When the summer heat sets in, many people head to the pool to cool off and get some exercise. Swimming is a fantastic, low-impact workout — but it’s also more demanding on the body than it looks. Without good technique, swimmers can develop injuries that keep them out of the water and put a damper on the whole season. One of the most common of these is swimmer’s shoulder.

What Is Swimmer’s Shoulder?

Swimmer’s shoulder is an overuse injury — the most common injury swimmers face. It typically shows up as a sharp pain during your stroke and a dull, throbbing ache afterward. It develops from the repetitive stress placed on the shoulder as the arm enters and pulls through the water, especially in freestyle and butterfly, where the shoulder rotates inward again and again.

The culprit is volume plus mechanics. A swimmer can take somewhere around 3,000 arm strokes in a single hour in the pool, and every one of those strokes carries the shoulder through its range of motion. When that enormous repetition is combined with imperfect technique — or performed on a fatigued, under-conditioned shoulder — the rotator cuff tendons can become pinched and irritated over time. The good news is that swimmer’s shoulder is largely preventable, and the two biggest levers are your technique and your strength.

Refine Your Technique

Small changes to your stroke mechanics can dramatically reduce the stress on your shoulder:

• Enter fingertips-first, not thumb-first. Your hand should slice into the water flat, with the fingertips leading. A thumb-first entry forces the shoulder into excessive internal rotation — the exact position that leads to impingement.
• Don’t cross the midline. Your hand should enter the water roughly in line with your shoulder, not reaching across the center of your body. Crossing over rotates the shoulder inward under load and pinches the rotator cuff.
• Roll your whole body. Efficient freestyle comes from rotating your torso side to side, not just swinging your arms. Good body roll lengthens your reach and takes strain off the shoulder.
• Keep a high elbow through the pull. A high-elbow catch distributes the workload more evenly and keeps you from muscling the stroke with your shoulder alone.

Strengthen and Prepare Your Shoulders

Over a long season, swimmers tend to develop a strength imbalance in the shoulder — and that imbalance is a major risk factor for injury. Building strength is one of the most effective ways to protect yourself:

• Rotator cuff and scapular work. Banded external and internal rotations, plus rowing motions and shoulder-blade squeezes, help balance and stabilize the shoulder.
• Core and posture. A strong core keeps your body aligned in the water so your shoulders don’t have to compensate, and good upper-body posture out of the pool carries over into your stroke.
• Warm up before you swim. A few minutes of gentle, active movement prepares the shoulder for the demands ahead.

It’s worth noting that swimmers often already have plenty of shoulder flexibility, so prevention is less about aggressive stretching and more about building stability and control around a mobile joint — alongside solid technique.

Manage Fatigue and Training Load

Because swimmer’s shoulder is an overuse injury, how much you swim matters as much as how you swim. Build your yardage up gradually rather than jumping into long, hard sessions, and be mindful that form tends to break down as you tire — which is exactly when injuries happen. Backing off before fatigue wrecks your technique is a form of prevention in itself.

Listen to Your Body

Some muscle soreness after a swim is normal. But pain that shows up during your stroke, or a throbbing that lingers afterward, is a signal worth respecting. If that happens, ease off, and applying ice can help calm the irritation. If the pain persists despite rest, it’s wise to see a physical therapist. A PT can analyze your stroke mechanics, address the muscle imbalances and mobility restrictions behind the problem, and build a strengthening plan for the whole kinetic chain — not just the shoulder itself.

By fine-tuning your mechanics, strengthening the right muscles, and respecting your body’s signals, you can keep swimmer’s shoulder at bay and enjoy a carefree summer in the pool. If you’re dealing with shoulder pain that won’t quit, the team at Advance Physical Therapy is here to help you get back in the water.