In reality, your knee crosses in front of your toes on every running stride.
I once interviewed a doctor who has a lot of experience in treating runners and whom I shall not name in this context. We were discussing running injures and their causes. In the course of this conversation, the doctor mentioned that he often sees patients who have been prescribed corrective exercises such as squats and lunges by other practitioners. When he asks these patients to demonstrate the exercises, he says, he is often horrified by their form, which the preceding practitioners have apparently allowed them to get away with. For example, their knees move past their toes at the bottom of the lunge or squat movement.
You have probably heard this caution many times: Never let your knees move past your toes when squatting or lunging. It’s bad for your knees.
This caution is actually 100 percent false. A myth without a shred of truth to it. One of those classic fitness fallacies that emerges from the exercise-is-dangerous mentality that pervades the fitness club culture and becomes “true” by repetition, as “expert” after expert hears it and then repeats it without ever questioning it. But the knees-over-toes rule is in fact based on nothing substantive — not on any evidence of a link between squat or lunge form and injury nor even on any anatomical rationale. Worse, the rule is not merely useless but potentially harmful. Ironically, unnatural efforts to keep your knees behind your toes when you squat or lunge are far more likely than the opposite to hurt you.
Allowing the knee to pass in front of the toe when squatting or lunging is completely natural. Humans do it automatically from the time they are old enough to squat down to pick up a ball. Ask any two-year-old to do that and watch her knees.
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Your knee passes in front of your toe on every stride of every run. Good thing, too, or you’d be a terrible runner.
Also, good luck climbing a flight of stairs without allowing your knees to pass in front of your toes.
In 2003 the Journal of Strength and Conditioning published a study in which volunteers were asked to squat two ways: allowing the knees to pass in front of the toes and not allowing them to do so. They found that not allowing the knees to pass in front of the toes reduced knee torque. That’s good, right? Wrong. Because this technique also increased hip torque by more than 1,000 percent! Those forces displaced from the knees by squatting unnaturally were simply transferred to the low back, a joint that is far more susceptible to injury in a squatting exercise than the knees.
Not everyone should aim to get their knees past their toes when squatting or lunging, however. It’s a matter of individual anatomy. People with shorter legs often squat and lunge quite naturally without excursion of the knees beyond the toes. Taller folks tend to naturally push the knees beyond the toes. You need to let your individual body move as it was designed to do.
For a variety of reasons, most people do squat or lunge with bad form. So it’s a good idea to learn correct technique from someone who knows what he’s talking about. If the person teaching you correct squat or lunge technique tells you not to let your knees past your toes, you now know that he doesn’t know what he’s talking about.
About The Author:
Matt Fitzgerald is the author of numerous books, including Racing Weight: How To Get Lean For Peak Performance (VeloPress, 2012). He is also a Training Intelligence Specialist for PEAR Sports. To learn more about Matt visit www.mattfitzgerald.org.