Quick answer: if you can't reach as far up your back as you used to, or one shoulder falls noticeably short of the other when you try, that's shoulder stiffness worth paying attention to. A simple hand-behind-back check tells you where you stand, and if tightness at the back of the shoulder is part of the picture, the sleeper stretch is one of the exercises we use most often to help restore that reach.

Why this matters

Struggling to do your bra strap up, reach the seatbelt behind you, or scratch that spot between your shoulder blades? That loss of reach behind your back is one of the most common ways shoulder stiffness shows up, and it's easy to write off as just getting older or being "a bit tight". Left unchecked, though, it often doesn't stay the same, other movements and muscles compensate, and what started as mild stiffness can gradually turn into something more restricted and harder to shift. Checking it early, while it's still just stiffness, is usually the quicker and easier fix.

Why shoulders get stiff

Your shoulder is the most mobile joint in your body, which is exactly why it's so good at losing range when something isn't quite right. Stiffness can come from the joint capsule itself tightening up, as in frozen shoulder, from tight muscles at the back of the shoulder pulling on the joint, from rotator cuff related pain making certain positions guarded and restricted, or simply from posture and long periods spent at a desk or behind a wheel.

Whatever the cause, reduced internal rotation, the movement that lets you reach up your back, tends to be one of the first ranges to suffer. That's why it's such a useful thing to check.

How to test your own shoulder stiffness at home

This test is sometimes called the hand behind back test, and it's one we use regularly in clinic.

How to do it: reach one arm up behind your back, palm facing out, as if trying to touch your bra strap or shirt tag. At the same time, reach your other arm over the same shoulder from above, and see how close your hands get, or whether they touch at all. Then swap sides and compare.

What to notice:

  • The gap between your hands - some people can touch or overlap fingers, others can't close the gap at all. What matters most is comparing one side to the other.
  • Which side is more limited - a clear difference between left and right points to something specific going on with that shoulder, rather than general stiffness.
  • What you feel - a stretching sensation is normal. Sharp pain, or a sudden catch partway through the movement, is not, and is worth getting checked rather than pushing through.

It's a screen, not an exact measurement

Finlay McDonald, Physiotherapist at our Crouch End N8 clinic, points out that this test is influenced by more than just the shoulder joint itself: your shoulder blade and upper back both move to help your hand travel up your spine. If you're dealing with a different shoulder symptom rather than stiffness, our guide on how to self-diagnose shoulder pain may help you work out what's going on before you book in.

"A quick home check is a useful early indicator, but it isn't a diagnosis. It gives us a starting point, then a proper assessment tells us what's actually driving the stiffness." — Finlay McDonald, Physiotherapist, BOOST PHYSIO Crouch End

A stretch that helps: the sleeper stretch

If tightness at the back of your shoulder is limiting how far your hand travels up your back, the sleeper stretch is one of the exercises we reach for most often. It's simple, needs no equipment and can be done at home.

How to do it: lie on your side on the affected shoulder, arm out in front of you and bent to 90 degrees at the elbow. Using your other hand, gently press your forearm down towards the floor until you feel a stretch at the back of the shoulder. Hold, then release.

Clinical research on this exercise, including work published in the Journal of Orthopaedic & Sports Physical Therapy, has looked at modified versions of the sleeper stretch to help it target the back of the shoulder more effectively while avoiding unwanted strain elsewhere in the joint, which is why getting the exact position right matters more than how far you push it.

A word of caution: the sleeper stretch is best suited to stiffness from a tight posterior capsule, the kind we often see in people who do a lot of overhead reaching or throwing, or who've had a stiff shoulder for a while. If you're in an acutely painful phase, such as early frozen shoulder, forcing this stretch can aggravate things rather than help, so it's worth getting assessed first.

When stiffness is a sign to get it checked

If your reach behind your back has been reduced for a few weeks, if it's affecting everyday things like getting dressed or sleeping on that side, or if stiffness is joined by pain that wakes you at night, get it assessed rather than waiting it out. Shoulder stiffness has a lot of possible causes, and what helps one shoulder won't always help another, so a proper assessment is what tells you which of these exercises, if any, are the right ones for you.

Our approach: every tool for your best recovery

At BOOST PHYSIO, we believe your best recovery comes from having every tool available, not relying on just one. That's why our physiotherapists combine hands-on manual therapy with targeted exercise rehabilitation, tailored specifically to you and adjusted as you progress. We've seen first-hand, time and again, that patients get the best and most lasting results when both are used together. It's the thinking behind our promise: Your Best Recovery, Guaranteed.

At BOOST PHYSIO Crouch End, we offer:

  • ✓  Same day physiotherapy appointments
  • ✓  Male and female clinicians
  • ✓  Treatment recognised by Bupa, AXA Health, Vitality, WPA and Aviva

Book your assessment online now, call 020 8201 7788 or WhatsApp us.

Frequently asked questions about shoulder stiffness

Mild morning stiffness that eases within the first hour or so of moving around is common and usually nothing to worry about. Stiffness that doesn't ease as the day goes on, or that's getting worse week by week, is worth having looked at.
It depends heavily on the cause. Stiffness from posture or muscle tightness often responds within a few sessions, while a true frozen shoulder can take several months to resolve fully, even with good treatment, because of how the joint capsule itself behaves.
It's a safe stretch for most people with posterior shoulder tightness, but if you haven't had it confirmed that's what's causing your stiffness, you could be missing the actual driver, or aggravating a more irritable shoulder. A quick assessment makes sure you're doing the right thing for your shoulder rather than guessing.
General stiffness usually affects movement to some degree but still allows a reasonable range, and tends to improve steadily with the right exercises. Frozen shoulder is a specific condition where the joint capsule tightens significantly, often causing a marked, progressive loss of movement in several directions alongside pain, and it typically needs a more structured, longer term management plan.

Written with Finlay McDonald, Physiotherapist at BOOST PHYSIO Crouch End, and the BOOST PHYSIO team. This article is general guidance and is not a substitute for an individual physiotherapy assessment. References: Wilk KE, Hooks TR, Macrina LC, "The Modified Sleeper Stretch and Modified Cross-body Stretch to Increase Shoulder Internal Rotation Range of Motion in the Overhead Throwing Athlete", Journal of Orthopaedic & Sports Physical Therapy, 2013.