Measuring Performance FTP vs LT

I recently requested questions from those that follow PPC on Facebook and Twitter and while I was going through some of the question one stood out as an excellent question for a standalone article. Thanks, Jim!

The question is as follows:

“I’ve been using Lactate Threshold to shape my workouts for years, is Functional Threshold Power more important, or should they be used in conjunction and if so, how? Jim L.”

Before I jump into answering the question directly let’s look at the ways we coaches and athletes measure performance. Most of us will use things like speed, cadence, weight and time to see how we are doing compared to our last ride or a friends ride. Those athletes who are coached or self-coached know that the way to get faster and stronger on the bike is to train within training zones.

I have written about training zones here and here so I won’t go into the specifics of training zones other than to say that these zones are built around perceived exertion, heart rate and or power. Rarely will a coach prescribe a training zone on perceived exertion so this now limits us to zones built on Heart Rate and or Power.

So how do we go about setting training zones?

We perform various tests. I also won’t be going into how to perform the tests as I have already written about this. If you would like to download copies of the testing protocols that I use for both heart rate and power as well as get access to my training zone calculators simply subscribe to the PPC newsletter at the right of the page!

What measures are captured to set training zones?

Lactate threshold (LT) or aerobic threshold (AeT)) is the exercise intensity at which lactate (more specifically, lactic acid) starts to accumulate in the blood stream. LT/AeT are tested in lab environments where blood is drawn to measure blood lactate levels during a ramped test using a treadmill or ergometer.

VO2 max (also maximal oxygen consumption) is the maximum capacity of an individual’s body to transport and use oxygen during incremental exercise, which reflects the physical fitness of the individual. The name is derived from V – volume, O2 – oxygen, max – maximum.  VO2 max testing can both be done in the field, at home or in a lab setting utilizing a treadmill or ergometer.

Functional Threshold Power (FTP) is a measurement of power meters. It is considered to be the highest power level you can maintain for one hour without growing fatigued.  FTP testing can both be done in the field, at home or in a lab setting utilizing a power meter or ergometer.

So which one is a better method to establish training zones?

It depends on the coach, athlete, athletic disciplines and technology available to the coach and athlete. When I set training zones for athletes I use V02 Max for HR Zones in Cycling and Running and FTP for cyclists that training and race with a power meter. While I am not a sports scientist I do read their posts, articles, and books and have adopted the methods of testing and setting training zones. So while I won’t say that measuring FTP vs. LT is better I can say that there are more ways to measure performance-using FTP than there is for LT when it comes to cycling.

What do I gain by measuring FTP as a cyclist?

FTP is just one of many measures of training and racing with a power meter. There are whole spectrum of Critical Power (CP) measurements that range from 1sec – 90 min and these CP measures can be compared to the output of peers to see how you compare as an athlete by adding your data to a Power Profile Chart. We also have Performance management charts that can help us plan training and even predict peak fitness ahead of an event or a race.

The future is here

I whole heatedly believe that when athletes train and race with power it gives them an advantage over athletes that train and race just with HR.  Power removes guesswork that comes from just riding hard and allows even the most time strapped athletes to make big increases in performance when they train smarter!

So is HR data even useful anymore to cyclists?

Absolutely, I still require all athletes to capture HR data as it helps to understand cumulative fatigue. I also emphasize HR Training Zones for easy rides and recovery rides over power. The reason being is back to fatigue. I think Heart Rate can tell us more about ourselves on easy days than power can. While power can be affected by some external variables it isn’t nearly as much as HR. So rather than adding to an athletes fatigue on easy days I have the athletes use HR training Zones 1-2 on easy days and ignore what their power meter is telling them. Now if power is lower than HR on an easy day then I know that there is a certain amount of fatigue. If the power is higher than the HR 1-2 training zone then I know that an athlete is either well rested or their Zones may need to be updated.

So is training with power right for me?

If you have been training and racing with heart rate zones and data for awhile now I strongly encourage you to think about purchasing a power meter and learn everything you can about working with power data. We learn most of what we are going to know about our fitness with HR data within 2-3 years of structured training.

Want to learn more about power?

Not sure where to start when it comes to training with power, power meters, and power terminology? I have created 3 clinics on that will help you to make sense of power terminology, power meter selection and how power is used to measure performance. Check out all the new Power virtual clinics here!

Until next time,

Train Smarter not Harder

Coach Rob


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