There’s no shortage of opinions in yoga about what constitutes safe practice for people with disc problems, particularly in the lumbar spine. To make sense of these differing views, it helps to look again at the anatomy of the intervertebral disc and the history of ideas about what causes disc injury.

The anatomy

Most yoga practitioners are familiar with the broad picture: each spinal disc has a tough outer ring (annulus fibrosus) surrounding a gel-like inner centre the nucleus pulposus). The annulus consists of concentric layers of collagen fibres, each angled alternately to the next. This architecture makes it exceptionally resilient to both internal pressure and external stress.

The nucleus, being hygroscopic, draws in water from surrounding tissues, keeping the disc plump and able to resist compression. Although the disc itself has almost no blood supply, the adjacent vertebral bone and its endplates are vascularised, allowing nutrients to diffuse into the disc through osmosis and gentle spinal movement.

A healthy annulus is immensely strong – strong enough that, under load, the vertebral bone will often fail before the disc itself. That’s worth bearing in mind when considering how “vulnerable” our discs really are.

Rethinking “Wear and Tear”

The causes of disc prolapse – when the nucleus pushes through a damaged annulus—are still debated. While ageing is often blamed, the data tell a different story. Disc prolapse is actually less common after sixty, and men are affected roughly twice as often as women, possibly because of heavier manual work. Prolonged sitting is also implicated, though evidence remains weak.

In the mid-twentieth century, compression was widely accepted as the main cause of disc injury. Swedish researcher Alf Nachemson measured pressures in the lumbar spine and suggested that flexion could generate up to 13 kilonewtons (kN) of compression – enough, he thought, to damage the annulus. This led to the long-standing advice to “bend with a straight back” to protect the discs.

Compression or Torsion?

A Broader Perspective

So where does this leave yoga practitioners? Somewhere between theory and lived experience.

The compression theorists warn against flexion; the fascial theorists see flexion as necessary and protective. Both are partly right. But context – how much load, how much repetition, how much awareness – matters more than allegiance to any one model.

To see this in perspective, look at people who bend for a living: rice-planters in Asia, potato-pickers in Lancashire, seed gatherers in Africa. They move with ease and adaptability, guided not by biomechanical theory but by felt experience. Children too bend naturally, combining spinal and knee flexion fluidly. It would be odd if evolution had designed a movement pattern that was intrinsically unsafe.

Perhaps the most helpful approach is to re-educate our attention rather than prescribe shapes.

• The spine is designed to flex, extend, and twist.
• Safety depends on gradual adaptation and proprioceptive feedback, not on keeping the back straight.
• What matters most is how movement feels – coordinated, supported, and free from strain.

If a movement feels easy and well-distributed, it’s likely safe. If it feels sharp, guarded, or asymmetrical, it’s a signal to pause or adjust.

For yoga teachers, this means encouraging students to develop sensitivity rather than rules. The question is not Is flexion safe? but How am I organising myself as I move?

The spine thrives on movement, variety, and responsiveness. When yoga practice fosters these qualities, it becomes not just safe for the discs, but nourishing for the whole body–mind system that supports them.