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Kinovea - Forums → General → Measure Min, Max and average angle measurements while pedaling on bike
Hi
I want to take measurements form a video of my sitting position on my bike.
My question is:
In case i want to measure a specific angle, does the software knows to take the specific angle collect the data through the pedaling cycle and show the average, min and max of the specific angel? This is in case the pattern of pedaling repeats itself
Thx
Ronen
Hi,
I would say the angle-angle diagram will be the closest thing to cyclical motion analysis, it lets you see the value of a joint angle in relation to the value of another joint angle. It's used for repeating motion like running, swimming or cycling. Each cycle of motion will appear as an oblong ellipsoid shape from which you can infer information. I guess it depends on whether you can define cycle boundaries in terms of a reference joint angle.
There is no stats done on measurements at the moment, for this you will have to export the data to a spreadsheet and run the computation there.
For reference I repost the angle-angle snapshot in case you haven't seen what they look like.
Hi.
Thx tor your reply. How can i measure the average angel beteen hip knee and heel repeatly without going over picture by picture using the diagram? I need the angle value when the leg is in 6 oclock.
As mentioned there is no automatic extraction of the average, so you will have to settle on eye-balling it from the curves passing at a point or doing the computation by hand or in a spreadsheet. Min and Max can be read on the plot.
I need the angle value when the leg is in 6 oclock
Do you mean when the leg is vertical or when the crank is vertical and the pedal is at the 6 o'clock of the sprokets?
There is a tool for "angle-to-vertical" but unfortunately it is not usable with the angle-angle diagram at the moment.
There might be a simpler way to do this with a custom tool and I'm not an bike fitting expert so please take the following as inspiration only.
If you can show how you normally measure it for a single cycle maybe I can come up with a better solution.
You could add a regular angle tool to act as a reference for when the pedal hits the 6 o'clock mark. Set one of its leg horizontal and the other vertical, with the end of the horizontal leg tracking the pedal or a marker on the foot, aligned with the pedal, and the other two points placed in such a way that the background behind them will not change. This way the angle is always less than 90° when the pedal is up, and 90° when it's at 6 o'clock.
Then add another angle for the knee joint angle.
Something like this:
The blue angle will act as a reference. It will read 90° when the pedal is at 6 o'clock and less than 90° otherwise.
You track these for a while: right click on each angle and do "tracking > start tracking", then progress frame by frame verifying that the auto-tracking is solid and adjust it along the way when necessary, then "tracking > stop tracking" when you are done.
Then go to Tools > angle-angle diagrams, and you should get something like this:
If you look at when the reference angle (X-axis) is at 90°, you can see that the knee angle is around 118 to 120°.
Kinovea - Forums → General → Measure Min, Max and average angle measurements while pedaling on bike