Repetitive Strain Injuries at Work: Proving the Job Caused It

A delivery driver’s elbow begins to ache after months of lifting heavy packages. A data analyst notices numbness in her fingers that gets worse by the end of each workweek. Both are facing a reality that thousands of workers confront every year: a repetitive strain injury, or RSI, that does not fade with rest. If the employer or its insurance carrier denies the claim, the financial hurt can be immediate—medical bills pile up, paychecks stop, and families scramble.

Under workers’ compensation law, a repetitive strain injury is just as real as a broken bone from a fall. The difference is that proving the job caused it requires connecting dots that can take years to form. Insurance adjusters often frame these conditions as ordinary wear and tear, age-related changes, or weekend hobbies. For an injured worker and their family, understanding what the law demands—and what evidence moves the needle—can be the difference between a string of denials and the benefits that support recovery.

Proving Causation Under Workers’ Compensation: More Than Just Saying ‘It Happened at Work’

The law does not hand out benefits simply because someone hurts while on the clock. For a repetitive strain injury to be compensable, the worker must show that the condition arose out of and in the course of employment. That phrase is a legal term of art. “In the course of” means the injury occurred while performing job duties at work, or during an activity reasonably related to work. “Arising out of” goes further—it demands a causal link between the specific tasks the worker performed and the medical harm.

In practical terms, that link is rarely obvious. Carpal tunnel syndrome, tendinitis, cubital tunnel syndrome, and even some forms of back strain develop gradually. By the time an employee seeks treatment, months or years of repetitive motion have already taken a toll. The insurance carrier may seize on that gap and argue the condition is simply a coincidence or the result of normal aging. To prevail, the worker must present evidence that the job was a substantial contributing factor, not merely a backdrop.

Medical documentation forms the foundation of that proof. A treating physician who takes a detailed occupational history and records that the patient’s symptoms are consistent with the specific repetitive tasks—such as gripping, twisting, keying, or lifting—anchors the claim. When a doctor states that the repetitive nature of the job, rather than age-related degeneration or off-duty activities, is the primary driver of the condition, the argument for compensability becomes far harder to dismiss. Without that opinion, the claim often collapses into a battle of assumptions that the insurer usually wins.

The legal standard in a workers’ compensation hearing is not beyond a reasonable doubt; it is the much lower civil standard of preponderance of the evidence. Still, meeting that threshold demands more than a worker’s testimony that “it hurts after work.” An injured person needs objective findings on MRI or nerve conduction studies, a medical explanation that connects those findings to specific exertions on the job, and a coherent timeline that shows the emergence of symptoms during a period of known physical stress at work.

In some workplaces, an ergonomic assessment can unlock a claim. If a health and safety expert inspects a workstation and finds that the chair height, desk layout, or tool vibration imposes abnormal stress on muscles and tendons, that report serves as powerful third-party evidence. It also shifts the employer’s attention toward fixing the hazard, which can prevent others from suffering the same injury.

How to Counter the Most Common Employer Defenses to Repetitive Strain Claims

When an insurer reviews a claim for carpal tunnel or tendonitis, a handful of defenses appear over and over again. The most familiar is that the condition is degenerative—just the result of getting older. The carrier may point to an X-ray that mentions mild degenerative changes and argue that the job had nothing to do with it. But arthritis in a joint does not automatically explain nerve compression in the wrist. A skilled physician can review the imaging, test nerve function, and address why the distribution of symptoms aligns with the mechanical demands of the job rather than with a systemic disease.

Another common tactic is to blame hobbies or a second job. An adjuster might suggest that knitting, gardening, or playing video games is the real culprit. While outside activities can contribute, the law in most states recognizes that a workplace aggravation of an underlying problem is still compensable. If work duties accelerated the need for treatment or made a manageable condition disabling, the employer remains responsible. Keeping a simple daily log