Search results for "biomechanics"
showing 10 items of 281 documents
Microstructure-oxidation resistance relationship in Ti3AlC2 MAX phase
2020
International audience; Spark Plasma Sintering and Hot Isostatic Pressing were used to synthesize coarse-grained and fine-grained Ti3AlC2 specimens. Moreover, Spark Plasma Sintering processing parameters were modified in order to vary the TiC, Al2O3 and TixAly impurity and the porosity contents in the fine-grained samples. The influence of the Ti3AlC2 microstructure on the oxidation resistance was assesed. It is demonstrated that the grain size can drastically modify the oxidation resistance. The higher density of grain boundaries, in fine-grained specimens, increases the number of Al diffusion paths and leads to the formation of a protective alumina scale. In coarse-grained sample, Al diff…
Maximum forces acting on the abdominal wall: Experimental validation of a theoretical modeling in a human cadaver study
2011
Incisional hernias following median laparotomy have a high incidence and recurrence rate after repair, so that a better understanding of the linea alba biomechanics is desirable. The mechanical stress exerted on the linea alba in living humans is primarily generated by the musculature. In this human cadaver study, intraabdominal pressure was simulated by insertion of a balloon that was increasingly filled to maximal pressures of 200 mbar. The related forces acting transversely on the linea alba at maximum pressure were found to be between 41.6 and 52.2 N/cm (mean = 45.9 N/cm), which is in agreement with a recent modeling of the related forces.
Experimental Characterization of the Human Meniscal Tissue
2018
The meniscus plays a critical role in load transmission, stability and energy dissipation in the knee joint. Loss of the meniscus leads to joint degeneration and osteoarthritis. In a number of cases replacement of the resected meniscal tissue by a synthetic implant might avoid the articular cartilage degeneration. None of the available implants presents optimal biomechanics characteristic due to the fact the biomechanics functionality of the meniscus is not yet fully understood. Mimicking the native biomechanical characteristics of the menisci seems to be the key factor in meniscus replacement functioning. This is extremely challenging due to its complex inhomogeneous microstructure, the la…
Does Function Determine the Structure? Changes in Flexor Hallucis Longus Muscle and the Associated Performance Related to Dance Modality: A Cross-Sec…
2020
Background and Objectives: Flexor hallucis longus pathology is one of the most common conditions of the ankle and foot in dancers, due to the high demand of dance movements performed in an extreme plantar flexion and dorsiflexion range of motion. The objectives of this study were to determine the bilateral differences between the thickness and cross-sectional area of the flexor hallucis longus muscle in dancers, to establish possible differences between dance modalities, and to analyze whether there is a correlation between ultrasonographic parameters or performance variables and the dance modality. Material and Methods: A sample of 50 (29 classical and 21 contemporary) full-time pre-profes…
Masseter and temporalis muscle electromyography findings after lower third molar extraction.
2018
Background The main clinical application of electromyography is to detect abnormalities in muscle function, to assess muscle activity for purposes of recruitment, and in the biomechanics of movement. Objectives To analyze electromyography (EMG) findings for masticatory muscles during chewing following surgical extraction of lower third molars, and to determine any correlation between pain, inflammation, trismus, and the EMG data registered. Material and Methods This prospective study included 31 patients. Surface EMG was used to study masseter and temporalis muscle function before lower third molar extraction and 72 hours and seven days after surgery. Clinical variables, pain, inflammation,…
Technological advancements in the analysis of human motion and posture management through digital devices
2021
Technological development of motion and posture analyses is rapidly progressing, especially in rehabilitation settings and sport biomechanics. Consequently, clear discrimination among different measurement systems is required to diversify their use as needed. This review aims to resume the currently used motion and posture analysis systems, clarify and suggest the appropriate approaches suitable for specific cases or contexts. The currently gold standard systems of motion analysis, widely used in clinical settings, present several limitations related to marker placement or long procedure time. Fully automated and markerless systems are overcoming these drawbacks for conducting biomechanical…
Self-healing silk from the sea: role of helical hierarchical structure inPinna nobilisbyssus mechanics
2019
11 pages; International audience; The byssus fibers of Mytilus mussel species have become an important role model in bioinspired materials research due to their impressive properties (e.g. high toughness, self-healing); however, Mytilids represent only a small subset of all byssus-producing bivalves. Recent studies have revealed that byssus from other species possess completely different protein composition and hierarchical structure. In this regard, Pinna nobilis byssus is especially interesting due to its very different morphology, function and its historical use for weaving lightweight golden fabrics, known as sea silk. P. nobilis byssus was recently discovered to be comprised of globula…
Contribution to the investigation of dynamic responses of human tissues under high velocity impacts using finite element modeling
2022
Thoracic injuries happen frequently in various frameworks of high velocity impact biomechanics. Rib fractures and lung injuries are the most common hard and soft tissue injuries in human thorax. This thesis aims to contribute to the investigation of dynamic responses of human tissues especially ribs and soft tissues under high velocity impacts using finite element modeling. Firstly, a novel strain-rate-dependent elasto-hydrodynamic constitutive law of the synthetic polymer Styrene-Ethylene-Butylene-Styrene (SEBS) gel was proposed and implemented as a user material subroutine in Radioss (Altair Hyperworks) to interpret dynamic behaviors of SEBS gel under various loading configurations. Numer…
Estimation of errors in mechanical efficiency
1990
Errors in measurements of mechanical work, net energy expenditure and mechanical efficiency (ME) were calculated, when subjects performed isolated eccentric or concentric muscle actions and combinations of these actions [stretch-shortening cycle (SSC) exercises] with a special sledge apparatus. The relative error of mechanical work was 6.1%. When estimating the error of energy metabolism from oxygen consumption the error would be about 4% (McArdle et al. 1981). The maximum error of ME was the sum of these two values (10.1%). Obviously the error of ME was less than 5%, because 30 muscle actions were averaged and, in addition, the errors of mechanical work and energy expenditure were not in t…
Plantar Pressure Differences Between Nordic Walking Techniques
2017
Abstract High plantar pressure has been associated with increased risk of injury. The characteristics of each physical activity determine the load on the lower limbs. The influence of Nordic Walking (NW) technique on plantar pressure is still unknown. The aim of this study was to analyze the differences between plantar pressure during NW with the Diagonal technique (DT) versus Alpha technique (AT) and compare them with the pressure obtained during normal walking (W). The normality and sphericity of the plantar pressure data were checked before performing a two-way repeated measures ANOVA in order to find differences between speeds (preferred, fast) and the gait (NW, W) as within-subject fac…