The mass availability of the modern power meter in the last decade has meant that more individuals have access to data that is objective and comparable.
Understanding the why of testing
Understanding the why of testing Functional threshold power (FTP) is a representation of the exercise intensity at which lactate (stay tuned to our blog for future discussions on the misunderstood bad boy of exercise physiology) begins to accumulate in your blood stream. This is what is called our lactate threshold. Other terms used include onset of blood lactate (OBLA), LT2 and maximal lactate steady state (MLSS). Please note that for simplicity of this article, each of those terms can be complex and require more explanation not relevant at this point. Basically it’s a level where production exceeds uptake and disappearance. And is an indirect marker that reflects the exercising muscles ability to match energy supply and demand and point at which muscle fatigue begins to set in. The closer you exercise to this level or above also determines the physiological strain your body will experience.
If you want a picture of this, imagine your lactate threshold as a person inside a house, while your Maximal Oxygen Uptake or VO2 max is the roof. The taller the person gets i.e. improving exercise output at which lactate begins to accumulate, the closer they get to the ceiling, the greater % they use of their aerobic capacity available to them. Although the accumulation of lactate in the blood is generally considered to be around 4mmol/L, the POINT at which this occurs in terms of exercise intensity is different for everyone (see Fig 1 below).
Fig 1: Lactate threshold shift to the right in response to training (Craig et al., Physiological tests for elite athletes, Human Kinetics, 2000).
Your coach will be able to determine your ceiling (aerobic capacity/VO2max), as well as the size of the person underneath the ceiling (FTP/lactate threshold) and objectively determine the best approach in terms of training going forward to maximize your potential.
Coggan Classic levels
Along came Dr. Andy Coggan and functionalized this OBLA/MLSS/LT2 idea into what today is the ubiquitous 20min FTP test. Although MLSS can be maintained for around 45min to just over an hour and thus a test of equal duration would suffice. Coggan felt 20min for the average cyclist was a more practical approach. To account for average fatigue over that hour which would occur, the 5% or X0.95 of your 20min average power is factored in. Once you begin one of our programs or are on our premium monthly coaching packages, you will be briefed on your session plan about how to perform the test. Upon determing your FTP, we can set your training levels.
Once you have your new FTP and training levels. This feeds into our electronic platform called Training Peaks (TP). TP has various functions and the most important of these are the training metrics.
Training metrics allow us at The Threshold to tract your training load (CTL), training stress (ATL) and training balance (TSB) and this comes from an important number associated with your FTP called Training stress score (TSS).
TSS- this is the relative value given for a workout depending on how close you trained to your FTP number. 100% FTP for an hour would score you 100 TSS. Once we have a stress score for your workout, this begins to accumulate a stress in the body and begins to weight over 90days to give us a chronic training load (CTL).
CTL- is a measure of the average training stress and load your body has been subjected to over the last 90days. Associated with CTL is acute training load (ATL) which is a representation of the fatigue your body is carrying and weights it over the last 7 days. Subtracting ATL from CTL will give us your training stress balance (TSB)
TSB- this reflects your freshness and can be seen as a snap shot in number form reflecting your ability to train hard and recover well. Generally numbers can range from positive to negative. The more positive, the more fresh and ready to go you will be. The more negative, the harder you are training but not necessarily allowing proper recovery.
Fig 2: Example of the metrics mentioned above and how they integrate in the performance manager. This is your training fingerprint!
As you come along this journey with us, you will learn much more about other key factors and metrics that will allow you to become a better athlete.
We look forward to helping you!
MSc (Med) Biokinetics Wits
(Hons) Sports Science UP
Certified Strength & Conditioning Specialist
Ironman Certified Coach