Why it is important to know this term?

Your Functional Threshold Heart Rate (FTHR) or your Functional Threshold Power (FTP) are essential numbers for all athletes and is something that everyone should know.  That includes sprint athletes right up to and including Ironman athletes. Knowing your FTHR is the first step in being able to set up your training zones. Secondly, completing a block of training to then improve your FTP assists you in establishing an endurance base that allows you to branch into more specific training plans that are designed to meet your limiters and the demands the event will place on you.

Your FTHR is the highest possible average heart rate you can produce for either a 40km time trial on the bike or a 10km run. This number does not vary much, however, the speed, pace or power you produce does vary according to how fit you are. So as a starting point for any training program it’s good to know your FTHR. Then you can benchmark your training and setup some training goals depending on the event you are focusing on. Once you have these reference points you can realistically address you goal paces in training and evaluate your progress along the way.

Once you have established your FTHR you can then use Joe Friel’s heart rate training zones table to find approximately your and training and race pace intensities. For example, an Ironman athlete would typically race an Ironman event at the bottom of zone 2, depending on their experience. An half Ironman athlete would normal race their event at the bottom of zone 3 and your Olympic distance athletes would race anyway from zone 4 to zone 5a.

Below are the results of a 40km time trial I did in Tokyo 2009. The conditions were not that great during this test as the local council had erected 4 temporary gates on the bike path which caused me to slow down to about 10kph twice for each 10km out and back I did.

Table 1: 40km Time Trial 28th June 2009

Graph 1: 40km Time Trial; Tokyo 2009

My results for this test produced an average heart rate of 162bpm and an average speed of 39.9kph. The most important number here is my average heart rate which is now called my FTHR = 162bpm. Because I had to slow down 8 times during the test (see graph 1 and the blue line) I adjusted my FTHR to be 165bpm. In the polar software there is an edit correction option so I smoothed out the heart rate drops and this resulted in a new average heart rate of 165bpm and an average speed of 40.8kph. Back in 2004 I did this same test and my average heart rate then was 166bpm, so as you can see after 6 years of training this number does not change. My speed does, back in 2004 I was averaging 35kph.

Table 3 below shows how I then setup my training zones. This then gives me the information I need to know in terms of how hard I should be training in respect to the event I am targeting. This also gives me a starting point to start setting up a race day plan. For an experienced Ironman athlete your optimal race day intensity on the bike should be at the bottom of zone 2 to mid zone 2. With the right training I should be able to hold 136-140bpm on the bike and still be fresh enough to run a decent marathon. Novices Ironman athletes would be racing just under the top of zone 2 and Elite Ironman athletes would be capable of racing towards the bottom of zone 3. All of this though will depend on the principle of specificity, which essentially means ‘meeting the demands of the event’. If you are training to meet the demands of the event you are setting yourself up to race at the right intensities according to your experience and goals. While there are other ways to measure your FTHR or maximum heart rate (MHR) I find completing a 40km time trial to be the most effective method for setting up your heart rate training zones.

In summary, by doing a functional threshold test you are creating a starting point or benchmark for setting your training goals and a training plan that will address your weaknesses in order to enable you to race to your strengths. It’s important to do testing to clearly identify what you can do, so that you’ll know what you’ll need to do in order to get you where you want to be.

My next article will talk about ‘Meeting the demands of the event: Understanding the principle of Specificity’

Hope it helps

Fluro

Table 1: Heart rate Training zones

References

1. Friel, J., (2004). The Triathletes Training Bible, (Second Edition). Velo Press, Boulder Colorado.

2. Byrn, G., Friel, J., (2009). Going Long; Training for ironman distance triathlons. Velo Press, Boulder Colorado.