Date: 10th January 2019
Author: Mark Wood & Chris Wood
“Make sure your knees don’t go over your toes when you squat”
This common myth is becoming more and more prevalent in the health and fitness industry and today we will be picking it apart.
The most common issue attributed to allowing the knees to move forward over the toes is that it puts too much strain on your knees and makes you more prone to knee injuries. So far, only ONE study has found a relationship between squatting and potential knee injury, and that study was published over 50 years ago (Klein, 1961). Thankfully, research has since moved forwards and here is what we know now…
1) It is true that when your knees travel forwards over your toes there is an increased rotational force (torque) and shearing force placed on your knees
2) In healthy people, these forces are greatly BELOW your bodies capabilities; meaning your knees can handle it (Fry et al, 2003)
Those with existing knee injuries whom are currently undergoing physiotherapy may have found themselves prescribed some form of exercise where movement of the knees over the toes are restricted, such as in a ski squat (Figure 2).
In early stage rehab, injuries particularly to the patellofemoral joint may include such exercises in order to maintain regular load on the quadriceps muscle group, but also reduces the loading of the tendons and supporting ligaments. This is also because the patella makes greatest contact with the femur when at 90 degrees of flexion (Figure 3), carrying an estimated force of 6.5 times bodyweight through the joint. Anything passed this in early stages will cause increased irritation to existing symptoms. Later stage rehab will involve more functional exercises.
Traditionally, there are 3 main forms of squatting; 1) High Bar Back Squat, 2) Low Bar Back Squat, and 3) Front Squat. The high bar back squat has become the most commonly used by gym goers, with the cue given to ‘rest the bar across your trap muscles’.
As with any exercise, we must keep our centre of gravity within our base of support. If not, we will lose balance and fall over. Once the bar is placed on your back, this then becomes your new centre of gravity, and must stay within your base of support at all times (Figure 4)
As you can see in Figure 5 (Image B), as we begin to descend into the squat, restricting forward knee movement would mean that the bar / your centre of gravity will be forced backwards, causing an excessive forward lean of our torso to bring the bar back into the centre. It has previously been reported that an increased forward lean is linked to greater forces applied on the lower back (Russell and Phillips, 1989), so it then becomes important to take into consideration what is happening to your lower back when you restrict your knee movement.
When compared to Figure 5 (Image A), the forward movement of the knees allows for a more upright posture to be adopted. While this does place greater stress on your knees, as previously mentioned, the ‘solution’ most people tend to find by leaning forward too much ironically directs the stress into your hips and lower back. At this point it becomes imperative to find an optimal position for each individual in order to avoid unnecessary stress at either region.
If we go back to the study linking knee injury to squatting (Klein, 1961), the problem lies with the very first movement of squat. Figure 5 demonstrates how beginning the squat by pushing the knees forwards FIRST shifts our centre of gravity forward and makes us unbalanced. The same rule applies if we begin the squat by pushing the hips backwards first, pushing our centre on gravity backwards and again making us unbalanced. Whereas cueing movement of the hips and knees simultaneously, and movement of the hips down as opposed to backwards ensures better positioning. This not only keeps you balanced, but it also allows for a deeper squat as you afford yourself greater available range of movement at the ankles. The main focus when assessing travel of the knees in a squat should be when the knees move over the toes and not if.
1) All about the Hips and Ankles. Look at what joint moves first and where the weight is relative to the base of support. Ensure they move at the same time with the hips going straight down, not back.
2) Even though increased force is applied at the knees when over the toes, healthy knees have the capacity to handle it.
3) Aim to keep an even distribution of weight between hips and knees; avoid placing excessive stress at either joint
4) Remember the movement cues
Fry AC, Chadwick Smith J, & Schilling BK. Effect of knee position on hip and knee torques during the barbell squat. JSCR. 2003; 17(4): 629-633
Horschig, A & Sonthana, K. (2016). Can the knees go over the toes?.Available: HTTPS://SQUATUNIVERSITY.COM/2016/01/29/CAN-THE-KNEES-GO-OVER-THE-TOES-DEBUNKING-SQUAT-MYTHS/. Last accessed 2nd Feb 2018.
Klein, K.K. The deep squat exercise as utilized in weight training for athletes and its effect on the ligaments of the knee. J. Assoc. Phys. Mental Rehab. 15:6–11. 1961.
Russell, P.J., & Phillips, S.J. A preliminary comparison of front and back squat exercise. Res. Q. Exerc. Sport 60:201–208. 1989.
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