INTRODUCTION:Our knowledge of the risk factors involved in the process by which acute pain becomes chronic has improved. Psychological conceptualizations of chronic pain presently include (1) the pain-tension cycle, with special reference to a diathesis-stress model, (2) the operant conditioning model, and (3) the interrelationship between vulnerability to pain attacks on the one hand and body posture, gait and activities of daily living on the other. With reference to these conceptualizations and to psychological procedures for the enhancement of self-management strategies, a low back school was implemented at the worksite as a preventive measure. The target population is characterized by (1) rare but recurrent pain episodes, (2) mild pain that has had little impact on daily activities, and (3) pain contingent on particular activities or situations. LOW BACK SCHOOL: A low back school called "Turn your back on backache" consists of the following elements: (1) analysis of labour conditions and adaptation of the worksite to the person, (2) relaxation and stress management, (3) training of posture, gait, and activities of daily living, and (4) stretching and stengthening of the muscles involved. The programme comprises 12 2-h sessions and is conducted by a physiotherapist according to a manual, after an introduction to self-management procedures including behavioural training for working with groups. For homework, participants are asked to practise the exercises demonstrated. METHOD AND RESULTS:In a preventive context, pain ratings should be of minor importance as an outcome measure. Assuming that future pain is interrelated with present behaviour, changes in behaviour should be the predominant criteria applied to assess the effects of the training. Therefore, as well as assessments of pain episodes and wellbeing, a behavioural observation method based on video-taped behavioural assessment in a standardized situation was used. Course members had to demonstrate a sequence of different activities, including standing and walking, lifting and bending. Each sequence was rated on a four-point scale reflecting the degree to which adequate posture and gait were achieved. The final scale consists of 13 items with an inter-rater-reliability of 0.91 (Cronbach Alpha). The data for 283 persons attending in 31 courses in different industrial and administrative settings was used to evaluate the outcome. A marked decrease in pain episodes and an increase in health status and wellbeing were reported. Behaviour that was learned in the course had been incorporated into everyday activities at the worksite. The behavioural observation method was utilized in a subgroup of this sample who were on the staff of a university hospital. The study used a 2x2 repeated-measures design with the between-subject factor of treatment condition (training vs nontraining) and the within-subject factor of assessment period (pre-treatment=t1, post-treatment=12, 9-month follow-up=t3) allowing for analyses of variance (AN-OVA). Following a matched-pair design, for every person that participated in the training a control person was included in the study to allow control for gender, age, and occupation. This sample consists of 74 pairs and comprises nurses, administration personnel, physicians and physical therapists. Most (80%) are female. So far only 28 pairs have been reassessed at t3. A comparison of the overall scores obtained with the above items before and after treatment demonstrates an extremely significant interaction effect, indicating an increase of adequate behaviours in the treatment group. At the follow-up assessment, the observed effect was maintained. CONCLUSIONS:(1) A back school training for the worksite results in a decreased frequency of back pain episodes and an increase in reported health status and wellbeing. (2) The effects of behavioural training of posture, gait, and activities of daily living in hospital staff are clearly demonstrated by observational methods. (3) Assuming that present posture, gait, and daily activities are interrelated with future pain conditions, an increase in the exercise of adequate behaviours indicates a preventive effect of the back school programme.