The current guidelines for non-specific CLBP, recommend a conservative approach with exercise therapy, as first line treatment. Endurance and resistance training are two examples of recommended exercise therapies. However, it appears that none is recommended as superior over the other.

The lack of studies using HIIT in CLBP subjects, is the reason why it is needed to conduct an investigation about its effects.

However, firstly it is needed to assess the feasibility and safety of the HIIT protocol, to integrate it in the daily practise and future research.

In a single-center, single-blinded randomized feasiblity study, the investigators aim to prove the feasibility and safety of a 12 week HIIT programm.

Inclusion Criteria:

• Oswestry disability index (ODI) Score ≥ 14%
• Low back pain for at least 3 months.
• Declared suitable by their physician or hospital consultant to start an exercise programme and to perform a graded exercise testing to determine the heart rate peak.
• Good understanding of German or English, written and spoken.
• Age between 29 - 69
• No or stopped physical therapy.

Exclusion Criteria:

• Pre-existing unstable heart disease or suspected angina pectoris, cardiac dysrhythmias, heart failure, aneurysm or aortic stenosis.
• Known pregnancy.
• Previous low back spinal surgery in the last 2 years.
• Tumour, spinal stenosis, spinal fractures or radiculopathy.
• Comorbid health conditions like diabetes mellitus, rheumatoid arthritis or other systemic inflammatory diseases.