Journal of biomechanics
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Journal of biomechanics · Feb 2018
The contribution of the supraspinatus muscle at sub-maximal contractions.
During maximum effort, the supraspinatus muscle contributes approximately 50% of the torque need to elevate the arm, but this has not been examined at sub-maximal levels. The purpose of this study was to determine the contribution of the supraspinatus muscle to shoulder elevation at sub-maximal levels. Seven healthy subjects (four males, three females) performed isometric ramp contractions at the shoulder. ⋯ The effect of angle (p = .67) and % maximal voluntary contraction (p = .13) on supraspinatus contribution were not significant. The maximum is slightly less than reported in a previous suprascapular nerve block study using maximal contractions. The results from this study can be used to assess supraspinatus contribution in rotator cuff tears, after rehabilitation interventions, and as a restraint in computation modelling.
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Journal of biomechanics · Jan 2018
Tensile behaviour of individual fibre bundles in the human lumbar anulus fibrosus.
Disc degeneration is a common medical affliction whose origins are not fully understood. An improved understanding of its underlying mechanisms could lead to the development of more effective treatments. The aim of this paper was to investigate the effect of (1) degeneration, (2) circumferential region and (3) strain rate on the microscale mechanical properties (toe region modulus, linear modulus, extensibility, phase angle) of individual fibre bundles in the anulus fibrosus lamellae of the human intervertebral disc. ⋯ Our preliminary results showed that neither degeneration nor circumferential region significantly affected the fibre bundles' mechanical behaviour. However, when the fibre bundles were tested at higher strain rates, this resulted in significantly higher linear moduli and lower phase angles. These findings, compared with data from other studies investigating single and multiple lamellae sections, suggest that degeneration has minimal effect on outer anulus mechanics irrespective of structural level, and the inter- and intra-lamellar arrangement and continuity of the fibre bundles may influence the lamellae's regional behaviour and viscoelasticity.
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Journal of biomechanics · Jan 2018
A computational model for false lumen thrombosis in type B aortic dissection following thoracic endovascular repair.
Thoracic endovascular repair (TEVAR) has recently been established as the preferred treatment option for complicated type B dissection. This procedure involves covering the primary entry tear to stimulate aortic remodelling and promote false lumen thrombosis thereby restoring true lumen flow. However, complications associated with incomplete false lumen thrombosis, such as aortic dilatation and stent graft induced new entry tears, can arise after TEVAR. ⋯ Predicted thrombus growth over time was validated against follow-up CT scans, showing good agreement with in vivo data in all cases with a maximum difference between predicted and measured false lumen reduction below 8%. Our results demonstrate that TEVAR-induced thrombus formation in type B aortic dissection can be predicted based on patient-specific anatomy and physiologically realistic boundary conditions. Our model can be used to identify anatomical or stent graft related factors that are associated with incomplete false lumen thrombosis following TEVAR, which may help clinicians develop personalised treatment plans for dissection patients in the future.
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Journal of biomechanics · Jan 2018
Comment LetterResponse to the letter to the editor by Morin JB et al. regarding "Sprint mechanics return to competition follow-up after 2 hamstring injury on a professional soccer player: A case study with an inertial sensor 3 unit based methodological approach" (Setuain et al. 2017).
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Journal of biomechanics · Jan 2018
Comment LetterLetter to the Editor regarding «Sprint mechanics return to competition follow-up after hamstring injury on a professional soccer player: A case study with an inertial sensor unit based methodological approach» by I. Setuain, P. Lecumberri, and M. Izquierdo.