As I am ending the last major block of training before my final taper and race of the season, I am naturally performing a few test workouts to check improvement over last few weeks, as well as determine my race strategy come race day. I mentioned earlier that my bike FTP (Functional Threshold Power) had increased 4.5%, but I wanted to take this post to explain what exactly that means, and how I arrived at the results. First up, a few definitions.
- Lactate Threshold- The effort level at which lactic acid begins to pool in the muscles because the body is producing it faster than it can clear it from the muscles.
- FTP: Functional Threshold Power- the amount of power (Measured by a power meter in watts) one can sustain for 1hr. Essentially the lactate threshold for cycling.
- Threshold Pace– The pace one can sustain for 1hr. Essentially the lactate threshold for running (and swimming).
- LTHR: Lactate Heart Rate– The heart rate measurement for lactate threshold. While not as accurate as FTP or Threshold Pace because of other variables (caffeine, heat, hydration, etc), cause be used in place of pace or power if necessary (ie. no power meter, broken power meter, hilly run course, etc.)
So, after that are we all thoroughly confused? Good. Basically, these are all the same… but different. When you run the test I am describing below, you are testing for the effort level that you could sustain if you were going 100% for 1hr and “leave it all on the course.” Now, rarely will you actually go this pace in a multisport event, and in a single sport event you may go over this effort since the event is shorter (ie. a 5k). But once we know this number we can A.) compare tests over a period of time to judge increases in fitness and B.) set race goals based on our current level of fitness. So, how do we get these numbers? I’m glad you asked!
First of all, you need some way to record this information. a GPS watch with heart rate (HR) strap is the most versatile tool to use (Another post coming later about that). The rest of this post is written assuming you have these basic tools. A power meter is another tool for the bike as well.
Start with a good warm-up. I generally do 10 minutes with the first 5 easy to moderate pace and then do a few quick sprints with walk (or easy spin) breaks between . I make sure the last 1:30 is another easy- moderate pace.
At that point the test starts. Hit the “lap” button on your watch and go at a pace that is hard, but that you think you can hold for 30 minutes. The more of these you do, the better your pacing will be. after 10 minutes, hit the “lap” button again but continue at the same pace. The effort should stay steady over the whole 30 minutes and you should feel drained at the end.
After 30 minutes, hit “lap” one more time and start your cool down. Generally I either walk or spin easy for about 5 minutes.
INTERPRETING THE RESULTS
Now, what are the results? Your threshold pace or FTP (depending on the sport) is the average pace or power from the entire 30 minutes. Your LTHR is your heart rate from ONLY THE LAST 20 MINUTES. This is because it takes some time for your heart rate to catch up and truly indicate your effort level. It also may be that you went out too hard and your heart rate may have spiked at the beginning and later stabilized.
Now, what do you do with these numbers? Well, you can set your training zones for the next block of training (there are multiple schools of thought on this, so I won’t get into them here) and you can also determine your race plan as mentioned before. Most importantly, you can compare results over time and see all the great improvement your training has developed!
With that… It’s about time for me to head out and test my run LTHR and Pace!