Repetitive Strain Injury (RSI): Symptoms, Causes and Prevention at Work

What is a repetitive strain injury?

Repetitive strain injury (RSI) is a general term for pain caused by repeated movement of part of the body. That is how the NHS defines it, and it is deliberately broad. RSI is a label for a pattern of symptoms rather than a single disease.

CCOHS places RSI inside the larger group of work-related musculoskeletal disorders (MSDs): painful disorders of muscles, tendons and nerves. It describes "repetitive strain injuries" as a sub-group of MSDs mainly caused by repetition, which can also be caused by forceful motions or awkward postures. Other names you may hear include cumulative trauma disorders, overuse syndrome and soft tissue disorders.

This article is general information, not medical advice. If you have persistent or worsening pain, numbness or weakness, see a doctor or physiotherapist.

If you suspect your desk setup is contributing, the workstation self-assessment is a quick way to spot the usual risk factors.

What are the symptoms of RSI?

The NHS says RSI symptoms usually start gradually and can include:

• Pain, which may feel like burning, aching or throbbing.
• Tingling, pins and needles, or numbness.

CCOHS adds that MSD symptoms can include joint stiffness, muscle tightness, redness and swelling, and in some cases skin color changes and decreased sweating of the hands. Nerve compression can cause muscle weakness, pins and needles, and numbness.

RSI can affect the shoulder, elbow, forearm, wrist and hand, and CCOHS notes that because almost all work uses the arms and hands, most MSDs affect the hands, wrists, elbows, neck and shoulders.

How does RSI progress?

CCOHS describes three stages. Not everyone follows them neatly, and the boundaries are blurry, but they are a useful warning system.

Stage	What happens (CCOHS)
Early	Aching and tiredness of the affected limb during the shift, gone by night and on days off. No drop in work performance.
Intermediate	Aching and tiredness start early in the shift and persist at night. Reduced capacity for repetitive work.
Late	Aching, fatigue and weakness persist at rest. Difficulty sleeping and doing light duties.

CCOHS's advice is to treat the first pain, numbness or tingling as a signal that muscles and tendons need rest and recovery. Otherwise an injury can become long-standing and sometimes irreversible. The earlier symptoms are recognized, the sooner they can be addressed.

What causes RSI?

The NHS lists common causes, including:

• Repetitive activities such as typing, hairdressing, decorating or assembly-line work.
• Sports with lots of repetitive movement, such as golf or tennis.
• Poor posture when sitting or standing at work.
• Regular use of hand-held power tools.

CCOHS explains that ordinary movements like gripping, twisting, reaching and bending are not harmful in daily life. What makes them hazardous at work is continual repetition, often with force, at speed, and without enough time to recover. It lists the work patterns linked to MSDs:

• Fixed or awkward body positions.
• Continual repetition of movements.
• Force concentrated on small parts of the body, such as the hand or wrist.
• A pace of work that doesn't allow enough recovery between movements.
• Exposure to heat, cold or vibration.

CCOHS also notes that psychosocial factors such as stress and muscle tension can contribute.

The NHS adds an important balance: repetitive or strenuous work does not always cause RSI, and many people do the same job for years without problems. Arm pain is often caused by a combination of things, including aging.

Which conditions fall under RSI?

CCOHS lists the most common upper-body disorders and their occupational risk factors:

Disorder	Occupational risk factors (CCOHS)
Tendinitis / tenosynovitis	Repetitive wrist or shoulder motions, sustained hyperextension of the arms, prolonged load on the shoulders
Epicondylitis (elbow tendinitis)	Repeated or forceful forearm rotation combined with wrist bending
Carpal tunnel syndrome	Repetitive wrist motions, awkward hand positions, strong gripping, mechanical stress on the palm, vibration
De Quervain's disease	Repetitive hand twisting and forceful gripping

Only a clinician can diagnose which, if any, applies to you.

Can RSI come from typing and computer work?

Computer work looks low effort, but OSHA points out that using a mouse for several uninterrupted hours can expose the small muscles and tendons of the hand to hundreds or even thousands of repetitions, without adequate recovery time. Holding a static posture, such as looking at the screen, also fatigues the neck and shoulder muscles.

Desk-specific risk factors from OSHA's eTool:

• Keyboard too low, so the wrists bend upward. OSHA notes this can make the finger tendons and sheaths bend around the wrist bones.
• Mouse placed far away, pulling the arm out from the body and loading the shoulder.
• Mouse sensitivity set wrong, forcing either a tight grip or large wrist movements.
• Hard desk edges or wrist rests pressing on the forearm (contact stress).

The same principles apply on the factory floor, where force and pace usually matter more. Our guide to work-related musculoskeletal disorders covers industrial jobs.

How can repetitive strain injury be prevented at work?

Prevention targets the risk factors: repetition, force, awkward posture, static loading and lack of recovery.

Fix the workstation

• Keyboard directly in front, at about elbow height, with straight wrists (OSHA keyboards).
• Mouse close to the keyboard, in line with the elbow, set to a light-touch sensitivity (OSHA pointer/mouse).
• Chair, desk and screen set for a neutral posture. See good sitting posture and our desk setup checklist.

Change how the work is done

From OSHA's work process guidance:

• Vary tasks and mix in non-computer work.
• Use keyboard shortcuts (Ctrl+S, Ctrl+P) to cut mouse use.
• Alternate the mouse hand where possible.
• Take short micro breaks to stand, move and run through a few simple desk stretches.

HSE says short, frequent breaks are better than long, infrequent ones, such as 5 to 10 minutes every hour rather than 20 minutes every 2 hours.

Train people to spot early symptoms

OSHA notes that workers who don't know the signs of MSDs may not report them, and delays can mean more severe injury. Awareness training should cover risk factors, how to adjust equipment and how to recognize discomfort.

Assess and reassess

HSE requires a new DSE assessment when users complain of pain or discomfort, among other triggers. For industrial tasks, structured tools such as RULA give a repeatable score for upper-limb posture; see our RULA assessment guide. For hand and wrist jobs, a Strain Index calculation shows which of force, repetition or posture to fix first. ViveLab's posture analysis from video can estimate a RULA score from a phone video on-device, as a starting point for a trained assessor to review.

What should you do if you have RSI symptoms?

The NHS self-care advice for RSI:

• Keep active. You may need to limit activity at first, then increase it gradually.
• Don't rest the area for more than a few days. Resting too long can make the body part weaker and less flexible.
• Try a cold pack wrapped in a towel on the area for up to 20 minutes every 2 to 3 hours.
• Ask a pharmacist about painkilling tablets or gels.
• Talk to your employer about changes such as how you work or your hours.

The NHS says to see a GP if symptoms aren't going away or are getting worse. Treatment may include physiotherapy, occupational therapy (which can identify the cause and suggest workspace changes), and sometimes steroid injections. Surgery is rarely needed.

Most people with repetitive strain injury manage their symptoms and get better without further treatment, according to the NHS.

Next steps

Preventing repetitive strain injury at a desk comes down to setup, variety and recovery time. Run the workstation ergonomic assessment to find the risk factors at your desk, fix the keyboard and mouse first, and build short breaks into every hour. For eye symptoms that often travel with heavy computer use, see eye strain remedies.