title: Pennation angle dependency in skeletal muscle tissue doppler strain in dynamic contractions.
abstract: Tissue velocity imaging (TVI) is a Doppler based ultrasound technique that can be used to study regional deformation in skeletal muscle tissue. The aim of this study was to develop a biomechanical model to describe the TVI strain's dependency on the pennation angle. We demonstrate its impact as the subsequent strain measurement error using dynamic elbow contractions from the medial and the lateral part of biceps brachii at two different loadings; 5% and 25% of maximum voluntary contraction (MVC). The estimated pennation angles were on average about 4° in extended position and increased to a maximal of 13° in flexed elbow position. The corresponding relative angular error spread from around 7% up to around 40%. To accurately apply TVI on skeletal muscles, the error due to angle changes should be compensated for. As a suggestion, this could be done according to the presented model.
authors.affiliation: School of Technology and Health, Royal Institute of Technology (KTH), Huddinge, Sweden. frida.lindberg@sth.kth.se
authors.forename: Frida
authors.initials: F
authors.lastname: Lindberg
authors.forename: Fredrik
authors.initials: F
authors.lastname: Öhberg
authors.forename: Gabriel
authors.initials: G
authors.lastname: Granåsen
authors.forename: Lars-Åke
authors.initials: LÅ
authors.lastname: Brodin
authors.forename: Christer
authors.initials: C
authors.lastname: Grönlund
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004551:Elbow Joint / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000502:physiology*; D012044:Regression Analysis; D012815:Signal Processing, Computer-Assisted; D012984:Software; D018608:Ultrasonography, Doppler / Q000379:methods*