Over the past couple of years I've been suffering from frequent left calf muscle injuries. Basically when I run I get a sore left calf and occasionally I get a minor muscle tear. Earlier in the year I bit the bullet and went to see a physio about it. The advice from the physio was:
- I needed to rest it to let it heal, and
- The reason I get calf injuries is because my left leg is weaker then my right leg, (in fact the whole of the left side of my body is a relative weakling).
So the recommendation from the physio was to rest and then also to do a lot of left side strengthening, (e.g. knee bends, hopping up and down steps, doing interesting things with elastic resistance bands).
The "weak left side" diagnosis rings true through some other observations:
- When I swim breast stroke I'm told my left leg kicks much less strongly than my right leg,
- When I cycle and get tired, my left knee drops inwards and knocks against the cross bar,
- When I went to buy new running trainers from a running specialist they did video analysis as I ran on a treadmill. This showed my left foot landing and then rolling inwards too much which puts stress on my knee and calf muscle.
So when two things happened at once in a week during August 2013 (calf going ping again and the arrival of my RasPi camera module) I decided to do some scientific analysis. The plan was to use my RasPi camera module to analyse me doing some physical jerks, do a period of strengthening and then repeat the analysis.
So first I needed to have a decent setup for the camera module. Using the magic of Lego I built this rig:
MP4Box -fps 30 -add video1.h264 video1.mp4
(I had to install the MP4Box application to do this).
Here's a video of me jumping on the spot:
Transferring the video to a PC and using Quicktime, I could advance the video frame by frame. I select the frame where my foot was planted and just about to spring up, so to my mind the point where there is maximum stress on my leg. I did a print screen, pasted the image to Word and then drew straight lines from the middle of my knee downwards. Here's the image I got:
So the line on my right leg goes down pretty straight from the middle of my knee to my heel. On my left leg my knee is really turned outwards. More evidence of my dodgy left side.
Here's the equivalent for me running on the spot. First the video:
The running video:
<Insert this when YouTube stops being so dumb>
...with the image: