Internal impingement (posterosuperior impingement)

What it is

With the arm up and rotated fully back, the underside of the rotator cuff makes contact with the back and top rim of the socket and the labrum sitting on it. That contact happens in everyone and is normal. It becomes a problem when it happens too often, too hard, or with the ball sitting slightly out of position in the socket, and the underside of the cuff and the labrum start to fray. This is the most common source of back of shoulder pain in volleyball hitters.

How volleyball causes it

The cocking phase of the spike approach puts the shoulder in maximal external rotation with the arm abducted, and the jump serve does the same with an even longer arm path. In that exact position the cuff is trapped between the ball and the back rim. Two things make it worse: a tight posterior shoulder that shifts the ball backwards and upwards in the socket, and a shoulder blade that stops tilting back properly once it fatigues late in a session. Hitters who drive the elbow behind the line of the body, often to get around a low or tight set, spend more time in the worst position and collect this faster.

ServingAttacking

What it feels like

• A sharp, deep pinch at the back of the shoulder exactly when the arm is furthest back
• It only hurts at high effort. Warm up swings and passing are fine, full swings and jump serves are not
• Nothing in the gym reproduces it. Pressing, rowing and daily life feel normal
• The arm feels heavy or dead late in a long session and the swing shortens
• Tender when you press deep into the back of the shoulder joint line
• Usually paired with an obvious loss of inward rotation on the hitting side

Stop and get it seen if

• A feeling that the shoulder slips, shifts, or nearly comes out in the cocking position. That is instability and it changes the whole picture.
• Catching, locking, or a clunk that stops the arm mid movement.
• A dead, numb, or tingling arm that persists after you stop playing instead of clearing within minutes.
• Sudden weakness lifting the arm or rotating it outwards after one specific swing.

What recovery usually looks like

Stages, not a schedule. Everyone moves through these at their own pace, and the ranges are wide because real recoveries are.

1. 1. Unloading the cocking position

   2 to 6 weeks

   Keep the shoulder out of end range hitting long enough for the irritated tissue to settle, while the rest of training continues

   • No pain at the top of the reach in everyday movement
   • Standing float serve or controlled tosses without symptoms
   • Back of the shoulder no longer tender to press
   • Able to reach overhead and rotate through range without the pinch

2. 2. Fixing what put you there

   4 to 10 weeks

   Regain internal rotation, posterior cuff strength, mid back mobility and blade control, because this is a mechanical setup problem more than a tissue problem

   • The internal rotation gap between sides is shrinking on repeat measurement
   • The blade holds position while slowly lowering the arm from overhead
   • Overhead loading tolerated without provoking the pinch
   • Can reach the cocking position slowly with no symptoms

Ready to play again when

• Full speed hitting with no pinch at the reach back position
• No symptoms 24 hours after a full hitting session, on two or three sessions in a row
• Internal rotation on the hitting side back to a normal range for you and stable week to week
• Jump serve at competitive effort without protecting the arm

Keeping it from coming back

This is ordinary training, so unlike the rest of this page it does tell you what to do.

• Cross body stretch and sleeper stretch daily on the hitting side. Loss of internal rotation is the single most changeable thing feeding this injury.
• Mid back mobility work, for example foam roller extensions and open book rotations, so the reach back comes partly from the upper spine instead of entirely from the shoulder.
• Prone Y and T raises plus side lying external rotation for the posterior cuff and lower trapezius, which control where the ball sits in the socket at end range.
• Serratus anterior work such as bear crawls and landmine presses, because a blade that stops tilting back closes down the space at the top of the swing.
• Ask a coach to watch whether your elbow drives behind your body line at cocking, especially on tight sets. Better sets and a cleaner arm path fix more shoulders than any exercise.