A systematic review of mechanisms of gait speed change post-stroke. Part 2: exercise capacity, muscle activation, kinetics, and kinematics

Background: Regaining locomotor ability is a primary goal in stroke rehabilitation and is most commonly measured using changes in self-selected walking speed. However, walking speed cannot identify the mechanisms by which an individual recovers. Laboratory-based mechanistic measures such as exercise capacity, muscle activation, force production, and movement analysis variables may better explain neurologic recovery. Objectives: The objectives of this systematic review are to examine changes in mechanistic gait outcomes and describe motor recovery as quantified by changes in laboratory-based mechanistic variables in rehabilitation trials. Methods: Following a systematic literature search (in PubMed, Ovid, and CINAHL), we included rehabilitation trials with a statistically significant change in self-selected walking speed post-intervention that concurrently collected mechanistic variables. Methodological quality was assessed using Cochrane Collaboration's tool. Walking speed changes, mechanistic variables, and intervention data were extracted. Results: Twenty-five studies met the inclusion criteria and examined: cardiorespiratory function (n=5), muscle activation (n=5), force production (n=11), and movement analysis (n=10). Interventions included: aerobic training, functional electrical stimulation, multidimensional rehabilitation, robotics, sensory stimulation training, strength/resistance training, task-specific locomotor rehabilitation, and visually-guided training. Conclusions: Following this review, no set of outcome measures to mechanistically explain changes observed in walking speed were identified. Nor is there a theoretical basis to drive the complicated selection of outcome measures, as many of these outcomes are not independent of walking speed. Since rehabilitation literature is yet to support a causal, mechanistic link for functional gains post-stroke, a systematic, multimodal approach to stroke rehabilitation will be necessary in doing so.