What is shoulder impingement?
Shoulder impingement occurs when the tendons and bursa that sit between the ball of your shoulder (humeral head) and the bony roof above it (acromion) get pinched during movement. Imagine a rope (the rotator cuff tendon) running through a narrow tunnel. If the tunnel gets narrower — or the rope gets swollen — they rub against each other, causing pain and inflammation.
The pain typically occurs when you lift your arm out to the side or overhead, in a range called the "painful arc" — usually between 60 and 120 degrees of shoulder abduction. Below 60 degrees, there is enough space. Above 120 degrees, the structures have cleared the acromion. Between those angles, the space is at its narrowest, and that is where the pinching happens.
Why it happens in rugby players
Rugby players are particularly susceptible to shoulder impingement because of the specific demands the sport places on the shoulder:
- Heavy bench pressing — the primary upper-body exercise in most rugby programmes. High pressing volumes (3-5 sessions per week for some players) overdevelop the anterior deltoid and pectorals while the rotator cuff and scapular stabilisers lag behind. This muscular imbalance pulls the humeral head forward and upward, narrowing the subacromial space
- Lineout throwing — hookers perform hundreds of overhead throws per week. The repetitive overhead motion loads the subacromial structures in the exact range where impingement occurs
- Overhead lifting — push presses, overhead presses, and jerks in the gym place the shoulder under high load at full elevation. If scapular control is poor, the acromion does not tilt out of the way, and impingement results
- Falls onto the shoulder — tackles and being driven into the ground compress the shoulder joint, potentially inflaming the subacromial bursa or aggravating existing tendon irritation
- Swimming for recovery — many clubs use pool sessions for recovery. The freestyle stroke places the shoulder in the impingement zone hundreds of times per session. For a player with subclinical impingement, recovery swimming can become the trigger that tips them into pain
The modern understanding: impingement is a symptom, not a diagnosis
Historically, shoulder impingement was treated as a structural problem — the acromion was "too hooked" or the space was "too narrow," and surgery was needed to shave the bone. Modern research has changed this view significantly. In most cases, the impingement is caused by how the shoulder moves, not what it is shaped like.
The underlying problems that cause impingement are usually modifiable:
- Weak rotator cuff — the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis) compress and depress the humeral head during movement, keeping it centred in the socket. When they are weak, the humeral head rides upward, reducing the subacromial space
- Poor scapular control (scapular dyskinesis) — the scapula must rotate upward and tilt posteriorly when the arm is raised. If the muscles controlling this movement (serratus anterior, lower trapezius) are weak, the acromion fails to clear out of the way, pinching the structures beneath it
- Tight pectorals and anterior shoulder — tightness in the pec minor and anterior deltoid pulls the scapula forward into a protracted position, which tilts the acromion downward and narrows the subacromial space from above
- Poor thoracic mobility — a stiff, kyphotic thoracic spine (common in rugby players from prolonged sitting and forward-leaning postures) limits scapular upward rotation. The scapula cannot move properly on a stiff ribcage
Conservative management
Because impingement is driven by modifiable factors, conservative management that addresses the root causes is highly effective. The approach targets four areas simultaneously:
- Rotator cuff strengthening — external rotation exercises (cable, band, or side-lying dumbbell), prone Y and T raises, and empty-can/full-can exercises. Start with light weights and high reps (3 sets of 15-20). Progress load gradually over 6-12 weeks
- Scapular stabilisation — serratus anterior wall slides, lower trapezius prone lifts (prone Y raise), scapular push-ups (push-up plus), and banded pull-aparts. These muscles control scapular rotation during arm elevation
- Thoracic mobility — foam roller extensions, open-book rotations, and cat-cow exercises. Improved thoracic extension allows the scapula to rotate fully during overhead movements
- Pressing volume management — reduce bench pressing frequency and volume during the acute phase. Modify bench press angle (incline or floor press to limit range of motion). Replace overhead pressing with landmine pressing (reduced impingement risk). Increase rowing and pulling volume
Training modifications during recovery
| Exercise | Modification | Reason |
|---|---|---|
| Flat bench press | Reduce to 1-2 sessions per week. Use a closer grip. Stop 2-3 cm above the chest | Limits end-range shoulder extension, reducing anterior humeral glide |
| Overhead press | Replace with landmine press or high-incline dumbbell press | Reduces impingement-zone loading while maintaining pressing strength |
| Dips | Avoid until pain-free. The deep shoulder extension position is provocative | Maximal anterior humeral translation occurs at the bottom of a dip |
| Rows | Increase volume. Add face pulls, band pull-aparts, and prone Y raises | Strengthens the posterior shoulder and improves the pressing-to-pulling ratio |
| Swimming (recovery) | Replace freestyle with backstroke, or substitute with pool walking or aqua jogging | Freestyle places the shoulder in the impingement zone repeatedly |