A new article about pulling mechanics

[Scrofula]

Actually right now it has no issues because nothing's been earnestly run! I'm tickled pink to just get mutant segments drawn. But there're lots of issues to be had, both in terms of how to model and how to generalize results:
.getting realistic limb lengths/angles/masses set up
.improving the simple assumption of midpoint COMs for each segment
.setting up angle shifts over time so that resultant forces are realistic
.getting horizontal and vertical torques/forces calculated
.disallowing certain paths (bar hits knees / hitching / system COM goes beyond foot)
.allow for limb shifts (arm bend, shoulder shrug)
Even with all this there are certain biological realities (e.g. stretch reflexes) and physical realities (e.g. friction) that make real life so damn interestingly complicated, and thus make perfect models impossible. All models are wrong; some models are useful. But I'll try my best. Why? I have no clue. But you always start off simply, so Senor Stick's snatch 1st pull is where I begin.

As a starting point, there's a lot of free motion capture data and human 3d models out there. These will probably give you more realistic anthropometry than just eyeballing it.

Once you have a reasonably realistic model, it would be very interesting to run some sort of optimization algorithm to try and automatically discover efficient pulling mechanics, and see how well they match the techniques that humans have come up with. I'm tempted to do this myself, but I'm unlikely to have the time in the near future. Some day maybe.

[Alex Bond]

I have only heard one decent argument in favor of a non-vertical bar path. Obviously a vertical bar path is more mechanically efficient, a shorter distance you have to move the bar. But, the human body is not a forklift. People will be stronger in certain positions than in others, depending on factors x, y, and z. So if a deviation from a vertical bar path puts the lifter in a position where they can apply force better, this may end up allowing more total force to be applied to the bar, more than canceling out the minor inefficiency from deviating from vertical. I think that is argument could possibly be true - however, it hasn't been proven so and I'm not sure it's even possible for it to be proven so. And I think that if one wants to deviate from the mechanically efficient path, the burden of proof is on them.

[Tom Campitelli]

But, the human body is not a forklift.

Greg Everett makes this argument both in writing and in person and while I like Greg, that's not a reason. It's a line to get chuckles. The question becomes, "How does deviating from the vertical bar path put the lifter in a better position, especially in the second pull?" This becomes problematic because once the weights have come off the ground by a few inches, the bar is back over the midfoot, the back angle has become quite horizontal, and the shoulders are in front of the bar. That is, the lifter is in the position Rip always talks about before the bar has even gotten to the bottom of the knee. If you are in a deadlift-esque position well before the second pull ever gets started, I am unsure of how a more vertical back angle with the bar over the toes helps with putting the lifter in a different, let alone advantaged, position when it comes time to jump.

[Gymmoser]

We should not confuse a CrossFit coach with an Olympic Weightlifting Coach. I am sure they are great CrossFit coaches but we really should leave Olympic Weightlifting to Olympic Weightlifting Coaches.

[Damien Thompson]

I don't think Greg would ever refer to himself as a Crossfit coach past or present, if that is who you are referring to.

I think he has proven himself as a weightlifting coach via the quality of his knowledge, books, articles and lifters.

[Gymmoser]

I have only heard of him on the crossfit site. I have never heard of him or seen him in any of the Weightlifting circles. Maybe he is new, I will check around.

Is there something wrong with being a CrossFit coach?

[Ello]

I have only heard of him on the crossfit site. I have never heard of him or seen him in any of the Weightlifting circles. Maybe he is new, I will check around.

Is there something wrong with being a CrossFit coach?

Depends on your perceived connotation with CrossFit. For me it denotes excessive metcon with an incurable desire beat the crap out of your body on a daily basis.