According to the National Institute for Health and Care Excellence, up to 60% of adults can expect to experience low back pain at some time in their lifetime.

If you’ve already started to get the odd niggle, you’ve probably added some lower back-specific stretches into your routine. But your pain might actually be caused by a smaller, harder-to-stretch muscle: the psoas.

The psoas is the biggest and (ideally) strongest part of the hip flexors, a group of muscles that surround your pelvis. The psoas itself wraps from your lower back to the top of your quad, so is used anytime you lift your leg (eg when walking, running and lunging). But it’s not just these activities that put pressure on the muscle – sitting down shortens the psoas, which can lead to tightness.

Lower back pain: try these psoas stretches to reduce tension in your hips and back, as recommended by personal trainers