Baseline characteristics of training and prospective patient cohorts.
| Characteristic | Patient Cohorts | P a | |
| Training(n = 139) | Prospective(n = 14) | ||
| Age, y, mean (range) | 41.4 (20−65) | 34.5 (24−47) | 0.009 |
| Women, n (%) | 43 (31) | 2 (14) | 0.19 |
| Race/ethnic group, n (%) | 0.57 | ||
| Non-Hispanic | 137 (99) | 14 (100) | |
| White | 122 (88) | 13 (93) | |
| Black | 15 (11) | 1 (7) | |
| Body mass index, mean ± SD | 30.0 ± 6.2 | 31.5 ± 5.3 | 0.32 |
| Smoker, n (%) | 49 (35) | 1 (7) | 0.04 |
| Workers’ compensation, n (%) | 120 (86) | 10 (71) | 0.13 |
| Oswestry Disability Index score, mean ± SD | 56.5 ± 11.3 | 54.7 ± 14.1 | 0.65 |
↵a Determined using t test.