A backbend in Yoga is a type of asana or pose that incorporates backwards movement of the body through space and might entail some degree of spinal extension.
Spinal extension is when the primary curve of the thoracic spine or mid-back decreases corresponding to an increase in the secondary curves of the lower back and the curve at the back of the neck. This range of motion depends on the student’s body type or genetics and the type of backbend they want to perform.
A spinal extension does not necessarily involve a large movement of the spine through space. On the other hand, a backbend might require other joints, other than the spine’s, to be involved – like the knee or the hip joints.
Many students are guided into and used to moving into a backbend on an inhale. A reason for this might be that an inhale does tend to create a natural opening in the ribcage which could resemble a mini spinal extension. Even though this might be stabilizing and feel more familiar and accessible, it depends on the situation. Everyone has a different breathing pattern history and during breath, some people might tend to mobilize their chest area more than their belly area and vice versa. Also, any emotional experiences associated with either inhaling or exhaling should be considered.
Many students might find that exhaling is a better and easier way for them to access a backbend. If you are a Yoga teacher, during class pick one student and notice if you can see their specific breathing pattern and whether it is properly serving and supporting their backbend; then you might cue them accordingly. Also, you can offer other possibilities and instruct the class to get into a backbend on an exhale as a short-term experiment, so they can notice their habits and then make a choice that will serve them best at that moment.
People’s practice might change over time, just as their breathing patterns and ways of getting into a backbend might change. So teach in a way that the students can find their own way and understand that these experiences can change on a day to day basis.
Have you experimented with getting into a backbend from both an inhale and an exhale? If so, what did you notice?