Thrower's shoulder

What it is

Repeated throwing or serving produces predictable adaptations: the back of the shoulder capsule and the muscles behind it tighten, internal rotation is lost, and external rotation increases. Some of this is a useful adaptation - it is part of how throwers generate velocity - and beyond a threshold it becomes a problem.

When internal rotation loss exceeds the gain in external rotation, the head of the humerus shifts position during the late cocking phase, the cuff and labrum are stressed abnormally, and the whole chain compensates. The elbow is where a great deal of that compensation ends up, which is why shoulder and elbow problems travel together in throwers.

What it feels like

• Pain at the back or front of the shoulder during throwing or serving
• Loss of velocity or control before the pain becomes obvious
• A dead arm sensation after throwing
• Noticeably less internal rotation on the throwing side
• Sometimes inner elbow pain rather than shoulder pain, from the same problem

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Posterior capsule tightening

Repeated deceleration of the arm after ball release stresses the back of the capsule, which thickens and tightens. This is the anatomical basis of the internal rotation loss.

Posterior muscle tightness

The external rotators and posterior deltoid work eccentrically to decelerate the arm thousands of times. They shorten and stiffen, adding to the restriction.

Humeral retroversion

In athletes who threw during adolescence, the upper arm bone itself twists slightly. This is a bony adaptation, not a soft tissue one, and it accounts for part of the rotation difference in a way that stretching cannot change.

The head shifting during late cocking

With restricted internal rotation the humeral head shifts backward and upward as the arm is cocked. That changes the contact between structures and stresses the labrum and cuff abnormally.

Rotator cuff and scapular fatigue

Both fatigue through an outing and across a season. Once they cannot control the joint, the passive structures take the load and the mechanics deteriorate further.

Throwing volume

As with youth throwers, total volume is a dominant risk factor at every level. Pitch and serve counts matter.

Poor trunk and hip contribution

A throw is a whole-body movement. When the legs, hips and trunk contribute less, the arm has to generate more, and the shoulder pays for it.

Throwing while fatigued

Mechanics deteriorate with fatigue and injuries cluster late in outings and late in seasons.

No off-season

Year-round throwing removes the recovery period during which the adaptations partly reverse. It is strongly associated with injury at every age.

Not measuring the rotation

The internal rotation deficit is measurable and trackable. Athletes who monitor it and address it before it exceeds the threshold have fewer problems.

Who tends to get it

• Baseball and softball pitchers, javelin throwers, volleyball and tennis players
• Anyone with a measurable internal rotation deficit on the throwing side
• Athletes throwing year-round with no off-season
• Those with weak scapular and cuff musculature
• Anyone throwing through fatigue or with high volumes

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineRotation Sports (Golf, Racquet & Throwing)

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

A dead arm, sudden loss of throwing velocity with pain, numbness in the hand, or a shoulder that clunks or slips - specialist review; night pain in an over-40 thrower may be a cuff tear

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Posterior soft tissue restriction responds to stretching over six to twelve weeks and needs maintaining throughout a throwing career. Bony retroversion does not change and does not need to - the target is total rotation and soft tissue mobility rather than symmetry. Structured programmes combining stretching, cuff and scapular strengthening and volume management reduce shoulder and elbow injuries in overhead athletes, and monitoring the rotation deficit is the cheapest early warning available.

Prevalence basis: Systematic review of GIRD and upper-extremity injury risk in overhead athletes (Archives of PM&R 2024); overhead athlete screening cohorts

Others the same routine covers

These share the Rotation Sports (Golf, Racquet & Throwing) routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.