Force Velocity Quality Levels
The 1080 software checks validity before presenting the force velocity results. If the quality of the data is not valid, no profile will be generated.
Validity is based on these criteria:
- Load, mode and speed settings are correct ()
- Individual's height and weight are correctly entered
- The individual's run was appropriate to perform the force velocity calculations
- The distance must be a minimum of 20 meters (or 20 yards). Any distance shorter than this will not be accepted.
- The runner must maintain their acceleration long enough to reach their top speed. Refer to the quality levels table below for details.
- Runner was running resisted. Force velocity cannot be computed for assisted runs.
- Confidence check. This is a validity check comparing the measured run with the force velocity fitted curve.
Run Distance Quality Levels
The shorter the run, the lower the confidence in the calculated metrics. The required distance varies for each runner but can be estimated using the runner's tau () value according to this table:
| Distance (multiples of ) | Quality |
|---|---|
| Good quality | |
| Poor quality. Use caution when interpreting the results. | |
| Very Poor quality. Use caution when interpreting the results. | |
| Data is not suitable for Force/Velocity (results will not even be available) |
If the run is too short, this will be indicated with a yellow or red badge:
See Performing a Force Velocity Run for practical guidelines on how long to run.
Confidence Value
The confidence value is a measurement of how well our force velocity algorithm managed to calculate accurate and values.
It is done by comparing the actual, measured run with the curve fitting done by the force velocity algorithm.
Figure: Fitted curve (dashed line) on top of the measured smooth speed curve (solid)
The result is a value between 0 and 1, where 1 is a perfect match. Good results are typically around 0.99. One way to think about these values are as percentage accuracy (0-100%).
| Confidence Value | How to interpret the results |
|---|---|
| Good quality. The values reliably reflect the athlete's true abilities with accuracy. | |
| Poor quality. The results can be displayed, but use caution when interpreting them for decision-making. | |
| Very Poor quality. The results can be displayed but should be interpreted with caution. | |
| Unusable data. Force velocity profile results not displayed. |
If the confidence is in one of the poor or very poor ranges, a warning is shown in the user interface next to the metrics:
How to avoid low confidence
The most common reasons for getting the extremely low confidence values:
- The athlete did not provide maximum effort throughout the run. Example, slowing down immediately after reaching top speed.
- Poor start. Example, measurement was accidentally triggered prior to acceleration by other athlete movements.
- Excessive line sway interfering with the measurement. Changing mode and/or resisted load of the machine can perhaps mitigate this. Example, use NFW mode and 3 kg load.