The purpose of the present study is to determine the association between factors known to be associated with the development of chronic low back pain (psychological and biological) and the evolution of functional disability in individuals with a history of low back pain. To do so, 100 individuals with a history of nonspecific low back pain will be followed over a period of 18 months. During this time frame, participants will be evaluated three times in the laboratory (initial, at 6 months and at 18 months) to determine pain and tolerance thresholds, pain inhibition processes as well as neuromuscular activation. Moreover, these participants will be assessed every three months (initial, 3, 6, 9 12, 15 and 18 months) for functional disability and pain intensity levels of their low back pain as well as for psychological symptoms usually associated with the development of chronic low back pain. It is hypothesized that high psychological symptoms measured initially will be associated with high functional disability throughout the study .

Inclusion Criteria:

• To have experienced at least one episode of disabling (resulting in loss of work or modified tasks at work) nonspecific low back pain in the past three years.

Exclusion Criteria:

• Specific causes of low back pain, arthritic conditions, other chronic pain conditions

Individuals with a history of nonspecific low back pain