Known as a both spiritual and physical practice, yoga requires practitioners to not only approach it with a clear and humble mind, but also to understand the anatomy to be able to develop into deeper practices and asanas.
Movements of muscles and joints
Before starting with yoga practice, we need to know how our body works to come into different postures. Here is how muscles and joints play a vital role to complete the different movements and stabilize our body.
The muscle of our body has 3 main types – skeletal, cardiac and smooth muscle. In yoga practice, we focus on the skeletal muscle mostly as the later 2 are most found in organs with involuntary movements. For skeletal muscles, there are 4 types of contractions when a muscle is engaged:
- Concentric: muscle shortens when contracting. For example, when we lower the body into Chaturanga (low plank position), the biceps will shorten to create the tension and support our upper body.
- Eccentric: muscle lengthens when contracting. From the previous example, if we are transiting from Chaturanga to Urdhva Mukha Swanasana (upward facing dog), the biceps will need to lengthen to push our upper torso up.
- Isotonic: muscle maintains constant tension through range of motion. This happens mostly when we are maintaining certain postures, such as Malasana (squatting).
- Isometric: muscle creates tension but no change in length of fibers or does not move bones. One example is the triceps muscle when we are staying at side plank position.
In our skeletal system, there are 3 types of joints as well – fibrous, cartilaginous and synovial. While the first 2 types are barely movable, synovial joints are the key joints for us to focus. There are 6 types of synovial joints based on the different structure and moves that the joint can perform:
- Pivot: the joints which can rotate around a single axis, such as the joint in between C1 and C2 vertabrae that allows us to turn our heads to left and right side.
- Hinge: the joints which can open and close in one plane like a door hinge, such as our elbow and knee joints.
- Saddle: the joints that can move in 2 planes that are vertical to each other, but not freely-movable due to the limitation of the saddle-shaped bone. A good example is our wrist joint, which can perform dorsiflexion and plantarflexion, and also allows us to shake our hand along the same plane of the palm when waving to someone.
- Plane: the joints that allows 2 planes to glide in parallel, such as the joint between tarsal bones.
- Condyloid: this type of joints are generally formed by 2 round-shaped bones and allow certain degree of movement in 2 planes vertical to each other. Example – when we move the thumb, it can either bend into the palm/flex further away, or it can also move nearer or further from our index finger.
- Ball-and-socket: the most freely-movable type of joints in our body, which includes our shoulder and hip joints.
Examples of yoga anatomy application
After knowing the key movements in muscle and joints, we can apply the knowledge to yoga postures and know how we may further improve.
Using shoulder stand as an example – for new yoga practitioners, shoulder stand seems to be a very challenging pose to complete. Let’s deep dive into the movement by analyzing the muscle and joint movements.
Shoulder joint is a ball-and-socket joint which is freely moveable. For this posture, the movement involved is called external rotation, whereby the shoulder joint rotates towards the back of the body with scapulae squeezing towards each other. Thus while practicing shoulder stand, we should try to bring our elbows as close as possible to maximize the external rotation and better stabilize our body.
From the muscle perspective, we need sufficient strength and flexibility in our 4 rotator cuff muscles (supraspinatus, infraspinatus, teres minor and subscapularis) to accomplish the shoulder external rotation. In order to support the weight of our body, the arms muscles (such as biceps and brachioradialis), as well as pectoralis major and deltoid need to be strong and support our entire body within this triangular shape that the muscles formed.
References:
- 200-hr Yoga TTC manual 2019, Tirisula Yoga
- Take online courses. earn college credit. Research Schools, Degrees & Careers. Study.com | Take Online Courses. Earn College Credit. Research Schools, Degrees & Careers. (n.d.). Retrieved September 25, 2022, from https://study.com/academy/lesson/the-six-types-of-synovial-joints-examples-definition.html#:~:text=the%20human%20body.-,Joints%20are%20formed%20where%20bones%20come%20together.,are%20found%20in%20your%20hands.
