Circum-menarcheal bone acquisition is stress-driven: a longitudinal study in adolescent female gymnasts and non-gymnasts
Mechanical loading through youth exercise is highly modifiable and represents a strategy to maximize peak adult bone mass, with the potential for broad implementation across the population to lower fracture risk. For girls, cirum-menarcheal growth is critical, with around 50% of adult bone acquired over a 4-year period. Here, we prospectively followed 10 gymnasts and 12 age-matched non-gymnasts across approximately 4 years circum-menarche. A combination of pQCT and subject-specific finite element models were used to measure differences in bone acquisition and structure between the groups, and to determine the degree to whi...
Source: Journal of Biomechanics - July 17, 2018 Category: Biomedical Science Authors: Karen L. Troy, Tamara A. Scerpella, Jodi N. Dowthwaite Source Type: research
Uncovering the structure of the mouse gait controller: mice respond to substrate perturbations with adaptations in gait on a continuum between trot and bound
Animals, including humans, have been shown to maintain a gait during locomotion that minimizes the risk of injury and energetic cost. Despite the importance of understanding the mechanisms of gait regulation, ethical and experimental challenges have prevented full exploration of these. Here we present data on the gait response of mice to rapid, precisely timed, spatially confined mechanical perturbations. Our data elucidate that after the mechanical perturbation, the mouse gait response is anisotropic, preferring deviations away from the trot towards bounding, over those towards other gaits, such as walk or pace. (Source: ...
Source: Journal of Biomechanics - July 17, 2018 Category: Biomedical Science Authors: A. Vahedipour, O. Haji Maghsoudi, S. Wilshin, P. Shamble, B. Robertson, A. Spence Source Type: research
Knee moment outcomes using inverse dynamics and the cross product function in moderate knee osteoarthritis gait: A comparison study
The objective was to determine whether discrete features of the sagittal and frontal plane knee moments calculated using inverse dynamics compare to knee moments calculated using a cross product function. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 17, 2018 Category: Biomedical Science Authors: Derek James Rutherford, Matthew Baker Tags: Short communication Source Type: research
Residual force enhancement during submaximal and maximal effort contractions of the plantar flexors across knee angle
Following active muscle lengthening, steady-state isometric force is elevated compared with an isometric contraction without prior lengthening for the same muscle length and activation level. This property of muscle contraction is known as residual force enhancement (RFE). Here, we aimed to determine whether neural factors may mask some of the mechanical benefits of RFE on plantar flexion torque production. Inherent to lengthening contractions is an increase in cortical and spinal-mediated inhibition, while knee flexion places the medial gastrocnemius at a neuromechanical disadvantage. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 16, 2018 Category: Biomedical Science Authors: Brian H. Dalton, Vincenzo S. Contento, Geoffrey A. Power Source Type: research
Mechanical performance of lumbar intervertebral body fusion devices: An analysis of data submitted to the Food and Drug Administration
Lumbar intervertebral body fusion devices (L-IBFDs) are intended to provide stability to promote fusion in patients with a variety of lumbar pathologies. Different L-IBFD designs have been developed to accommodate various surgical approaches for lumbar interbody fusion procedures including anterior, lateral, posterior, and transforaminal lumbar interbody fusions (ALIF, LLIF, PLIF, and TLIF, respectively). Due to design differences, there is a potential for mechanical performance differences between ALIF, LLIF, PLIF, and TLIF devices. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 16, 2018 Category: Biomedical Science Authors: Jonathan H. Peck, Katherine D. Kavlock, Brent L. Showalter, Brittany M. Ferrell, Deepa G. Peck, Anton E. Dmitriev Source Type: research
Jet collisions and vortex reversal in the human left ventricle
Unnatural dynamics of the notorious vortex in the left ventricle is often associated with cardiac disease. Understanding how different cardiac diseases alter the flow physics in the left ventricle may therefore provide a powerful tool for disease detection. In this work, the fluid dynamics in the left ventricle subject to different severities of aortic regurgitation is experimentally investigated by performing time-resolved particle image velocimetry in a left heart duplicator. Diastolic vortex reversal was observed in the left ventricle accompanied by an increase in viscous energy dissipation. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 16, 2018 Category: Biomedical Science Authors: Giuseppe Di Labbio, Lyes Kadem Source Type: research
Poisson's Ratio of Bovine Meniscus Determined Combining Unconfined and Confined Compression
In this study, equilibrium Poisson's ratio of bovine meniscus (n=6) was determined experimentally by combining stress-relaxation measurements in unconfined and confined compression geometries. The average Young's modulus, aggregate modulus and Poisson's ratio were 0.182 ±0.086 MPa, 0.252±0.089 MPa and 0.316±0.040, respectively. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: E.K Danso, P. Julkunen, R.K. Korhonen Tags: Short communication Source Type: research
Computation of the role of kinetics, kinematics, posterior tibial slope and muscle cocontraction on the stability of ACL-deficient knee joint at heel strike - Towards identification of copers from non-copers
Rupture of anterior cruciate ligament (ACL) undermines normal activity and function of the knee joint and places it at higher risk of re-injury and degeneration. ACL reconstruction surgery neither necessarily ensures return to pre-injury activities nor alleviates risk of long-term degeneration. Here in this computational investigation of a lower-extremity hybrid model at heel strike (HS) of gait, we search for factors that influence the stability of the joint and hence the distinct performances between post-ACL injury copers and non-copers. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: M. Sharifi, A. Shirazi-Adl, H. Marouane Source Type: research
Biomechanical Analysis of Fluid Percussion Model of Brain Injury
Fluid percussion injury (FPI) is a widely used experimental model for studying traumatic brain injury (TBI). However, little is known about how the brain mechanically responds to fluid impacts and how the mechanical pressures/strains of the brain correlate to subsequent brain damage for rodents during FPI. Hence, we developed a numerical approach to simulate FPI experiments on rats and characterize rat brain pressure/strain responses at a high resolution. A previous rat brain model was improved with a new hexahedral elements-based skull model and a new cerebrospinal fluid (CSF) layer. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Haojie Mao, Lihong Lu, Kewei Bian, Fredrik Clausen, Niall Colgan, Michael Gilchrist Tags: Short communication Source Type: research
Alterations in Trunk Bending Stiffness Following Changes in Stability and Equilibrium Demands of a Load Holding Task
The contribution of the trunk neuromuscular system (TNS) to spine stability has been shown in earlier studies by characterizing changes in antagonistic activity of trunk muscles following alterations in stability demands of a task. Whether and/or how much such changes in the response of TNS to alteration in stability demand of the task alter spinal stiffness remains unclear. To address this research gap, a repeated measure study was conducted on twenty gender-balanced asymptomatic individuals to evaluate changes in trunk bending stiffness throughout the lumbar spine ’s range of flexion following alterations in both stabi...
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Iman Shojaei, Cazmon Suri, Jaap H. van Die ën, Babak Bazrgari Source Type: research
Predicting foot placement for balance through a simple model with swing leg dynamics
Stepping is one important strategy to restore balance against external perturbations. Although current literature have proposed models to predict the recovery foot placement, swing leg actuation is rarely taken into account. In this paper, we combine the capturability-based analysis with swing leg dynamics and seek to contribute to the following problem: for a biped system recovering balance from external perturbations, how to choose a step position and duration in minimizing swing actuation cost? We expand the linear inverted pendulum model with an actuated linear pendulum mounted on the pelvis, the addition of which is p...
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Lei Zhang, Chenglong Fu Source Type: research
The mechanics of agonistic muscles
In this study, we tested two assumptions that have been made in experimental studies on muscle mechanics: (i) that the torque-angle properties are similar among agonistic muscles crossing a joint, and (ii) that the sum of the torque capacity of individual muscles adds up to the torque capacity of the agonist group. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Heiliane de Brito Fontana, Seong-won Han, Andrew Sawatsky, Walter Herzog Source Type: research
A Subject-Specific Finite Element Musculoskeletal Framework for Mechanics Analysis of a Total Knee Replacement
In this study, we presented a methodology to develop a subject-specific FE-MS model of a human right lower extremity including the interactions among the subject-specific MS model, the knee joint model with ligament bundles, and the deformable FE prosthesis model. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Liming Shu, Ko Yamamoto, Jiang Yao, Prabhav Saraswat, Yao Liu, Mamoru Mitsuishi, Naohiko Sugita Source Type: research
Variogram-based evaluations of DXA correlate with vertebral strength, but do not enhance the prediction compared to aBMD alone
Ancillary evaluation of spinal Dual-energy X-ray Absorptiometry (DXA) via variogram-based texture evaluation (e.g., Trabecular Bone Score) is used for improving the fracture risk assessment, despite no proven relationship with vertebral strength. The purpose of this study was thus to determine whether classical variogram-based parameters (sill variance and correlation length) evaluated from simulated DXA scans could help predicting the in vitro vertebral strength.Experimental data of thirteen human full vertebrae (i.e., with posterior elements) and twelve vertebral bodies were obtained from two existing studies. (Source: J...
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Xuanliang Neil Dong, Yongtao Lu, Matthias Krause, Gerd Huber, Yan Chevalier, Huijie Leng, Ghislain Maquer Tags: Short communication Source Type: research
Scapulothoracic kinematic pattern in the shoulder pain and scapular dyskinesis: A Principal Component Analysis approach
This study aimed to evaluate the scapular kinematics in patients with shoulder pain and in asymptomatic participants with and without SDK using PCA. (Source: Journal of Biomechanics)
Source: Journal of Biomechanics - July 15, 2018 Category: Biomedical Science Authors: Denise Martineli Rossi, Renan Alves Resende, S érgio Teixeira da Fonseca, Anamaria Siriani de Oliveira Source Type: research
