Kinematic Quantification of Lever Positioning Manipulation Under Different Working Conditions and Analysis of Related Individual Factors

Longhao Chen^*Qiong XiaKaizheng WangZiyu ZhangZhizhen LvLijiang Lv^*

• The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China, Hangzhou, China

Abstract Background: Lever positioning manipulation (LPM), an innovative technique derived from traditional lumbar extension manipulation in traditional Chinese medicine(TCM), has demonstrated clinical efficacy for lumbar disc herniation (LDH). Given the critical influence of operational parameters and patient-specific factors on outcomes, quantitative analysis of LPM kinematics is essential for personalized treatment. Objective: To quantify the kinematic parameters of LPM, explore correlations among various kinematic parameters, and investigate the influence of individual characteristics on the kinematic parameters of the manipulation. Methods: Kinematic data were captured from 107 volunteers using an optical motion system during bilateral and unilateral LPM. Parameters included retroflexion preload angle (RPA), adduction preload angle (APA), retroflexion force-applied instant angle (RFIA), adduction force-applied instant angle (AFIA), rotation instant loading angle (RILA), instant adjustment time (IAT), maximum velocity (Vmax), and maximum acceleration (Amax). Individual characteristics including age, sex, height, weight, waist circumference (WC), lumbar curvature (LC), lumbar lordosis angle (LLA), lumbosacral angle (LA), and femur length (FL) were also measured. Correlation analyses were conducted between kinematic parameters and subject characteristics. Results: No significant bilateral differences were found in unilateral LPM among healthy group (p > 0.05). RILA-U significantly differed between healthy volunteers and LDH patients (p < 0.05). Marked differences between manipulation modes were observed in RFIA, IAT, Vmax, and Amax (p < 0.05). Correlation analysis revealed multiple significant associations among kinematic parameters. WC and FL were common factors associated with parameters in both LPM modes, while LA and LC showed specific correlations with unilateral LPM parameters. Conclusion: This study quantitatively analyzed the kinematic characteristics of two LPM working modes using an optical motion capture system. The results indicated that LPM operators demonstrated good consistency in bilateral manipulation. Unilateral LPM showed superior instantaneous kinematic properties and operational efficiency compared to bilateral LPM. Both modes facilitated coordinated lumbar-pelvic-hip regulation with complex parameter interactions. Key kinematic parameters correlated with WC and FL in both modes, while unilateral LPM was further associated with LA and LC. These findings reveal intricate parameter–phenotype couplings and provide empirical support for personalized LPM optimization, underscoring the need for patient-specific manipulation strategies.