Garmin, with the release of the new fēnix 7 series, introduced the new Stamina feature, developed in collaboration with Firstbeat Analytics. Those familiar with video games will have heard of it, and the meaning is the same: Stamina is the ability to express oneself in a continuous effort in which endurance skills are required. And, lo and behold, the definition is also perfect for describing running and cycling.
Specifically, by dropping definition into our sports, with the Stamina feature you can see how you are drawing on your reserves and-potentially-how much time or distance you have left to run out of energy if you continue with the level of effort you are doing.
It basically tells you “how much you’re going to get” if you keep moving with the effort you’re putting in.
This leads to the most important effect of this new feature: with Stamina, you can manage your energy to perform at your best without running the risk of bursting before the finish line or the end of your workout or, on the contrary, finishing with dissatisfaction because you have not expressed your full potential.
How does it work?
I’ll spare you the basic theory on VO2max and FTP, but-basically-it’s important to understand only one basic concept: if you run or threshold pedal, you’ll be able to do so for between 40 and 60 minutes; beyond that, you’ll necessarily have to slow down. The somewhat lower limit, on the other hand, is the one that allows us to make prolonged efforts such as, for example, running a marathon.
With lower effort, you can get to run even more.
What decides how long you will run with a given effort, therefore, are many factors: damage to muscle fibers, perception of fatigue, carbohydrate consumption; just to name a few. So you can imagine how complicated it is to be aware of what is happening to our body while we are exerting effort. And so here comes Stamina to represent it with two closely related data: Stamina and Stamina Potential.
Stamina and Potential Stamina
As I told you, the two values are interconnected: Stamina represents how much energy “stays in your tank” if you keep up the effort you are making. As you can imagine, sprints, accelerations, climbs, shoulder-to-shoulder battles, and any off-threshold exertion tend to reduce our aerobic capacity and especially have a limited duration before we have to decelerate due to excessive lactate buildup.
Slowing down, when you see that your Stamina is decreasing too fast, can help recovery and continue the trial.
Stamina Potential helps us in this because it represents how far we could go if we return below the threshold, how much “gasoline” we have left.
As you can see from the graph below representing an interval training, in orange is marked Stamina, in gray is marked Potential Stamina, and in light blue is marked Pace. As we go at a pace around 60 percent, the Stamina practically coincides with the potential but, when we accelerate, the two values diverge and then get closer again as we slow down for recovery.
Autonomy
As you may have noticed, I am using the automotive comparison with gasoline a lot. Exactly as in the car’s on-board computer, the sportwatch with the Stamina feature not only gives you its value but also gives you a prediction of how long or how far you can go.
This feature is most useful because it allows us to calibrate effort according to our goal. If you are missing the last 10 km and the device gives you a longer range, you can speed up a bit. In the reverse case, it will be better to slow down a little so as not to run the risk of bursting.
It takes some time for Stamina to get to know you
This is a bit of a stretch; it is not Stamina that knows you but your Garmin. In fact, at least 15 outputs will be required for the device to make a prediction of your Stamina values.
In truth, the minimum information needed to calculate Stamina is VO2max. Which implies runs with heart rate monitor and GPS or bike rides with cardio and power sensor. It is also important that your personal maximum heart rate is set correctly on the device, otherwise it could have a cascading effect that negatively affects the reliability of Stamina and compromises VO2max, lactate threshold/FTP, and current intensity assessments.
One last consideration, precisely because it is the sportwatch that learns about us, keeping it on our wrist throughout the day will give it a chance to better understand what our reactions, habits and fitness are.
For info on Garmin fenix 7 go to: Garmin.com
