Hello, friends. I was asked recently by a student why her knees/knee tendons hurt in standing pike/standing split. “They feel like they’re pulling. Ripping? Like my knees are trying to turn inside out.” Yes! This girl has brilliant proprioception, and that’s exactly what’s happening. Let’s explore:
If the greater trochanter is stacked directly above the center of the feet, the femurs and tibias line up beautifully with the gravity vector. This is a very strong position because the weight of the body is supported by dem giant bones through their long axis. The knee joint isn’t stressed into a weird position that puts pressure on its stabilizing ligaments and tendons because everything is stacked.
This is true regardless of where the upper body is: If the greater trochanters are stacked over the centers of the feet, the femoral chondyles sit squarely on top of the tibia heads applying equal pressure to all the squishy junk in the inner joint space like menisces and shit.
Gravity pulls straight down on every body part, regardless of where you put it. To help visualize this, imagine that the body is made of a million tiny pieces and each one has its own gravity vector pulling straight down on it. Next, look at where our gravity vectors are in relation to the feet, which are the base of support for the entire body in this position. All of the gravity vectors are pulling in front of them or straight down through the long bones of the leg and through the centers of the feet. This is great. Knees like this.
HOWEVER, if you thrust the pelvis backward allowing the greater trochanters to pass behind the feet, the femurs and tibias are no longer in line with the gravity vector. Gravity is as gravity does, and still pulls straight down from the greater trochanters.
Again to help visualize, imagine a million gravity vectors, each pulling on a different tiny body part. Look at how many are behind the center of the feet. Many people push their hips back to this position because it centers the weight of the body over the feet making a flat back forward fold much easier to balance and sustain. This position also alleviates pressure on the calves, which are often tight from training gorgeous foot point. I get that reasoning and am totally sympathetic. Your knees don’t care.
What this boils down to is a force due to gravity pulling straight down on the knees themselves. Now, this happens in our stacked position as well, it just doesn’t piss of the soft tissue because the weight is supported primarily by the bones. Here, the femurs and tibias are no longer vertical, so the weight of the body is supported by the tendons and ligaments of the knee rather than by the long bones of the leg, and that means:
…that the knees want to bend like this! The knee is a hinge and even though there are ligaments and other squishy things that keep it from hinging the wrong way, you can rest assured that if you put enough pressure on it will 100% hinge backwards. With only the pressure of a standing pike or standing split of course your knee won’t turn inside out, but the force in that direction is still absolutely there. Regardless of your pain or lack thereof, this position encourages hyperextension of the knee.
All of that said, I come back to my strongly held view that there is no wrong. If your knees hurt or feel unpleasant in this position, don’t do it: it’s not for you. If you’re like me and don’t have quite full knee extension or you want pretty pretty ballet hyperextension and this position doesn’t cause you pain, you might want to MINDFULLY use it to achieve your goal. (I don’t have to rage about mindful training because your coaches are already flogging you mercilessly if you train a skill/drill/conditioning/stretch without first knowing why, right?)
Final sidebar on this: Bringing the body forward over the feet does demand quite a bit more ankle dorsiflexion, which most our calves will inhibit. Embrace the calf stretch. It’s good for almost every single one of us and now you’re lengthening your entire posterior chain instead of just your hamstrings: functional laziness everybody!