Background: The International Classification of Functioning, Disability and Health (ICF) model, created by the World Health Organization, provides a theoretical framework that can be applied in the diagnosis and treatment of various disorders. Objects: Our research purposed to ascertain the relationship between structure/function, activity, and participation domain variables of the ICF and pain, pain-associated disability, activities of daily living (ADL), and quality of life in patients with chronic low back pain (LBP). Methods: Two-hundred patients with chronic LBP (mean age: 35.5 ± 8.8 years, females, n = 40) were recruited from hospital and community settings. We evaluated the body structure/ function domain variable using the Numeric Pain Rating Scale (NPRS) and Roland–Morris disability (RMD) questionnaire. To evaluate the activity domain variable, we used the Oswestry Disability Index (ODI) and Quebec Back Pain Disability Scale (QBDS). For clinical outcome measures, we used Short-form 12 (SF-12). Pearson’s correlation coefficient was used to ascertain the relationships among the variables (p < 0.05). All the participants with LBP received 30 minutes of conventional physical therapy 3 days/week for 4 weeks. Results: There were significant correlations between the body structure/function domain (NPRS and RMD questionnaire), activity domain (ODI and QBDS), and participation domain variables (SF-12), rending from pre-intervention (r = –0.723 to 0.783) and postintervention (r = –0.742 to 0.757, p < 0.05). Conclusion: The identification of a significant difference between these domain variables point to important relationships between pain, disability, performance of ADL, and quality in participants with LBP.

Background: The presence of the lumbopelvic-hip neuromuscular chain is essential for dynamic spinal stabilization; its therapeutic effects on dynamic movements of the distal extremity segment and underpinning motor mechanism remain unknown and warrant further study on participants with low back pain (LBP). Objects: We aim to compare the effects of the broken chain exercise (BCE) and connected chain exercise (CCE) on electromyography (EMG) amplitude and onset time in participants with and without LBP. Methods: Randomized controlled clinical trial. A convenience sample of 40 nonathletic participants (mean age: 24.78 ± 1.70) with and without LBP participated in this study. All participants underwent CCE for 30 minutes, 30-minute daily. We measured EMG amplitude and onset times on bilateral erector spinae (ES), gluteus maximus (GM), hamstring (HAM), transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) during the prone hip extension (PHE) test before and after the BCE and CCE. We used multivariate analysis of variance (MANOVA) to analyze the amplitude and onset time difference between exercises (BCE and CCE) and Pearson’s correlations to determine any synergistic relationship among the HAM, GM, bilateral TrA/IO, and ES muscles. The statistical analyses were used at p < 0.05. Results: MANOVA showed that CCE was more decreased on EMG amplitude in HAM and bilateral ES, while increased GM and contralateral TrA/IO than BCE (p < 0.05). MANOVA EMG onset time data analyses revealed that the main effect of the conditions was significant for all HAM, GM, and bilateral ES muscles, whereas the main effect for the group was significant only for GM and contralateral ES in healthy and LBP groups. Pearson’s correlation coefficient was computed to assess the relationship between BCE and CCE on dependent variables. In most of the muscles, there was a strong, positive correlation between the two variables, and there was a significant relationship (p < 0.001). Conclusion: CCE produced more effective and coordinated core stabilization and motor control mechanism in the lumbopelvic-hip muscles in participants with and without LBP during PHE than BCE.

Background: While the formal test has been used to provide a quantitative measurement of core stability, studies have reported inconsistent results regarding its test-retest and intraobserver reliabilities. Furthermore, the validity of the formal test has never been established. Objects: This study aimed to establish the concurrent validity and test-retest reliability of the formal test. Methods: Twenty-two young adults with and without core instability (23.1 ± 2.0 years) were recruited. Concurrent validity was determined by comparing the muscle thickness changes of the external oblique, internal oblique, and transverse abdominal muscle to changes in core stability pressure during the formal test using ultrasound (US) imaging and pressure biofeedback, respectively. For the test-retest reliability, muscle thickness and pressure changes were repeatedly measured approximately 24 hours apart. Electromyography (EMG) was used to monitor trunk muscle activity during the formal test. Results: The Pearson’s correlation analysis showed an excellent correlation between transverse abdominal thickness and pressure biofeedback unit (PBU) pressure as well as internal oblique thickness and PBU pressure, ranging from r = 0.856–0.980, p < 0.05. The test-retest reliability was good, intraclass correlation coefficient (ICC1,2) = 0.876 for the core stability pressure measure and ICC1,2 = 0.939 to 0.989 for the abdominal muscle thickness measure. Conclusion: Our results provide clinical evidence that the formal test is valid and reliable, when concurrently incorporated into EMG and US measurements.