The Biomechanics of Strength 3: The Squat (Part 2).

In part one of these guides to squatting mechanics, we dealt with some of the basic principles that people should employ in order to squat safely and effectively, especially in relation to how the knee in particular is loaded. In this follow up article, we are going to take a look at how performance of the squat can influence loading and muscle activation patterns across the joints of the ankle, hip and spine and how dysfunction in movement at these joints can impair squat performance.

Hip mobility and muscle activation is extremely allowing for completing a proper squat, especially at higher knee flexion angles. Recruitment of the big muscles around the hip, especially the glutes, is essential for anyone looking to maximise their squatting strength. A common occurrence in those with poor hip mobility and muscle activation patterns is the generation of abnormal pelvic movement which can increase stress through the lumbar region of the spine, increasing risk of injury. Flexibility training specific to the muscles around the hip/pelvis is a quick and effective way to increase hip mobility and facilitate better and safer squat mechanics.

The spine is commonly injured as it is vulnerable during the squat if proper spine stabilisation does not take place, especially the lumbar region. The spine is capable of handling compressive forces well, but shearing forces have an increased risk of injury. For this reason, the lumbar spine should maintain as neutral a position as possible, and this can be achieved through focussing on engaging the big muscles of the back, including the lats which span the spine. Maintaining a ‘tight’ back will also help fix the bar position; it is important to note that the bar should be pulled into and held in position by retracting the shoulder blades (you should feel the back muscles engage) and not just pulling with the arms. Under no circumstances should the bar just be resting on the back with heavy squatting because as the hips start to flex forward, this is likely to translate into curvature of the upper back and severe rounding of the lower back. The spine is mobile at each joint to a point, but excessive spinal movement can lead to shearing forces being generated in the different segments of the spine. Although, some tilting forward may occur during deep squatting, especially during low bar squatting, which is an attempt to maintain the bar over the most efficient bar path, directly over the mid-foot where our balance and point of application are at their most efficient. Even in this situation, efforts should be made to keep the spine in as neutral position as possible. If spinal position cannot be safely maintained then the use of strengthening exercises to improve both muscle strength and activation, such as good mornings, can be effective accessory exercises to improve the squat

Bar position can also have a big influence with how much forward lean we need to maintain the bar over the centre of our base of support. In a high bar squat, the bar should be pretty close to being over the centre of our base in our starting, standing position. This means that typically in a high bar squat we can start the squat by flexing the knees first and keeping the upper body in a more upright position, creating a relatively long moment arm from the knee to the path the bar travels, and this means that the quads are going to be performing most of the work through the entire range of motion, with the glutes being brought in later on in the movement as we approach large knee flexion angles.

In the low bar position, we typically have to start the squat by tilting the hips first before flexing the knees, and this is because as the bar is posterior to our base of support at the start position, we need to lead with the hips to keep the bar over our base of support and generate the most efficient bar bath. This positon shortens the moment arm from the knee to the bar path and increases the loading away from the quads to the bigger muscles of the glutes. This need to flex the hips and shoot the glutes backwards shifts the point of loading in such a way that the glutes and hamstrings are recruited much earlier in the movement, causing lengthening of these muscles and that of the lower back much earlier in the squatting movement than a high bar squat; which in most people, this leads to a decreased range of motion, but the capacity to handle more weight and these factors cause the familiar ‘folding’ often seen with low bar squatting.

The main factors that will determine the bar position you use are related to an individual’s skeletal structure (including shoulder mobility, as a low bar position can be difficult to achieve pain free for some people), their dominant muscle groups and of course the goals of the squat, whether this be maximum strength, targeting of specific muscles for development or if these are in line with performance, goals for other sports. For example, Olympic weightlifters will generally high bar back squat or front squat as this is the position most transferrable to the movement demands for the clean and jerk.

Lack of mobility at the ankle can also have a profound effect on squat performance. From an injury prevention perspective, one key rule of squatting is that, from a frontal view, the feet should be positioned in a stance that allows the knees to be maintained over the toes (we covered this in a bit more detail in part one!) To enable this, most people will need to keep their feet rotated slightly outward at an angle of around 10 degrees. A good indicator that ankle mobility is not optimal is the heels attempting to lift off the ground during the squat (although there can be other reasons for this). There are two main ways to counter this: Firstly, working on ankle mobility, in particular stretching the Achilles tendon and the muscles around the ankle, allowing the ankle to move into a greater range of dorsiflexion, the anatomical term for the foot moving towards the body. Secondly, the use of weight lifting shoes with a wedged heel can also ‘open up’ the ankle joint, allowing for increased range of motion during the squat. Some people may use plates or blocks under the heel to diagnose this issue, however we strongly recommend against using these to help in working sets as these can be unstable, especially in trainers with a thick, springy sole. Squatting should be performed in shoes with a solid, relatively rigid sole. Running shoes or cross trainers would NOT be recommended, especially for heavy squatting.

Despite anecdotal evidence that the stance width and changes in foot position can be adjusted to target different muscle groups within the quadriceps, this has not been supported with measurement of muscle activation patterns. We suggest that stance width and foot position for heavy squatting should be where you feel the most comfortable to squat to an appropriate depth, maintain balance and have the strongest base of support.

In summary, your squat technique will be determined on individual structure, strengths and weaknesses and of course, your overriding goals. However, there needs be an awareness of some key guidelines that will help you squat safely and how movement dysfunctions at the joints of the body may be impairing your performance. So, if you struggle with a squat, the best piece of advice we can give is to get a trained eye to look at your squat and design a program to help you improve the individual weaknesses that might be holding you back, including mobility and strengthening of the key prime movers involved in the movement. On a final note, despite all of this, it is possible that some people will still not be able to squat as deep as others, and ass to grass squatting may not be just difficult, but impossible for some people, and this is a topic for another time. However, squatting to ‘depth’ as we defined it in part one (please go give that a read!) with a decent amount of weight, should be achievable for a vast majority of people with proper coaching, programming and a little bit of patience.

Thanks for making it this far,

Team TTC.