Table 2.

Reasons for ineligibility

Reason for ineligibilitya	Number of subjects (N=1,941)
No current low back pain	1,146
Duration of low back pain <3 months	324
Current or past medical history of severe systemic disease	127
No palpatory tenderness over lumbar facet joints	101
Less than 18 years of age	85
Current lumbar fracture or instability of the spine	45
Marked limitation or inability to carry on physical activity without cardiac discomfort	42
Morbidly obese	33
Psychiatric illness or lack of cognitive ability	32
Not interested in study participation	28
Current history of severe osteoporosis	27
Evidence of central nervous system disease	23
Treated by a chiropractor in the past 6 months	22
Current and known substance abuse	19
Not fluent or literate in English language	17
Currently receiving care for LBP from other provider, therapist, or physician	15
Treated by a physical therapist in the past 6 months	15
Currently pregnant	1
Not willing to sign the informed consent	77

^aSubjects may be excluded for more than one reason