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Leg Sinking Torque of the Pull

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General fitness, health and nutrition
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13 September 2003
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14 September 2003
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Larry Weisentha
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  1. Introduction:

    This is _not_ yet another one of those "Larry vs TI" threads. It is, rather, an attempt to identify
    a problem in stroke technique and to discuss potential approaches to solving the problem.

    I pre-discussed this with Terry Laughlin, and he graciously gave me permission to temporarily post
    several pictures of him swimming on my website, for the purpose of facilitating this discussion:

    weisenthal.orgTI 1.jpg

    weisenthal.orgTI 2.jpg

    weisenthal.orgTI 3.jpg

    weisenthal.orgTI 4.jpg

    I took these images from a circa 1997 instructional video which I purchased from Total Immersion as
    part of a workshop I attended in the Fall of 1997. They show Terry swimming (not drilling) and they
    illustrate a very important point.

    Image #1 shows Terry just starting the catch with his right hand. His body position is good, but not
    quite perfectly horizontal.

    Image #2, captured only a fraction of a second later (note time stamp), shows him during the
    power phase of the stroke. His posture is not optimum (bisect the angle between his thighs and
    you will note a slight forward bend at the waist. His head is down, and his butt is well under
    the water line.

    Image #3 was captured at the perfect moment when he is applying absolutely no downward force at all.
    His horizontal body position is close to perfect.

    Image #4, again only a fraction of a second later (again note time stamp) shows him in mid-pull with
    the left hand. The posture is again nowhere near optimum, and the butt is again well under the
    water. Bisect the thighs, and the trunk is again somewhat forward flexed.

    What is important here is the contrast between body position when it is streamlined and gliding
    versus when it is pulling (best shown in the contrast between #3 and #4). This graphically
    illustrates the principle of "Miller Torque," in which downward forces applied ahead of the center
    of buoyancy will push upwards that part of the body in front of the center of buoyancy and sink the
    legs. Note that Miller torque is maximized when downward forces are applied farther out in front of
    the body. If you reach way forward and then start applying forces before your hand has descended to
    the position where you can apply rearward, as opposed to downward forces, this will increase Miller
    torque and sink your legs further. But Miller torque is unavoidable, even with a perfect high elbow
    catch, whenever force is applied ahead of the center of buoyancy. The more that one "front quadrant"
    swims, the greater will be the tendency to produce Miller torque, by virtue of moving the moment arm
    further in front of the fulcrum, which is the center of buoyancy.

    Now, as Eric recently pointed out in the thread entitled "The Most Sacred Cow," it is striking how
    many elite swimmers -- virtually a who's who of the fastest swimmers in the world -- do the
    following. Coincident with the catch and pull of their strong side (the side which produces the
    greatest Miller torque), they tilt their heads forward, maintaining good posture, which is to say,
    maintaining the same degree of lumbar lordosis (or lower back arching) that is maintained when one
    "stretches to full height" when standing upright on land. In point of fact, many of the most
    prominent swimmers (e.g. Evans, van den Hoogenband, de Bruijn, Munz, Hackett) incorporate a distinct
    head lift at this time also.

    What does the head lift do?

    Well, the Miller torque sinks the butt by elevating the forward part of the body and, therefore,
    sinking the rearward part of the body (on the opposite side of the center of buoyancy fulcrum). A
    forward head tilt increases the back arch, increases the amount of the head which is above the
    water, increases the weight of the forward part of the body, and, therefore, counteracts Miller
    torque. The higher the head is lifted, e.g.

    weisenthal.orgmunz.art

    the greater the counterbalance to Miller torque.

    Look at the above and underwater clips of Janet Evans:

    weisenthal.orgevans uw.mpg

    Note how extremely high she lifts her head, coincident with her strong side pull. Note how, when she
    does so, her butt actually rises up in the water (in contradistinction to the images of Terry, where
    the opposite happens, as he maintains his relatively poor posture and "hidden head"
    (downward-looking) position).

    I think that Total Immersion-style swimming would be improved, were the swimmers taught to maintain
    good posture in the water (maintain a prominent lower back arch, of the type which exists when one
    stretches oneself to full height on land) and to tilt their heads to look somewhat forward,
    coincident with the catch and pull of their strong sided hand. With time, there will be a tendency
    to develop of bit of a head lift, and this should not be discouraged, if it is both natural and
    comfortable.

    Kicking with a kickboard is extremely useful, in that it specifically strengthens the muscles
    necessary to maintain good posture (lower back arch) in the water, helps the swimmer get used to an
    arched back posture, helps the swimmer get used to looking forward with an arched back, and
    improves the kick.

    Larry Weisenthal

    Certitude is poison; curiosity is life

  2. Oops, gave the incomplete URL for the Janet Evans underwater clip...it is:

    weisenthal.orgevans uw.mpg

    .. Sorry Larry Weisenthal

    Certitude is poison; curiosity is life

  3. Wow, great stuff Larry!

    Thanks for all the effort in putting this together and thanks to Terry for letting you post
    his pictures.

    The whole "press your buoy" versus "arch your back" is starting to get as clear as I think it ever
    will. I know you'll never convince Donal because with respect to this issue, having eyes he sees
    not, and having ears he hears not.

    Mr. Laughlin's posture IS different than such swimmers as Peter VDH and Grant Hackett. The web
    contains a number of video clips of those men swimming. If you freeze the video at the moment of
    downsweep, you will see that the body position of each man is nearly identical. Namely, some
    head pop-up (more in Hackett than VDH), arched backs, and right leg up and bent in preparation
    for a downbeat. That position does look more "slippery" than Terry's.

    -Eric

  4. (Larry Weisenthal) said:

    I pre-discussed this with Terry Laughlin, and he graciously gave me permission to temporarily post
    several pictures of him swimming on my website, for the purpose of facilitating this discussion:

    weisenthal.orgTI 1.jpg

    weisenthal.orgTI 2.jpg

    weisenthal.orgTI 3.jpg

    weisenthal.orgTI 4.jpg

    I suggest you look at these, too, and draw your own conclusions. I corrected Larry's clips for
    parallax and drew a few guidelines. The red are my best guess as to the lines of Terry's body. The
    blue appears to be the surface and bottom of the pool. The white is just a horizontal line for
    reference.

    donalfagan.comTL 2.jpg

    donalfagan.comTL 4.jpg

    Donal Fagan AIA Donal@DonalO'Fagan.com (Anglicise the name to reply by e-mail)

  5. On Fri, 06 Jun 2003 17:26:24 GMT, Donal Fagan <Donal@DonalO'Fagan.com> wrote:

    OK, the full series, corrected for horizontality:

    donalfagan.comTL 1.jpg

    donalfagan.comTL 2.jpg

    donalfagan.comTL 3.jpg

    donalfagan.comTL 4.jpg

    Donal Fagan AIA Donal@DonalO'Fagan.com (Anglicise the name to reply by e-mail)

  6. Regarding Fagan's drawings:

    The blue line allegedly tracing the water surface is parallel with the bottom blue line. Measuring
    the bottom blue line from the black line on the pool bottom, there is a 4.5 mm distance on the left
    end and a 6.2 mm distance on the right (in #2). Thus, I don't believe that the top blue line (and
    therefore the white line (alleged body axis) is parallel with the surface.

    These are only meaningful also in comparison with the other images (#1 and #3). If Laughlin is,
    indeed, parallel with the water surface in #2 and #4, then he must be REALLY swimming
    "downhill" in #3!

    Laughlin's body alignment clearly changes between #3 and #4 (when he has the leg sinking torque of
    the pull). Look at the position of his butt vis a vis the water surface in #3 and #4. On the surface
    in #3. Well below the surface in
    #4. If his body is really parallel with the surface in #4, then his whole body
    must have submerged equally in just a fraction of a second...but that didn't happen. What happened
    is that the horizontal alignment of his body tilted upward forward of the center of buoyance and
    downward rearward of the center of buoyancy.

    Larry Weisenthal

    Certitude is poison; curiosity is life

  7. (Larry Weisenthal) said:

    The blue line allegedly tracing the water surface is parallel with the bottom blue line.

    Actually I followed the line of bubbles. When I had finished, I saw that the line was also parallel
    to the line of floats in the background. So I'm fairly confident in that line.

    The surface line differs from the pool bottom by a few degrees. Since many pools have sloped floors,
    I didn't see this as important.

    Quoted message said:

    Measuring the bottom blue line from the black line on the pool bottom, there is a 4.5 mm distance
    on the left end and a 6.2 mm distance on the right (in #2).

    It is misleading to take dimensions from a perspective. Lines that are really parallel tend to merge
    closer together to a common point, called the "vanishing point." None of those bottom lines will
    *measure* the same distance apart from one end of the photo to the other.

    Quoted message said:

    These are only meaningful also in comparison with the other images (#1 and #3). If Laughlin is,
    indeed, parallel with the water surface in #2 and
    #4, then he must be REALLY swimming "downhill" in 3!

    I would've done those, too, but I'm supposed to be working here.

    Donal Fagan AIA Donal@DonalO'Fagan.com (Anglicise the name to reply by e-mail)

  8. (Larry Weisenthal) said:

    The Fagan analysis really comes down to the accuracy of the "white line" which is an eyeballed
    estimate of the axis of the swimmer.

    No it isn't. As I wrote, "The white line is just a horizontal line for reference." So, you guys can
    compare Terry's horizontal bearing to that line.

    Reading is *fun*damental!

    Donal Fagan AIA Donal@DonalO'Fagan.com (Anglicise the name to reply by e-mail)

  9. (Larry Weisenthal) said:

    I think that Fagan's anatomic relationships are faulty.

    Hey, the dog and the pony aren't complaining.

    Donal Fagan AIA Donal@DonalO'Fagan.com (Anglicise the name to reply by e-mail)

  10. Donal Fagan <Donal@DonalO'Fagan.com> wrote in message
    news:<[email hidden]>...

    Quoted message said:

    On Fri, 06 Jun 2003 17:26:24 GMT, Donal Fagan <Donal@DonalO'Fagan.com> wrote:

    OK, the full series, corrected for horizontality:

    donalfagan.comTL 1.jpg

    donalfagan.comTL 2.jpg

    donalfagan.comTL 3.jpg

    donalfagan.comTL 4.jpg

    Interesting drawings, Donal. Your talent in the digital realm is indeed prodigous.

    However, I'm not sure parallel lines drawn near the surface, near the bottom of the pool, or through
    the swimmers body really tell us anything.

    Here's the bottom line, and it's the only one that matters. Terry's butt is underwater. Well
    underwater.

    I just looked again at the video I have of Grant Hackett which is shot from the pool deck. His rump
    remains clear of the water at all times. Futhermore, coincident with his left arm pull his hips rise
    well out of the water.

    He couldn't do this if we was bending at the waist and forcing his chest and head into the water to
    some extent. I'm sorry to be the bearer of bad news, but this whole "press your buoy" thing just
    ain't the way the elites swim.

    -Eric

  11. Well the argument is getting silly if we're having to take sides on who has the more accurate
    drawing/diagram. I don't know anything about Terry's background as a swimmer but is it a valid
    comparison to make between his swimming style and that of an elite swimmer? Most, if not all, the
    swimmers I coached have a better and more effective stroke than me.

    Paul

  12. (4precious) said:
    Quoted message said:

    donalfagan.comTL 1.jpg

    donalfagan.comTL 2.jpg

    donalfagan.comTL 3.jpg

    donalfagan.comTL 4.jpg

    Quoted message said:

    Here's the bottom line,

    Terry's butt is the bottom line, huh?

    Quoted message said:

    ... and it's the only one that matters. Terry's butt is underwater. Well underwater.

    *All* of Terry is well underwater except for the back of his head and his pulling arm. He's not
    swimming very fast, as I recall.

    He's not quite as horizontal in #'s 2 & 4, but he's hardly dragging his legs. The important thing is
    that his lower body isn't a source of drag because it follows in the wake of his upper body.

    What's interesting to me is that he is looking forward in almost every frame, so I wonder if this
    video was shot before he adopted the head-down idea.

    And goodbye for a few days. I've got a van to load and this computer goes, too.

    Donal Fagan AIA Donal@DonalO'Fagan.com (Anglicise the name to reply by e-mail)

  13. In 4precious said:


    If by "bending at the waist" you mean arching his back, then I agree. Hackett's lower back remains
    arched through the stroke.

    Hard to say from the video. He certainly has phases of "more arch" and "less arch". I'm not sure
    that he ever loses the arch completely, but his upper back is so well muscled he could lose the arch
    and I wouldn't be able to tell.

    Ross

  14. [email hidden] (4precious) wrote in message
    news:<[email hidden]>...

    Quoted message said:

    I just looked again at the video I have of Grant Hackett which is shot from the pool deck. His
    rump remains clear of the water at all times. Futhermore, coincident with his left arm pull his
    hips rise well out of the water.

    He couldn't do this if we was bending at the waist and forcing his chest and head into the water
    to some extent. I'm sorry to be the bearer of bad news, but this whole "press your buoy" thing
    just ain't the way the elites swim.

    -Eric

    I have a video clip of Grant Hackett swimming which is shot half from deck level and half from
    below the water - I think I got it from Donald Graft's website when that was still accessible
    (thanks, Donald).

    From the deck level, his butt raises and lowers slightly and is not always above the water, though
    remains very close to it. It raises up clear of the water co-incident with his right-arm entry.

    From below the water this becomes clearer. As his right arm enters, he drives his head and chest
    into the water - almost a butterfly-dolpin movement. At this time he also practically *stops*
    kicking until the right-arm catch is complete.

    He is definitely bending at the waist and forcing his head and chest into the water in this phase of
    his stroke.

    Maybe some others have the video clip. It was called "hackett2.mpeg" when I downloaded it.

    Liz D

  15. "Liz D" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    I have a video clip of Grant Hackett swimming which is shot half from deck level and half from
    below the water - I think I got it from Donald Graft's website when that was still accessible
    (thanks, Donald).

    From the deck level, his butt raises and lowers slightly and is not always above the water, though
    remains very close to it. It raises up clear of the water co-incident with his right-arm entry.

    From below the water this becomes clearer. As his right arm enters, he drives his head and chest
    into the water - almost a butterfly-dolpin movement. At this time he also practically *stops*
    kicking until the right-arm catch is complete.

    He is definitely bending at the waist and forcing his head and chest into the water in this phase
    of his stroke.

    Maybe some others have the video clip. It was called "hackett2.mpeg" when I downloaded it.

    You're welcome, Liz.

    I've put the clip online so people can see what you are referring to:

    shelob.mordor.nethackett2.mpg

    Right click and Save Target As... Then play it from your hard disk.

    Don

  16. [email hidden] (Liz D) wrote in message
    news:<[email hidden]>...

    Quoted message said:

    [email hidden] (4precious) wrote in message
    news:<[email hidden]>...

    Quoted message said:

    I just looked again at the video I have of Grant Hackett which is shot from the pool deck. His
    rump remains clear of the water at all times. Futhermore, coincident with his left arm pull his
    hips rise well out of the water.

    He couldn't do this if we was bending at the waist and forcing his chest and head into the water
    to some extent. I'm sorry to be the bearer of bad news, but this whole "press your buoy" thing
    just ain't the way the elites swim.

    -Eric

    I have a video clip of Grant Hackett swimming which is shot half from deck level and half from
    below the water - I think I got it from Donald Graft's website when that was still accessible
    (thanks, Donald).

    From the deck level, his butt raises and lowers slightly and is not always above the water, though
    remains very close to it. It raises up clear of the water co-incident with his right-arm entry.

    From below the water this becomes clearer. As his right arm enters, he drives his head and chest
    into the water - almost a butterfly-dolpin movement. At this time he also practically *stops*
    kicking until the right-arm catch is complete.

    He is definitely bending at the waist and forcing his head and chest into the water in this phase
    of his stroke.

    If by "bending at the waist" you mean arching his back, then I agree. Hackett's lower back remains
    arched through the stroke. He also looks forward the whole stroke. There's no evidence of "press
    your buoy", which would look like a slight bowing at the waist (not arched) and looking at the
    bottom of the pool. The curve of his body line is "concave upward" throughout his stroke. There's no
    evidence of any "concave downward" body position, which is what you see a bit of in the photos of
    Terry Laughlin on Larry's website.

    -Eric

  17. I did my best to capture a still image of the instant when Liz is saying that Hackett has the
    "highest" butt (I repeat that there is swim suit fabric above the water at all times when Hackett
    swims, so any vertical oscillations are pretty minuscule). Anyway, this is the point where his left
    hand has nearly completed its pronounced push back, his right hand is extended maximally forward, he
    has ceased his kicking (so his muscular legs and thighs have started to drop, relative to his
    pelvis/butt, which remain right at the surface), and his head and shoulders have dropped down from
    the position where they had been previously elevated, owing to the coincidence of the strong right
    hand pull, three brisk leg kicks, and head tilt/lift.

    Anyway, I think that the captured image shows the continued pronounced arch to his lower back, which
    he never loses. Again, it is easiest to keep the butt up at this point in the stroke, because there
    is no leg sinking ("Miller"😉 torque being applied, because there is no
    forward-of-the-center-of-buoyancy pulling going on. His butt appears to be more prominently upward
    because his lower back arch is less extreme at this point than when he is tilting his head forward
    and his thighs and legs are falling below his pelvis, because he has stopped kicking.

    weisenthal.orghackett.bmp

    wider angle view of the same thing at

    weisenthal.orghackett.jpg

    Larry Weisenthal

    Certitude is poison; curiosity is life

  18. -- 3rd try...keep posting the wrong URL 🙁

    Images of Grant Hackett:

    (top frame) at 12:40.7 of his Olympic gold medal 1500 swim

    (bottom frame) at 12:41.3 of his Olympic gold medal 1500 swim

    weisenthal.orghackett2.htm

    I'm going to try again.

    This doesn't have to be viewed as a "battle" between pro-"TI" and anti-"TI" forces. It's really just
    to address a single, isolated problem in swimming.

    The problem is the universal tendency of the pull to sink the hips (in retrospect, I wish that I'd
    titled this thread "hip" sinking torque of the pull, as this would be more accurate. What the kick
    accomplishes is to elevate the legs, relative to the hips/pelvis, in people with heavy legs (men
    much greater than women). What body position (i.e. "balance"😉 accomplishes is to keep the hips
    (pelvis) elevated, which is the number one key to streamlined ("fish like"😉 swimming.

    The purpose of showing the Laughlin images wasn't to compare Terry with Grant Hackett (a hugely
    unfair comparison; I don't want anyone comparing ME with Grant Hackett...or with Terry Laughlin, for
    that matter). It was simply to compare Terry with himself. I think that the images show that his
    hips do sink when he pulls. If you don't think so (possibly because some of you are more gifted in
    spatial relationships or architectural perspective or whatever), then maybe I should have found a
    more clear cut example. If anyone doubts the hip sinking torque of the pull, then just get the
    smallest pullbuoy which barely floats your hips/pelvis, tether your ankles, then start to pull and
    note the position of your hips during the pull as opposed to when you are streamlined but not
    actively pulling. This was similar to the exercise originally described by Miller, which preceded
    Yanai's published paper by a couple of months.

    I've also been noting (for years) that some of the world's greatest swimmers prominently tilt their
    heads forward and raise their heads coincident with the strong side pull. I've explained how, in the
    presence of an arched lower back, this has the effect of raising the hips and, thus, when executed
    synchronously with the strong sided pull, has the effect of counteracting the leg sinking effect of
    the pull. I described a very simple (and, I think) persuasive exercise to convince anyone
    sufficiently motivated to try it that raising the head in the presence of an arched back actually
    does raise the hips.

    I think that the top and bottom Hackett images (link provided above) provide a beautiful mental
    image of this.

    The top and bottom images are 0.6 seconds apart on the original NBC videotape (official race time
    stamps are on the uncropped images).

    Note the body positions relative to the lower (blue) lane line. You can see, I think, that the
    position of the pelvis and butt, relative to the blue lane line beneath, changes very little, if at
    all. Now look at the position of Hackett's head and back, relative to the same bottom blue lane
    line. If anyone doubts the accuracy of my description of Hackett as having a marked head tilt and
    head lift, I hope that these images will put those doubts to rest. This is what Janet Evans does,
    what Diana Munz does, what Peter van den Hoogenband does, what Jason Lezak does, and what many
    others of the world's fastest swimmers do. No one teaches them to swim this way (quite the
    contrary), but they do it for reasons I've described before and they keep doing it because it works.

    The way to improve "TI" is to counteract the hip sinking torque of the pull, by arching the lower
    back and increasing this arch during the early stages of the pull by tilting the head forward, to
    look ahead, just before turning the head to the side to breathe. Once you start doing this, it will
    gradually become more prominent and, with time, you may even begin to develop a bit of a head lift.
    You'll start swimming like the greats and your body position will never have been so good.

    Easy, simple, common-sensical, even. Inconsistent with conventional wisdom and sacred cows, but
    entirely consistent with that which is all around us, in the world of elite competitive swimming.

    Larry Weisenthal

    Certitude is poison; curiosity is life

  19. Oh, phooey. I posted the two Hackett images, 0.6 seconds apart, stacked on top of each other at

    weisenthal.orghackett2.htm

    I can view this the way it is supposed to by using MS Word, but not consistently with the built in
    AOL browser. I'm worried that others may have trouble also.

    Here are the two images, to be viewed separately (not nearly as informative as viewing them stacked
    upon each other for direct comparison):

    weisenthal.orghackext.bmp

    weisenthal.orghackpull.bmp

    I'll try and figure it out tomorrow and re-post it on my website, if I'm able to get it right.

    Larry Weisenthal

    Certitude is poison; curiosity is life

  20. O.K. I FINALLY got the images to display correctly, stacked one over the other.

    weisenthal.orghackett2.htm

    To review:

    The problem is the universal tendency of the pull to sink the hips.

    I've been noting (for years) that some of the world's greatest swimmers prominently tilt their heads
    forward and raise their heads coincident with the strong side pull. I've explained how, in the
    presence of an arched lower back, this has the effect of raising the hips and, thus, when executed
    synchronously with the strong sided pull, has the effect of counteracting the leg sinking effect of
    the pull. I described a very simple (and, I think) persuasive exercise to convince anyone
    sufficiently motivated to try it that raising the head in the presence of an arched back actually
    does raise the hips.

    I think that the top and bottom Hackett images (link provided above) provide a beautiful mental
    image of this.

    The top and bottom images are 0.6 seconds apart on the original NBC videotape (official race time
    stamps are on the uncropped images).

    Note the body positions relative to the lower (blue) lane line. You can see, I think, that the
    position of the pelvis and butt, relative to the blue lane line beneath, changes very little, if at
    all. Now look at the position of Hackett's head and back, relative to the same bottom blue lane
    line. If anyone doubts the accuracy of my description of Hackett as having a marked head tilt and
    head lift, I hope that these images will put those doubts to rest. This is what Janet Evans does,
    what Diana Munz does, what Peter van den Hoogenband does, what Jason Lezak does, and what many
    others of the world's fastest swimmers do. No one teaches them to swim this way (quite the
    contrary), but they do it for reasons I've described before and they keep doing it because it works.

    The way to improve "TI" is to counteract the hip sinking torque of the pull, by arching the lower
    back and increasing this arch during the early stages of the pull by tilting the head forward, to
    look ahead, just before turning the head to the side to breathe. Once you start doing this, it will
    gradually become more prominent and, with time, you may even begin to develop a bit of a head lift.
    You'll start swimming like the greats and your body position will never have been so good.

    Easy, simple, common-sensical, even. Inconsistent with conventional wisdom and sacred cows, but
    entirely consistent with that which is all around us, in the world of elite competitive swimming.

    Larry Weisenthal

    Certitude is poison; curiosity is life

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