The effect of walking speed on spinal loads and trunk muscle forces using subject-specific musculoskeletal modeling:...

Gait analysis of patients with spinal disorders at different walking speeds helps clinicians diagnose conditions and investigate treatment/rehabilitation effectiveness. A subject-specific database for trunk muscle forces and lumbar spine loads of healthy individuals during different walking speeds is therefore useful.

Ten healthy participants walked at three speeds (slow, normal, and fast) while motion and force-plate data were collected. Force in trunk muscles and loads on the lumbar spine discs were estimated using subject-specific musculoskeletal simulations in OpenSim. Model predictions at different walking speeds were statistically compared.

The time-dependent subject-specific force in all major trunk muscles and compression/shear loads at all lumbar spine discs (T12-S1) were reported for all walking speeds. Significant differences were observed in the average of peak compression between the fast and both slow/normal walking speed conditions across all lumbar discs (p <  0.001). With the exception of the L4-S1 discs, significant differences in the average of peak anterior-posterior and medio-lateral shear loads were also found between the fast and both slow/normal walking speed conditions. Significant differences (p <  0.007) in the average of peak muscle forces were generally found between the fast and both slow/normal walking speed conditions.

This study presents a normative, subject-specific database of lumbar loading and muscle forces during walking at multiple speeds. These data provide a useful reference for future research in spinal biomechanics and musculoskeletal modeling. Furthermore, the database may serve as a baseline for assessing altered gait patterns and spinal loads in individuals with spinal disorders, supporting future clinical applications.