Search results for "Biomechanical"
showing 10 items of 524 documents
Assessment of bioelectrical activity of pelvic floor muscles depending on the orientation of the pelvis in menopausal women with symptoms of stress u…
2017
Background Menopausal women often experience the prolapse of the uterus, bladder and rectum resulting from the failure and weakening of the pelvic floor muscles (PFM). Strengthening of the PFM through the standard exercises is recognized as an effective way of preventive measures and conservative treatment of the symptoms listed above, but still need to be improved. Aim The goal was the objective assessment of resting and functional bioelectrical activity of PFM in women during menopause and its comparison in three different positions of the pelvis: anterior pelvic tilt - position 1 (P1), posterior pelvic tilt - position 2 (P2), and neutral pelvic tilt - position 3 (P3). Design Prospective,…
Pectin biopolymer mechanics and microstructure associated with polysaccharide phase transitions.
2019
Polysaccharide polymers like pectin can demonstrate striking and reversible changes in their physical properties depending upon relatively small changes in water content. Recent interest in using pectin polysaccharides as mesothelial sealants suggests that water content, rather than nonphysiologic changes in temperature, may be a practical approach to optimize the physical properties of the pectin biopolymers. Here, we used humidified environments to manipulate the water content of dispersed solution of pectins with a high degree of methyl esterification (high-methoxyl pectin; HMP). The gel phase transition was identified by a nonlinear increase in compression resistance at a water content …
Vertical ground reaction force measurements and video measurements provide comparable estimates of distance moved by mice during artificial light and…
2011
Video-based measures of spontaneous activity of rodents are of interest in studying, e.g. physiology. However, video-based tracking methods typically require light. The purpose of the present study was to develop a video based method for tracking movements of mice during a dark period. The method was applied in comparing the dark and light period activities of mice. Ten male mice were used in the present study. The activity of the animals was monitored simultaneously with video and ground reaction force (GRF) recordings during consecutive 12h periods of artificial light and dark. Texture based background subtraction method was used to track the mouse from the video recording, while the weig…
Mechanical energy states during running.
1978
Changes in total mechanical work and its partitioning into different energy states (kinetic, potential and rotational) during a step cycle of running were investigated on six well trained athletes who ran at the test speeds of 40, 60, 80, and 100% (9.3 +/- 0.3 m/s) of maximum. Cinematographic techniques were utilized to calculate the mechanical energy states as described by Norman et al. (1976), using a 13 segment mechanical model of a runner as the basis for the computations. The data showed that both the kinetic and rotational energy increased parabolically but the potential energy decreased linearly with increases in running velocity. The calculated power of the positive work phase incre…
Force-, power-, and elasticity-velocity relationships in walking, running, and jumping
1980
Ground reaction forces and mechanical power were investigated when the subjects walked normally, while they were racing or running at four speeds, and when they performed the running long jump take-off. In addition, the apparent spring constants of the support leg in eccentric and concentric phases were investigated at the four running speeds, during the running long jump take-off, and in the triple jump. Six club level track and field athletes, four national level long jumpers, and six national level triple jumpers took part in the study. Cinematographic technique and a mathematical model of hopping (Alexander and Vernon 1975) were employed in the analysis. Force and power values were foun…
Collision with and avoidance of obstacles by blind cave fish Anoptichthys jordani (Characidae).
1985
Blind Mexican cave fish (Anoptichthys jordani) were released into unknown surroundings and their swimming tracks were recorded. During the first 24 h in a new tank, i.e., in unfamiliar environments, the average swimming velocity of the fish was higher than during the remaining time in the tank. Collision with obstacles was recorded by an electrical contact detection method. Single frame analysis of video-recordings revealed that collision can be correlated with tail movements when the fish is close to an obstacle, whereas avoidance correlates with gliding during approach to an obstacle. These behavior patterns are discussed in the context of the flow field hypothesis and inhibition of the l…
Mechanical power and segmental contribution to force impulses in long jump take-off
1979
Changes in total mechanical work, its partitioning into different energy states, mechanical power, force-time characteristics, force impulses of body segments and mass center's pathway characteristics during long jump take-off were investigated on four national and six ordinary level athletes. Both cinematographic and force-platform techniques were used. The data showed that the national level jumpers had higher run-up and higher take-off (release) velocities in horizontal and vertical directions. In addition, they were able to utilize efficiently the elastic energy stored in the leg extensor muscles at take-off impact. This was seen in high support leg eccentric and concentric forces, whic…
Stiff landings are associated with increased ACL injury risk in young female basketball and floorball players
2016
Background: Few prospective studies have investigated the biomechanical risk factors of anterior cruciate ligament (ACL) injury. Purpose: To investigate the relationship between biomechanical characteristics of vertical drop jump (VDJ) performance and the risk of ACL injury in young female basketball and floorball players. Study Design: Cohort study; Level of evidence, 3. Methods: At baseline, a total of 171 female basketball and floorball players (age range, 12-21 years) participated in a VDJ test using 3-dimensional motion analysis. The following biomechanical variables were analyzed: (1) knee valgus angle at initial contact (IC), (2) peak knee abduction moment, (3) knee flexion angle at …
Muscle effort is best minimized by the right-dominant arm in the gravity field
2021
AbstractThe central nervous system (CNS) is thought to develop motor strategies that minimize various hidden criteria, such as end-point variance or effort. A large body of literature suggests that the dominant arm is specialized for such open-loop optimization-like processes whilst the non-dominant arm is specialized for closed-loop control. Building on recent results suggesting that the brain plans arm movements that takes advantage of gravity effects to minimize muscle effort, the present study tests the hypothesized superiority of the dominant arm motor system for effort minimization. Thirty participants (22.5 ± 2.1 years old; all right-handed) performed vertical arm movements between t…
Detecting Ankle Instability With an Instrumented Ankle Arthrometer: An Experimental Study.
2019
A new instrumented device was developed to quantify ankle joint stability during an anterior talar drawer test. The aim of the present study was to validate this device comparing bone kinematics with arthrometer measurement outcomes. An anterior talar drawer test was performed with 14 cadaver legs using a custom instrumented ankle arthrometer. Using clusters of bone-pin markers, the relative three-dimensional movement of calcaneus, talus, and fibula was simultaneously measured. Anterior drawer test was applied on the intact foot and after sequentially sectioning the anterior talofibular ligament, the calcaneofibular ligament, and the posterior talofibular ligament. Cutting the anterior talo…