Use of kinematic algorithms to distinguish people with chronic non-specific low back pain from asymptomatic subjects: A validation study

Objective: To determine whether kinematic algorithms can distinguish subjects with chronic non-specific low back pain from asymptomatic subjects and subjects simulating low back pain, during trunk motion tasks.Design: Comparative cohort study.Subjects: A total of 90 subjects composed 3 groups; 45 chronic non-specific low back pain patients in the CLBP group; 45 asymptomatic controls people in the asymptomatic controls group. 20/45 subjects from the asymptomatic controls group composed the CLBP simulators group as well. Method: During performance of 7 standardized trunk motion tasks 6 spinal segments from the kinematic spine model were recorded by 8 infrared cameras. Two logit scores, for range of motion and speed, were used to investigate differences between the groups. Group allocation based on logit scores was also calculated, allowing the assessment of sensitivity and specificity of the algorithms. Results: For the 90 subjects (pooled data), the logit scores for range of motion and speed demonstrated highly significant differences between groups (p<0.001). The logit score means and standard deviation (SD) values in the asymptomatic group (n = 45) and chronic non-specific low back pain group (n = 45), respectively, were -1.6 (SD 2.6) and 2.8 (SD 2.8) for range of motion and -2.6 (SD 2.5) and 1.2 (SD 1.9) for speed. The sensitivity and specificity (n = 90) for logit score for range of motion were 0.80/0.82 and for logit score for speed were 0.80/0.87, respectively. Conclusion: These results support the validity of using 2 movement algorithms, range of motion and speed, to discriminate asymptomatic subjects from those with low back pain. However, people simulating low back pain cannot be distinguished from those with real low back pain using this method

Maximal aerobic power in patients with chronic low back pain: a comparison with healthy subjects

The objective of the study was to compare the maximal aerobic capacity of patients with chronic low back pain with healthy asymptomatic controls matched for age, gender and level of physical activity at work and during sports activities. Reported data in the literature with respect to aerobic capacity in patients with chronic low back pain are not conclusive. Nevertheless, based on the assumption that chronic low back pain leads to deconditioning, physical training programs are widely used as a treatment. A total of 70 patients with chronic low back pain and 70 healthy asymptomatic subjects completed questionnaires regarding demographics and performed a graded maximal exercise test until exhaustion on a cycle ergometer. The maximal aerobic power was measured by indirect calorimetry. Heart rate, respiratory exchange ratio and blood lactate levels were also measured. The test was considered maximal when VO2max achievement criteria were obtained. VO2max values were compared among groups. The absolute and normalized for weight values of VO2max measured in patients with chronic low back pain were significantly lower than that of the control group. Independent comparison between men and women showed that absolute values of VO2max are also significantly lower in men and women with chronic low back pain. Women reached absolute and normalized for weight VO2max values significantly lower than those of men, both in chronic low back pain and control group. In conclusion, chronic low back pain patients, especially women, seem to have a reduced aerobic capacity compared to healthy asymptomatic subjects