Differences in pre-swing posture between successful and tripping steps in individuals with stroke

Tripping is a major cause of falls in individuals with stroke. While prior studies have examined externally induced perturbations or distal joint kinematics, the mechanisms underlying intrinsic tripping-related near-falls during walking remain unclear, particularly during the pre-swing phase preceding swing initiation.

Does altered thoracic and pelvic posture during the pre-swing phase contribute to tripping-related near-falls in individuals with stroke, independent of lower limb joint kinematics?

Tripping-related near-fall trials were retrospectively extracted from routine forward walking assessments using three-dimensional motion analysis. Thirty-nine individuals with stroke (62.5 ± 11.4 years; 10 women; 17 right hemiplegia; 110.1 ± 41.4 days post-stroke) with tripping-related near-falls were included. The kinematic and spatiotemporal parameters recorded for the same participants during the pre-swing phase were compared between successful gait trials and tripping-related near-fall trials. The thorax and pelvic alignment, anterior-posterior pelvic position relative to the paretic foot, step parameters, and bilateral lower limb joint kinematics were analyzed.

Compared with successful trials, near-fall trials showed greater anterior pelvic (p = 0.012) and thoracic tilt (p = 0.037), increased anterior pelvic displacement (p = 0.003), reduced non-paretic step length (p = 0.003), and greater non-paretic hip flexion (p = 0.003).

Tripping-related near-falls appear to be associated with impaired thoracic and pelvic control during pre-swing rather than isolated deficits in paretic knee or ankle motion. These findings emphasize the importance of addressing proximal postural control, in addition to non-paretic stance limb function, to better understand and prevent tripping-related falls after stroke.