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Squat Biomechanics: Butt Wink – What is it, What Causes it, & How Can it be Improved?

“Butt wink” is a common issue for the majority of squatters. But what exactly is butt wink, what causes it, and can it be improved? If so, how?

Proper Spinal Alignment

Proper Spinal Alignment

In the video below, you will learn:

  • The biomechanics of squatting pertaining to the lumbopelvic hip complex (click HERE to see another video on the biomechanics of the LPHC during other exercises such as the hip thrust and back extension)
  • Length changes in two-joint muscles during the squat (hamstrings and rectus femoris)
  • The importance of ankle dorsiflexion mobility to prevent low back rounding (click HERE to read how limited ankle dorsiflexion causes knee valgus as well)
  • How anatomy influences hip mobility
  • Why motor control and not just hip flexibility is critical for optimal performance
  • Why properly functioning glutes are critical in the squat (click HERE to read why they’re critical in a lunge as well)
  • Why daily goblet squats are a good idea (click HERE for a good article and video on goblet squats)
  • Why rock-bottom full squats aren’t for everyone (click HERE to read more about proper squatting technique)


  • Shawn Fears says:

    I was just listening to a podcast interview with McGill in which he was talking about “the Scottish hip”. Good stuff as usual Bret.

  • Great video Bret. Individual differences in structural make up certainly play an often overlooked role.

  • JR says:

    “Why properly functioning glutes is critical in the squat (click HERE to read why their critical in a lunge as well”


    You must’ve been sleepy when typing that one up 😉

    Great video, Bret!

  • uros says:

    very good post (like always). Thanks.
    Can you (if you didn’t) write something about squat asymmetry.
    A lot of people have this problem. Especially athletes from asymmetric sports.
    This picture show what I’m talking about (I found it on web).

    • J.J. says:

      Agree on this one!!

    • david says:

      This is a common problem with glute medius weakness. In your picture the gentlemen seems to have a weak left glute medius. The glute medius is a hip stabilizer and its action is hip abduction.

      You would have to test his left glute medius by either repetitive hip abductions or trendelenburg test.

      Get patient to do clams and monster walks to help strengthen the gluteus medius and this will help correct this asymmetry.

  • Allison says:

    Great video Bret!! If you butt wink at the bottom of your squat( not excessively)and you think it is possibly due to bad ankle mobility would you suggest to put plates under your heels then or just work or just work on flexibility ?? I tried it and it made a world of a difference in the ease of my squat!! Crazy!!

    • Bret says:

      Do both Allison. Work on ankle dorsiflexion mobility daily and do a set of goblet squats right afterward to help “cement” the mobility gains and blend them into your movement patterns. But when you squat heavy, use plates, at least for the time being (perhaps down the road you won’t need them but maybe you always will). Good question!

      • Allison says:

        Thanks!! I noticed after elevating my heels I’m feeling my squat a lot more in my quads now and not as much in my glutes as before with my “normal” squat. Hmmm.

  • patrick says:

    thanks coach!

  • will says:

    Bret ,

    You are the man.

    I am glad that you addressed ” anatomical ” differences in people’s hips. So often you read the Muscle and fitness, muscle rx , poliquin, and all the other b.s. magazines say that if you are not going ” ass to grass” then you are p*ssy and might as well not squat at all.

    Some people have different torsion angles at the hip that affects range of motion.
    – Excessive anteversion: torsion angle greater than 15 degrees
    – retroversion: torsion angle less than 15 degrees.

    I think the best advice to give some one is to maintain a neutral spine as long and as deep as you can and pain free. Don’t force range of motion. Over time let them naturally create more range of motion. Maybe even throw in daily squatting like you suggested in a blog post last month.

    Thank you for the video.

  • Kyla says:

    Thanks Bret and skelly! This was a great video. I used to have butt winking issues and after trying a lot of things I started working on my glutes more (following a lot of what you do and say) with heavy kb swings, heavy back extensions and more recently hip thrusts ( following strong curves). I also went back to basics and did/do tons of goblet squats and lighter weight than previously to perform the squat properly. This has helped so much and now I am not winking. Using skelly helped a lot to see how ankle mobility affects the spine at the bottom of the squat. I am interested next to see if I can get my squat lower. What is good ankle mobility and how do I know if mine is bad?
    Thanks so much for the video!

    • Patrick O'Flaherty says:


      You can test your ankle dorsiflexion by measuring the distance in inches between the front of your toes (barefeet or socks only, no shoes) and a wall. After a general warm-up for the whole body and specific warm-up for the calves (don’t do this cold or you’ll get inaccurately poor results), stand facing the wall with a staggered stance. Start with the toes of your foot closest to the wall 1″ from the wall and your hands on the wall. Then flex your knees and without your heel raising off the floor, touch your front knee to the wall. Keep doing this in 1/4 to 1/2 inch increments until your heel comes off the floor. Then switch your stagger stance and repeat for the other leg. 4 inches is the minimum. Anything less is poor. Less than 1/2″ variance between your left and right side is acceptable.

      Hope this helps!

  • PJ says:

    Great detailed overview on the dreaded butt wink!

    Do you happen to have any research on the motor control aspect of this handy?

    I’m in a Motor Control class right now at AT Still so I’m especially interested in this aspect! 🙂

    Thanks for the great video

  • Maria says:

    Great video Bret and so timely for me as I’ve been focusing on trying to lose my butt wink.

    I have a short torso and long legs and have dropped back squats (for now) because I find it difficult keeping my torso up.
    I love goblet squats and have no trouble getting deep, after spending time in Asia I’ve adopted this style of squatting, BUT my butt does tuck under.

    Today I tried using some plates under my heels and while it helped significantly with my form, I did get a shooting pain in my left knee as I progressed through the set, needless to say I stopped but I haven’t experienced this sensation before when squatting….hmmm…this is my dominant leg and I often catch myself pushing through on it more…don’t know if that accounts for something but its another thing I’m trying to correct!
    Anyway, I’m working on ankle and hip mobility drills and unilateral exercises. Hopefully I can improve my squat.


  • J.J. says:

    Oh man – whatever you do turns out to be gold 😀

    Well, enough with the sweet talk 😉
    I got some questions!

    1) I am currently following your Strong Curves beginner-programme, and I am wondering how many sets of each warm up-exercise I should do?
    2) I feel my lower back is weak and my wrists are really skinny. I am thinking on working to improve it with isolation exercises, since it hasn’t really improved just with the other exercises. Which types of exercises will you suggest (maybe you can suggest exercises for the lower back that isn’t just isolation?), and how often and when in the Strong Curves programme should I do them?

    Thanks so much for Strong Curves – my butt is certainly kicking in 😀

  • Jon says:

    What about stretching the posterior capsule of the hip?

  • Nic says:

    I get butt wink when I squat, unless I purposely push my knees out or stand wider so goblet squats seem good for me. My ankle dorsiflexion is extreme, definitely no tightness there whatsoever. I have posterior pelvic tilt when I walk anyway and I’m not sure if glute exercises would be beneficial or a hinderance. My hip flexion (with knee flexion also) is around 130º, straight leg it’s around 85º with a lot of tightness in the hamstrings. I’m following a fairly standard program specifically for posterior pelvic tilt involving SMR of the hamstrings and glutes, stretches for the rectus abdominis, knee raises with neutral spine, and lying hip flexion with R-bands to help strengthen my flexors. I have incorporated glute exercises in my training in the past but was told by a trainer that working my glutes and hammies might be detrimental to my p-tilt. I have to admit when I do knee raises with anterior tilt afterwards my hips feel much more neutral but as the day goes on this disappears. Is it a case of conditioning my flexors and smr for the glutes or am I barking up the wrong tree? Thanks Bret.

  • Donald says:

    As a self taught personal trainer, some things I confront with my clients leave me confused. I want to do the best but sometimes I get stumped and I do research in order to make sure I get better as a trainer and service my clients concerns. This video has opened up a lot of information that I have been looking for. I thank you for your insight on what you consider important to your audience. Please keep up the great work and insightful information.

  • Martin says:

    This is fantastic. I have been doing an online personal trainers course and it has nothing like the information you have here. What you have done is to point out the “unknown unknowns” what we didn’t know that we didn’t know. It is scary that so-called professionals with a massive following still peddle nonsense because they are too lazy and proud to look for information and learn.

    I have one suggestion. Do you think it is a good idea to squeeze the glutes together as you get deeper in the squat to activate the glutes? The action of squeezing the glutes together seems to inhibit the lumbar spine from flexing and keeps the arch.


  • Gill says:

    Hi Bret

    Just so you know, you are the voice I hear in my head when training and doing squats, deadlifts, glute bridges, hip thrusts and just about everything now.

    Fortunately I like your voice and you say good stuff!

    Great post, as always and timely, I was just about to regress (again) a client with some butt wink- but as everything else is working well, I’m going to work in more ‘other’ squats and get some more ankle stretching/mobs going, see if we can fix it that way.

    Thanks- very sincerely

  • Jenn says:

    Hey Bret,

    Good stuff. I am a sufferer of the “Butt Wink”. This video was posted at our box’s Facebook page to help others. Arizona State taught you well 🙂

  • Kev says:

    Hi Bret,

    Thanks for taking the time to put out a very informative video. Any chance you can write an article / put out a video explaining the causes of a squat turning into a good morning?

    I have a few assumptions but would rather have an expert provide some clarity.


  • Roy Reichle says:

    Hey Bret;

    Great information here! Most, if not all, of my clientele are older and non-athletic, and so much of what they see in the various media is not suitable for them. In my studies as a trainer, I focused on anatomy and have been able to work better with these individuals as they struggle toward their goals. This video taught me a few new points and I am grateful. Keep up the good work!

  • Georganna says:

    Thank you for the visual!!! So helpful for us visual learners. I have always struggled with going deep into my squat. Now I have some great tools to keep in mind. Much appreciated. Anxiously awaiting the delivery of your “Strong Curves” book!!!

  • bert says:

    Because I didn’t hear you say it Brett. And no one in the comments.. What makes a big difference for me… Forgetting about the cue that is always given to me : Sit back !!! In the past I had that cue to much in my head !! Keep your knees behind your toes.. I learned that focussing on going back makes it so difficult. To much focus on the posterior. Make squatting more quads… From an biomechanical view it is impossible to keep your soine straight going past parrallel when you keep your knees strict behind your feet/toes. AND it is important to break at your knees before you extend your hips. That’s as important. Break at your knees.

    That made the differance for me. Strange at first because the stress is more on the quads and you’re much more compact in moving down and up. It’s much easier to stay straight-up.

    My point is equal to bretts point of “Dorsiflexion”.. Don’t let your tibia stay straight on top of your feet..

  • Daniel says:

    So after 3 years of back pain when squatting, it turns out I have a disc bulge. It’s not pressing against the spinal cord, but still there. Here is my form when body and barbell squatting. Got a slight butt wink, other than that, anything that could be causing the pain when squatting? if I hold something and pull myself forward when squatting, the back pain seems less.
    I foam roll legs and ITB, roll piriformis, am doing ankle mobility work. stretching. core work. not sure what else I can do. feels sore for days after too.

  • Dan says:

    A fairly lightweight question about the Scottish Hip. As someone of Scottish-Danish ancestry, my Cantonese girlfriend enjoys to laugh at my lousy squat.

    I won’t be using my ethnicity as an ‘out’, but how did my forebears manage to get down to poop? Or is it more than they could squat deep, but a bit rounded?

  • Stephen says:

    Great video. Really emphasizes the need to evaluate the entire kinetic chain. Can’t tell you how many times we have improved an athletes squat depth and form with increasing their ankle joint mobility or flexibility. Trent Nessler has some great ways to improve neuromuscular control of the limbo pelvic region if anyone is interested

  • Nice post, Bret, I absolutely agree with motor control as a necessity for improving squat depth and preventing butt wink. Shoving your knees out with feet forward allowing the combined motions of flexion and ext. rotation of the femur can help clear that anatomical block you speak of. Also, mobility exercises driving the femur posteriorly in the acetabulum can help to optimize joint position. One thing that is sometimes forgotten in my opinion, is the effect of load ordering on squat mechanics (Check this out for some more info: If the hamstrings and glutes aren’t loaded initially in the squat, motor control is lost and the ability to actively control the femur during the eccentric portion of the squat is lost contributing to butt wink. Good stuff man, thanks


  • Matt says:


    Excellent video, thank you so much for sharing. I was curious if you have had any experience with the Ultimate Sandbag Bear-hug Squat. I have a fairly prominent lumbar lordosis and the butt wink often shows itself at the end range of my deep squats. I was amazed at how deep I could get with flat feet and a neutral spine with this exercise.

    Keep ’em coming!

  • Andrew says:

    Re: Ankle dorsiflexion. Should we be focusing on Soleus and FHL more so than our gastrocs. (the gastrocs being bi-articulate shortens at the knee and lengthens at the ankle – just like the hamstring…)
    And how about simple glute tightness? Being uniarticulate, lengthening through hip flexion. If the individual does not have excessive hip external rotation to counter could this be a possible cause as well?

  • patricia says:

    this is a crazy response Bret but for me its kinda like when I do the jamaican booty shaking what they now try to call Twerking lol

  • Emma says:

    Brett, this has to be the BEST explanation of butt wink. I will be watching it over and over. Your grasp of anatomy and ability to translate it back in everyday speak is fantastic ! Thank you !

  • Deana says:

    Bret what is the importance in the position of your upper body when squatting? I have really long legs (35″ inseam) but a short torso so when I squat in order to keep my back straight and without butt wink or falling backwards my torso seems to lean forward quite a bit. I have had people tell me I need to pretty much be vertical with my upper body. HELP!!!! thank you

  • nick says:

    I have found that stretching my adductors, hamstringsand glutes while strengthening my lower back and hip flexors has helped me tremendously with maintaining back integrity at the bottom of the squat and my squats are now more powerful and comfortable. Posterior pelvic tilt at the bottom of a squat which results in butt wink and back pain is caused mainly by having tight or overly powering hamstrings, adductors and glutes vs lower back/hip flexors.

    • Bret says:

      Nick, did you watch the video? It’s not caused mainly by having tight or overpowering hamstrings. It’s mainly due to pelvic anatomy in my opinion.

  • James says:

    So it’s okay that the knee passes over the toes when you’re at the bottom of the squat to gain a deeper squat? If that’s the case I could have gone deeper this whole time.

  • Eva says:

    The beauty of the internet. Almost 3 years on since you put this out Bret and it’s still helping people. Your discription of the biomechanics of squating in this video with the help of skelly has just unveiled a whole load of mysteries on this move for me. Thanks a million for sharing your good work 👍

  • Karen says:

    Superb, logically-explained video – very helpful! Loved the skeleton which I found surprisingly helpful. Will have to find out more about ankle dorsiflexion as being non-weight bearing for 3 months (for severe knee fracture) has left my ankle quite inflexible. Thanks, Bret. I appreciate a lot of the helpful information on your site.

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