect…

The best way to do this ride is to have a power meter onboard in addition to your heart rate monitor. While in the base period I like to have athletes use their heart rate monitors to set the effort, what happens to power is the real story. The best way to explain this is to use graphics.

Example 1: 1% decoupling	Example 2: 11% decoupling

Here you see two examples (double click for a larger view) of riders doing a steady, multi-hour, zone-2 ride. In both cases they are doing an excellent job of maintaining a steady heart rate as evidenced by the red line staying almost flat on both charts. But notice what happens to power (black line). In example 1 power closely parallels heart rate. That’s good. It says that the rider is staying “strong” throughout the ride. There is no fading of power (or slowing down, if you will, even though that’s not a very precise way to measure output on a bike). I call this separation of heart rate and power ‘decoupling.’ In fact, the graph shows us that in example 1 there was only 1% of decoupling. In other words, power declined only 1% over the course of two hours of riding.

For the rider in example 2, however, the decoupling is 11%. He is fading significantly as the ride progresses. From these two examples I can tell you unequivocally that rider #1 is in much better aerobic condition than rider #2. If all they had were heart rate monitors we wouldn’t know this. Heart rate is only effective when we can compare it with something else. By itself it tells us nothing about aerobic fitness.

So does this mean that if you don’t have a power meter you shouldn’t do this workout? No, not at all. It’s still beneficial to your aerobic system. You just can’t measure your progress or know for certain when you’ve achieved good aerobic fitness. What you can do is maintain a steady HR on a familiar loop, and watch how your avg speed drops off later in the ride (decoupling) vs. past rides where you might have been fitter – or monitor for future rides on this loop that at same constant low HR you are holding on to your avg speed better, late in the ride.  What you can always do in this case is to pay close attention to how you feel. If in good aerobic condition you should be able to finish the ride strongly, albeit tired. If you’re totally wiped after four hours and are struggling just to limp home although heart rate remains in the 2 zone, your aerobic fitness probably needs a lot of work.