Myth: The knees should never project ahead of the toes during any exercise.
In a study titled, “How many clueless aerobic instructors and personal trainers still follow this archaic nonsense,” done by The Journal of Stupidity, it was shown that a vast majority of fitness professionals still believe the above myth to be true. Matter of fact, the same study showed that many fitness professionals would rather see you club a baby seal (that’s just mean) than witness your knees project over your toes while under their supervision.
Needless to say, they’re wrong. Sarcasm aside, having the knees project over the toes is perfectly normal and occurs quite frequently in everyday life. Just ask anyone who participates in football, karate, dance, or mudwrestling. Heck, try walking up a flight of stairs without your knees going over your toes. Despite all of this, many fitness professionals still claim that the knees going over the toes during weight bearing exercise is dangerous. I’ll even go so far as to say that this guideline has assumed the stature of law in the aerobics world.
In past writings, both Eric Cressey and Alwyn Cosgrove have referenced one study which kinda debunks this whole myth.
Fry AC, Smith JC, Schilling BK. Effect of knee position on hip and knee torques during the barbell squat. J Strength Cond Res. 2003 Nov;17(4):629-33.
The above study examined joint kinetics during back squats under two conditions. The first condition placed a board in front of the participants’ shins, which restricted forward displacement of the knee. In the second condition, movement wasn’t restricted at all. They squatted normally and the knees were allowed to pass the toes (GASP).
The researchers found that restricting the forward excursion of the knees during the squat (not allowing the knees to go over toes) increased anterior lean of the trunk and promoted an increased “internal angle at the knees and ankles.”
The results showed a 22% decrease in knee torque and a 1070% increase in hip torque! That stress has to go somewhere. Keeping the knees behind the toes definitely reduces the forces on the knee, but those forces were transferred more than tenfold to the hips and lower back. Translation: that’s an ouchie.
