Full Can Test
Also known as full can, supraspinatus test, Jobe test.
Checks: The supraspinatus, one of the four rotator cuff muscles
What this checks
This checks whether the supraspinatus, one of the small muscles that steady the shoulder, is irritable or weak. It gently loads that muscle in the position where it has to work hardest.
Do not do this test if
you have had a recent significant shoulder injury, you cannot lift the arm at all, the shoulder is very painful at rest or at night, you have pins and needles or weakness spreading down the arm, or you feel unwell with the pain. See a doctor first if any of those apply.
How to do it
Step 1
Stand tall with your arm by your side
- Stand or sit upright with your shoulders relaxed and level.
- Keep your elbow straight but not locked.
Step 2
Lift the arm to shoulder height, out and slightly forward
- Raise the arm to about shoulder height.
- Bring it about 30 degrees forward of straight out to the side, so it lines up with your shoulder blade.
- Keep the elbow straight.
Step 3
Turn the thumb up towards the ceiling
- Rotate the whole arm so your thumb points up, as if holding a full can of drink you do not want to spill.
Step 4
Press the arm up gently against light resistance
- Have someone press down softly on your forearm, or press the back of your wrist up under the edge of a table.
- Hold for about 5 seconds using only light effort.
- Note any pain or give-way weakness, and compare with the other side.
What your result means
Likely normal
A negative result usually looks like this.
- You can hold the arm up smoothly at shoulder height.
- Only mild, even effort on both sides, with no sharp pain.
- The arm does not drop or wobble when light pressure is added.
Possible problem
A positive result usually looks like this.
- Sharp or pinching pain in the top or outer shoulder when you press up.
- Clear weakness on the tested side compared with the other arm.
- The arm drops, or you hitch the shoulder up to keep it there.
Tips for a clearer result
Small things that make the test easier to read.
- Do it in front of a mirror so you can watch both shoulders.
- Always compare the sore side with the other side.
- Stop if the pain is sharp rather than a mild stretch or ache.
How to read this
A positive result may point towards an irritated or weak rotator cuff tendon in the shoulder, but it cannot confirm it - plenty of other things cause similar shoulder pain, and only a hands-on assessment can tell you for sure.
This is a guide, not a diagnosis. It cannot rule a problem in or out - a physiotherapist can. If your symptoms are severe, spreading, or you feel unwell, see a doctor. Please do not start exercises based on these tests without guidance from a physiotherapist who has assessed you; doing so is at your own risk.
Points towards
If your result points to a problem, these condition guides are a good place to start reading.
Reproduced your pain?
A positive result is worth getting looked at. Book a £40 online assessment with an HCPC-registered physiotherapist, wherever you are in the UK.
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