As we practice yoga more and more, we realize that not all posture cues are suitable and/or beneficial for us (not to mention the patterns, habits and injuries we have accumulated over the years).
Multi-level yoga classes can be confusing with all the different instructions. Should I allow my knee to travel beyond the heel when I am in standing poses? Warrior2 or Triangle should my hips face the mat, even if my knees are bent inward. Do I push my foot into my calf in Eagle position or towards my hips for Full Lotus pose despite feeling pain in my knees? Do my buttocks need to be in Hero Pose? Or should they rest on the ground for Full a href=”https://www.ekhartyoga.com/resources/yoga-poses/lotus-pose”>Lotus pose, even though my knees are hurting and my butt lifts?
This article will discuss the anatomy and biomechanics surrounding the knee joint. It also explains how to safely practice certain strengthening and stretching poses in yoga.
The knee joint
The condylar hinge knee joint is made up three bones (femur and tibia) and is called a condylar joint. The longest bone in the body, the femur bone, is also part of the knee joint. The tibia, which is the larger of the two lower leg bone, is also the most important. The fibula, which is thinner and more lateral, is one of four bones that can compromise the ankle joint. The patella tendon is the attachment of the kneecap (patella), which is a continuation from the quadriceps muscles rectus fimoris, vastus medialis, vastus goldis, and vastus intermedius. The patella tendon attaches at the superior tibia’s anterior portion and is part of the patellofemoral Joint.
This is where injuries can occur if too much femoral force (e.g. Warrior1 or Warrior2 with the knee moving beyond the ankle and heel). In higher centre of gravity positions such as these, it is important to stack your knee over your heel. It is safer to allow your knee to move beyond the ankle joint during lower centre of gravity positions such as Anjaneyasana. This is because most of the weight is going down to the mat’s back knee. Warrior 2 and Triangle require that you stack your knee over your heel.
There are many degrees of freedom
Six degrees of freedom are available for the knee joint: flexion/extension and varus/valgus. There is also an internal/external rotation. Two movements that are common to the knee (a hinge joint) are flexion and extension. They can be found in the Sagittal plane. The knee is flexed by the quadriceps and quadriceps muscles.
The medial/lateral varus movement and internal/external rotation at the knee joint are very minimal when the knee joint is extended. These four degrees of freedom are only accessible when the knee is bent. Because our knees are flexed, we can explore the possible knee varus/vagus/rotation when we do poses like Garudasana (“Eagle”), Virasana (“Hero”) or Padmasana (“Lotus )…”).
If we attempt to rotate a flexed leg beyond its capabilities, it can cause injury to our knee ligaments. This is often done to compensate for the lack of internal or exterior rotation in the knee or hip. Some people might not be able to get their feet around their ankles in Eagle pose or sit down on Hero pose. There isn’t enough internal rotation for them to safely perform this pose. For those without sufficient external rotation, Lotus pose may not be safe.
Four ligaments to ensure stability in the knee
The four deep knee ligaments (anterior and posterior cruciate ligaments, medial and lateral collateral ligaments), ensure that the femur (or slowly with repetitive motion) does not shift away from one another. This prevents traumatic and debilitating injuries to most ligaments. The ligaments are not elastic, and will not return to their original form if they are stretched too much.