Examination of the Relationships Among Physiological Stress, Iliopsoas Tightness and Non-Specific Chronic Low Back Pain in an Adult Population
Date
2023-08-31
Authors
Nash, Arielle
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Abstract
One of the most prevalent forms of pain to be linked to stress is non-specific chronic low back pain (nsCLBP). Existing studies have shown evidence of a link between stress and nsCLBP, muscle tension induced dysfunctional biomechanics and nsCLBP, and stress and muscle tension. However, little research has explored the interconnections among muscle tension, stress and nsCLBP. The purpose of this study was to investigate the relationships between these variables. Two age and sex matched subgroups (nsCLBP, and noPain) with 17 participants each (M = 8, F= 9) were created from an overall participant group (n =39, M = 18, F = 21, 23- 63 y). Iliopsoas tightness was assessed by measuring hip extension angle (HE) with a goniometer on the left (HE L) and right (HE R) side using the modified Thomas test. Heart rate variability was recorded in laying supine position for 12-minutes. A 5-minute segment extracted for analysis of low frequency power (LF; ms2), high frequency power (HF; ms2), LF/HF ratio and the inter-beat intervals of normal N-N sinus beats (SDNN; ms). Cortisol concentration (CORT; nmol/L) was measured using a passive drool sample taken within 2 hours of waking. Each participant was measured for all variables in one session. Significant positive correlations were found between HE and HF (r(37) = .36 - .43, p < .05) and HE and SDNN (r(37) = .27 - .41, p ≤ .05). LF/HF and CORT were negatively correlated to HE L (r(36) = -.36, p = .01). The nsCLBP group measured significantly lower ranges of motion than the noPain group for both the left and right side hip extension, with the largest difference in means of HE between groups found on the right side (8.96o ± 3.10, t (32)= 2.88, p =.003). There were no significant differences in CORT or HRV between the groups. The results demonstrate that iliopsoas tightness can negatively impact physiological stress and vice versa. The findings also provide evidence that individuals with nsCLBP have, on average, less range of motion in hip extension when compared to pain free individuals. In addition, the correlation between muscle tension and stress is stronger among individuals with nsCLBP than among pain-free individuals.
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Keywords
psoas, back pain, stress, HRV, heart rate variability, cortisol, muscle tension, hip flexor, hip extension, Thomas test