The ability to squat has different purposes for different people. For some, dropping the centre of gravity smoothly and easily enables safe lifting of a load at work, or effective agility and momentum control. For others it is a high load strength activity, which comes with its own entire canon of beliefs and approaches.
Regardless, if you are squatting, symmetry is a desirable factor.

Yesterday, a client came with the issue of her squat.

She had been training in the gym and noted that her trunk appeared to destabilise as she squatted. She described this as her spine shifting from side to side during the motion. She also had vague left knee symptoms associated with exercise.
On initial observation of the squat motion, the trunk did indeed shift during the motion, mostly in the frontal plane.

What was happening at the pelvis?

The pelvis drifted further towards the right side as the squat continued. The trunk was trying to accommodate that motion. In a squat, the pelvis should carry the trunk downwards, and in this case, it was not doing that effectively.

What was happening at the hips?

The left hip bent earlier and faster than the right, causing a rotational motion of the pelvis towards the left. This rotation created the counter motion of pelvic motion sideways to the right. Weight bearing was biased onto the left leg. The left knee was therefore coping with a combination of increased loading when compared to the right, while also being subjected to a rotational motion as the pelvis shifted across. No wonder it was grumbling.

So, is this a hip timing issue?

Certainly it can be, and this is something that we deal with frequently. The right anterior hip musculature could not easily release into a smooth bending action, creating a delay.
However, it wasn’t the whole story.
By stepping back to take in the whole picture, it was possible to see that the client’s start position involved rotation of her thorax to the left. Her left shoulder was sitting back and slightly down.
Try that for yourself – in quiet standing, turn your shoulders a little to the left, allowing the left shoulder to fall back. What do you notice happens in your hips?
In this case, the right hip was pulled forward as the shoulders turn to the left.
Experiment with dropping your centre of gravity from this position – can you feel how the left hip bends more easily and more deeply than the right? This was what the client was experiencing.
Interesting!
The solution was to ensure that the client started with her shoulders and hips square and aligned. She felt that this was a very strange position, however when she moved into the first part of her squat, she found that she could feel weight all the way through her right leg and into a grounded right foot. This reduced the loading on the symptomatic left knee, and created a level pelvic platform with which to support the trunk.
So what do we take from this?
Firstly, the trunk motion was merely a reaction from the body to what was happening underneath it. It did not require core stability training, and indeed was not “unstable”. Its undesirable motion was its attempt at a solution for accommodating the asymmetry below. In that sense it was really rather clever.

Secondly, focusing on keeping the pelvis straight was not going to work until the hip timing was sorted out.
Thirdly, changing the loading between legs required sorting out the mechanics above. Trying to consciously push weight into the right leg would only have achieved greater movement dysfunction.
Lastly, remember that just as the lower body sets up whatever it carries above it, so does the upper torso affect what is below it.

It’s all about the big picture…