Butt Wink- Is it an Issue?

Butt wink – What it is, what are the possible causes and how can it be solved.

I have recently started to coach again since I left the military at a great place in Nottingham called Sanctuary Fitness and Conditioning. It has been great getting back to coaching and helping people towards their fitness goals. I have observed some movement patterns that would be considered an increased risk of injury, but in particular the movement termed “Butt Wink”. During this article, I want explore the term butt wink and what we can do to reduce this.

What is a butt wink?

The ”Butt Wink” or in its correct terminology is a posterior tilt of the pelvis at the bottom of the squat position. In essence the pelvis tucks and creates a flat back or flexion of the lumbar region of the spine (3). It is suggested that this movement can increase the risk of injury, but it is also suggested that under lighter loads this is fine (3). We need to contextualise this, poor movement patterns are fine and are safe, however, if we conduct poor movement patterns under heavy loads there is an increased risk to injury. The spine has be made to flex, extend, rotate and laterally flex with no issues. The issue arises when a spine is moved into a position that it is not used too or moving into a position too fast, the mechanoreceptors in the tendons and muscles get alarmed and try to protect the body from injury. This area of interested may be covered at another time, let’s focus on the butt wink for now.

When we consider Olympic Weightlifters, on stage at big events, we sometimes see them catch a heavy load with poor mechanics and still finish the lift with no injuries. Firstly, they will be close to their maximum lifting capacity so form, in some cases may not be perfect. They only get to these loads at competitions, in training these lifters are normally between 60-80% 1 Rep Max (RM) (8). They conduct a lot of mobility, so they can move into positions that may be deemed bad positions without injury. For the general public it would be advisable not to be in these positions.

What are the risks?

It is suggested that during the butt wink movement the anterior part of the vertebrae can be depressed, creating compressive force on the intervertebral disc, in turn increasing the risk of a herniated disk. If this movement is repeated over time the risk of injury increases even more. It has been suggested that a half-squat loaded with between 0.8 to 1.6 times bodyweight, produced compressive forces in the lumber region of the spine, equating to 6 to 10 times bodyweight (1). Adams et al., (2), mentions that the ultimate compressive strength in individuals 40 years and younger is estimated to be approximately 7,800 N. So reality, some strong individuals could be creating compressive forces beyond 7,800 N but not see failure of tissues occur. It is suggested that failure does not occur due to the individuals spine adapting to the mechanical stress and increasing tolerance to the compressive forces (2). It has also been inferred that squatting in a flexed lumbar spine transfers the forces from the supporting muscles to the passive tissues increasing the risk of disc herniation (3).?

How can it be solved?

It has been suggested that there are various causes to the butt wink, these range from weak gluteal muscles, reduced ROM (Range of Motion), instability and finally poor set up position before the descending into the bottom squat position (3). It would be beneficial that a movement assessment would be needed to identify the actual cause of the poor mechanics. However, that said a number of solutions have been recommended, such as bracing creating intra-abdominal pressure (IAP), focusing the direction of gaze to either straight ahead or slightly upwards and finally reducing the depth of the squat (4, 5, 7). In the case of weak gluteal muscles, glute activation exercise prior to each set can help, such as glute bridge hold or crab walk during warm-ups. From experience, widening the stance width may also help, which increases the involvement of the gluteal muscles (3).

Summary

The butt wink movement should not be considered a huge issue when the individual is not heavily loaded, but consistent movement of this nature under heavy load increases the risk of injury especially if the body is not conditioning to being in this position. There are some solutions but it would be suggested that have a number of them, to see which one suits you the best, or maybe a number of them will help reduce the butt wink. However, it would be advised that a movement assessment would identify the root cause or causes of the butt wink.

References

1.????Cappozzo, A; Felici, F; Figura, F; and Gazzani, F. Lumbar spine loading during half-squat exercise.?Med Sci Sports Exerc?17: 613-620, 1985.

2.????Adams, MA; May, S; Freeman, BJ: Morrison, HP: and Dolan, P. Effects of backward bending on lumbar intervertebral disc: Relevance to physical therapy treatments for low back pain.?Spine?25: 431-437, 2000.

3.????Schoenfeld, BJ. Squatting kinematics and kinetics and their application to exercise performance.?J Strength Cond Res?24: 3497-3506, 2010.

4.????Vakos, JP, Nitz, AJ, Threlkeld, AJ, Shapiro, R, and Horn, T. Electromyographic activity of selected trunk and hip muscles during a?squat?lift. Effect of varying the lumbar posture.?Spine?19: 687-695, 1994.

5.????McGill, S, Norman, RW, and Sharatt, MT. The effect of an abdominal belt on trunk muscle activity and intra- abdominal pressure during?squat?lifts.?Ergonomics?33: 147-160, 1990.

6.????Miyamoto, K, Iinuma, N, Maeda, M, Wada, E, and Shimizu, K. Effects of abdominal belts on intra-abdominal pressure, intra-muscular pressure in the erector spinae muscles and myoelectrical activities of trunk muscles.?Clin Biomech?14: 79-87, 1999.

7.????Donnelly, DV, Berg, WP, and Fiske, DM. The effect of the direction of gaze on the?kinematics?of the?squat?exercise.?J Strength Cond Res?20: 145-150, 2006.

8. Gonzalez-Badillo, JJ; Izquierdo, M; and Gorostiaga, EM. Moderate volume of high relative training intensity produces greater strength gains compared with low and high volumes in competitive weightlifters. J Strength Res 20: 73-81, 2006.