Tracker Video Analysis

[JTurner]

Just copying this straight from my log.

Originally Posted by JTurner

So, although I should be revising for tomorrows exam, I've spent the last couple of hours playing with a program I found. Being an engineering student, I think it's awesome. It's called Tracker and basically you open up a video in it, set up a co-ordinate system and reference an object size and from this you can do all sorts, calculate velocities, acceleration etc.. Mike Tuchscherer uses a lot of stuff like this, although he has a Tendo unit and has some real precision with the way he approaches training. I find this stuff really interesting so thought I'd share it quickly.

Here is a snapshot of one of my benches this morning.


Having set the y-axis roughly along the bar path I set the graphs on the right to be y-acceleration/y-velocity against y-displacement. The graphs can pin point where the acceleration was lowest, i.e the weakest point of the lift. Can also see that the bar path isn't straight, for the first part of the lift the bar moves backwards, maybe over-tucking the elbows.

This is just a rough play around with it and it isn't the best camera angle but I still think this can come in useful for analysing lifts.

It's available to download here: Tracker Video Analysis and Modeling Tool for Physics Education

This is an article I found about its use but I haven't had time to read it thoroughly: Strength Musings: Weakness Identification: Version 2.0

[BendtheBar]

Thanks JT. This looks like a very useful tool. Going to download and play with it tonight when I get home.

[BendtheBar]

Were you able to analyze multiple lifts and watch for things such as deteriorating speed?

It would be interesting to perform single reps with 80, 85% and 90% and monitor speed deterioration to see about, on average, when and where things start to break down (slow down). Would like to plot reps and speed and watch to see how the graph shakes out.

[JTurner]

Originally Posted by BendtheBar

Were you able to analyze multiple lifts and watch for things such as deteriorating speed?

It would be interesting to perform single reps with 80, 85% and 90% and monitor speed deterioration to see about, on average, when and where things start to break down (slow down). Would like to plot reps and speed and watch to see how the graph shakes out.

Haven't played around enough to say, it might be hard to plot them continuously, mainly because it would include the eccentrics so plotting against displacement would get messy. Although if you plotted velocity against time I don't see why you wouldn't get a decent graph of rep velocity over time.

There's quite a lot to play around with anyway, it's a general physics program so it might take some time to get it working nicely for lifting.

[JTurner]

Be aware though, it can be frustratingly "glitchy" and doesn't always like being told what to do.

[BendtheBar]

I was thinking about the possibility of editing out the eccentric. I assume it can calculate average speed? I am mainly concerned with looking at average speed on a rep by rep basis...plotting/analyzing it myself.

[JTurner]

Originally Posted by BendtheBar

I was thinking about the possibility of editing out the eccentric. I assume it can calculate average speed? I am mainly concerned with looking at average speed on a rep by rep basis...plotting/analyzing it myself.

That's a good idea, it would be nice if you could set multiple frame sections to analyse but there's only beginning and end. Yes you can analyse all the final data and also copy it, might be easier to work with in excel so you can split it up into separate curves and compare.

Just playing around this is a plot for three reps, eccentrics included. You can see how the curve flattens out over the reps.

[JTurner]

To add to the previous, found a pretty simple way of getting the average velocity for each rep even when they're together. For the deadlift triple in the previous post the averages were 0.3093, 0.2133 and 0.1740. Even if they aren't completely accurate with m/s they're all relative to each other.