Is passing your knees over your toes a knee injury waiting to happen or the strength building technique you need to prevent them? Let’s see together where the research takes us!
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Is it safe to allow your knees past your toes when you exercise? Most people will instinctively tell you no, that it’s dangerous or might hurt your knees. But is it really? If it’s dangerous to let knees past your toes in a squat, what about when you walk down the stairs? What about on the jiu-jitsu mat? It’s time we take a closer look at what that expression really means, where it originated from, and whether it’s advice we should still be following today.
When you squat, whether in the gym with a barbell or at home with your kids, you have the option to sit straight down, bending at the knees, or stick your butt back bending more at the waist. The former will require more work from the knees and quads, while the latter will ask more of the hips and glutes.
Both styles have a time and a place, and one is not inherently better than the other. However, over the past several decades, the idea has emerged that the more knee-dominant squat, where the knee is allowed to track forward past the toe, is unsafe, potentially injurious, and should be avoided. This article aims to examine where that claim originated from and whether or not that claim is supported by modern research.
The notion that squatting with a more aggressive shin angle could be potentially dangerous began with a 1978 study at Duke University whose findings were echoed by another study in 20031,2. Researches demonstrated that allowing the knees to travel forward past the toes in a squat placed 28% more load on the knee than a more vertical shin position. Fair enough. Greater load through a joint means greater stress and, potentially, greater risk for injury.
However, the same could be said for any major joint placed under load during exercise. Push-ups direct force into the shoulders. Deadlifts place large loads on the lumbar spine. Yet, both of these exercises are still staples of most basic fitness programs.
Why? Because stress is also the driver of adaptation. For anything but especially exercise, the entire premise of training is that we challenge the system with something it hasn’t done before or finds challenging. Then we remove that stress and allow it to recover, and the next time that same task is not quite as difficult. That’s how the body works.
Stress + Recovery = Adaptation
By removing the stress altogether, however, we eliminate the possibility of adapting to that stress and getting stronger. Then, our knees may actually be at risk. It should be noted that training knees over toes is not the only method of strengthening the knees. However, by avoiding that position entirely, we not only lose out on the potential benefit of that training stimulus, but we run into some unintended consequences as well.
The same study that showed a 28% increase in load through the knee also found a 1000% increase in stress on the lumbar spine when the knees were prevented from tracking past the toe1. That’s right, researchers saw a 10x increase in force through the lower back simply from adopting a more vertical shin angle. By trying to protect one area of the body, we inadvertently throw another under the proverbial bus.
And just think about how often you get into these positions in training. Try shooting a double leg without letting your knee past your toe; you’d look ridiculous. Training is going to get you into some pretty weird positions, and even if you don’t train just going downstairs, getting out of the car, picking your keys up off the floor, and countless other daily activities are going to result in your knee over your toe.
So not only is it impractical (if not impossible) to completely eliminate these scenarios from your life, the less equipped we are to deal with them, the more likely we are to get injured!
There is compelling research to suggest that it is the IN-ability to put your knee past your toe (ie. Ankle dorsiflexion) that is directly correlated with increased incidence of knee ligament injuries, including ACL tears3,4. Combine that research with a growing cultural stigma against squatting with the knees forward, and it provides possible evidence as to why the United States has seen such a sharp rise in knee injuries and knee replacements in recent decades compared to other countries5.
So what does this mean for all of us just trying to stay fit and enjoy our time on the mat without joint pain? Perhaps the solution is to become more equipped to handle these positions rather than avoiding them entirely. In the same way, you train your weakest submissions and sweeps extra, so they improve on the mat, you can do the same thing with your body.
The trick starts at a level you can do pain-free, even if that means using lighter weights than you’re used to or even putting the weights down altogether and using assistance. There is no such thing as starting too conservatively.
One of the best places to start is elevating your heels with a Slantboard, bumper plate, textbook (the thick ones that tell you not to squat knees over toes work best!), or anything else you have available. The slant allows you to get all the way down without bending over, ensuring the hips don’t cheat and help out too much. 100 reps of these full squats, using as much support as you need for assistance and not working through any pain, is an amazing way to start strengthening the tendons and ligaments in your knees.
As long as you start at a level that is safe for you and pain-free, full-bend squatting can be a tool like any other that, when used appropriately, can help you become a stronger, healthier human being. Daily life can be pretty tough on the body, especially if we want to stay active, train, and play sports. Training the body to be stronger and more durable gives us the best chance we have to handle those challenges, stay healthy, and keep enjoying the things we love.
1. Fry, A. C., Smith, J. C., & Schilling, B. K. (2003). Effect of knee position on hip and knee torques during the barbell squat. Journal of strength and conditioning research, 17(4), 629–633. https://doi.org/10.1519/1533-4287(2003)017<0629:eokpoh>2.0.co;2
2. McLaughlin, T. M., Lardner, T. J., & Dillman, C. J. (1978). Kinetics of the parallel squat. Research quarterly, 49(2), 175–189. Kinetics of the parallel squat – PubMed (nih.gov)
3. Wahlstedt, C., Rasmussen-Barr, E. Anterior cruciate ligament injury and ankle dorsiflexion. Knee Surg Sports Traumatol Arthrosc 23, 3202–3207 (2015). https://doi.org/10.1007/s00167-014-3123-1
4. Fong, C. M., Blackburn, J. T., Norcross, M. F., McGrath, M., & Padua, D. A. (2011). Ankle-dorsiflexion range of motion and landing biomechanics. Journal of athletic training, 46(1), 5–10. https://doi.org/10.4085/1062-6050-46.1.5
5. Robert Trasolini, M. D. (2019, June 4). Four reasons for rising ACL tears and other knee injuries. Four reasons for rising ACL tears and other knee injuries | Northwell Health. https://www.northwell.edu/orthopaedic-institute/news/insights/four-reasons-for-rising-acl-tears-and-other-knee-injuries#:~:text=More%20than%20100%2C000%20ACL%20reconstructions,the%20American%20Academy%20of%20Pediatrics.