Most people are aware of positions that are bad for their body. Sitting with a laptop on the coffee table or desk comes to mind. Or looking down at the phone. These are obvious, bad positions. However, people don’t typically think of: (1) sitting on low, soft, deep couches watching TV or (2) lying down reading with the head propped up as something that could be harmful to them. These are common positions people are in everyday and both involve flexed positions of the spine. In the clinic I find that being in these specific positions for extended periods often accompany ‘flare-ups’ of back or neck pain.

Does this mean that flexed positions of the spine are bad? No – flexion is a normal movement of the spine that occurs everyday whether it’s putting on socks and shoes, reaching down to pick something up, or looking down. There are also sports like rowing or biking that involve repetitive flexion movements. It only starts to have a negative effect when the joints are not ‘centrated’ with movement and is repeated again and again over time. This could be true for any spinal or joint movement in the body, but is seen a lot with spinal flexion (this is described more in this post).

Spinal flexion is an everyday movement, which when not in joint centration will have a negative effect.

So what is ‘ joint centration’? ‘Centration’ means that the joints (where two bones connect) have maximally congruent contact throughout the motion. In the spine, flexion with joint-centration would look like a uniform curve with movement (the above picture shows a non-uniform curve). The muscles around the joint would be balanced throughout the motion with the agonist and antagonist muscles co-contracting. Without joint centration, there would be an imbalance in the muscles and increased pressure/strain on passive structures like ligaments, cartilage, and discs. Over time this strain on passive structures would eventually contribute to injuries or flare-ups.

With the two positions described above, most people are in these positions multiple hours a day — multiply that by days, weeks, and months throughout the year and it’s no wonder many people injure themselves in their low back and neck. What’s most important here is to be in a joint-centrated position — whether in a static position or with dynamic movement. However, with flexion it’s much more difficult to maintain joint centration in a static position for extended periods of time due to gravity and fatigue of the muscles and structures. Maybe it could be possible for some people to be in these static positions here and there, but if it’s for multiple hours per day consistently everyday, this may eventually contribute to injury or aggravation, especially for those with a history of low back or neck pain, or those who have had de-centrated joints for a long time.

In general, the safest position of the spine would be to keep joint centration while in a straight, ‘neutral’ position as this would put the least amount of strain and pressure on passive structures. Instead of sitting on a low/soft/deep couch try a normal chair with back support and padding under your glutes, keeping your glutes all the way to the back of the chair (or a higher/firmer/less deep couch!). If you want to read lying down, try lying with a pillow under your head and the book or phone above you. The neck shouldn’t be in excessive flexion, so the face should be angled slightly higher than the chin or… lie on your side with a pillow between your knees and a folded pillow under your head. This will keep your spine in a straight position.

The goal for each patient would be to train these ideal, joint-centrated positions as this would be the best way to prevent injury from happening in the first place. It starts with training trunk stabilization on the back with the spine horizontal and progressing to more upright and dynamic movements. In this way the brain would start to automatically and subconsciously control this joint centration.

Links:

“The daily toll of flexion on our spines” - BLOG post describing negative effects of repetitive flexion

“How should I be sitting (or standing)” - BLOG post describing ideal sitting position
“Sleeping position and pillow type” - BLOG post describing neutral sidelying and supine position

Questions or comments? Contact us below.

Two common flexed positions to avoid

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