So I had a chance to videtape myself this Sunday doing power clean & jerks in the Gym, and although I have corrected some of the most glaring defects I identified in my last taped session, there is still a lot of work to do to be able to get to some half respectable weights.
Instead of linking the videos themselves, something any non talented human could do (and probably brag about them, even when the weights were modest -from 90 to 95 kg, that's between 200 and 210 pounds, for those of you metrically illiterate), I'm going to share a somewhat more refined analysis, which requires a minimal drawing ability (at least, the ability to translate what's seen in the videos in the venerable "stick figure" form):
Inspired by the writings of coach Dan Bell I decided the cause was probably some incorrect position earlier than what I thought, and I found it in my starting position, with hips too high. I've been concentrating since then in starting with the hips lower (as flexibility is not much of a limiting factor now, I can do that easily, it provides for a more dynamic pull from the floor, also), hoping everything else would automatically improve.
The middle sequence is the visual translation of what I was still doing two days ago. The starting position is indeed much better, but I still straighten the knees too soon (right after the bar passes them), so the 2nd pull still consists mainly in a (somewhat shorter) whiplash backwards. The shorter whip explains why, although I feel faster and stronger I have difficulties moving weights that were easier for me to clean with my previous, uglier style: Having less space to accelerate the bar I probably have to rely more in the traps shrugging (inded, I feel the traps considerably more tired after my C&J's than I used to).
So now I see that what I have to focus on is keeping the legs bent for a little longer, so I reach the power position (and start the 2nd pull) in an even more upright position and, more important, with the legs able to significantly contribute to propelling the bar upwards (not forward). I have to start immediately bending the elbows (upward & outward) so the bar travels in as vertical a trajectory as possible, keeping it close to the chest so I can catch it w the elbows up, sparing the wrists, but that will be a second phase.
I'm happy to report that Yesterday I snatched (a day after updating my analysis of the clean, which most likely applies also to the snatch) I already focused on keeping knees bent in that move and felt a much, much more powerful 2nd pull. So let's see how well I'm able to apply this insight to the clean...