Hi everyone !

I am trying to measure muscle fascicle length changes during active contractions using Tracker. I want to configure tracker so it can track a muscle fascicle and measure how its length changes during movement (an example so you can understand https://www.youtube.com/watch?v=8lTp_7tHOlQ ). In the videos that I provide bellow you can see the muscle fascicles, the superficial and the deep fascia (take a look here to understand the terms http://imgur.com/a/GTe4x ). I can understand that the quality might be poor to track a single fascicle as they seem to disappear, but if you look closely the superficial fascia seems not to move while the deep fascia moves a lot. Ultimately what I want is to measure the horizontal (and also vertical) movement of the deep fascia so to calculate how much the fascicles elongated. Is there a configuration to track the movement of the deep fascia ?

Now as an additional point, I am aware that the video margins are not big and a lot of the fascia moves out of the screen. For that reason I will probably track point A (in the picture http://imgur.com/a/GTe4x ) measure its distance from point B, and then once point A leaves the screen to measure how much did point B move so as to calculate the distance that point A moved (assuming the distance between the two points does not change).

Here is a a better quality video but with lower framerate (44 Hz).
https://www.youtube.com/watch?v=x4QgCWtC6Lg


Here is a low quality video but with high framerate (117 Hz).
https://www.youtube.com/watch?v=Lkc6v9hZxb4

I could send you the video files if you cannot download them from youtube. Could you please play a bit with those two videos and tell me if you have found a way to successfully track the fascicle length changes ? Ultimately what I want to measure is how much the deep fascia ( the middle white line you see in the video) is moving.

Thanks,
Georgios