Morteza Asgari1, Mohammad Ali Sanjari2, Hamid Reza Mokhtarinia3, Samaneh Moeini Sedeh4, Kinda Khalaf5, Mohamad Parnianpour6. 1. Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran. Electronic address: morteza_asgari@alum.sharif.edu. 2. Biomechanics Lab, Rehabilitation Research Center, Faculty of Rehabilitation, Department of Rehabilitation Basic Sciences, Iran University of Medical Sciences, Tehran, Iran. Electronic address: sanjarima@alum.sharif.edu. 3. Department of Ergonomics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Electronic address: hrmokhtarinia@yahoo.com. 4. Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran. Electronic address: s_moeini@mech.sharif.edu. 5. Department of Biomedical Engineering, Khalifa University of Science Technology and Research, Abu Dhabi, United Arab Emirates. Electronic address: kinda.khalaf@kustar.ac.ae. 6. Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran. Electronic address: parnianpour@sharif.edu.
Abstract
BACKGROUND: Comparison of the kinematic variability and dynamic stability of the trunk between healthy and low back pain patient groups can contribute to gaining valuable information about the movement patterns and neuromotor strategies involved in various movement tasks. METHODS: Fourteen chronic low back pain patients with mild symptoms and twelve healthy male volunteers performed repeated trunk flexion-extension movements in the sagittal plane at three different speeds: 20 cycles/min, self-selected, and 40 cycles/min. Mean standard deviations, coefficient of variation and variance ratio as variability measures; maximum finite-time Lyapunov exponents and maximum Floquet multipliers as stability measures were computed from trunk kinematics. FINDINGS: Higher speed significantly reduced the kinematic variability, while it increased short-term Lyapunov exponents. Long-term Lyapunov exponents were higher at self-selected speed and lower in low back pain patients as compared to control volunteers. Floquet multipliers were larger at self-selected speed and during higher pace trunk movements. INTERPRETATION: Our findings suggest that slower pace flexion-extension trunk movements are associated with more motor variation as well as local and orbital stability, implying less potential risk of injury for the trunk. Individuals with and without low back pain consistently recruited a closed-loop control strategy towards achieving trunk stability. Chronic low back pain patients exhibited more stable trunk movements over long-term periods, indicating probable temporary pain relief functional adaption strategies. These results may be used towards the development of more effective personalized rehabilitation strategies and quantitative spinal analysis tools for low back pain detection, diagnosis and treatment, as well as improvement of workspace and occupational settings.
BACKGROUND: Comparison of the kinematic variability and dynamic stability of the trunk between healthy and low back painpatient groups can contribute to gaining valuable information about the movement patterns and neuromotor strategies involved in various movement tasks. METHODS: Fourteen chronic low back painpatients with mild symptoms and twelve healthy male volunteers performed repeated trunk flexion-extension movements in the sagittal plane at three different speeds: 20 cycles/min, self-selected, and 40 cycles/min. Mean standard deviations, coefficient of variation and variance ratio as variability measures; maximum finite-time Lyapunov exponents and maximum Floquet multipliers as stability measures were computed from trunk kinematics. FINDINGS: Higher speed significantly reduced the kinematic variability, while it increased short-term Lyapunov exponents. Long-term Lyapunov exponents were higher at self-selected speed and lower in low back painpatients as compared to control volunteers. Floquet multipliers were larger at self-selected speed and during higher pace trunk movements. INTERPRETATION: Our findings suggest that slower pace flexion-extension trunk movements are associated with more motor variation as well as local and orbital stability, implying less potential risk of injury for the trunk. Individuals with and without low back pain consistently recruited a closed-loop control strategy towards achieving trunk stability. Chronic low back painpatients exhibited more stable trunk movements over long-term periods, indicating probable temporary pain relief functional adaption strategies. These results may be used towards the development of more effective personalized rehabilitation strategies and quantitative spinal analysis tools for low back pain detection, diagnosis and treatment, as well as improvement of workspace and occupational settings.
Authors: Sharon M H Tsang; Grace P Y Szeto; Angelina K C Yeung; Eva Y W Chun; Caroline N C Wong; Edwin C M Wu; Raymond Y W Lee Journal: PLoS One Date: 2021-11-18 Impact factor: 3.240
Authors: Hamid Reza Mokhtarinia; Azadeh Hosseini; Azam Maleki-Ghahfarokhi; Charles Philip Gabel; Majid Zohrabi Journal: Health Qual Life Outcomes Date: 2018-05-15 Impact factor: 3.186