The Definition of Repetitive Strain Injury

Definition of Repetitive Strain Injury

A repetitive strain injury (RSI) is damage to muscles, tendons, nerves or other soft tissues that builds up over time from repeated movements, sustained or awkward postures, or forceful exertions. Unlike an injury from a single event, such as a fall, an RSI develops gradually and may get worse if the work that causes it continues.

RSIs are a type of musculoskeletal disorder (MSD). Related terms include cumulative trauma disorder, repetitive motion injury, overuse injury and, in the UK, upper limb disorder. The National Institute for Occupational Safety and Health (NIOSH) uses the broader term work-related musculoskeletal disorders.

RSIs most often affect the hands, wrists, elbows, shoulders and neck. They occur in many jobs, including assembly and manufacturing, meat and poultry processing, warehousing, construction, healthcare, office and computer work, and retail checkout.

Common Types of Repetitive Strain Injury

• Carpal tunnel syndrome: pressure on the median nerve at the wrist, causing numbness, tingling and weakness in the hand.
• Tendinitis and tenosynovitis: inflammation of a tendon or its sheath, often in the wrist, elbow or shoulder.
• Lateral epicondylitis: often called tennis elbow, pain on the outside of the elbow from repeated gripping and wrist extension.
• Trigger finger: a finger catches or locks when bent because of tendon inflammation.
• De Quervain's tenosynovitis: inflammation of tendons at the base of the thumb.
• Rotator cuff injuries: shoulder tendon damage from repeated or sustained overhead work.
• Neck and upper back strain: often linked to static postures at workstations.

Causes and Risk Factors

Physical risk factors

NIOSH explains that physical stress on the body comes from the force, repetition and postures required by job tasks. Common risk factors include:

• Repetition: doing the same motion many times with little variation or rest.
• Force: gripping, pinching, pushing or pulling with high effort.
• Awkward postures: bent wrists, raised elbows, reaching overhead or twisting.
• Static postures: holding the same position for long periods.
• Contact stress: hard or sharp edges pressing on the palm, wrist or forearm.
• Vibration: from power tools or equipment.
• Cold: cold temperatures can reduce dexterity and increase grip force.

Work organization factors

NIOSH also identifies work organization factors, such as high workloads, repetitive work, fast pace and little control over how the job is done, as contributors to musculoskeletal disorders.

Signs and Symptoms

• Aching, burning or throbbing pain.
• Numbness or tingling, especially in the fingers.
• Weakness, clumsiness or reduced grip strength.
• Stiffness or reduced range of motion.
• Swelling or tenderness.
• Symptoms that start during work and gradually last longer after the shift ends.

Early reporting matters. Symptoms caught early are usually easier to treat, and the job can be adjusted before the injury becomes long term.

Regulations and Recordkeeping

United States

OSHA does not have a specific ergonomics standard. An ergonomics rule was issued in 2000 but was repealed by Congress in 2001 under the Congressional Review Act. OSHA can still cite employers for serious ergonomic hazards under the General Duty Clause, Section 5(a)(1) of the OSH Act, and it publishes industry-specific ergonomics guidelines.

Work-related RSIs are recorded on the OSHA 300 Log using the same general recording criteria as other injuries and illnesses in 29 CFR 1904.7, such as medical treatment beyond first aid, restricted work or days away from work.

United Kingdom

The Health and Safety (Display Screen Equipment) Regulations 1992 require employers to assess workstations used by display screen users and reduce the risks.

How to Prevent Repetitive Strain Injuries

Engineering controls

• Redesign workstations so work is at elbow height and within easy reach.
• Use tools with better handles, lower weight and lower vibration, and use powered tools or fixtures to reduce force.
• Use adjustable chairs, monitor arms and keyboard trays for computer work. See office ergonomics.
• Automate the most repetitive or forceful tasks where practical.

Administrative controls

• Use job rotation between tasks that use different muscle groups.
• Schedule short, frequent breaks and allow new or returning workers time to build up to full pace.
• Train workers to recognize symptoms and report them early without fear of discipline.
• Set up an ergonomics program that includes job analysis, worker involvement and follow-up.

Medical management

Provide prompt evaluation by a health care provider when symptoms are reported, and use modified duty while the worker recovers.

Example of Repetitive Strain Injury

At a parcel sorting center, several workers on the labeling line reported wrist pain and tingling in their fingers within a few months. An ergonomic review found that each worker applied labels with a pinch grip about 1,500 times per hour while reaching across a wide belt, with their wrists bent.

The company narrowed the belt, raised the work surface to elbow height, and replaced hand labeling with a print-and-apply machine for standard parcels. It also set up rotation between labeling and scanning every two hours and encouraged early reporting. Two workers with symptoms received medical evaluation and temporary modified duty. New symptom reports from the line dropped over the following year.

Frequently Asked Questions: Repetitive Strain Injury

Is a repetitive strain injury a recordable injury?

It can be. A work-related RSI is recordable if it meets OSHA's general recording criteria, such as needing medical treatment beyond first aid, restricted work, job transfer or days away from work.

Does OSHA have an ergonomics standard?

No. OSHA's ergonomics rule was repealed in 2001. OSHA can still address serious ergonomic hazards under the General Duty Clause and through voluntary guidelines.

Can RSIs happen in office jobs?

Yes. Long periods of keyboard and mouse use, poor workstation setup and static postures can cause RSIs in the wrists, arms, shoulders and neck.

Are wrist braces a good way to prevent RSIs?

Braces and supports are not a substitute for fixing the job. Prevention should focus on reducing repetition, force and awkward postures through workstation and task design.