The five, at a glance
Ranked on three things: how hard each one works the cuff in muscle-activity studies, how well it keeps the deltoid out of the way, and how easily you can load it progressively in a gym off Kingsway or at home.
| Rank | Exercise | Main muscles | Starting load | Sets × reps |
|---|---|---|---|---|
| 1 | Side-lying external rotation | Infraspinatus, teres minor | 1 to 2 kg | 3 × 10–15 |
| 2 | Cable or band external rotation | Infraspinatus, teres minor, supraspinatus | Lightest cable pin | 3 × 12–15 |
| 3 | Full can | Supraspinatus | 1 to 3 kg | 3 × 10–12 |
| 4 | Prone raise with the thumb up | Supraspinatus, rear deltoid | 0.5 to 1 kg | 3 × 8–12 |
| 5 | Cable or band internal rotation | Subscapularis | Lightest cable pin | 2 × 12–15 |
How this ranking was built
This is a review of the published research, and nobody was put through a trial for it. The candidates were the cuff exercises that recur across rehab programmes: the five here plus the empty can, pendulums, wall slides and face pulls. Checked September 2026.
The muscle numbers come from three fine-wire EMG studies: Reinold and colleagues in 2004 (seven external rotation exercises, 10 people), Reinold in 2007 (full can, empty can and prone raise, 22 people) and Boettcher in 2009 (five supraspinatus positions, 15 people). All used healthy shoulders, so they tell you which exercise works a muscle hardest. Whether a programme fixes a painful shoulder comes from the trials in the last section.
1. Side-lying external rotation
The highest measured activity for two of the four cuff muscles, with your arm at your side and a dumbbell you could hold all day.
How to do it
Lie on your good side, towel roll between elbow and ribs, elbow at 90 degrees. Rotate the forearm up towards the ceiling, one second up, three seconds down. Keep your body stacked; rolling back is the cheat.
What the data shows
In the 2004 study it produced 62% of maximal activity in the infraspinatus and 67% in teres minor, the top figure for both of the seven exercises tested.
Load it like this
Start at 1 to 2 kg. When you hit 15 clean reps on every set for two sessions running, go up by 0.5 to 1 kg.
Why it ranks first
Top activity, lowest-risk position, cheapest kit. Nothing else on the list beats that combination.
2. Cable or band external rotation
The standing version, and the one you can load in small jumps on any cable stack.
How to do it
Stand side-on to a cable at elbow height, working arm furthest away, towel roll under the elbow. Rotate out, pause, return over three seconds. At home, a band on a door handle does the same job.
What the data shows
Boettcher found external rotation positions worked the supraspinatus as hard as the "can" exercises with significantly less deltoid, and worked the infraspinatus harder still. One movement, three cuff muscles.
Load it like this
Lightest pin, 3 sets of 12 to 15. Most people can run this four or five days a week if the shoulder is no worse the next morning.
Why it ranks second
Broader reach than number one and easier to progress, with a lower single measured figure for the infraspinatus.
3. Full can
The lifting exercise for the supraspinatus, done thumb up.
How to do it
Thumb up, raise the arm about 30 degrees forward of straight out to the side, to shoulder height. Three seconds down. Stop at shoulder height while it is sore.
What the data shows
In the 2007 study the full can, the thumb-down empty can and the prone raise all hit the supraspinatus to a similar level. The full can did it with the least deltoid: middle deltoid at 52% of maximum against 77% for the empty can.
Load it like this
1 to 3 kg, 3 sets of 10 to 12, twice or three times a week.
Why it ranks third
It is the direct supraspinatus lift, and it asks more of a painful shoulder than the two rotations.
4. Prone raise with the thumb up
The hardest position on the list, and the one to finish with if you swim, climb, play padel or press overhead.
How to do it
Face down on an incline bench, arm hanging. Thumb up, raise the arm out to about 100 degrees, slightly forward of straight out, to body level. Lower slowly. Most people need 1 kg at most.
What the data shows
The 2004 study recorded the highest supraspinatus activity of anything measured here, 82% of maximum, alongside 87% for the middle deltoid and 88% for the rear deltoid.
Load it like this
0.5 to 1 kg, 3 sets of 8 to 12, twice a week, added once the first three feel easy.
Why it ranks fourth
Top cuff activity, heavy deltoid involvement, and the position most likely to flare an irritable shoulder. Earn it.
5. Cable or band internal rotation
The front of the cuff. Subscapularis is the biggest of the four, and Escamilla's 2009 review puts it at around 30% of the torque that lifts your arm out to the side.
How to do it
Stand side-on, working arm nearest the cable, towel under the elbow. Rotate in across your stomach, return slowly.
Load it like this
2 sets of 12 to 15, twice a week. Your pressing and rowing already load this muscle, so it needs less volume than the external rotations.
Why it ranks fifth
It completes the cuff. The stand-alone evidence for it is thinner than for the other four.
Side by side
| Exercise | Arm stays low | Low deltoid | Fine on a sore shoulder | Kit |
|---|---|---|---|---|
| Side-lying external rotation | Yes | Yes | Yes | Dumbbell |
| Cable or band external rotation | Yes | Yes | Yes | Cable or band |
| Full can | To shoulder height | Partly | Sometimes | Dumbbell |
| Prone raise with the thumb up | No | No | Rarely | Incline bench, dumbbell |
| Cable or band internal rotation | Yes | Yes | Yes | Cable or band |
The 12-week plan, and what to pick
Twelve weeks is the number to plan around. In a Swedish trial of 97 people already on the waiting list for shoulder surgery, three months of a specific cuff and shoulder-blade programme meant 24% went on to choose the operation within a year, against 63% of the group doing general exercise.
Dose matters as much as selection. A 2020 systematic review found low-certainty evidence that a higher-load, higher-volume programme improved function by 20 points on a 100-point scale at three months, with little difference in pain. Translation: keep adding weight.
Pick by situation
- Sore at night, aches after work. Numbers 1, 2 and 5 only, no added load for the first fortnight.
- Pressing hurts at the bottom of a bench. Drop the bench to a floor press, run 1, 2 and 3 on every upper body day, bring the bench back at 70% in week four.
- Padel, swimming or overhead lifting. All five, prone raise added in week three.
- Ten minutes, three days a week. Numbers 1 and 2, three sets each. That is the minimum that still works.
- Arm suddenly weak after a fall, or a known full-thickness tear. Get it assessed first. In the Swedish trial a full-thickness tear predicted a poorer result from exercise, while a partial tear did as well as an intact tendon.
Training at home with a band and no cable stack? Mid Sussex Osteopaths, a physiotherapy and osteopathy clinic in Haywards Heath, ranks the same five for home use in its rotator cuff strengthening exercises. Band external rotation comes first there, and the table marks which of the five suit a sore shoulder.
Stop and get seen if
- Sudden inability to lift the arm after a fall or a heavy lift.
- Pain with pins and needles or numbness running down the arm.
- Night pain that stops you sleeping for more than a week, whatever position you lie in.
- A hot, swollen shoulder, or shoulder pain with fever.
Straight answers
What is the best exercise to strengthen the rotator cuff?
Side-lying external rotation. It produced 62% of maximal activity in the infraspinatus and 67% in teres minor, the highest of seven external rotation exercises in a fine-wire EMG study, with your arm at your side and a light dumbbell.
How heavy should rotator cuff exercises be?
Light to start, 1 to 2 kg for most people, and heavier over time. Add 0.5 to 1 kg when every set reaches the top of the rep range with clean form for two sessions running.
How long does it take to strengthen the rotator cuff?
Plan on 12 weeks of two or three sessions a week. That was the length of the programme in a trial where 24% of people went on to choose shoulder surgery, against 63% on general exercise.
Should I do the empty can?
Skip it. The full can works the supraspinatus to the same level with far less deltoid, 52% of maximum against 77%, and sits better on a sore shoulder.
Can I keep lifting with a rotator cuff problem?
Usually yes, with the painful movements modified. Keep pain during the set at 4 out of 10 or below, settling within an hour and no worse the next morning, and build the cuff work in alongside.