AGE-RELATED DIFFERENCES IN SPINAL MOTION DURING GAIT

Schmid S.^1,2, Bruhin B.^2,3, Ignasiak D.², Romkes J.⁴, Taylor W.R.², Ferguson S.J.², Brunner R.^4,5, Lorenzetti S.²

¹Bern University of Applied Sciences, Health Division, Bern, Switzerland, ²ETH Zurich, Institute for Biomechanics, Zurich, Switzerland, ³Swiss Federal Institute of Sports, Magglingen, Switzerland, ⁴University of Basel Children's Hospital, Laboratory for Movement Analysis, Basel, Switzerland, ⁵University of Basel Children's Hospital, Orthopaedic Department, Basel, Switzerland

Background: Although the importance of upper body motion in bipedal gait has been emphasized for several decades, little evidence is available regarding normative data with respect to ageing. In addition, most studies investigating trunk kinematics have not provided adequate quantification of spinal motion, resulting in a limited understanding of the biomechanical behavior of the healthy spine during gait. In order to be able to comprehensively investigate pathologies that directly or indirectly affect the spine, however, accurate knowledge of the biomechanics of a healthy spine during gait with respect to age is critical.

Purpose: To assess spinal curvature during gait in healthy adolescents, adults and elderly individuals and to provide a basis for future investigations involving pathologies.

Methods: Fourteen adolescents (10-18 years), 13 adults (19-35 years) and 15 elderly subjects (≥65 years) were included. Using a previously validated enhanced optical motion capture approach, sagittal and frontal plane spinal curvature angles, general trunk kinematics and spatio-temporal gait parameters were measured during shod walking at a self-selected normal speed. Group differences were investigated using effect sizes and analyses of variance with Tukey HSD post hoc tests. In order to detect the clinical relevance of a kinematic difference, the results were considered in relation to a minimal clinically important difference of 5°. In addition, kinematic parameters were investigated for a possible gait speed dependency using linear regression analyses.

Results: Adults presented higher average thoracic kyphosis (+10.6°, d=1.16, p=0.031) and lumbar lordosis (+12.6°, d=0.88, p=0.055) compared to adolescents. Lumbar spine range of motion (ROM) in the frontal plane was smaller in adolescents than in adults (-8.4°, d=1.84, p=0.001) and the elderly (-6.3°, d=1.26, p=0.007), whereby a gait speed dependency was found for the difference between adolescents and elderly (R2=0.169, p=0.027) but not for the difference between adolescents and adults (R2=0.027, p=0.413). In addition, elderly subjects walked significantly faster than the adolescents (+0.09, d=2.01, p=0.001), but not than the adults.

Conclusion(s): Postural differences indicated that lumbar lordosis and thoracic kyphosis increase throughout adolescence and reach their peak in adulthood. The absence of excessive thoracic kyphosis in the elderly could be explained by a previously reported subdivision in those who develop excessive kyphosis and those who maintain their curve. Furthermore, adults displayed increased lumbar spine frontal ROM as compared to the adolescents, whereas the increased values in elderly individuals were found to be related to higher gait speeds.

Implications: This dataset provides an insight into the age-dependent kinematics of the healthy spine and can serve as a basis for understanding pathological deviations and monitoring rehabilitation progression.

Funding acknowledgements: 1. Health Division of the Bern University of Applied Sciences
2. Swiss Physiotherapy Association
3. AOSpine International (Project CPP FFOB_OC_14)

Topic: Human movement analysis

Ethics approval: This study was approved by the “Ethikkommission Nordwest- und Zentralschweiz” and the “Ethikkommission der ETH Zürich”.

All authors, affiliations and abstracts have been published as submitted.