Sustained joint load in extreme positions (namely maximally flexed or extended positions) has been described as causing pain. The aim of the present study is to analyse eight different sitting work postures with respect to extreme positions, and to assess the mechanical load and the levels of muscular activity arising in defined extreme positions of the cervical spine. Ten healthy female workers from an electronics plant took part in laboratory experiments. For seven of these, levels of neck and shoulder muscular activity in sitting postures with the cervical spine in different manually-adjusted extreme positions were recorded using surface electrodes. Loading moments of force about the bilatei-a1 motion axis of the atlantooccipital joint (Occ-C1) and the spinal cervico-thoracic motion segments (C7-TI) were calculated. Extreme or almost extreme positions occurred in sitting postures with the thoraco-lumbar back inclined slightly backwards or with the whole spine flexed. Electromyographic (EMG) activity levels were very low in the manuallyadjusted extreme positions. The load moment for the OccXl joint when the whole neck was flexed was only 1-2 times the value for the neutral position of the head, but for C7-Tl it increased to 3-6 times. It is concluded that extreme positions of the cervical spine do occur in sitting work postures, and that the levels of muscular activity in such positions are low. Thus, recordings of muscle activity and calcufations of load moment alone are not a sufficient basis for evaluating work postures: thorough recordings of spine positions should be included.

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People who undergo co-ordinated rehabilitation have more working days after the intervention period than those with conventional rehabilitation. This way for rehabilitation actors to co-operate gives better outcomes for rehabilitation cases with long previous sick leave, but not for cases with less previous sick leave. It also generates economic gains at several levels.