Flexi Stretch
Why your lower back tightens up
Sitting for hours puts your hip flexors in a shortened position and switches your glutes off. When you stand up, those short hip flexors pull the front of your pelvis down, your lower back arches to compensate, and the muscles either side of your spine spend the day holding a position they were never meant to hold. That is the ache.
Which is why a routine aimed only at your back tends to disappoint. The useful work is upstream and downstream: open the hips, lengthen the hamstrings, and give the lower back gentle movement rather than aggressive stretching.
See someone first if: the pain radiates down a leg, you have numbness, tingling or weakness in a foot, you have any change in bladder or bowel control, the pain followed a fall or accident, or it wakes you at night. Those are for a doctor or physiotherapist, not a stretching routine.
Before you start
- Go gentler than feels necessary. An irritated back responds badly to force. Aim for a mild, pleasant pull — around a 3 out of 10.
- Warm up first if you can. Five minutes of walking, or doing this after a shower, makes a real difference.
- Hold for 30 seconds and breathe out slowly. A held breath keeps the muscle guarding.
- Little and often. Once a day, most days, beats a punishing session twice a week.
The routine
Do it lying down, in this order. It takes about ten minutes.
30 seconds each side
1. Knee to chest
Lie on your back with both knees bent. Draw one knee towards your chest with both hands, keeping the other foot flat on the floor. Gentle, low-effort length across the lower back and glute — a good opener.
30 seconds each side
2. Supine spinal twist
Still on your back, arms out in a T. Let both knees fall slowly to one side and turn your head the other way. Keep both shoulders in contact with the floor — the twist matters more than how far the knees drop.
30 seconds each side
3. Figure-four glute stretch
Cross your right ankle over your left thigh, then reach through and pull the left thigh towards you. Tight glutes are a very common contributor to lower back tightness, and this is the most reliable way to reach them.
30 seconds each side
4. Lying hamstring stretch
Raise one leg towards the ceiling, hands behind the thigh, other leg flat. A soft bend in the raised knee is fine and often better — locking it out tends to make people round the lower back, which is exactly what you are trying to avoid.
30 seconds each side
5. Kneeling hip flexor stretch
Kneel on one knee, other foot forward. Tuck your tailbone under before you shift forward — that tuck is what turns this from an unhelpful lower-back arch into an actual hip flexor stretch.
30 seconds
6. Child's pose
Kneel, sit back towards your heels, and walk your hands forward with your forehead resting down. Widen your knees if your hips are tight. Breathe into your back and finish here.
What to avoid
- Standing toe touches. Rounding forward under load is the position most likely to irritate an already unhappy lower back. Use the lying hamstring stretch instead.
- Bouncing. It triggers a protective reflex that tightens the muscle further.
- Stretching into sharp pain. Tension is fine. Sharp, burning or electrical sensations are a stop signal.
- Total rest. For ordinary mechanical back stiffness, staying still usually makes it worse. Gentle movement is the treatment.
Common questions
How often should I do this?
Once a day, most days, is the sweet spot. If your back is particularly stiff in the mornings, doing it in the evening often helps more.
Should stretching hurt?
No. You want a mild pull that eases as you hold it. If a stretch is still sharp after ten seconds, come out of it and reduce the range.
How long before my back feels better?
Many people feel looser immediately after a session. Meaningful change in day-to-day stiffness usually takes two to four weeks of near-daily practice. If nothing has improved after a month, see a physiotherapist.
Is there a guided version of this?
Yes — the Back plan in Flexi runs this kind of routine with a timer, illustrations and voice guidance, so you are not counting seconds while lying on the floor.
This guide is general information, not medical advice, and Flexi is a fitness and wellbeing app rather than a medical device. Persistent or severe back pain deserves a proper assessment from a doctor or physiotherapist.