The “butt wink” is a colloquialism for when the pelvis tucks under at the bottom of the squat. Research indicates that allowing the lower back to go into flexion makes it is more difficult to avoid staying out of flexion in other movements (i.e., butt winks before deadlifts could be dangerous). The rounding of the lower back can also aggravate pain and lead to injury.



The pistol - or one-leg squat - is even more complex given that holding the free leg upward often leads to more lower back rounding. So is it okay to let the lower back round in pistols but not in squats?


Breaking Muscle Shop

As with most discussions there is no one right answer. People have different anatomies, mobility, and strength levels. There are people who can do pistols with little lower back rounding (see the photo of Alanna below). Many of us are on the path of perfecting our movement patterns, but we have some rounding in our pistols. So, let’s look at the good, the bad, and the ugly of rounding the lower back in pistols.


The Good

In the video below, StrongFirst instructors Karen Smith and Mike Hartle, discuss why it is okay to let the lower back round in a pistol and not in a squat. A weighted squat carries a much higher load on the spine, which can cause damage when the spine flexes (rounds). But a pistol has more load in the front and if tightness is maintained in the midsection, the back is protected.



Renowned lower back researcher Stuart McGill suggests that starting in a flexed (rounded) position and ending in the same flexed position is better than allowing the spine to flex at the bottom. It is the changing position at the bottom that causes the most damage (probably related to not holding a tight midsection to protect the spine). If you were to start a pistol in a tight (hollow hold-like) position and maintain it throughout, it might be “good.” In the video above, you can see Karen Smith generate tension before she starts her pistol movement.


The Bad

Ryan DeBell, in the video below, describes the double standard we hold for pistols and squats. Pistols done for movement training are different than pistols done for conditioning. Training to do proper pistols can be beneficial for building stability, mobility, and strength:


  • Stability is built because you have to counteract the rotational movement (if the arch collapses) and the valgus knee (the knee collapsing inward).
  • Mobility can be built using this pattern due to the required ankle dorsiflexion and the hamstring flexibility needed to lift the passive leg).
  • Strength is built in the active leg, but the hip flexors must also be strong to hold up the passive leg.


The “bad” comes in when people move from practicing the pistol as a movement pattern (building the skill) and start using it for conditioning. Probably one of the biggest issues with any high-intensity program is when people use movements that are not properly patterned with high reps and/or high weights.



The Ugly

A 1996 study by Michael Adams and Patricia Dolan found that five minutes of repeated rounding of the low back led to a seventeen percent reduction in the ability to stay out of flexion. Thus, if you were to do pistols (with a rounded back) followed by deadlifts, you would have less ability to hold your lower back in position. Repeated rounding in pistols and squats can reduce your ability to round in other movements where it might matter more.


What to Do

There is no quick fix to perfect the pistol. Rather, you must treat the movement as a skill. Skills take time to develop. Here are three keys to getting into a better pistol position (there are many progressions to learning the pistol, but these are keys to staying in a good position):


  • Key #1 Abdominal Tightness - The first key to protecting the back in a pistol is to learn how to create tension in the abdominal region. Last week, we discussed the one-arm pushup. The same techniques of tension can be applied to the pistol. Learning to build tension in the plank will help brace the back in the pistol. Dan John’s goblet squat can help teach you how to remain upright with proper bracing.
  • Key #2 Counterweighted pistols - A counterweighted pistol will allow you to get in a more upright position as your body will not have to bend forward as much to balance. A small kettlebell (12-16kg) or plate will work. As you use the counterweight make sure you stay tight (key #1). (Thanks to Brett Jones for this idea.)
  • Key #3 The Intangibles - As mentioned above, individual differences in anatomy will change the way you squat and do your pistols. You will need to figure out what you need to mobilize to get into better position.



Problem Spots

There are two areas where we usually see problems in the pistol - ankle mobility and hip mobility. If you put one foot up on a box or table, you can stretch the hip and the ankle. While you do this stretch, make sure you keep your low back from rounding. Think about your pelvis keeping an anterior tilt (if you aren’t sure what an anterior tilt is, it is the last movement in the Three Amigos salute). 


"Your goal is to feel comfortable in that upright position without feeling like the top of your thigh is getting pinched into position (technically speaking, we want the head of the femur to smoothly move in the hip socket)."

If you can lean the knee forward over the toe (without the heel rising) then you probably have sufficient ankle mobility. If you do not have this ability, your lower back will probably round to act as a counterbalance and you may fall over backward when you attempt pistols in a good position.


If your ankle mobility is good, then you can work on your hip mobility by finding taller boxes and tables. Your goal is to feel comfortable in that upright position without feeling like the top of your thigh is getting pinched into position (technically speaking, we want the head of the femur to smoothly move in the hip socket). If you feel that pinching, then pushing down on the top of the thigh can help make more room in the hip joint.



Is the butt wink okay in the pistol? It probably depends on your intentions behind using the movement. If you are doing pistols for conditioning, the butt wink is to be avoided as teaching your body rapid flexion will not be good when your back needs the support. You can see this illustrated in this CrossFit Games event where pistols are followed by deadlifts.



But for building the skill of pistols, a little rounding of the back makes sense. The pistol can also be a great way of training hip stability, which is also useful for avoiding valgus knee caving. Thus, rounding in the back is okay for training pistols, but until the proper movement pattern is achieved it should not be used for conditioning.


Note: Special thanks to Brett Jones and Ryan DeBell for their helpful thoughts.


More Like This:


1. Adams, M. A., and P. Dolan. “Time-Dependent Changes in the Lumbar Spine’s Resistance to Bending.” Clinical Biomechanics (Bristol, Avon) 11, no. 4 (June 1996): 194–200.

2. Demoulin, Christophe, Vincent Distree, Marco Tomasella, J.-M. Crielaard, and M. Vanderthommen. “Lumbar Functional Instability: A Critical Appraisal of the Literature.” In Annales de Réadaptation et de Médecine Physique, 50:677–84. Elsevier, 2007.

3. McGill, Stuart M., Richard L. Hughson, and Kellie Parks. “Changes in Lumbar Lordosis Modify the Role of the Extensor Muscles.” Clinical Biomechanics 15, no. 10 (2000): 777–80.


Photo 1 courtesy of Craig Marker.

Photo 2 courtesy of Ryan DeBell.