The influence of hemiparesis on triceps surae morphological and mechanical properties in stroke survivors

Yes this identifies a problem but gives no fucking clue what to do about solving that problem. If only we had a stroke leader who made sure all stroke research was useful to survivors. Ok, atrophy exists, 'What the fuck is your doctor doing to solve that?'

The influence of hemiparesis on triceps surae morphological and mechanical properties in stroke survivors

Authors: Dias, Caroline Pieta^{a; b} | Lanferdini, Fábio Juner^a | Onzi, Eduardo dos Santos^a | Goulart, Natalia Batista Albuquerque^a | Becker, Jefferson^c | Gomes, Irênio^d | Vaz, Marco Aurélio^{a; *}

Affiliations: [a] Exercise Research Laboratory, School of Physical Education, Physical Therapy and Dance, Federal University of Rio Grande do Sul, Porto Alegre, Brazil | [b] School of Physical Education, Faculty of Serra Gaúcha, Caxias do Sul, Brazil | [c] Neurology Service, São Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil | [d] Biomedical Gerontology and Neurology Department, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil

Correspondence: [*] Corresponding author: Marco Aurélio Vaz, Exercise Research Laboratory, School of Physical Education, Physical Therapy and Dance, Federal University of Rio Grande do Sul, Rua Felizardo, 750, CEP 90690-200, Porto Alegre, RS, Brazil. Tel.: +55 51 33085860; E-mail:marco.vaz@ufrgs.br

Abstract:  

BACKGROUND: Hemiparesis causes a reduction in neuromuscular structure and function and affects the contractile properties of the plantar flexors. 

OBJECTIVE: To compare the triceps surae volume, activation and mechanical properties in hemiparetic stroke survivors to those of healthy subjects. 

METHODS: Twelve hemiparetic stroke survivors (mean age, 62 years) and twelve healthy subjects (mean age, 60 years) participated in the study. The triceps surae muscle volume was estimated by ultrasound and anthropometric data. Plantar flexor muscle activation and dorsiflexor co-activation were measured with surface electromyography, and isometric plantar flexor moment was measured with an isokinetic dynamometer. Muscle quality was determined by the moment/muscle volume ratio. One-way ANOVA was used for between-groups comparisons (α = 0.05). 

RESULTS: The paretic and non-paretic limbs of stroke survivors showed smaller muscle volume (∼ 36% and ∼ 35%, respectively) than the dominant limb of healthy subjects (p< 0.01). The muscle quality was similar between the non-paretic limb and the dominant limb of healthy subjects (p> 0.05) but was lower in the paretic limb (p< 0.05). Peak moment was lower (∼ 61%) in the paretic and non-paretic (∼ 33%) limbs compared to the dominant limb of healthy subjects (p< 0.01). The paretic limb showed lower gastrocnemius medialis activation than did the non-paretic (∼ 45%) and dominant (∼ 33%) limbs of healthy subjects (p< 0.01). 

CONCLUSION: Structural and functional losses are higher in the paretic than in the non-paretic limb and in the non-paretic compared to a healthy limb.

Keywords: Muscle volume, muscle activation, plantar flexor moment, muscle quality, hemiparesis

DOI: 10.3233/IES-160613

Journal: Isokinetics and Exercise Science, vol. Preprint, no. Preprint, pp. 1-8, 2016

Received 3 July 2015

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Accepted 8 February 2016

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Published 9 May 2016

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