Passive hip range of motion is reduced in active subjects with chronic low back pain compared to controls.

BACKGROUND Non-specific low back pain is a common condition often without a clear mechanism for its presentation. Recently more attention has been placed on the hip and its potential contributions to non-specific chronic low back pain (NSCLBP). Emphasis in research has mainly been placed on motor control, strength and endurance factors in relation to NSCLBP. Limited focus has been placed on hip mobility and its potential contribution in subjects with NSCLBP. PURPOSE/AIM The aim of this study was to compare passive ROM in hip extension, hip internal rotation, hip external rotation and total hip rotation in active subjects with NSCLBP to healthy control subjects. The hypothesis was that active subjects with NSCLBP would present with decreased total hip ROM and greater asymmetry when compared to controls. DESIGN Two group case controlled. SETTING Clinical research laboratory. PARTICIPANTS 30 healthy subjects without NSCLBP and 30 active subjects with NSCLBP. Subjects categorized as NSCLBP were experiencing pain in the low back area with or without radicular symptoms of greater than three months duration. MAIN OUTCOME MEASURE Passive hip extension (EXT), hip internal rotation (IR), hip external rotation (ER) and total hip rotation ROM. A digital inclinometer was used for measurements. RESULTS There was a statistically significant difference (p<0.001) in hip passive extension ROM between the control group and the NSCLBP group bilaterally. Mean hip extension for the control group was 6.88 bilaterally. For the NSCLBP group, the mean hip extension was -4.28 bilaterally. This corresponds to a difference of means between groups of 10.88. There was no statistically significant differences (p>0.05) in hip IR, ER, or total rotation ROM between groups. CONCLUSIONS The results of this study indicate that a significant difference in hip extension exists in active subjects with NSCLBP compared to controls. It may be important to consider hip mobility restrictions and their potential impact on assessment of strength in NSLBP subjects. Future studies may be needed to investigate the relationship between measurements and intervention strategies. LEVEL OF EVIDENCE 2b.