I did some searching these forums and the UK forums for an answer to this and found a little bit of material, but not everything I needed.
When I was doing a 6k yesterday, even at low ratings (i did a 16/18/20/22/20/18 pyramid, changing every 1k), the erg was moving backwards. It moved about two meters, then i had to get up and move it forwards (killing my split average) because my back was colliding with the erg behind me.
After the 6k, I did a pair of Tabata intervals, and had the exact same problem. Now these were at ratings of like 36-40, and it moved about the same, two meters per piece. I've had the same problem before on sprint pieces (500m, 250m, 100m), and even my coach isn't sure why it moves backwards so much (backwards as in behind me, not backwards as rush would move a boat).
What would cause this? Is there some technical error in my stroke? I can try to get a video posted soon if necessary. I was thinking that because I'm really light (140 lbs) that there's not as much intertia holding the erg down when I take a really powerful stroke.
Help would be appreciated!
erg jumps backwards
The basic principle is that the inertial forces we generate when changng direction need to be absorbed in the flywheel and not by the floor. So smooth strokes with no jerks and no unnecessary movement.
More specifically, you are pulling the machine with your legs. Try pulling a harder finish wth your arms after slight leanback, so that you stop moving back before release and so don't need to haul yourself forward with your feet. Feet out can be useful shock tactics for this. If you see a big difference with and without, you need to change something.
Try intentionally moving the machine in both directions, with straps, you'll soon see what does it. A slippery floor will help.
More specifically, you are pulling the machine with your legs. Try pulling a harder finish wth your arms after slight leanback, so that you stop moving back before release and so don't need to haul yourself forward with your feet. Feet out can be useful shock tactics for this. If you see a big difference with and without, you need to change something.
Try intentionally moving the machine in both directions, with straps, you'll soon see what does it. A slippery floor will help.
08-1940, 179cm, 75kg post-op (3 bp).