The purpose of the research is to carry out an epidemiological study of the relation between the risk of back pain and the nature of tasks carried out by coalminers. Those among the current workforce of two modern collieries who have suffered back pain during a defined, recent period will be identified from medical records.

A case-control study will then examine the association between the nature of tasks performed at work and other factors, and the risk of back pain.

The subjects, selected according to their medical records, will be workers who have suffered back pain over a recent period . Controls will be selected from colliery workers who have not suffered back pain.

These men will be invited to answer a detailed questionnaire about their jobs and movements of the back performed during the last six months, and any previous history of back pain. This questionnaire will be designed by a team including an orthopaedic surgeon, an epidemiologist, an ergonomist, a statistician and a programmer. It will attempt to determine in detail what movements of the back have been performed regularly, with information on the direction, loading, frequency and range of these movements and associated posture.

METHODS AND MEANS BY WHICH THE AIMS ARE TO BE ACHIEVED

The movements and activities performed by cases and controls will be compared using contingency tables and logistic regression methods as appropriate. The relative risks of performing particular tasks and of making particular movements will be described. In addition, a comparison will be made of the distribution of jobs between cases and all others in the collieries.