Swimming Injuries: Shoulder, Knee, Ears, Concussion and Water Safety

This article contains affiliate links: if you buy through them we may earn a commission, at no extra cost to you. Learn more.

It’s 5:30 a.m., the pool deck still smells of chlorine and coffee, and a 15-year-old is rolling her right shoulder before the first set, the way she has every morning for a month. Her coach notices. Swimming is kind to the body, with no tackles or hard landings, but it asks the same few joints to repeat the same motion thousands of times a week, and the water has its own dangers. This page covers swimming injuries at every level, from summer-league kids to college, masters and Olympic swimmers: the overuse problems that show up most, the medical issues the pool causes, the rare but serious emergencies, and when to stop and see a professional.

This page is general information, not medical advice. If you’re hurt, see a sports medicine doctor, physical therapist (PT) or certified athletic trainer (AT). For the bigger picture of the sport, start at our swimming hub.

How swimmers get hurt

Mostly by doing a lot of one thing. In a national study of high school swimming and diving (2008–2019), almost half of swimmers’ injuries (48.6%) were to the shoulder, about two-thirds happened in freestyle, and 58% were overuse injuries rather than one sudden event. In NCAA swimming and diving, the shoulder was again the most injured body part, and female swimmers had a higher overuse injury rate than male swimmers. A 2021 review of adult swimmers found the same three trouble spots: shoulder, knee and lower back. Divers are different: in the high school data their most common injuries were to the head and face, mostly from hitting the water or the board.

Swimmer’s shoulder

“Swimmer’s shoulder” is the name for pain at the front or top of the shoulder that builds with training. The American Academy of Orthopaedic Surgeons (AAOS) calls shoulder pain from repetitive stroke motion the most common swimming injury. In one study of 80 elite young swimmers aged 13–25, 91% reported shoulder pain, and the main cause on MRI was irritation of a rotator cuff tendon (the supraspinatus). The more hours and the more distance they swam each week, the more likely that tendon was affected. Stroke preference made no difference.

What helps, according to AAOS and the research: a 5–10 minute warm-up before getting in, strengthening the muscles around the shoulder and upper back, mixing strokes, and not training through pain. In a 2025 randomized trial, competitive swimmers aged 16–35 who did a five-exercise shoulder program twice a week for 12 weeks (with light weights or elastic bands) kept their rotator cuff strength better balanced over the season than swimmers who didn’t. There’s more on fitting this into a week on our swimming training page.

Breaststroker’s knee

The breaststroke whip kick bends, twists and snaps the knee together every stroke, and the inside of the knee takes the strain. In a survey of 391 competitive swimmers, 73% of breaststroke specialists and 48% of other swimmers reported knee pain, and the pain involved the inner knee ligament (the medial collateral ligament) and the inner edge of the kneecap. Older swimmers and those with more years in the sport reported more pain. The same study found injury rates rose sharply when swimmers’ hips were opened too little or too wide at the start of the kick. An earlier study found the pain usually began within three years of starting breaststroke, and that swimmers without pain kicked differently from those with it.

The practical message: inner-knee pain during breaststroke kick is a technique and load problem first. Tell your coach early, cut back on breaststroke kick sets while it settles, and have a PT or sports medicine doctor look at it if it lingers or starts hurting outside the pool.

Low back pain

Butterfly and breaststroke arch the lower back again and again, and dolphin kicks off every wall add more. AAOS notes that young athletes in sports with frequent overstretching of the lower spine are more likely to develop spondylolysis, a stress fracture in a small bone at the back of the spine. It can feel like a muscle strain that gets worse with activity and better with rest, sometimes with stiffness and tight hamstrings. A young swimmer with back pain that lasts more than a couple of weeks, or that hurts when arching backward, should be checked by a doctor rather than stretched through it.

Swimmer’s ear, skin and chlorine

Swimmer’s ear (otitis externa) is an infection of the outer ear canal. The CDC says to watch for pain when the outer ear is tugged or pressed, itching inside the ear, drainage, redness and swelling, and to see a healthcare provider for ear pain or drainage. It usually needs prescription ear drops. To keep ears dry, the CDC suggests a swim cap, ear plugs or custom-fitted swim molds; tilting each ear down and pulling the earlobe to let water drain; drying ears with a towel; and asking your provider about ear-drying drops. Don’t put swabs or anything else in the ear canal, and don’t try to remove ear wax, which protects the canal.

Red eyes, itchy skin and coughing are often blamed on chlorine, but the CDC explains that the strong “chlorine smell” is usually chloramines: irritants formed when chlorine mixes with sweat, urine, dirt, skin cells and products that wash off swimmers. They can cause red, itchy eyes, skin irritation and rashes, and nasal irritation, coughing and wheezing; they can trigger asthma attacks, and they’re more common in poorly ventilated indoor pools. Showering for a minute before you swim removes most of the dirt, and well-fitting goggles protect the eyes. For dry skin after daily practice, the American Academy of Dermatology suggests short, warm (not hot) showers, patting skin dry and applying a fragrance-free moisturizer within a few minutes. Swimmers with asthma that flares at the pool should talk to their doctor.

Concussion: walls, lanes and dives

Swimmers do get concussions: a backstroker who misses the flags and hits the wall head-first, two swimmers colliding in a crowded warm-up lane, or a dive into a lane that wasn’t clear. Backstroke flags hang 5 yards (or 5 meters) from the wall so swimmers can count strokes to the turn. USA Swimming requires feet-first entry during meet warm-ups, with racing starts only in designated sprint lanes, under a supervisor on deck.

The CDC’s HEADS UP rule is the same in the pool as on a field: if you think someone may have a concussion, take them out for the rest of the day until a health care provider clears them. “When in doubt, sit them out.” Signs include looking dazed, slow answers, clumsiness, mood changes and vomiting; swimmers may report headache, dizziness, nausea, blurry vision or feeling foggy. Call 911 for the CDC’s danger signs: one pupil larger than the other, a headache that worsens and won’t go away, slurred speech, weakness or numbness, repeated vomiting, seizures, growing confusion, or loss of consciousness. Return is gradual and step by step, with no same-day return after a diagnosed concussion (AMSSM), and final clearance from a licensed provider.

Drowning and hypoxic blackout: the warnings every swimmer needs

Good swimmers drown too. The CDC says drowning happens in seconds and is often silent, and more children aged 1–4 die from drowning than from any other cause. Strong, fit swimmers face a specific danger: hypoxic blackout (often called “shallow water blackout”). The American Red Cross, the YMCA of the USA and USA Swimming warn together that hyperventilating before swimming underwater and extended breath-holding are dangerous and potentially deadly. Over-breathing lowers carbon dioxide, which can delay the body’s urge to breathe until oxygen runs so low that the swimmer passes out underwater, without warning.

• Never hyperventilate before swimming underwater (CDC), and don’t play breath-holding games or do “how far can you go underwater” challenges.
• Never swim alone. Use the buddy system and swim where a lifeguard or coach is watching (CDC, AAOS).
• Never dive into shallow or murky water. AAOS reports more than 1,900 spinal cord injuries from diving each year, most causing paralysis of all four limbs. Check the depth, enter feet first if you’re not sure, and swim away from the board after a dive.
• Skip alcohol before and during swimming (CDC, AAOS), and don’t swim when exhausted, very cold or overheated.
• For families: the American Academy of Pediatrics (July 2026 policy statement) says swim lessons can start after a child’s first birthday, alongside close supervision, life jackets, four-sided pool fencing and CPR. Lessons don’t replace watching.

Gear many swimmers keep in the bag

None of these prevent injury on their own, so ask your PT, athletic trainer or doctor what fits you. But many swimmers carry moldable silicone ear plugs like Mack’s Pillow Soft to keep water out of their ears, a light band kit like the THERABAND Beginner Kit for shoulder exercises before practice, and a chlorine-removal shampoo and body wash like the TRISWIM Swim Care Set for the post-practice shower. Anyone with ear tubes or a past ear problem should ask their doctor before using plugs or ear drops.

When to see a sports medicine doctor, PT or athletic trainer

• Right away (emergency): a swimmer pulled from the water unconscious or not breathing normally (call 911 and start CPR if trained), any concussion danger sign, or a diving injury with neck pain, numbness or weakness (keep them still and call 911).
• Within a day or two: a suspected concussion, ear pain or drainage, or a shoulder that suddenly can’t lift or feels like it slipped.
• Soon: shoulder, knee or back pain that lasts more than a week or two, pain that changes your stroke, pain at night or at rest, or back pain in a young swimmer that hurts when arching.

Who does what: a sports medicine physician diagnoses and decides on imaging; a physical therapist builds the rehab and the stroke-by-stroke return; a certified athletic trainer is on deck at many high schools and colleges and is often the first to spot a problem. Bring your training log, because overuse injuries follow load. After an injury, look after the basics on our swimming recovery page, and see how other sports handle it on our soccer injuries page.

Swimming injuries: FAQs

What is the most common swimming injury?

Shoulder pain from overuse. AAOS calls it the most common swimming injury, and in national high school data almost half of swimmers’ injuries were to the shoulder, most of them overuse injuries.

Should I swim through shoulder pain?

No. AAOS advises not training through pain; cut back how hard or how often you swim and get it checked if it doesn’t settle. In elite swimmers, more weekly hours and distance were linked with more rotator cuff tendon problems, so the fix often starts with the training load.

Why do breaststrokers get knee pain?

The whip kick strains the inside of the knee on every stroke. In one survey, 73% of breaststroke specialists reported knee pain. How wide the hips open at the start of the kick seems to matter, so a coach’s eye on technique is the first step, with a PT if pain lingers.

How do I prevent swimmer’s ear?

Keep your ears as dry as possible: cap, ear plugs or swim molds while swimming, then tilt and drain each ear and towel-dry. Ask your provider about drying drops, and never put swabs in the ear canal (CDC).

What is shallow water blackout?

It’s passing out underwater from lack of oxygen, usually after hyperventilating or long breath-holding. The Red Cross, YMCA and USA Swimming call it hypoxic blackout and say both habits are dangerous and potentially deadly. Never hyperventilate, never do breath-holding contests, and never swim alone.

Can you get a concussion swimming?

Yes: from hitting the wall on backstroke, collisions in warm-up lanes or diving. The CDC rule applies: remove the swimmer, no return that day, and clearance from a health care provider before they swim again.