I’m sure you’ve heard the phrase on the gym floor or in a group exercise class “keep your knees behind your toes” while squatting. As a fitness professional it aggravates and puzzles me why this is such a wide spread and accepted myth among gym goers. I understand it comes from a place of care because they want to avoid injury but their worry is misplaced because there are plenty of other gym myths that are much worse for you that people do on a daily basis.
First I’ll explain the reason people say this so much. What they are trying to avoid is patellar tendonitis and this inflammation of the tendon in the knee. People believe when your knees come far past the toes that puts to much stress on the knees to handle. Or what could be the case is trying to avoid poor squat mechanics however I know the average gym goer does not know that so I feel this idea is less so.
I understand the reason why someone originally said this though and that’s because many peoples first movement when they perform a squat is to shoot their knees forward. And thus the cue “keep your knees behind your toes” was born however what it really should be is “initiate the movement with pushing your hips back”. If your first movement during the squat is at the knee joint you're immediately going to be off balance.
An extremely important and often overlooked part of the squat is balance. There are really few absolutes with squatting because many things depend on individuals body types but you must always keep your center of gravity over the middle of your foot. If your first movement in the squat is at the knee joint you will only be able to keep your center of gravity over the middle of your foot for so long until your heels come off the ground.
Once your heels come off the ground forget about balance or being able to squat any kind of weight. You want to be pushing through the middle of your foot and you should even be able to wiggle your toes at the end ranges of motion of the squat.
Now that we’ve identified the issue how do we fix it? We need to practice sitting back into our squat and many people aren’t comfortable with doing that. To help, you can practice box squats and you do exactly as the name says, sit on a box. Now at this point you will get to a certain depth that you will have to bend your knees to keep your center of gravity in the middle of your foot. This is okay for your knees to come forward at this point and they might even come past your toes if you are doing deep squats. In fact if you are doing “ass to grass” squats I guarantee your knees will come far past your toes but this is really great for strengthening not only your muscles but also the connective tissue like bone and ligaments. Many people believe that deep squats are detrimental to your joints but really it’s the opposite. If you never work in these ranges of motion you will lose the ability to get there and have an increased chance of arthritis setting in when you get older.
The big takeaway from this whole article is that you should be concerned of when the knees past the toes not if they do so. Also do not be satisfied with limited range of motion squats. Work on your ankle and/or hip mobility until you can get to those “ass to grass squats” because that is the most functional. First thing to go is mobility, I have several older clients who are extremely limited in their mobility and it makes it tough to get around in daily life but also complicates the way you train.