Video: A comparison of two start positions in the clean

[Mark Rippetoe]

First, note the possibility that Alan's arms are longer than hers, and that she may be using a wider grip than Alan. Second, she starts in the conventional-wisdom bar-forward-of-the-mid-foot position, which brings the hips down and shortens the moment arm between the hip and bar. Third, if she has been taught the conventional-wisdom Olympic lifting pull, she intends to accelerate the bar at the top, whereas Alan was being coached to accelerate the whole bar path. Her pull/anthropometry/grip width generates a higher second pull position, his generates better acceleration/bar velocity and a lower contact point on the thigh. These 4 still pictures cannot demonstrate your point #1. The higher hips start generates a better acceleration through the pull.

[Matthew_888]

Great!
I think I understand what you said about point 2.
Considering point 1, I made a link in the previous post to the video.
Here is the video: the "knees sliding under the bar" part of the video starts at 7:20 and end at 7:23.

[Mark Rippetoe]

Both lifters are doing a double knee bend, Alan's first knee extension is more complete than hers. This is due to her low-hips/knees-forward start.

[Matthew_888]

Is there a video showing the Rip version of the Clean with a vertical bar bath?

What appears to deviate the trajectory of Alan's bar is that he bumps into it quite hard.
I hope MBasic does not mind that I've used his image too much.
I've drawn an orange arc in between two green vectors below to show the deviation.
This deviation is a power leakage.
All things being equal, I would rather see a vertical bar path, at least as strait as Lydia's.
I cannot determine if the bump is due to Alan's execution of the Clean or because of the Clean methodology itself.
I guess that if at least one lifter could show a vertical bar path (as strait as Lydia's) then Alan's execution may be blamed (which it's likely wrt the conditions of execution), else maybe it's something else?

[Polishdude20]

This backward movement of the body's mass will create a reaction against the mass of the bar, causing it to swing forward a distance proportional to the difference between the masses of the body/barbell system. The heavier the bar relative to the upper body, the smaller the bar path loop (a snatch would be expected to loop more than a clean, and this is one reason why snatches are more sensitive to technique). The more you lay back, the worse the loop. So the idea must be a vertical bar path, even though it is not possible under most circumstances. Vertical is the most efficient ideal bar path, a loop of some degree will usually occur, and the loop must be minimized.

Because if this, should we put more emphasis not in the path of the bar but the path of the center of gravity of the whole system? Sure the bar goes out more forward but the lifter's body goes out more backward. This doesn't keep the bar over mid foot but keeps the whole system's center of gravity over the midfoot.

[Mark Rippetoe]

Yes, and the most efficient approach to doing so is to keep the bar path as close to vertical over the mid-foot as possible so that force production is used as efficiently as possible, i.e. doing work against gravity while minimizing extraneous and inefficient moment forces.

[Bobr]

So, let's say high ass setup is better for the power clean, since it allows the bar to travel higher. I would be interested to see if the same applies for the full clean, where bar height does not matter (that much), and transition to a vertical torso, full squat is needed. Any thoughts on that?

[Mark Rippetoe]

Why does the height of the pull not matter in a clean?

[bgl500]

Biggest thing I see is when the hips are in the lower position they have to rise first. Just seems more efficient to put them where they want to be in the first place.

[Scaldrew]

Biggest thing I see is when the hips are in the lower position they have to rise first. Just seems more efficient to put them where they want to be in the first place.

This guy gets it.