NURSE-study is a randomized controlled trial aiming at prevention of chronic LBP and related functional disability. Volunteers, female nurses (n~1200) from wards with bed patients of two geriatric hospitals and the university central hospital in Tampere, Finland will be invited to participate in the study. Each participant (n=160) will be randomized into one of the four study groups after the eligibility has been determined. A method of sequentially numbered sealed envelopes will be used to assign participants into study groups.