Swimmer’s Shoulder: Understanding the Difference Between Impingement and Rotator Cuff Tendinopathy
The open-water season has a particular cruelty about it. Swimmer’s Shoulder is the main cause, you train through the winter, you put in the lake sessions as the water warms up, and then, just as triathlon season or your first sea swim comes together, your shoulder starts complaining. Not dramatically, at first. More of a dull ache at the front, a twinge at the top of the stroke, something you tell yourself will ease off once you warm up. Sometimes it does. Often, it does not.
At Joint Care Clinics, we see a steady rise in shoulder presentations from swimmers and triathletes through late spring and into summer, and a question that comes up frequently is whether the pain is shoulder impingement, rotator cuff tendinopathy, or something else entirely. The two conditions share some symptoms and the same general territory in the shoulder, but they are not the same thing, and understanding the difference matters if you want to get back in the water quickly and safely.
Why Swimmers Are Particularly Vulnerable
The freestyle stroke places the shoulder through an extraordinary range of motion, repeated thousands of times in a single session. Each time your arm enters the water and pulls through, the tendons of the rotator cuff pass beneath the acromion, a bony arch at the top of the shoulder. In a healthy shoulder with good mechanics, this happens smoothly. In a shoulder that is fatigued, asymmetrical in its muscle balance, or working through an inefficient stroke pattern, that space becomes compressed, and the tissues within it begin to be irritated.
Open-water swimming adds variables that pool training does not, including sighting, bilateral breathing under variable conditions, and sometimes a wetsuit that alters shoulder mobility and load. Triathletes face the additional challenge of transitioning from a swim to a bike and then a run, meaning the shoulder never fully recovers between disciplines during race preparation.
Shoulder Impingement: What Is Actually Happening
Shoulder impingement, more specifically subacromial impingement, occurs when the soft tissues that run through the subacromial space, primarily the supraspinatus tendon and the subacromial bursa, are repeatedly pinched between the upper arm bone and the acromion above. This is a mechanical problem, and it tends to produce a very recognisable pattern of pain.
The discomfort is typically felt at the outer edge or front of the shoulder, particularly when you raise your arm between roughly sixty and one hundred and twenty degrees. Swimmers often notice it most at the catch phase of the stroke or when reaching forward during entry. The shoulder may feel stiff in the morning, and certain sleeping positions, particularly lying on the affected side, become impossible.
Importantly, impingement in its earlier stages is not the same as a structural injury to the tendon. The tendon may be irritated and inflamed, but it remains intact. This distinction matters because it influences how quickly things can improve with the right input and whether further investigation is needed to rule out something more significant.
What Tends to Cause It in Swimmers
A combination of overuse, poor stroke mechanics, and muscular imbalance around the shoulder blade is the most common culprit. Weak lower trapezius and serratus anterior muscles, for example, can alter how the shoulder blade moves during overhead motion, reducing the subacromial space and increasing the likelihood of impingement. High mileage in a short period, as often happens when athletes ramp up their training ahead of a race, is a frequent trigger.
Rotator Cuff Tendinopathy: A Different Problem
Rotator cuff tendinopathy refers to a degenerative or reactive change within the tendon tissue itself, most commonly in the supraspinatus tendon. Rather than a straightforward inflammation response, tendinopathy involves a breakdown in the normal collagen structure of the tendon, which becomes thickened, disorganised, and less able to manage load effectively.
The symptom picture overlaps with impingement in some ways, but there are differences worth knowing. Tendinopathy pain tends to be more localised, often described as a deep ache within the tendon itself rather than a broader shoulder discomfort. It is frequently load-related, meaning it worsens during or after exercise and then settles with rest, only to return when training resumes. The notorious morning stiffness is common, and the shoulder can feel weak, particularly during rotational movements or when you try to stabilise your arm against resistance.
Tendinopathy can develop without an acute injury. It is often the result of cumulative load over time, and in swimmers, it tends to accumulate gradually and insidiously rather than arriving with a single dramatic moment.
How Do You Tell Them Apart?
Honestly, in a clinical setting, the distinction is not always obvious from symptoms alone. The two conditions frequently coexist, and impingement can, if left unmanaged, eventually contribute to tendon changes that become more akin to tendinopathy. This is one of the reasons that trying to self-diagnose from online symptom lists rarely gets swimmers to a clear answer.
At Joint Care Clinics, we use diagnostic musculoskeletal ultrasound to look directly at the structures involved. Ultrasound is particularly well suited to assessing the rotator cuff tendons and the subacromial bursa in real time, and it allows us to see whether there is bursal swelling, tendon thickening, early tendon changes, or something more significant like a partial tear. This is not information you can reliably extract from a physical examination alone, and it makes a tangible difference to how we direct your care.
A consultation at Joint Care Clinics combines a structured clinical assessment with on-the-spot imaging, so you leave knowing what you are dealing with rather than taking a best guess home with you.
If you would like to understand more about what a shoulder assessment involves, our private shoulder pain treatment page sets out the process in full.
When Should a Swimmer Seek an Assessment?
The honest answer is earlier than most people do. The instinct, especially among athletes with a race in the diary, is to push through and see whether the shoulder settles down. Occasionally it does. More often, continuing at full intensity with a symptomatic shoulder means you are training on a structure that is already under stress, which increases the risk of the problem becoming more established or progressing to something structurally significant.
Some clearer signs that an assessment would be worthwhile rather than simply waiting it out include pain that persists beyond a week or two of modified training, discomfort that is present at rest or at night rather than only during activity, any noticeable loss of strength in the arm, and pain that is getting progressively worse rather than plateauing. If your shoulder is altering how you stroke, whether you are protecting it consciously or not, it is worth getting a clear picture of what is happening.
What Treatment Looks Like
For many swimmers with impingement or early tendinopathy, treatment does not have to mean time out of the water. The approach depends entirely on what the assessment finds, but the aim is always to reduce the load on the irritated tissue, address any inflammatory component, and give the shoulder the conditions it needs to recover.
An ultrasound-guided cortisone injection into the subacromial space can be highly effective for impingement with significant bursal involvement, calming the inflammatory process and creating a window in which the shoulder can settle and be rehabilitated. For tendinopathy, the focus shifts more towards load management and, where indicated, targeted injection treatment to support tissue recovery.
Our clinician, Ram Rachaputi, has performed well over 30,000 ultrasound-guided procedures, and shoulder injections of this kind are among the most frequently requested at our clinics. The procedure is guided by live ultrasound imaging to ensure accuracy, which makes a meaningful difference to its effectiveness.
For a full overview of the shoulder conditions we assess and treat, including rotator cuff injuries, you can visit our rotator cuff injury page.
Getting Back to Training
Most swimmers and triathletes who come to us with impingement or tendinopathy do not want to stop. They want a clear diagnosis, an honest conversation about what is possible, and a realistic plan for getting back to full training. That is the kind of clinic we try to be.
We do not deal in generic timelines because every shoulder is different, but we will always give you a frank assessment of where things stand and what your realistic options are. Sometimes that means modifying training for a few weeks. Sometimes it means a single injection that allows recovery to happen much faster than rest alone would achieve. The starting point is always knowing exactly what you are dealing with.
Ready to Get Your Shoulder Assessed?
If you are heading into the open-water season with a shoulder that is not quite right, the most useful thing you can do is get it looked at properly now rather than in six weeks when a race has already passed you by. You do not need a GP referral to come to Joint Care Clinics, and we offer same-day appointments at our UK clinics.
Take a look at our treatment prices to understand what is involved, or get in touch with the team to book an assessment. Your shoulder will thank you before the start gun goes off.
Shoulder Impingement FAQs
Can I keep swimming if I have shoulder impingement?
It depends on the severity. Mild impingement with no structural damage can sometimes be managed with reduced volume and modified technique while you wait for an assessment. However, continuing to train at full intensity on an irritated shoulder carries the risk of the condition worsening or progressing to tendon damage. The safest approach is to have the shoulder assessed quickly so you know what you are actually dealing with before making that decision.
Is shoulder impingement the same as a rotator cuff tear?
No. Impingement is a mechanical problem in which the soft tissues of the shoulder become repeatedly compressed, producing pain and inflammation. A rotator cuff tear involves actual damage to one or more of the tendons. Impingement can, if it goes unmanaged, eventually contribute to tendon damage, which is one of the reasons early assessment is worth pursuing. A diagnostic ultrasound scan can confirm whether the tendon is intact.
How long does a swimmer’s shoulder take to recover?
There is no single answer because recovery depends on what is causing the pain, how long the problem has been building, and how quickly appropriate treatment begins. Impingement with bursal involvement can settle relatively quickly with the right intervention, often within a few weeks. Established tendinopathy tends to take longer and responds better to a structured plan. An early assessment gives you a much clearer picture of the expected timeline.
Do I need a GP referral to be seen at Joint Care Clinics?
No. You can self-refer directly and book an appointment without going through your GP first. We offer consultations that include on-the-day diagnostic ultrasound scanning, so you leave with a clear answer rather than a referral for a scan at a later date.