Exxentric App Metrics Explained: Relative Peak Power, Concentric Peak Power And SCORE

Exxentric CEO Fredrik Correa takes us through some of the most advanced metrics for measuring performance in the app, as well as his all-time favorite, the relative peak power metric. Read all about it below: 

Using our updated Exxentric App, you can deepen your training, peak your programming, and understand where you have room for improvement. It tracks your progression with the flywheel training in real-time. You will be able to measure peak power; both eccentric and concentric, force, power, and energy. These are all metrics that are combined to generate the SCORE of your workouts in the app.

Among all the new incredible features available on our enhanced Exxentric App, (workouts, training, dashboard, wishlist, SCORE) I highly recommend trying the relative peak power (W/kg body weight), which is an excellent metric, especially if you want to focus on a single metric. You wonder why? Here are some reasons:

  • It captures both power output and bodyweight, two key determinants for performance in sprinting and jumping among other things
  • It has a convenient scaling
  • When it improves, you improve!

However, to capture the maximum amount of info in a few key metrics, I suggest following both SCORE and relative peak power progression. 

Back to the relative peak power. What is it? Let’s break it down. 


The Relative Peak Power Metric Explained

Power = force * velocity, meaning the force you produce multiplied by the velocity. Force goes up when you increase intensity but also if you boost the resistance, in our case the inertia. Our muscles are more capable of producing force when moving slowly, which means our force output peaks when we just barely manage to move a weight, e.g. going very slow in a heavy lift. Velocity, on the other hand, is the movement speed so basically the opposite of when producing high force. To move fast we need a light resistance or put differently, when we are moving fast we have a lower capacity to produce force. 

The fact that power is the product of force * velocity means that it peaks when we produce a high force, but not maximal, and a high velocity, also not maximal, so we maximize power by having high velocity and force at the same time. As you can see in the graph, the power is actually close to zero when either force or velocity is maximal because the other factor is getting close to 0, and everything multiplied by 0 is 0. 

High power output is when we are throwing something, jumping as high as possible, or sprinting as fast as possible. We want to do a forceful movement at as high a speed as possible. Power output is therefore a key determinant in our performance in all athletic actions, hitting golf balls, throws, jumping, sprinting, change of direction, and so on.

The concept of power is a bit confusing, but once you get it, then average and peak power comes straightforward. Average power is the average of a period of time, like a repetition, a set over a specific time where peak power is the highest power during a motion. 

Average power makes more sense during continuous work, like cycling, where the average power output dictates the speed you are moving at. However, for athletic burst-type actions such as jumping, sprinting, or throwing, the peak power is better at describing how much energy you can put into motion. 


Concentric Peak Power Metric

The Exxentric app also measures concentric peak power, so let’s focus on that. This is a good metric, as  I described above, most of the actions move your body in some way, which means the body is the resistance in this case. Equal power output and the lighter body will move faster, higher, and quicker.

This is what makes the relative peak power so valuable, as it takes into account how much power you can produce in relation to the resistance you have to move, i.e your body weight. That’s why relative peak power is an excellent metric for predicting how high or long you can jump or how fast you can sprint. If you can maintain power output and cut weight you will jump higher, and sprint faster, and consequently your relative peak power metric will improve. On the other hand, if you improve your power output and maintain weight, your metric and your performance will also improve. 

Some elite athletes and coaches previously doing regular jump and sprint testing have actually stopped doing it and they focus on the relative peak power in the app instead. They are training on the kBox regularly to track their performance on a weekly basis training without doing these additional time-consuming tests with jumping or sprinting, which also require additional tools. 

So if you want to know if the training is helping you perform better, monitor how your relative peak power for those exercises improves or not and you will know! 


Practical tips!

You don’t need to monitor all exercises but a few key indicators for your performance. One example could be to monitor progression in squat, row, and high pull to give an understanding of performance for both the locomotion (squat – sprints, jumps) and the upper body actions (throws, pulls). You can of course add exercises or replace them with more specific ones for your sport such as lateral squats for skating, if you are in ice hockey or a rotational exercise for a tennis player or golfer, the principle is still the same. Remember, if the athletic action is very little dependent on your body weight like a golf swing, the concentric peak power output might be a better predictor. Consult with our training experts, if you need guidance on that. 


What are you waiting for? Take advantage of our amazing new features and take your flywheel training to the next level! 

Happy DOMS!

Fredrik Correa, M.D., CEO






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