A1 Journal article (refereed)
A test of the effort equalization hypothesis in children with cerebral palsy who have an asymmetric gait (2022)

Kulmala, J.-P., Haakana, P., Nurminen, J., Ylitalo, E., Niemelä, T., Marttinen Rossi, E., Mäenpää, H., & Piitulainen, H. (2022). A test of the effort equalization hypothesis in children with cerebral palsy who have an asymmetric gait. PLoS ONE, 17(1), Article e0262042. https://doi.org/10.1371/journal.pone.0262042

JYU authors or editors

Publication details

All authors or editors: Kulmala, Juha-Pekka; Haakana, Piia; Nurminen, Jussi; Ylitalo, Elina; Niemelä, Tuula; Marttinen Rossi, Essi; Mäenpää, Helena; Piitulainen, Harri

Journal or series: PLoS ONE

eISSN: 1932-6203

Publication year: 2022

Publication date: 21/01/2022

Volume: 17

Issue number: 1

Article number: e0262042

Publisher: Public Library of Science (PLoS)

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1371/journal.pone.0262042

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/79520

Abstract

Healthy people can walk nearly effortlessly thanks to their instinctively adaptive gait patterns that tend to minimize metabolic energy consumption. However, the economy of gait is severely impaired in many neurological disorders such as stroke or cerebral palsy (CP). Moreover, self-selected asymmetry of impaired gait does not seem to unequivocally coincide with the minimal energy cost, suggesting the presence of other adaptive origins. Here, we used hemiparetic CP gait as a model to test the hypothesis that pathological asymmetric gait patterns are chosen to equalize the relative muscle efforts between the affected and unaffected limbs. We determined the relative muscle efforts for the ankle and knee extensors by relating extensor joint moments during gait to maximum moments obtained from all-out hopping reference test. During asymmetric CP gait, the unaffected limb generated greater ankle (1.36±0.15 vs 1.17±0.16 Nm/kg, p = 0.002) and knee (0.74±0.33 vs 0.44±0.19 Nm/kg, p = 0.007) extensor moments compared with the affected limb. Similarly, the maximum moment generation capacity was greater in the unaffected limb versus the affected limb (ankle extensors: 1.81±0.39 Nm/kg vs 1.51±0.34 Nm/kg, p = 0.033; knee extensors: 1.83±0.37 Nm/kg vs 1.34±0.38 Nm/kg, p = 0.021) in our force reference test. As a consequence, no differences were found in the relative efforts between unaffected and affected limb ankle extensors (77±12% vs 80±16%, p = 0.69) and knee extensors (41±17% vs 38±23%, p = 0.54). In conclusion, asymmetric CP gait resulted in similar relative muscle efforts between affected and unaffected limbs. The tendency for effort equalization may thus be an important driver of self-selected gait asymmetry patterns, and consequently advantageous for preventing fatigue of the weaker affected side musculature.

Keywords: cerebral palsy; cerebral palsied; children (age groups); physical disabilities; walking (motion); steps; biomechanics; force production (physiology); asymmetry

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Ministry reporting: Yes

Reporting Year: 2022

JUFO rating: 1