Kinematic Changes of the Trunk and Lower Limbs During Voluntary Lateral Sway Postural Control in Non-specific Low Back Pain

Doa El-Ansary, Adrian Pranata, Oren Tirosh, Zhengquan Chen, Jia Han, Roger Adams
Purpose:

This study aims to explore the differences in kinematics and muscle activation when performing a voluntary lateral weight shifting task between patients with NSLBP and asymptomatic controls without pain.

Methods:

Twenty-eight participants volunteered in this study (14 in both the NSLBP group and the control group). The Sway Discrimination Apparatus was used to generate a postural sway control task, mimicking lateral weight shifting movements when initiating gait. Kinematic parameters, including range of motion (ROM) and standard deviation of ROM (Std-ROM) of the lumbar spine, pelvis, and lower limb joints, were recorded using a motion capture system during lateral weight shifting. The electroactivity of the trunk and lower limb muscles was measured through surface electromyography using root mean square (RMS). The significant level was 0.05. An independent t-test was employed to compare kinematic parameters, and muscle activation between the NSLBP group and the control group. A paired-sample t-test, adjusted with Bonferroni correction (significant level of 0.025), was utilized to examine differences between the ipsilateral weight shifting towards side (dominant side) and the contralateral side.

Results:

The results of kinematic parameters showed significantly decreased ROM and std-ROM of the ipsilateral hip in the transverse plane (tROM=-2.059, p=0.050; tstd-ROM=-2.670, p=0.013), as well as decreased ROM of the ipsilateral knee in the coronal plane (t=-2.148, p=0.042), in the NSLBP group compared to the control group. For the asymptomatic controls, significantly larger ROM and std-ROM were observed in the hip and knee joints on the ipsilateral side in contrast to the contralateral side (3.287≤t≤4.500, 0.001≤p≤0.006), but no significant differences were found between the two sides in the NSLBP group. In addition, the NSLBP group showed significantly lower RMS of the biceps femoris than the control group (tRMS=-2.186, p=0.044).

Conclusion(s):

Patients with NSLBP showed a conservative postural control pattern, characterized by reduced ROM of ipsilateral hip and knee joints and diminished activation of the biceps femoris. Lower activation of biceps femoris in the NSLBP group suggests diminished motor control of the hip and knee joints during voluntary lateral weight shifting, which is consistent with the kinematic characteristics observed in patients with NSLBP.

Implications:

It is essential to recognize the significance of assessing the changes in the voluntary postural control pattern, especially in hip and knee joints at an early stage, and regularly screen the performance of tasks requiring voluntary postural control, such as walking or climbing stairs. Interventions targeting voluntary postural control may also be important for NSLBP patients.

Funding acknowledgements:
The word was unfunded.
Keywords:
Low Back Pain
Gait
Proprioception
Primary topic:
Musculoskeletal: spine
Second topic:
Musculoskeletal: lower limb
Third topic:
Pain and pain management
Did this work require ethics approval?:
Yes
Name the institution and ethics committee that approved your work:
Ethical approval of this study was received from the Human Research Ethics Committee at Swinburne University of Technology
Provide the ethics approval number:
20225788-11032
Has any of this material been/due to be published or presented at another national or international conference prior to the World Physiotherapy Congress 2025?:
Yes

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