An overview of the kMeter functionality within the Exxentric App
Here you can select the endpoint of the set in different ways.
- Pre-defined number of reps
- Pre-defined time.
- Absolute power threshold to stay above.
- Stop at a certain drop-off from max power.
From session to session you might keep these settings the same but they are still important to look over especially when you first begin to use the app.
Pre-reps: these are the extra reps before the set and the data collection starts. These reps are used for acceleration and will be discarded in the workout summary. Iso mode means 0 pre-reps, usable if you want to go from a ISO-hold into dynamic action (pinch-release). Default is two pre-reps.
Auto start: kMeter Module and App senses rotation and starts by itself. Acquisition of data starts and begins without any interaction for the user on the screen. Default: on.
Voice assistance: Mute or choose auditive feedback with rep count, average, peak power, average speed or power limits. Power limits allow you to set a range and kMeter will give vocal and graphic feedback if you go outside of this range. Default: off.
Show result after exercise: with this activated (default) you will be brought to the result screen after a completed set. With this deactivated you will be brought back to the start screen and the next set and user. The data will always be saved either way but if you don’t see the result screen you won’t be able to add info to the set like VAS and comment.
Single turn mode: this mode only needs to be activated when using the Single-Turn Buckle on the kPulley. Default is deactivated. When activated it recalculates the numbers accordingly to account for the changes in the ROM-rotation relationship.
Power and force
Average power = average power for all reps in the set (except pre-reps) both CON and ECC phase.
CONC peak power = average CON peak power during all CON phases in the set (To see CON peak for every individual rep look at the graph).
ECC peak power = average ECC peak power during all ECC phases in the set (To see ECC peak for every individual rep look at the graph).
Peak overload % = ECC peak power / CON peak power. This metric is only relevant when the CON phase is, or close to, maximal.
Relative peak power = W / kg or W / lbs body weight
Average force = Approximated force based on calculations from ROM and power. Not to be used between users or exercises but works as an approximation for certain exercises by a certain user.
range of motion = how long the average rep was (in centimeters) over the whole set.
Average speed = average rep speed in m/s over the whole set.
Generated energy = energy put into the flywheel in kJ (not your expenditure which will be higher).
Repetitions = number of reps performed.
Workout time = duration of the set.
Inertia = the inertia you set in setup.
VAS = Visual analogue scale. User input after workout summary in the display. Stored in the database with all other data. Can be used to track effort or pain for example.
The app uses a formula to calculate a Score based on output* in combination with the amount of reps.
To get as high a score as possible, the output* and reps should be balanced with similar effort on both. A high output* with low reps will result in a lower score than a medium-medium relationship.
Table showing a simplified example:
* KJ, average Force, concentric-, eccentric-, and average Power.
Understanding the feedback
The data presented in the Exxentric app is estimated from velocity measurements by the kMeter sensor. The power is calculated and presented as average power per rep and peak power in CON and ECC to determine eccentric overload.
The power data is exact and consistent. Number of reps, rep time and energy expenditure are also exact while vertical motion (ROM) and force are more complicated calculations with more variables and should be considered as an approximation.
ROM and force data should not be used to compare different athletes or exercises but to be used in the same athlete and exercise. It can give information of progress overtime or changes with different inertial loading.
There is a kMeter walkthrough based on older versions of the kMeter Module and Exxentric App, available for free in our online kMeter intro course.