Intersegmental gait coordination differs by walking ability in subacute stroke.

The objective of this study was to characterize intersegmental gait coordination early after stroke (< 2 months post-onset). Stroke participants were divided into two groups based on self-perceived ability to walk faster than their normal speed: single-speed walkers (SSW, n = 18, normal speed 30 ± 13 cm/s) and dual-speed walkers (DSW, n = 17, normal speed 69 ± 26 cm/s, fast speed 100 ± 31 cm/s). Intersegmental coordination was compared between DSW and healthy controls (n = 20, 72 ± 5 cm/s) walking at comparable speeds, SSW and DSW walking at normal speeds, and within DSW walking at normal vs. fast speed. Sagittal plane elevation angles of the thigh, shank, and foot segments were analyzed using principal component analysis (PCA) to quantify absolute segment loadings on the three principal components and the variances explained by the three principal components. DSW showed only minor differences from healthy controls, indicating relatively preserved coordination. In contrast, SSW demonstrated markedly disrupted intersegmental coordination compared to DSW, particularly in the paretic leg (significant group x side interactions for 7 of 12 PCA parameters). Within the DSW group, increasing speed produced coordination changes that closely paralleled those of healthy controls. A gait speed of 42.3 cm/s best distinguished SSW from DSW (82% sensitivity, 91% specificity). These findings indicate that early after stroke intersegmental gait coordination varies with walking ability. Stroke individuals confident in walking faster than their normal speed exhibit coordination patterns more similar to healthy adults, while those limited to a single, slower speed show marked disruption. The results have implications for early gait training.(246 words)