Low back pain is a common disorder, occurring worldwide in both males and females in all age
groups. The prevalence is higher in females and the incidence peaks between 30 and 65 years.
It is currently the most frequent musculoskeletal cause of functional disability and it has a
major socio-economic impact on today's society. Although a small percentage of persons with
low back pain can be diagnosed with a specific underlying cause, almost 90% of persons with
low back pain present with symptoms of nonspecific origin. A part of these symptoms are only
of short duration, but 23% of all people will develop nonspecific chronic low back pain
Exercise therapy (ET) is currently an important component in the treatment of NSCLBP.
Previous studies analysed the effects of various modes of exercise therapy, such as motor
control therapy, core stability training and aerobic conditioning training. However, therapy
outcomes can be low, and guidelines in favour of using a specific program are contradictory.
It thus still remains unclear which therapy modality is best suited. Furthermore, no
recommendations are available about optimal training intensities during rehabilitation of
persons with NSCLBP.
Since as well aerobic as muscular deconditioning are apparent in persons with chronic low
back pain and improvements in overall physical fitness can affect therapy outcomes in this
population, ET specifically focussing on physical fitness can be advocated for NSCLBP
rehabilitation. High Intensity Training (HIT), has been promoted as an effective and
efficient training method for improving physical fitness and health related parameters in
healthy persons. Also, HIT resulted in successful reconditioning and improvement of
functional and disease related outcomes in persons with other chronic diseases such as
multiple sclerosis, heart failure, COPD and cardiometabolic diseases. Although some studies
showed promising results for the effect of HIT on low back pain such as high intensity
isolated, evidence is still scarce and study results are unclear because of methodological
The aim of this randomized clinical trial study is to evaluate the effects of a HIT program
on disease related outcomes, physical fitness and muscle contractile characteristics compared
to a conventional rehabilitation program in persons with NSCLBP.