Group level. Questions about physical load in work, work postures and manual materials handling were answered [20]. Psychosocial strain was measured by the Karasek and Theorell questionnaire [14]. High work demands were set above the 75 percentile of the index of these questions and low job control was set below the 25 percentile of the index of these questions. Strain was obtained by high demands and low control. Work satisfaction (one question, always/often on a four-level scale from never, sometimes, often, always) and supervisor support (one question, often/sometimes on a four-level scale from never, seldom, sometimes, often) were also measured.
There were five different questions about physical activities at work and leisure in the questionnaire. They covered duration, frequency, intensity and a combination of all three [21].
Health questions were: a) general health: “How would you estimate your general health right now?” Responses were on a 5-grade scale: excellent, very good, good, not so good, bad. Respondents were considered to be in good general health if they had answered excellent, very good or good; b) musculoskeletal well-being: “How often during the last three months have you had symptoms from: a) back, b) neck/shoulders, c) arms/wrists?” Responses were on a 5-grade scale for each symptom: always, many times a week, every week, sometimes, very seldom or never. Respondents were considered to have musculoskeletal wellbeing if they had answered very seldom or never; c) psychosomatic well-being: “How often during the last three months have you had symptoms from: a) having a headache, b) having a weak stomach?” Responses were on a 5-grade scale for each symptom: always, many times a week, every week, sometimes, very seldom or never. Respondents were considered to have psychosomatic well-being if they had answered very seldom or never; d) psychological well-being, Questionnaire Psycho Social (QPS) [22]. If the index showed more than 18, responded to very seldom or never, respondents were considered to have psychological well-being.