Muscular stability is essential to the spinal column to avoid harmful strain and injury to its structures. Sudden postural disturbances impose reactive internal forces through the spine. If the muscles do not react before the internal reactive forces propagate through the spine, there is a short fraction of time where the spinal column may lack sufficient muscular support. Studies have shown that in patients with low back pain deep abdominal and back muscle have a delayed response to reactive forces. The purpose of this study is to verify these findings and to investigate whether tailored interventions can improve the reaction time in stabilizing muscle around the lower spinal column i patients with subacute and chronic low back pain.

Inclusion Criteria:

• Unspecific subacute, subacute remitting and chronic LBP
• Both sexes, 20-60 yrs of age
• LBP between 2-8 on a 11-pt numeric rating scale

Exclusion Criteria:

• Previous back surgery
• Sick listed more than one year
• Radiating pain below knee or motor deficits
• Systemic diseases and "red flags"
• Diagnosed psychiatric disease
• Ingoing insurance claim
• Pregnancy