Diagnostic angles for bottom of squat. Multiple possible solutions? Diagnostic angles for bottom of squat. Multiple possible solutions? - Page 2

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Thread: Diagnostic angles for bottom of squat. Multiple possible solutions?

  1. #11
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    • phoenix arizona seminar date
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    Quote Originally Posted by Mark Rippetoe View Post
    Have you been to a seminar?
    Nope, it's something I'd like to do sometime in the future though.

    I've created a new figure, with more reasonable anthropometry, to help illustrate the question better.

    Here are shown eight different poses of the same lifter, all of which satisfy the primary constraints. What differs among them is the hip angle (and thus the back angle, knee angle, and shank angle). Also, assume that the hips are externally rotated by the same amount in all poses.



    The point here is that as you go from left to right, three different important things change:

    A: Hamstring tension.
    B: The work required on the bar (the first 5 configurations have roughly the same required bar displacement, but this increases from the 5th to the 8th configuration).
    C: The required flexibility.

    With regards to A, increased tension means better stretch reflex and more powerful contraction of the hamstrings, which contributes positively towards force production. It is likely not as simple as this, as I don't think force-length and force-tension relationships in skeletal muscle are monotonic (although I'm far from educated on this issue).

    For B, the increased work requirements is going to make the lift more difficult.

    For C, there are limits to how extensible a given lifter's hamstrings are, so they may not be able to adopt all of the illustrated configurations.

    Here is the question:

    What is the logic behind deciding upon a particular configuration? If, for example, a lifter was flexible enough to adopt the 8th configuration (far right), there would have to be a rationale behind not recommending he actually adopt it. Would the rationale be that it becomes too difficult because of the increased bar displacement requirements? If so, wouldn't that contradict the "over the longest effective range of motion" criterion that is often cited?

  2. #12
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    The four criteria for judging the effectiveness of a barbell movement are

    1. Most muscle mass used
    2. over the longest effective range of motion, so that
    3. You can lift the heaviest weight, and therefore
    4. get the strongest.

    My eye tells me that your 6th figure satisfies these criteria best. Have you been to a seminar? We spend 2.5 hours discussing this on Saturday morning.

  3. #13
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    Thanks again for the reply. Nope, as I said, it's something I might want to do in the future.

  4. #14
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    Spacediver, look at #2: the longest effective range of motion. "Effective" requires the proper motion of the knees and hips. In other words, which one of your sketches could you perform getting your knees set about 1/3 to 1/2 of the way down? Look at the pictures of the squat guy in The Book. Track his knees against the background in figure 2-23.

    I think you'll find this requirement knocks out a bunch of your solutions.

  5. #15
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    Quote Originally Posted by Karl Schudt View Post
    Spacediver, look at #2: the longest effective range of motion. "Effective" requires the proper motion of the knees and hips. In other words, which one of your sketches could you perform getting your knees set about 1/3 to 1/2 of the way down? Look at the pictures of the squat guy in The Book. Track his knees against the background in figure 2-23.

    I think you'll find this requirement knocks out a bunch of your solutions.
    With respect to the 8th solution (far right), why wouldn't you be able to set the knees in their position early in the descent? If anything, you'd set the knees in position probably by 1/4 of the way down in the 8th solution. What's wrong with doing that? What is "ineffective" about that? "Proper" motion of the knees and hips is only proper insofar as that motion produces favourable biomechanics. In a lifter that has the flexibility to adopt the 8th solution, why does is that configuration associated with unfavourable biomechanics?

    To me, an answer might be given on page 45, where it says that, during the start of the ascent of the squat, shifting the hips backwards (as opposed to upwards) means that the potential contribution of the quads towards useful knee extension is wasted as the knee angle opens up without upward bar movement. In a similar manner, I suppose one can make the argument that too open of a knee at the bottom of the squat means that the quads' potential is similarly wasted, in the same way that starting with too closed of a knee wastes the hamstrings' potential contribution.

    And if this is correct, then the answer to my question is that the optimal solution is one that provides the optimal contribution of the hamstrings and quadriceps.

  6. #16
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    Space, you're leaving out center of mass. Ask your stickman what the problem is in #8. He knows, because he can feel it...and he's about to move to a better position.

  7. #17
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    Quote Originally Posted by stef View Post
    Space, you're leaving out center of mass. Ask your stickman what the problem is in #8. He knows, because he can feel it...and he's about to move to a better position.
    Ah good point!

  8. #18
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    The whole not-falling-down thing constrains the squat. Bar position affects the angles that are possible - you can't deviate as much as your stick figures suggest; deviations are limited by strength to control the unbalanced position, especially at the bottom; and any deviation affects how well you can *train* the squat variant you are using. And that's why we use bar position to move between types of squats - it works better to put the bar on the delts and front squat than to try to just make a squat somehow look like a fs and vice versa.

  9. #19
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    Spacedriver: have you seen this: MySquatMechanics

    Right under where you enter the bar weight . . .
    be sure to click on the boxes for: "Show model. Show moment and angles. Show moment breakdown. Show muscle lengths."
    then scroll down below.

    Big effing rabbit hole.

  10. #20
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    I remember a user on this forum posted this a while back (I believe they created it too). Impressive work, thanks for linking it again, I do love the smell of rabbits, especially their glorious holes.

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