Walking ability is impaired in 80% of stroke patients. Although most of these patients regain their ability to walk, 40% require assistance while walking, and 60% have limitations in community ambulation. Half of the people with social ambulation one year after stroke, who are relatively well developed, can only walk 40% of the expected distance in the walking test. Hemiplegic gait is characterized by poor selective motor control, delayed and impaired balance reactions, decreased weight transfer to the affected limb, impaired forward progression of the trunk in an asymmetrical and non-fluid manner, and asymmetry. Many factors that cause gait asymmetry after stroke have been described, such as spasticity, muscle weakness, inappropriate contraction, and decreased central nervous system voluntary involvement. However, these factors are not sufficient to explain the asymmetry. It is also thought that extremity loading plays an important role in maintaining gait symmetry.

Walking speed is a crucial indicator of walking performance following a stroke. Both cadence and stride length, which determine walking speed, decrease after a stroke, resulting in reduced speed. While healthy individuals walk at an average speed of 1.3 m/s, post-stroke walking speed varies from 0.23 m/s to 0.73 m/s. Common post-stroke gait disorders such as decreased dorsiflexion and knee flexion significantly reduce walking speed by decreasing the foot’s ground clearance.

Post-stroke ambulation is classified based on walking speed. According to this classification, speeds up to 0.4 m/s are categorized as home-bound ambulation, speeds between 0.4 m/s and 0.8 m/s fall under the limited community ambulation category, and speeds above 0.8 m/s are considered community ambulation. Hemiplegic gait is characterized by temporal asymmetries such as increased double support phase, prolonged gait cycle, and decreased cadence. Although the stance phase increases for both extremities, the stance phase on the healthy side is more extended. The swing phase is prolonged on the hemiplegic side. While lengthening the double support phase is functional for balance, it is not economical for energy saving. The energy produced by the extremity in the pushing phase is absorbed by the leg receiving the weight, and prolonging this phase renders the mechanism inadequate. Extending the swing phase and shortening the stance phase on the hemiplegic side indicate the difficulty of bearing weight on this side.

Distance symmetry is calculated using stride length and needs to be more consistent for the stroke population. Although many studies report the paralytic stride length to be greater than the healthy side stride length, some studies mention the presence of asymmetry in the opposite direction, revealing a heterogeneous distribution for distance asymmetry. Balasubramanian reported that stride length symmetry is related to thrust during hemiplegic gait. Accordingly, the decreased paralytic repulsion force and the increased healthy-side repulsion force cause the relative lengthening of the paralytic step. The slowing down of the gait impairs the pendular feature of the gait and increases energy expenditure. Although the energy expenditure varies depending on the degree of weakness, spasticity, orthosis use, and education in stroke patients, it is 50-67% higher than in healthy individuals with the same body weight. These asymmetries can cause falls, increased energy consumption, abnormal joint loading, and associated joint damage, deformity, and pain.

References

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