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

starting strength gym
Page 1 of 2 12 LastLast
Results 1 to 10 of 20

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

  1. #1
    Join Date
    Nov 2012
    Location
    Toronto, Ontario
    Posts
    846

    Default Diagnostic angles for bottom of squat. Multiple possible solutions?

    If the constraints, at the bottom of the squat, are:

    1:the hip crease is just below the knees

    2:the barbell is over midfoot

    3:the bar is placed just under the spine of the scapula

    4:the spine is held in rigid extension

    then there are an infinite number of shank/knee angle combinations that satisfy this constraint. As a coach, and lifter, how does one decide which knee angle is best?

    I understand that as the knee angle becomes more acute, the hamstring tension reduces (bad thing), and that if you open up the knee angle too much, then you reach the limit of how acute the hip angle can be to keep the bar over midfoot (i.e. you can't go below a hip angle of 0 degrees).

    The question is this: How do you judge the correct combination of knee and shank angle? Is the "knees slightly over toes" the heuristic here?

  2. #2
    Join Date
    Jul 2007
    Location
    North Texas
    Posts
    38,820

    Default

    You judge the back angle, not the knee/shank angle. The correct back angle places the hips in the best position to drive the back/barbell upward using the most muscle mass. The resulting knee angle is a side-effect of this back/hips position, because the squat is not a "legs" exercise. This usually places the knees in the vicinity of the toes, either just forward or behind them, with some room for variation, shins not vertical, and is why the squat is the most difficult of the lifts to coach.

  3. #3
    Join Date
    Nov 2012
    Location
    Toronto, Ontario
    Posts
    846

    Default

    In this image, the constraints I mentioned in the first post are met in both cases. How do you judge which back angle places the hips in the better position for hip drive? The one on the left has very slack hamstrings, but the one of the right looks downright wrong (even though the hammies are tighter than on the left). Clearly, the ideal position for this lifter is somewhere in between. But how exactly do you determine this position?

    Please try to ignore the borderline alien anthropometry.


    Attached Images Attached Images

  4. #4
    Join Date
    Jul 2007
    Location
    North Texas
    Posts
    38,820

    Default

    As I said, there is room for variation. In this case you have drawn a figure with very short shanks, which skew the position in the direction of knees-forward of the toes, as in the figure on the left. So, the left figure is more correct in this instance. Remember also that this is a 2-dimensional representation of a 3-dimensional problem -- thighs are at an angle from the sagittal. But you're asking for a calculation, and I don't have one for you.

  5. #5
    Join Date
    Nov 2012
    Location
    Toronto, Ontario
    Posts
    846

    Default

    Cool, thank you. Yep, I get that the true femur and shank lengths are merely sagittal projections.

  6. #6
    Join Date
    Mar 2015
    Location
    Akron, OH
    Posts
    964

    Default

    Quote Originally Posted by spacediver View Post
    If the constraints, at the bottom of the squat, are:

    1:the hip crease is just below the knees

    2:the barbell is over midfoot

    3:the bar is placed just under the spine of the scapula

    4:the spine is held in rigid extension

    then there are an infinite number of shank/knee angle combinations that satisfy this constraint. As a coach, and lifter, how does one decide which knee angle is best?

    I understand that as the knee angle becomes more acute, the hamstring tension reduces (bad thing), and that if you open up the knee angle too much, then you reach the limit of how acute the hip angle can be to keep the bar over midfoot (i.e. you can't go below a hip angle of 0 degrees).

    The question is this: How do you judge the correct combination of knee and shank angle? Is the "knees slightly over toes" the heuristic here?
    As you implied, you're missing the "TUBOW" constraint; the knees shouldn't be too far in front of the toes. That will constrain the knee angle to an extent which will in turn constrain the back angle.

  7. #7
    Join Date
    Nov 2012
    Location
    Toronto, Ontario
    Posts
    846

    Default

    How about this.

    Starting assumption:

    The best position is the one where the knee angle is as large as possible while satisfying the aforementioned constraints in the first post.

    That way, the hammies are as stretched as possible.

    If this line of thinking is correct, then the right half of the figure would be correct, as that is the one that allows the most efficient use of the hamstrings. Of course, this assumes that the lifter is flexible enough to attain such an acute hip angle.


    Modified view:

    On the other hand, the range of motion is increased in the right half of the figure, so more work is required by the involved muscles.

    So perhaps there's a tradeoff between the increased efficiency of stretched hamstrings (which makes things easier), and the increased amount of work they have to do with the acute hip angles associated with more tightly stretched hamstrings (which makes things more difficult).

    And perhaps in most lifters, the sweet spot happens to be in a position where they reach the limits of their flexibility (and this position will be associated with knees just over toes or thereabouts).

  8. #8
    Join Date
    Jul 2007
    Location
    North Texas
    Posts
    38,820

    Default

    But the figures are incorrect, as I've already pointed out.

  9. #9
    Join Date
    Nov 2012
    Location
    Toronto, Ontario
    Posts
    846

    Default

    In terms of anthropometry, sure. But the (tentative) analysis I put forth could be applied to any anthropometry.

    Just to be clear, I'm not claiming that, even with that crazy anthropometry, the figure on the right would be correct.

  10. #10
    Join Date
    Jul 2007
    Location
    North Texas
    Posts
    38,820

    Default

    Have you been to a seminar?

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •