A lower back that complains after a day in a chair is one of the most common reasons people look up stretches at all. Below is a sequence of four, the order to do them in, and the honest version of how long it takes to feel different.
One thing first, because it decides everything else. Stretching is general fitness, not treatment. If what you have is pain rather than stiffness, the section on telling them apart matters more than the sequence does.
Why does sitting leave your lower back tight?
Sitting rounds the lower back forward and keeps it there. Your spine is built to move through that range, not to live at one end of it. The muscles running alongside it end up holding a position rather than changing one.
Two things ride along with that. The hip flexors at the front of the hip sit short, because a seated hip is a folded hip. The glutes go quiet, because a chair is doing their job.
So the tightness you notice low down often starts at the front of the hip. That is why the list below includes a lunge, which looks like it has nothing to do with your back.
Is it stiffness, or is it pain?
This is the part to read slowly, because the two want different things.
Stiffness tends to be dull, spread across an area, and it changes when you move. That is what a stretching routine is for.
Pain behaves differently. Pain that sharpens when you load the leg, pain that wakes you at night, pins and needles or numbness travelling below the knee, or any weakness in a leg or foot all want a professional opinion before you stretch into them. The same goes for anything that follows a fall or a lift that went wrong.
Lucy is not a clinician and cannot tell the difference from the outside. Only you can feel it, and only a professional can assess it. Our fitness and safety note covers the rest.
The four stretches, in order
The order matters slightly. The spine moves first, then the hips, then the spine again with the hips already open.
- Cat-cow. On hands and knees, arch and round the spine slowly, following your breath. Ten slow cycles. This is a movement, not a hold, so count cycles rather than seconds.
- Seated spinal twist. Sitting, cross one ankle over the opposite knee and turn your chest towards the top leg. About thirty seconds each side. Sit tall first, then turn, rather than turning and collapsing.
- Low lunge. Kneel on one knee, tuck your tailbone under until the lower back stops arching, then shift forward an inch. The tuck is the part people skip, and without it the stretch lands in the spine instead of the hip.
- Knees to chest. Lying down, draw both knees in and hold for about thirty seconds. This is the one to keep if you only have time for one.
None of these ask you to be flexible. Work in the range you have today, and ease off anything that pinches. Never force a stretch to reach the shape in a picture.
If the floor is the obstacle rather than the stretch, there are upright versions of all four, and we wrote about stretching when there is nowhere to lie down separately.
How long should you hold each one?
About thirty seconds for the twist, the lunge and the knees to chest. Shorter holds mostly move you through the range without settling into it.
There is good evidence on the dose. A 2025 meta-analysis in Sports Medicine pooled 189 studies and 6,654 adults and found that holds of thirty seconds worked as well as sixty, that the gains from a single session flattened at roughly four minutes per muscle group, and that around ten minutes per muscle group per week was the point beyond which more time added nothing. Splitting that weekly total across three sessions or six made no difference.
Two useful consequences. A long hold is not a better hold, and the weekly total matters more than any single session. We went further into this in how long you should hold a stretch.
One more finding from that Sports Medicine review, and it is the useful one: the largest improvements came from the people who started out the least flexible. Worth knowing if you have been putting this off because you cannot reach your toes.
What if it comes back every afternoon?
Tightness that returns on a schedule is telling you about your day rather than your stretching. The back is going straight back into the position it spent the morning in.
Stand up every forty minutes or so. Thirty seconds is enough to change the joint angle, and it does not have to be a walk. Raise your chair a little, so your hips sit slightly above your knees. Stretch in the evening as well as the morning, when those muscles have just spent hours held short.
The same pattern runs further up the spine, which is why a stiff neck at a desk behaves the same way.
Where Lucy fits
Lucy is an iPhone app of short guided stretching routines for people who sit all day. Be Kind to Your Back is six minutes and eight stretches, done on the floor, and it includes three of the four above. The timer counts each hold and tells you when to switch sides, so you are not watching a clock. It works offline and there is no account.
One routine is free in full rather than as a preview. The rest is a subscription with a 7-day free trial, priced in your own currency on the App Store.
FAQ
How long does it take to feel less stiff?
Nobody can promise you a timeline, and Lucy does not. What the research describes is a dose: the Sports Medicine meta-analysis above found roughly ten minutes per muscle group per week to be the point of diminishing returns, accumulated across any number of sessions. If weeks of consistent stretching change nothing at all, the limit is probably not flexibility, and that is worth asking someone about.
Should you stretch a back that already hurts?
Gentle movement within a comfortable range is usually fine for stiffness. Sharp pain, pain travelling below the knee, or anything with numbness or weakness is a reason to get it looked at first rather than to stretch harder. Discomfort and pain are not the same thing, and the difference is one only you can judge from the inside.
Does sitting on an exercise ball help?
A ball changes the shape of your sitting. It does not change the duration, and duration is the part that leaves your back feeling held. Whatever you sit on, standing up periodically does more than the seat does.
Can you do these at your desk?
The twist, yes. A standing version of the lunge, yes. Cat-cow and knees to chest need the floor, though a standing forward fold covers some of the same ground. The routine Nowhere to Lie Down is built entirely from stretches that work upright.
Do you need a mat?
No. Three of Lucy's sixteen routines need no floor at all, and the floor-based ones work on carpet or a rug. A cushion under the knees makes the kneeling ones easier.
Lucy walks through this sequence on a timer, one stretch at a time.