The purpose of this project is to investigate the occurrence of neck and back pain in a population of commercial helicopter pilots, and investigate factors related to the profession that can cause these problems. The project has a biological approach assessing the supporting and stabilizing muscles (multifidus) in pilots with chronic back and neck ailments. Pilots with low back problems are invited to a controlled intervention trial to investigate whether one can achieve improved spinal health with a rigid training régime. Primary trial outcome is improved neck and back multifidus muscles pathology and function as assessed by the extent of fat infiltration -as visualized on MRI - and the volume and ability of the lumbar multifidus muscles to contract as shown with ultrasound. The perceived effect on spinal health with sick leave frequency is also evaluated.

Inclusion Criteria:

• Pilots must experience low back pain in at least 1 of 3 flights or
• Pilots must have at least 2 episodes of low back pain of at least 24 hours duration over the last 12 months. Each episode is separated with at least one painfree month before and after each episode, or
• Pilots may have had more than 3 sick leaves due to low back pain over the last 5 years

Exclusion Criteria:

• contraindications for physical training/activity