Browsing posts in: Faster

The endurance athlete’s guide to fueling and weight loss part 2.5–More on muscles and energy systems


The Dual-fuel system revisited…

In one of the earlier parts, I talked about how muscle contraction is fueled either with glucose (glycolysis) or fatty acids (beta oxidation). I have since realized that there is more detail that I’d like include, so this is a part II of that post.

The phoshagen system uses stored creatine phosphate in the cell to create the ATP that ultimately drives the muscles. This can provide a *lot* of energy, but is limited to durations of 10-15 seconds because of limited supply of creatine phosphate in the cell. This is the system that is used for explosive power – weight lifting, sprinting, etc.

The glycolytic system uses glucose to create ATP. Strictly speaking – and this is a point I glossed over earlier – glycolysis only goes from glucose (or glycogen) to pyruvate. This step can occur both in the mitochondria and in the the cytoplasm of the cell, which means it can produce quite a bit of ATP quickly, but it’s only the first step in the full process of burning glucose. To keep the energy production high, something has to be done with the pyruvate, and it is converted to lactate. That lactate accumulates quickly, and that is what is making our muscles hurt during hard efforts.

The oxidative system – also termed “oxidative phosphorylation” or “mitochondrial respiration” – is the main energy provider for aerobic exercise. As discussed earlier, there are two feeds into the TCA/citric acid cycle:

Beta oxidation takes fatty acids and converts them to Acetyl CoA to feed into the TCA cycle. Or, we take the products from glycolysis and feed them into the same cycle. The important point is that those products can be pyruvate that was just created by glycolysis, or it can be lactate that was created during glycolysis elsewhere in the cell.

That’s enough context to now discuss different intensities:

At a moderate aerobic pace, we are getting all of our energy from the oxidative system; we are either converting fatty acids to Acetyl CoA or performing glycolysis to get pyruvate which is immediately fed into the TCA cycle.

As we increase the intensity, we need more glycolysis to produce more energy, and for that to keep working, we need to convert the pyruvate to lactate. That means we have more lactate around that we will need to feed into the TCA cycle to get rid of. That can happen both in the muscle that is exercising, but also in other muscle that is resting and in the liver and heart. At some point, the amount of lactate produced exceeds the body’s ability to get rid of – or “clear” – it, and tissue and blood levels of lactate increase much faster. That is what the term “lactate threshold” means, and a lot of high intensity training is looking to improve lactate clearance.

If we increase the intensity above the lactic threshold level, we accumulate lactate very quickly, and that means we cannot continue for very long.

Here’s a cool image that shows the relative contributions of the different energy systems:

Training intensity and fat loss

Knowing that is only burned by the oxidative system tells us something important about intensity; we can only burn fat at moderate intensity. The definition of “moderate” is going to vary quite a bit based on the availability of glucose during our endurance training, but one we have hit an intensity that maxes out beta oxidation, we will not be burning any additional fat. Extra intensity above that level will just lead to more glucose being burned.

For the longer term, we could improve our ability to burn fat by improving our ability to perform beta oxidation.

Muscle Fiber Type and energy sources



Muscle fibers can be categorized in a number of different ways; you may have heard them categorized into “slow twitch” and “fast twitch”. Slow twitch (type 1) fibers are utilized in longer-term exercise, and – since they have a lot of mitochondria – they can do a lot of aerobic metabolism, and therefore can be powered on fat. Fast twitch (type 2b) fibers have few mitochondria, and run mostly on glucose. And then the type 2a fibers are hybrids, though it probably makes more sense to think of muscle fiber type as a continuum rather that a set of discrete types.

What this means for our topic is that if you are doing the sorts of activities that recruit a lot of fast-twitch fibers, that’s going to require a lot of glucose. And therefore, you won’t burn a much fat from those sorts of activities, nor will you be able to do those activities well if you are very limited in glucose.


Part 3: Carbohydrate and Fat use in actual athletes…



Interaction among Skeletal Muscle Metabolic Energy Systems during Intense Exercise





Faster #9 – Recovery Nutrition…

You may have heard mention of limiting the amount of food that you take in while riding to 200-250 cal/hour (or in that range – it varies based on who you are and how hard you are riding). Because that’s considerably less than the amount you are expending (in many cases – if you are riding slowly and are quite fit, you may be able to take in enough food to meet your needs), even if you are getting carbs/protein from food during the ride, you will be typically finish your ride with depleted glycogen stores and low blood sugar.

Right after exercise, your body is better at absorbing and using carbohydrates and protein – that’s the whole purpose of recovery nutrition. This degrades over time, and after perhaps 2 hours or so you’re getting back to your normal absorption rate.

If you don’t get adequate recovery carbs/protein, your body will tear down your muscle tissue to get carbs to replenish your muscle glycogen. This will make your muscles hurt more and reduce any strength gains you might have made.

While you exercise, you also get appetite suppression. This lasts for a litle while after you exercise (about 30 minutes for me), and if you can get some recovery food, you can get your blood sugar up and avoid that “eat everything in sight” syndrome. If you are riding to lose weight, that can be important.

Now, the matter of what to eat. All the research I’ve read says that real food is just as good as recovery drinks. My experience is that recovery drinks have some real advantages. First, they are quick to prepare and consistent from time to time. Second, because they are liquid, they are absorbed faster than solid food (you don’t have to wait for them to break down). The obvious disadvantage is price, and the fact that you have to remember to bring them with you.

I’ve tried doing recovery with plain food. It may be that I’m not getting the right food, or it may be that my timing is too late (I sometimes drive home after a ride and don’t get home until at least 30 minutes after I’m done), or it may be something else, but I would often feel like I was missing something. Since starting on Endurox, I don’t get that any more, and it seems to have a significant impact both on how sore my legs are and how much energy I have later in the day.

Whether you need to worry about recovery depends on how you ride. Very generally, if you are a trained rider riding at moderate rates and eating along the way, you may be getting the majority of your energy from fat and the food you take in may be enough to keep your blood sugar up. Or, if you are only riding for an hour it’s probably not an issue. On the other hand, if you are riding 2 hours or more, don’t get many calories during your ride, or are riding at a speed that burns more carbs, or if you are training multiple days in a row, recovery nutrition can make a significant difference.

Food for fitness (Carmichael) is a decent reference on food and training in general.

Faster #8 – Cadence

Armstrong had a fast cadence, and he won a millon Tours de France, so we should all ride at a high cadence, right?

If you ask 10 cyclists about the importance of cadence, you’ll get 3 different answers and 7 blank looks. Cadence is confusing, but the basic fact is that riding at a higher cadence is faster, except when it isn’t.

High Cadence is Faster

So, you went out on that hilly century to ride with some friends. You felt good and fast on the hills, but by mile 50 your legs were burning, and you could barely make it up the later hills.

Power is the product of force – how hard you push on the pedals – and cadence – how fast your turn the pedals. Drop down a gear or two, push 20% easier and spin 20% faster, and you get up the hill at the same speed.

But you save your legs. If you’ve ever weightlifted, you know that a 20% difference in weight can make a huge difference in how many repetitions you can complete. The same effect is at work on your bike – spin instead of mashing, and you can climb 7 hills before your legs give out instead of 5.

It’s also true that riding at a higher cadence helps you develop a better pedal stroke, which recruits more muscles and uses them over a longer period of rotation, lessening the peak force for a given amount of power.

And it helps you accelerate faster when you need it.

Higher Cadence is Slower

When you spin, you put more load on your heart and less on your muscles. All things being equal, for a given amount of power, spinning faster will take more aerobic capacity, so you’ll be more out of breath on that climb.

And, if you spin all the time, you can develop a great aerobic system, but you don’t stress your leg muscles, and they don’t get stronger.

A Proper Balance

For a given individual in a specific state of training and a particular ride, there’s a “fastest cadence”. It’s the one where you use up your leg strength right as you finish the race. Ths could easily be faster than your current cadence, and it’s therefore worthwhile spending some time working on cadence.

My Cadence Story

When I got serious at cycling a few years ago, my average cadence was in the 80s, and I decided to work on getting better at it. By just trying to spin faster, I got myself up to a top cadence of around 100RPM, but I wasn’t very comfortable of it.

Then when I did the Carmichael training a couple of years ago, they specified specific cadence drills to do. I did them that summer, and over the past few seasons. My max on-bike cadence is now up into the mid 140s, and I can high 120+ pretty easily. My average is a little bit higher, but not a ton higher, partly because I spend a lot of time on low-cadence muscle tension work on climbs.

The Drill

On a flat or slight uphill with medium resistance, slowly increase your cadence over a period of 30 seconds until you hit your maximum comfortable cadence. Hold that for 30 seconds, and then slow down over the next 30 seconds. Slow down a bit if you start to bounce. Do 3-4 repetitions of this.  

Initially, two things will happen. First of all, you’re going to feel a bit out of control. That’s because your muscles aren’t used to spinning that fast and you need to “rewire” your brain to make them work at that speed. Second, you are going to get really out of breath because you aren’t very efficient at that speed yet.

Once that starts to feel a little more natural, increase the time at which you hold the top cadence to 60 seconds. Do this once or perhaps twice a week, but you don’t really need to overdo it.

I also find it useful to do one-legged pedalling drills, where you clip out one side and do a fixed number of revs (20-30 is a decent place to start) on one foot, then that same number on both feet, and then the other foot, etc. Do this one the flat and in a quiet area, or do it on a trainer, as they feel really weird.

I can hit the low 120s fairly easily now on the bike, 130 with some effort, and I saw 140 with a slight downhill a while back (though I was bouncing a bit at that speed). On the recumbant exercise bike at the club where I work out I’ve hit 160 for short periods.

Faster #7 – Heart Rate Monitors

Lots of the cool guys have heart rate monitors. Should you get one?

I’m going to assume that you are doing a set of structured workouts.

So, if you’re doing that, you need to set your training zones. You can do that by taking a percentage that you determine use 220-age or one of the other formulas, and then train based on that.

But there are a few problems with that. First of all, none of the formulas to determine max hr are of much use, as there are wide variances of maximum heart rate across the population.

But even if that formula does work for you, it’s a poor way to set ranges.

Basically, one of your goals is to push your anaerobic threshold to a higher percentage of your maximum heart rate. To do this, you may need to work out near your anaerobic threshold.

The problem is that that threshold is a moving target. A range set based on a maximum will likely be too high when you are untrained, and too low when you are well trained.

The right way to set ranges is to use a field test, like the Carmichael one. That will gve you better ranges, and a good way to track your progress over time.

The other big benefit of heart rate monitors is to get you to slow down. Most riders spend too much time working out right around their anaerobic threshold, which is bad.


Heart rate monitors are a great tool. Unfortunately, they can be a bit pricey, especially the ones that can upload your data to a computer.


Faster #6 – Cadence drills

To travel at a given speed, you need to put out a given amount of power. You can either do that by pedalling slowly and putting a lot of pressure on the pedals, or by pedalling faster and putting less pressure on the pedals.

Since the more pressure you put on the pedals, the faster your legs get tired, it’s preferable to pedal faster. Within reason.

First of all, there is a limit to how fast you can comfortably pedal. And second, spinning generally stresses your aerobic system more, so you can run out of breath more easily.

So high cadence isn’t somewhere you always want to go, but it’s a useful tool to have in your arsenal. And if you can ride smoothly at a high cadence, you will be able to ride smoothly at a lower cadence, which is a good thing.

You may have come across suggestions to aim for riding at 90 RPM. I’m going to make a different suggestion. If you are willing to work at it now and then, you can expand your RPM range all the way up to 120 RPM, and beyond.

To make good progress, you need to do focused drills that will work on your speed. Here’s the one that I like to do:

  1. Start at a comfortable cadence and a middle amount of pressure
  2. Over 30 seconds, gradually increase your cadence until you reach the point where your stroke becomes jerky or you start bouncing
  3. Back off the cadence slightly until you are smooth again
  4. Continue for 30 seconds
  5. Slow back down to your original cadence

Repeat this a couple of times, and you’re done for the day. The next time you get back to it, extend step 4 to a minute, and then ultimately aim for 2 minutes. You are retraining your neuromusclar system, and it will take a bit of time to do so, but over time you’ll smooth out again. Initially you will be a bit inefficient at this, so you might get out of breath. You can deal with this by going into a slightly easier gear, and over time it will get easier.

On normal rides, spend some time at a higher-than-normal cadence, but don’t try to push up your whole limits.

You don’t need a computer that supports cadence to do this, but it does help. With doing these now and then, I pushed my top cadence from 105 RPM up to 120 RPM, and on a ride last year I held 145 RPM for about a minute while pulling at the front of a paceline on a slightly downhill.

Rating: Good stuff. Will make you faster, but most importantly, will make you smoother and impress you’re riding buddies.


Faster #5 – Specificity

Initially, you just start riding. Perhaps you’re doing it for fitness, or to lose weight, or just for recreation. And then, at some point, you decide that you want to get a bit more serious, so you start riding a bit faster, riding a bit farther.

And then you plateau. You’re riding harder, but not getting any better.

The problem is that you’re riding “sorta hard”.

A bit of digression into training theory…

The purpose of training is to impose training stress on your body. The stress triggers your body to get better during recovery. But when you’re riding sorta hard, you aren’t riding hard enough to put a real training stress on your body. That’s why you plateau.

The way to get beyond this is to add specificity into your training. Rather than trying to work on all aspects of your riding – on all the energy systems that go into being fast – you work on them one at the time.

Or, in other words, your training is *specific* rather than being general. You might be doing:

  • Intervals, to stress your anaerobic system hard
  • Long steady rides to build up your aerobic system
  • Tempo work to push up your aerobic threshold
  • Muscle tension to improve your strength

And, you’ll be sure that you’re recovered so that you can get the full benefit from the hard workouts.

The disadvantage? Well, you have to have focus, and you have to work to fit the workout you want into group rides (if you go on group rides)

Speed Improvement: High
Coolness Factor: Low (this isn’t very sexy stuff)
Cost effectiveness: Epic. At most, you need a book, but you can get by with what you read on the internets.

Verdict: One of the best ways to improve your speed, if you can stick to it.

Faster #4 – Ceramic bearings…

Ceramic bearings – bearings with ceramic balls rather than steel balls – are a common choice by the top-end cyclists. So, how much do they really gain you?

If I can, I try to figure out what sort of maximum gains you might see when from a specific increase. In this case, we can do a decent job, as we know roughly how efficient bicycles are.

The best data that I’ve found suggests that modern drivetrains are about 95% efficient (though it’s hard to know exactly what they’re measuring). If we could get rid of all the lost, it would be like we increased power by 5%. So, a climb that took us 10 minutes would now take:

600 seconds * 0.95 = 570 seconds.

Which seems like an impressive difference.

Though, from a speed perspective on the flats, it’s not as big of a deal. 5% more power takes us from 15 MPH to 15.3 MPH, or from 20 MPH to 20.4 MPH.

But, we’re not going to get rid of all of that – there’s still some loss in the chain.

Cyclingnews did an article a while back on SRAM’s $190 bottom bracket that claims that it reduces frictional losses from 4% to 0.5%. Note that that also includes some other low-friction design changes and a low-friction grease. That’s gets you up that 10 minutes hill about 21 seconds faster.

On the other hand, Zipp claims that you get 2 watts at 25MPH with their ceramic wheel bearings. The handy Speed and Power Calculator estimates that 25MPH requires 300 watts with hands on the drops, which means you’re saving 2/300 or about 0.6% of your power. Not really a lot of savings there, though presumably you could save that much for each wheel, and gain a small amount of speed. They do note that the savings against the high-quality steel bearings they use on their other wheels is only about 1 watt.

We can also assume that both SRAM and Zipp are using the best ceramics they can find in their bearings, and there are very likely cheaper bearings that are going to have a lesser surface finish and therefore far fewer gains. I’d be especially leery of the improvement from other ceramic bottom brackets because my guess is that the seal design and lubricaton are significant factor, especially given the big difference in gains from using ceramic bearings between the bottom bracket and wheels. As for cost, I’ve seen 5 bearing sets for Mavic wheels for $300. Or, you can find a set of bearings for $35 on ebay.

In other words, buyer beware. Those ceramic bearings you saw on ebay may not be any faster than the ones you’re currently using.

Speed Improvement: Medium (pretty good for a hardware change)
Coolness Factor: High (all the pros are doing it)
Cost effectiveness: Low

Verdict: The bottom bracket looks nice, but yowsa, those parts are expensive. But, probably a better use of funds that that titanium seat post bolt you were thinking of buying…

Faster #3 – Ride with the fast guys

or girls…

This is probably the most common suggestion that riders give when asked how to get faster. I know that I got it, and it led me to head out on a lunch ride with some co-workers. At the time, I’d been riding for about a season, and had only done a small amount of riding with other people.

The “slow warm up” consisted of a 20MPH ride on a slight uphill, and then continued through a flat section. I spent the first 20 minutes dropping off the back, chasing, dropping off the back, chasing, and soon after that…

well, I’m sure you all know what happened then.

So, what is the training benefit of something like that? To do that, I’ll correlate it with some of the better approaches to training.

Riding with the fast guys is like doing intervals. Poorly. It can definitely make you faster, but the pain/reward ratio is higher than a lot of other approaches.

Speed Improvement:Low/Medium
Coolness Factor: Nil. Being dropped is not cool
Cost effectiveness: Low, for the amount of pain you endure


Faster #2 – Light Wheels

This time, we’ll talk about whether lighter wheels make you faster.  

This last summer, I upgrade from a set of Bontrager Race X Lite wheels (which run about 1900 grams) to a custom set from OddsAndEndos (which run around 1500 grams). That’s about 400 grams difference, which is about 0.9 lb.

The lighter weight will have two effects.

First, it’s going to give me less weight to climb. With me at about 165 pounds during the season and the bike overall weighing about 20 pounds, that means a drop of a pound will make me 184/185 or about 0.5% faster on climbs. On a 10 minute climb, that would be a savings of about 3 seconds.

Not really worth it for faster climbing (and you can probably guess what I’m going to say about light bikes in a future post)

So, what’s the big deal about lighter wheels? Well, it’s because they have a lighter rotational mass.

Whenever you start from a stop, you have to accelerate the bike and spin up all the rotating components of the bike. Because rotational inertia is proportional to the distance of the weight from the center of rotation, the weight of the rims + tires have the biggest effect. So, if you make them lighter, it takes less effort to do that.

This is especially important if you’re riding in pacelines or groups. Light wheels can reduce the amount of effort it takes to close gaps or grab onto the back of a paceline considerably, and those little efforts tire you out at a lot. If you ride by yourself at more of a constant speed, you probably aren’t doing as much accelerating, but it’s still a nice thing to do.

There are a few downsides of light wheels.

First, the lighter the wheel, the more expensive it is. My lighter wheels only cost about $500, but if you want to, you can easily spend $2000+ on a carbon wheelset.

Second, lightness may mean less durability, especially if you go for the really light stuff.

And finally, lighter wheels are a bit harder to control. Because there is less rotational inertia, it’s harder to hold a constant speed in a paceline, and the lower inertia also means that a given amount of force into the bars generates more lean angle. I notice this most on fast descents – I have to pay much more attention to keep the line that I want.

Speed Improvement: Medium to high (it may allow you to ride with a faster group where you couldn’t before)
Coolness factor: High
Cost effectiveness: Pretty good, if you look for some nice custom wheels.
Bonus benefit: You get to decide what hubs, spokes, colors, etc. if you go the custom route, and custom wheels are often tensioned better than machine-built wheels.

Faster #1 – Aero bars

I’ve wanted to write more, but I’ve kept getting involved in big articles, and running out of steam partway through them.

Instead of that, I’m going to write a series of short articles about whether something will make you faster or not.

First up: Aero bars

Drag reduction is important in going faster, and aero bars definitely do it. So, put the bars on your bike, and you’ll go faster…

Well, not so fast (ha ha!). You have to get used to the aero bar position, which requires flexibility that many cyclists lack, and you’ll need to learn to ride on them smoothly. And you have to put up with the derision of many road cyclists.

The reason is simple. Road cyclists are jerks. No, wait, that’s not it. Road cyclists often ride around either in packs or in peletons, and in either case aero bars are dangerous because neither brakes nor direction are as well controlled. Not to mention that you don’t get much benefit from them in a pack, because you don’t spend that much time in the wind.

So, road cyclists may look down on you. Exceptions to this are as follows:

  1. You ride in time trials.
  2. You are a triathlete (all triathletes are considered a bit strange by road cyclists)


Speed improvement: high
Coolness factor: low (most cyclists) high (time trailists)