Muscle torque production and kinematic properties in post-stroke patients: a pilot cross-sectional study

Purpose: Stroke-related hemiplegia is an important factor influencing parameters of gait. So far, limited papers have assessed temporo-spatial capabilities and their correlations with gait parameters in the early post-stroke stage. This pilot study evaluated the temporo-spatial parameters of gait and assessed the maximal isometric and isokinetic torque production of the plantar flexor and dorsiflexor muscles. Methods: 15 patients with lower limb spasticity and 15 healthy controls were included. Stroke severity was assessed using the Modified Ashworth Scale and the Barthel Index. Gait cadence, gait speed, and gait cycle were assessed using inertial sensors during a Timed Up and Go test. Maximal isometric and isokinetic torque production of the ankle plantar flexor and dorsiflexor muscles were assessed using an isokinetic dynamometer device. Results: Post-stroke patients had statistically significantly lower gait cadence than healthy participants (17%, p < 0.05). Statistically significantly lower values of vertical acceleration were also noted during a sit-to-stand movement task (42%, p < 0.05). Plantar flexion torque of the affected limb was significantly different during isometric (63%, p <= 0.01) and isokinetic work for 30 degrees/s (49%, p = 0.04), 60 degrees/s (58%, p = 0.01) and 20 degrees/s (53%, p = 0.01). Dorsiflexor muscles' torque production was significantly different in isometric activity (38%, p = 0.04). A statistically significant positive correlation occurred between the absolute peak torque of the dorsiflexor muscles in both static and speed phases of gait (Rs = 0.65, p = 0.04). Conclusions: Despite the low intensity of spasticity and early phase after stroke, differences in the muscle torque production and temporo-spatial parameters, as well as the correlations between them, were noticeable.