['To assess plantarflexion moment and hip joint moment after-effects following walking on a split-belt treadmill in healthy individuals and individuals post-stroke.', 'Cross-sectional study.', 'Ten healthy individuals (mean age 57.6 years (standard deviation; SD 17.2)) and twenty individuals post-stroke (mean age 49.3 years (SD 13.2)).', 'Participants walked on an instrumented split-belt treadmill under 3 gait periods: i) baseline (tied-belt); ii) adaptation (split-belt); and iii) post-adaptation (tied-belt). Participants post-stroke performed the protocol with the paretic and nonparetic leg on the faster belt when belts were split. Kinematic data were recorded with the Optotrak system and ground reaction forces were collected via the instrumented split-belt treadmill.', 'In both groups, the fast plantarflexion moment was reduced and the slow plantarflexion moment was increased from mid-stance to toe-off in the post-adaptation period. Significant relationships were found between the plantarflexion moment and contralateral step length.'] Is plantarflexion moment a contributor to step length after-effect following walking on a split-belt treadmill in individuals with stroke and healthy individuals?