Search results for "biomechanics"
showing 10 items of 281 documents
Modelling Keloids Dynamics: A Brief Review and New Mathematical Perspectives
2022
The keloids are fibroproliferative disorders described by an excessive growth of fibrotic tissue, which also invades adjacent areas (beyond the original wound borders). Since these disorders are specific to humans (no other animal species naturally develop keloid-like tissue), the experimental in vivo/in vitro research has not lead to significant advances in this field. One possible approach could be to combine in vitro human models with calibrated in silico mathematical approaches (i.e., models and simulations) to generate new testable biological hypotheses related to biological mechanisms and improved treatments. Since these combined approaches do not really exist for keloid disorders, in…
A few remarks about the computer implementation and the verification of some hyperelastic constitutive laws and an illustration with the mechanical r…
2022
In this short technical note, we are interested in the constitutive equations used to model macroscopically the mechanical function of soft tissues under mechanical loading. Soft tissues have the ability to undergo large elastic reversible deformations under quasi-static loading and are usually modelled using hyperelastic constitutive laws. Several constitutive equations have been defined in the literature by means of strain components or strain invariants isotropic hyperelastic models. This short technical note recalls how to derive the weak form for hyperelasticity equations, and how this weak form can be linearized. It also presents a semi-analytical solution for a simplified geometry re…
Test-Retest Reliability of Task Performance for Golf Swings of Medium- to High-Handicap Players
2022
Background: Golf swing performance in medium- to high-handicap players must be reliably measured to use this variable in both research studies and in applied settings. Nevertheless, there are no studies published on this topic and test–retest evidence is only available for low-handicap players. The aim of this study was to determine the number of attempts necessary to obtain a reliable measurement protocol for swing performance variables in medium- to high-handicap players. Methods: Ten amateur players (55.67 (13.64) years, 78.4 (11.4) kg, 1.75 (7.95) m) took part in a test–retest study in two experimental sessions one week apart. In each one, fifteen swings with a six iron and a driver wer…
A Non-Local Mode-I Cohesive Model for Ascending Thoracic Aorta Dissections (ATAD)
2018
This paper presents a non-local interface mechanical model to describe aortic dissection. In this regard, the mode-I debonding problem based on a cohesive zone modeling is endowed with non-local terms to include long-range interactions that are present in multi-layered biological tissue. Such non-local effects are related to the collagen fibers that transmit forces between non-adjacent elements. Numerical simulations are provided with different values of the non-local parameters in order to show the effect of the non-locality during the debonding processes.
Effects of marathon fatigue on running kinematics and economy
2007
International audience; The influence of marathon fatigue on both running kinematics and economy was investigated with 8 subjects. The measurements included a treadmill test at 3 steady submaximal speeds performed before and after the marathon. One complete left leg cycle was videotaped at 100 Hz from the left side at each speed. The analysis included contact time (braking and push-off') and flight time as well as displacements and angular velocities of the left hip and knee. This analysis was complemented by the measurements of the electromyographic (EMG) activity of the gastrocnemius muscle at each running velocity, and energy expenditure (E) of the last 30.s at the 2 slowest speeds. The …
Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury: A Prospective Study
2018
Background: Stiff landings with less knee flexion and high vertical ground-reaction forces have been shown to be associated with an increased risk of anterior cruciate ligament (ACL) injury. The literature on the association between other sagittal plane measures and the risk of ACL injuries with a prospective study design is lacking. Purpose: To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injury in young female team-sport athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 171 female basketball and floorball athletes (age range, 12-21 years) participated in a vertical drop jump test usin…
2020
In this paper a comprehensive system-level computational model of oculomotor pathways is presented. This model shows the necessity of embedding internal models of muscles biomechanics in the cerebellar Vermis to realize fast saccadic eye movements based on predicting the changes in muscles lengths. First, the eye biomechanics are described by nonlinear equations during “slow” and “fast” movements. Afterward, by analyzing these equations, a computational model, is deduced. Furthermore, each part of this model is interpreted as a possible function of an element in the oculomotor pathways based on physiological and anatomical pieces of evidence. In this model, two internal feedback loops compe…
Biceps Femoris Long Head Muscle Fascicles Actively Lengthen During the Nordic Hamstring Exercise
2021
Current debate exists around whether a presumed eccentric exercise, the Nordic hamstring exercise (NHE), actually causes active hamstring muscle lengthening. This is because of the decoupling that can occur between the muscle fascicle and muscle-tendon unit (MTU) length changes in relatively compliant human lower-limb MTUs, which results in MTU lengthening not necessarily causing muscle fascicle lengthening. This missing knowledge complicates the interpretation of why the NHE is effective at reducing running-related hamstring muscle injury risk in athletes previously unfamiliar with performing this exercise. The purpose of the study was therefore to investigate if the most-commonly injured …
Analysis of stability against falling by movement simulation in human walking
2014
Effects of a training program on stable vs unstable surfaces on postural stability. [Efectos de un programa de entrenamiento en superficies estables …
2019
The training surface can modulate the body’s response to training stimuli. The purpose of the article was to determine the influence of two types of training programs on stable/unstable surfaces on postural stability. 20 physically active participants with no history of lower limb injuries were randomly assigned to 3 groups (Control, Unstable Training, Stable Training), and performed supervised training in 16 sessions. Dynamic postural stability and static stability were assessed and tests were performed at baseline after completion of the training and 1, 2 and 4 weeks after the training process. The stable surface training group improved dynamic stability between the pre-test and the two f…