More than half of computer users developed neck or shoulder symptoms during the first year on a new job, a new study has found.

For three years, researchers tracked 632 men and women who were hired for jobs requiring 15 hours or more per week of computer use.

The workers' posture and risk factors were assessed at the beginning of the study, and the dimensions of their workstations were measured.

Keyboard position makes a difference

Every day, the participants recorded their work practices and incidence of musculoskeletal symptoms in their neck, shoulder, hands or arms.

Participants who reported symptoms were then examined for specific musculoskeletal disorders.

The researchers say this is the first time a group of computer users has been followed over time, so the number of new cases per year could be described.

The results showed nearly 40 per cent of participants developed a hand or arm symptom each year while using a computer and 21 per cent actually developed a disorder.

Poor posture and improper positioning of the monitor, keyboard and mouse are all risk factors for injury.

The study was led by Dr. Fredric Gerr of Emory University in Atlanta. It appears in the March issue of the American Journal of Industrial Medicine.