Volume 27, Issue 4 (In press 2026)
Arch Rehabil 2026, 27(4): 0-0 |
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orakifar N, Khorshidi Mal-Ahmadi R, Moftah R, Zahednezhad S, Nassaj G. Comparing Anticipatory Postural Adjustments of the Trunk and Lower Limb Muscles After Prolonged Standing Between Individuals with and Without Chronic Non-Specific Low Back Pain. Arch Rehabil 2026; 27 (4)
URL: http://rehabilitationj.uswr.ac.ir/article-1-3713-en.html
URL: http://rehabilitationj.uswr.ac.ir/article-1-3713-en.html
Neda Orakifar *1, Rouhollah Khorshidi Mal-Ahmadi2, Razieh Moftah3, Shahla Zahednezhad3, Gholamhossein Nassaj3
1- Department of Physiotherapy, School of Rehabilitation Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. & Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. , nedaoraki@yahoo.com
2- Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
3- Department of Physiotherapy, School of Rehabilitation Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. & Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2- Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
3- Department of Physiotherapy, School of Rehabilitation Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. & Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Abstract: (19 Views)
Objective: The aim of the present study was to investigate the effect of prolonged standing on the anticipatory postural adjustments of trunk and lower limb muscles in individuals with chronic nonspecific low back pain and compare it with healthy individuals.
Methods: In this quasi-experimental study, fifteen healthy subjects and fifteen individuals with chronic non-specific low back pain participated. Electromyographic activity of the right trunk and lower limb muscles (anterior tibialis, soleus, internal oblique/transversus abdominis, medial hamstrings, lateral hamstrings, and lumbar multifidus) was recorded during rapid right shoulder flexion before and after 30 minutes of standing. Onset latency and root mean square of muscles were calculated. The main and interaction effects of the variables were examined using two-way repeated measure analysis of variance with two factors: group (low back pain and healthy control) and time (before and after prolonged standing).
Results: For the onset latency, the interaction effect of group by time was significant for the tibialis anterior muscle (P-value = 0.046). The results of the post hoc test showed a lower latency of the tibialis anterior muscle in subjects with low back pain after prolonged standing compared to before prolonged standing (P-value = 0.003). Also, the results of the independent t-test showed a significant decrease in the latency of the tibialis anterior muscle in subjects with low back pain compared to healthy subjects after prolonged standing (P-value = 0.002). For the root mean square, the interaction effect of group by time was significant for the hamstring muscles medial (P-value ˂ 0.001) and lateral (P-value = 0.007). The results of the post hoc test showed a significant decrease in the root mean square value for the internal hamstring muscle (P-value = 0.009) and external hamstring (P-value = 0.007) in subjects with low back pain after prolonged standing compared to before prolonged standing. The effect size for all significant results was large (ηp2≥ 0.14).
Conclusion: Reducing the onset delay and reducing the activity level of some lower limb postural muscles during voluntary shoulder flexion movement after prolonged standing may represent a protective and compensatory strategy of the central nervous system in people with back pain. It may prevent further disturbances due to the feedforward activity of postural muscles and prevent further disruption of postural control in this difficult condition of instability that are accompanied by fatigue, discomfort, and pain in the lower limb and back muscles after prolonged standing.
Methods: In this quasi-experimental study, fifteen healthy subjects and fifteen individuals with chronic non-specific low back pain participated. Electromyographic activity of the right trunk and lower limb muscles (anterior tibialis, soleus, internal oblique/transversus abdominis, medial hamstrings, lateral hamstrings, and lumbar multifidus) was recorded during rapid right shoulder flexion before and after 30 minutes of standing. Onset latency and root mean square of muscles were calculated. The main and interaction effects of the variables were examined using two-way repeated measure analysis of variance with two factors: group (low back pain and healthy control) and time (before and after prolonged standing).
Results: For the onset latency, the interaction effect of group by time was significant for the tibialis anterior muscle (P-value = 0.046). The results of the post hoc test showed a lower latency of the tibialis anterior muscle in subjects with low back pain after prolonged standing compared to before prolonged standing (P-value = 0.003). Also, the results of the independent t-test showed a significant decrease in the latency of the tibialis anterior muscle in subjects with low back pain compared to healthy subjects after prolonged standing (P-value = 0.002). For the root mean square, the interaction effect of group by time was significant for the hamstring muscles medial (P-value ˂ 0.001) and lateral (P-value = 0.007). The results of the post hoc test showed a significant decrease in the root mean square value for the internal hamstring muscle (P-value = 0.009) and external hamstring (P-value = 0.007) in subjects with low back pain after prolonged standing compared to before prolonged standing. The effect size for all significant results was large (ηp2≥ 0.14).
Conclusion: Reducing the onset delay and reducing the activity level of some lower limb postural muscles during voluntary shoulder flexion movement after prolonged standing may represent a protective and compensatory strategy of the central nervous system in people with back pain. It may prevent further disturbances due to the feedforward activity of postural muscles and prevent further disruption of postural control in this difficult condition of instability that are accompanied by fatigue, discomfort, and pain in the lower limb and back muscles after prolonged standing.
Type of Study: Original |
Subject:
Physical Therapy
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This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 (CC-By-NC 4.0), which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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