In Yoga 216 INfrastructure, we look at asana through a lens of joint range of motion for each joint action.
Let’s unpack that.
First, what’s a joint?
A joint is the meeting of two bones:
In movement studies, we’re usually talking about synovial joints. A synovial joint is a freely-movable joint. Synovial fluid lubricates the movement of the joint (and nourishes the bones). Gentle movement of the joint generates synovial fluid (win-win!). Every synovial joint needs regular, gentle movement to keep it healthy!
Ok, what’s a joint action?
A joint action in the movement that can occur in a joint in a specific direction and manner.
Each joint can move through a certain set of actions and we try to leave it at that.
For example, your elbow only bends and straightens. (In anatomical terms: “flexes” and “extends”.) That’s it for the elbow! No matter how hard you try, you’ll never get your elbow, through the force of your own muscles, to spin in circles. (This is a good thing!)
Your hip, on the other hand, does spin in circles. And more. Several joints have the luxury –or the burden, depending on how you look at it– of being able to combine joint actions. This results in complex movement… or most of what we do all day.
Back to our breakdown: what’s range of motion?
Joint range of motion (or “ROM”) is the range through which a joint can move in it’s normal actions.
What about normal joint range of motion?
Each joint action has a “normal” range of motion. Normal ROM for a joint action is an average ROM that most people’s joints should be able to match. It is the range in which you can take an action without pain and with strength at all points across the range.
As an example, let’s look at your elbow again. The normal ROM for elbow extension is the ability to straighten your elbow all the way. The normal ROM for elbow flexion is the ability to bend your elbow until your fingertips graze your shoulder.
Some people have more than that, some have less. The norm is a starting place that we use if there are issues we need to investigate.