101: Lactate threshold (LT) vs. functional threshold power (FTP)

Lactate threshold (LT) and functional threshold power (FTP) are NOT the same thing, people!  I feel better now that I got that off my chest :-).

What is Lactate Threshold?

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Lactate threshold is determined by a blood lactate laboratory test (example in the image above) and is the point at which lactate begins to increase exponentially in the blood stream during said test.  Lactate threshold can also be seen as the inflection point on a line graph where the blood lactate concentrations are plotted for an athlete undergoing said test…

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As you can see from the above image, there is a clear inflection point where lactate begins to increase exponentially (11.8 mph for this runner) and does not stop increasing until the athlete fatigues and the test stops.  So, when this athlete is running slower than 11.8 mph, they are said to be “below lactate threshold.”  Their cells are producing lactate still, but they are able to use it efficiently and it does not build up in the blood stream.  When the testers increased the treadmill speed to 13 mph, the athlete was pushed “above lactate threshold” and their bodies began to produce even more lactate to meet energy demand.  Their cells are unable to clear the lactate efficiently at this intensity which causes an increase of lactate found in the blood stream.  As the testers increase the treadmill speed further, more and more lactate accumulates.

Remember, when lactate is used for energy, hydrogen is produced as a byproduct.  Hydrogen lowers the pH of our blood and causes acidosis (burning) in our muscles.  When acidosis gets to a point, the athlete must reduce their output as the pain and fatigue is too great to push any further.  This is an important number for athletes to know because it precisely tells them what point they can push to and be able to sustain it for a long time without too much risk of fatiguing early (think of an Ironman triathlon).  However, blood lactate tests are expensive, invasive, and aren’t really necessary with the advent of the power meter.

What is functional threshold power?

Functional threshold power (FTP) is the maximum power output an athlete can maintain in a quasi-steady state without fatiguing for 1 hour.  FTP is, in my opinion, is a better way to analyze current fitness and improvements because it is more readily available to the athlete, isn’t invasive, and can be repeated multiple times for FREE!  More about FTP here.

How did FTP and LT become confused to mean the same thing?  Because your maximum effort for 1 hour is commonly the same as your lactate threshold.  Dr. Andy Coggan realized this so he came up with the FTP concept and simplified things for everyone (yippee!).  However, your FTP is not your LT and your LT is not your FTP, got it!?

So, to recap: what is the difference between lactate threshold and functional threshold power?  LT is the point at which lactate increases in the blood stream exponentially whereas FTP is the maximum effort an athlete can maintain for 1 hour without fatiguing.

What should I eat before my ride?

What you eat before a ride depends upon a few factors including how much time you have before you start your ride, how long it will be, how intense it will be, how long between workouts you have had, and how fit you are (i.e. how quickly you can recover).  Before we get into what you should eat though, let’s talk a little bit about the science behind it…

Glycogen, as we remember from an earlier post, is the stored energy source found in our liver, muscles, and blood stream.  Of this stored glycogen, we have approximately 400 grams in our muscles, 100 grams in our liver, and 25 grams in our blood stream for a total of around 500 grams (1).  This equates to 1500-2000 calories (90-120 minutes) of stored energy before you even get onto the bike.  This storage amount can vary based on your previous workout and how well you did recovering and replenishing your calories and carbohydrates post-ride.  After a long and intense ride it can take up to 24 hours for your body to properly restore its glycogen stockpile.  This storage amount is also why people experience “bonking” around the 90 minute to 2 hour mark if they aren’t eating enough during their longer and more intense workouts due to their blood glucose levels dropping.  So, if you are frequently experiencing “bonking” symptoms, you need to be consuming more carbohydrates during your ride and recovering after workouts better!

How long you have before your ride is the biggest factor in what you should eat in my opinion.  The following are strictly guidelines on what has worked for me in the past.  Each athlete is different and some have iron-guts while others are very sensitive to what they eat before exercise.  You need to experiment and figure out what works for you, remember, NOTHING NEW ON RACE DAY!

3+ hours before

Basically I can eat anything I want if I have this kind of time and I try to wake up with 3 hours to spare if I will be racing >3 hours and riding >5 hours so I can get a large pre-meal in me.  Even though I have a lot of time, I will still stay away from foods that are high in fiber, unhealthy fats, and simple sugars.  Think of foods that will give you the “slow burn” and fuel you throughout the ride rather than burn up in the first hour.  I also don’t like to eat foods that I will “taste again” as they are being digested (ew!).

Ideas: Oatmeal, granola, yogurt, bagel, toast, rice, pasta.

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2 hours before

This is when the length and intensity of the ride play a role in what you should eat.  If I am racing a criterium or cyclo-cross event (high intensity/short duration), I usually will stick to liquids 2 hours pre-race to prevent any GI issues.  If I am training with low to moderate intensity and for a longer duration, I will eat a normal meal.  I ensure I have a recovery drink / post ride meal with me if I don’t eat much before the race/ride to keep my blood glucose levels from dropping too low.

Ideas: Bagel, rice, toast, fruit smoothie.

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1 hour or less before

Basically just liquids for me here.  If I am training in the morning before work I will just have a glass of OJ and hop on the bike.  If the ride is >2 hours I will make sure to pack a sandwich, rice cakes, gels, etc. with me to eat during the ride to keep my blood glucose levels topped up.  Then I will again ensure I get a decent recovery drink / post ride meal in me.  I always try to wake up with plenty of time to eat and digest if the ride is >3 hours long however, so no excuses on your next long ride, get your butt out of bed!

Ideas: Fruit juice.

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So, what you should eat before your ride depends on how long it is, how intense it will be, and how much time you have before you start your ride.  Fear not though, if you don’t have time to eat before and your ride will be <90 minutes and not too intense you will have enough glycogen stores to get you through it.  If you are riding longer or increasing the intensity, make sure you get up and eat something high in carbohydrates, low in fat, and low to medium in protein, and give your body at least 2 hours to properly digest it to avoid any GI distress.

Further Reading:

What should I eat during my ride?

What should I eat after my ride?

For more information on GC Coaching and how we can help you increase your fitness, please visit www.gaffneycyclingcoaching.com

References:

Carbohydrate. (2010, January 8). Retrieved December 4, 2015, from http://www.extension.iastate.edu/humansciences/content/carbohydrate

Climb Hills Faster | Watts Per Kilogram

“Man!  That guys watts per kilo must be off the charts!” is something you may hear at the local group ride or race and is usually directed towards a skinny dude that everyone dislikes once the road starts to turn uphill.  Think of grand tour winners (Chris Froome, Nairo Quintana, Marianne Vos, Anna van der Breggen, etc.) or those who are usually seen in polka-dots.  Basically, the athletes who wear extra small jerseys, but the sleeves still flap in the wind!

Watts, as previously discussed, are how much energy the cyclist is producing to propel his/her bike forward.  The more wattage the cyclist can produce, the faster they should be able to go.  A kilogram (kilo for short) is a metric measure of weight equal to 2.2 pounds.  So, to figure out your “watts per kilo” you first need to figure out what your average wattage over a given time period is and divide that by your weight in kilos.  This will result in a number that you can brag about (or maybe not) to your friends and explain why you always beat them on the climbs.

To give this more depth, an “untrained” rider can be predicted to produce ~1.8 w/kg in a 20 minute FTP test, and a “world champion” can be predicted to produce >6.5 w/kg during the same test! (1)

Why is having a high watt per kilo rating beneficial?

Simple!  It allows you to climb hills faster while at the same time expending less energy.  Imagine pushing a wheel-barrow up a hill.

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The less mass in it (i.e. body fat), the easier it will be to push and your legs won’t be as fatigued at the top.  This is why all grand tour winners, prolific climbers, and most professional cyclists look like a bag of bones with quads attached; they are able to use far less energy and move a lot quicker if they are as lean as possible.  This is also why the “weight-weenie” phenomenon has been gaining ground over the past few years; the lighter you can make your bike, the faster you can climb.  However, as the old saying goes, “I would rather lose a pound off my ass than off my bike.” 🙂

Keep in mind though that the lighter you are means you possess less overall power and brute force.  You won’t be at the pointy end of the bunch during a criterium sprint, you will get smoked in most track events, teammates will start to block you at the base of climbs during group rides (and you wont be able to do anything about it with your spaghetti arms), and people will constantly tell you to “eat a cheeseburger!”.  When push comes to shove though, in most of the larger road-races and stage races you can put far more time into your competitors in the mountains than the flats.

When can a high watt per kilo rating be unadvantageous?

Being a lean and powerful endurance athlete has more pros than cons, but sometimes brute force and momentum play bigger roles in races.  Some examples are track cycling, criteriums, and most cyclocross races where the bigger and stronger cyclists can push their weight around (pun intended).  Having increased mass means you need to produce less power to keep your momentum and therefore use less energy motoring on flats or descending compared to the skinny dudes.  This also means you can power up to speed faster and fly up short, but steep climbs without too much trouble.

To really drive this point home, take a look at Robert Forstemann’s legs, the German track cyclist who kills it in the sprint events, compared to Chris Froome’s legs, the reigning Tour de France champion…

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I am pretty sure you can figure out what pair of legs belongs to which athlete!  Froome technically has more w/kg compared to Forstemann and can definitely climb mountains a lot faster, but line these two up for a sprint and Froome will be eating dust.

So, what are watts per kilogram?  A measure of how strong a cyclist is based on how much energy they can produce and how light they are.  This is an important number for athletes looking to excel at stage races, hill climbing events, and single day races that involve a lot of elevation gain because they will be able to ascend and attack from a group using less energy than their “heavier” counterparts.

For more information on GC Coaching and how we can help you increase your fitness using power, please visit www.gaffneycyclingcoaching.com

References:

(1) Coggan, A. (2008, October 10). Power Profiling. Retrieved December 1, 2015, from http://home.trainingpeaks.com/blog/article/power-profiling