In vivo 3D muscle architecture quantification based on 3D freehand ultrasound and magnetic resonance imaging

Muscle architecture parameters, such as the fascicle length, pennation angle, and volume, are important muscle morphology characteristics. Accurate in vivo quantification of these parameters allows to detect changes due to pathologies, interventions, and rehabilitation trainings, which ultimately impact on muscles’ force-producing capacity. In this study, we compared three-dimensional (3D) muscle architecture parameters of the tibialis anterior and gastrocnemius medialis, which were quantified by 3D freehand ultrasound (3DfUS) and a magnetic resonance imaging (MRI) technique, diffusion tensor imaging (DTI), respectively. Sixteen able-bodied subjects were recruited where seven of them receiv…

The reliability of measuring medial gastrocnemius muscle-tendon unit lengths during gait

Background Ultrasound imaging combined with 3D motion analysis allows for in-vivo assessment of muscle-tendon unit lengths during gait. The clinical relevance of analysing the medial gastrocnemius (MG) and Achilles muscle-tendon junction (MTJ), MG mid-muscle belly fascicles (FAS) and muscle thickness was shown. However, their reliability error estimations over the gait cycle is unknown. Research question What are the intra- and inter-session errors associated with extracting MG belly, thickness, FAS and tendon lengths using ultrasound during gait in healthy participants? Methods 3D gait analysis was carried out in ten healthy adults as they walked on an instrumented treadmill at a comfortab…

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Revising the stretch reflex threshold method to measure stretch hyperreflexia in cerebral palsy

Funding Information: This work was supported by the Olvi Foundation, Research Foundation of Cerebral Palsy Alliance (PHD00321), Finnish Cultural Foundation, University of Jyväskylä, Academy of Finland (grants #296240, #307250, #327288, #311877, #326988), including “Brain changes across the life-span” profiling funding to University of Jyväskylä, Jane and Aatos Erkko Foundation (#602.274), and the Netherlands Organization for Scientific Research (NWO-016.186.144). Ministry of Education and Culture (OKM/28/626/2022). Hyper-resistance is an increased resistance to passive muscle stretch, a common feature in neurological disorders. Stretch hyperreflexia, an exaggerated stretch reflex response, …

Medial gastrocnemius muscle and tendon interaction during gait in typically developing children and children with cerebral palsy

1. IntroductionEfficient gait is dependent on optimal interaction between musclesand tendons [1]. Pathological changes in the extensibility of the MGmuscle fascicles, whole muscle-belly and Achilles tendon have beenreported in children with spastic cerebral palsy (CP) [2]. Studying therelative length of these tissues during gait can improve our understandingof their dynamics and, inferably, the control strategies used inCP. In-vivo dynamic ultrasound imaging has been used to visualise theinteraction between the MG muscle and tendon during 3D gait analysis.However, most studies combined ultrasound imaging of one variable(either fascicles or muscle-belly and tendon) with some form ofmusculosk…