Document Type

Article

Publication Date

3-2026

Publisher

Biomed Central (BMC)

Source Publication

Journal of NeuroEngineering and Rehabilitation

Source ISSN

1743-0003

Abstract

Background. Many stroke survivors cannot walk effectively, even after rehabilitation. Causes include impaired muscle activation, poor interlimb coordination, and limited restorative interventions. To address this, we developed CUped (pronounced “cupid”), a motorized split-crank pedaling device designed to compel use of the paretic limb and retrain interlimb coordination. We examined its within-session effects, comparing three proportional control schemes—assist (A), resist (R), and assist plus resist (A + R)—to identify which best promotes recovery-related movement.

Methods. Nineteen individuals with stroke and eleven controls pedaled in 5-min bouts, one per control scheme. Each bout included pre-test, exposure, and post-test periods. Participants were instructed to maintain a 180º interlimb phase relationship. Interlimb coordination and paretic limb use were quantified as the mean and standard deviation of phasing error (µE, σE) and net mechanical work (Wₙₑₜ), respectively. ANOVA was used to assess the effects of group, time, and control scheme; regression examined relationships between variables and conditions. Between-limb differences in pedaling velocity (Vdif) were also calculated and served as interpretive measures.

Results. In stroke, all control schemes reduced µE, with the largest reduction observed under A + R (p ≤ 0.019; ES: A − 15º, R − 11º, A + R − 21º). Only A + R reduced σE (p = 0.039; ES: −10º). Effects diminished with sustained exposure to control schemes (p <  0.001) and exceeded pre-test when they were terminated (p ≤ 0.027; np2 µE = 0.24, np2 σE = 0.49 ). This “rebound” was associated with an increase in Vdif from pre- to post-test (p <  0.001. np2≥0.53). There was an inverse relationship between baseline phasing error and changes in µE and σE during exposure, where greater baseline error was associated with larger improvements (p <  0.001, R² µE = 0.74, R² σE = 0.69). The R scheme increased Wₙₑₜ, whereas A and A + R reduced it (p ≤ 0.026; ES: A − 8.8 J, R 2.9 J, A + R − 5.8 J). These changes were inversely related to changes in µE (p = 0.002, R²: 0.69). Responses to CUped were similar in controls.

Conclusion. CUped improved interlimb phasing and paretic limb use, though effects were not enduring, and gains in one reduced the other, with the A + R scheme performing the best overall. Results support CUped’s potential to enhance recovery-related movement and provide insight into motor adaptation post-stroke.

Comments

Published version. 

Journal of NeuroEngineering and Rehabilitation, Vol. 23, No. 127 (2026): 1-29. DOI. This article is © Springer Nature. This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.

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