SKILL ANALYSIS THROUGH COMPUTER GRAPHIC FEEDBACK

Many experienced coaches can easily identify the athlete's performance errors and that athlete can try to correct the fault following the coach's direction; however, sometimes the athlete misunderstands the direction or does not fully understand what he/she should correct in the skill. At that point a high speed camera or a video camera may be used to facilitate the motion analysis. Although this allows the athlete to receive feedback about the performance, it does not allow a comparison of the performance with an ideal performance of another athlete without dependence upon the athlete's ability to memorize and recall the correct skill execution

Assessments of Arterial Stiffness and Endothelial Function Using Pulse Wave Analysis

Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability

Distribution of magnetic domain pinning fields in GaMnAs ferromagnetic films

Using the angular dependence of the planar Hall effect in GaMnAs ferromagnetic films, we were able to determine the distribution of magnetic domain pinning fields in this material. Interestingly, there is a major difference between the pinning field distribution in as-grown and in annealed films, the former showing a strikingly narrower distribution than the latter. This conspicuous difference can be attributed to the degree of non-uniformity of magnetic anisotropy in both types of films. This finding provides a better understanding of the magnetic domain landscape in GaMnAs that has been the subject of intense debate

The Use of Shear Rate-Diameter Dose-Response Curves As an Alternative to the Flow-Mediated Dilation Test

The brachial artery flow-mediated dilation test (FMD) is the non-invasive gold-standard used to test endothelial function. Reduced FMD precedes the development of atherosclerosis and provides an early marker for predicting future cardiovascular disease events. Although, this test is of high potential, it is somewhat limited by poor reproducibility. By utilizing hand warming and grip exercise combined with hierarchical linear modeling, shear rate-diameter dose-response curves may provide a novel and more accurate way to assess endothelial function in humans. Shear rate-diameter dose-response curves could potentially improve upon the traditional FMD measurement and serve as a superior clinical and research tool for assessing cardiovascular disease risk in a variety of populations. The current paper presents testable hypotheses and methodology for assessing the validity and reliability of an alternative to the current FMD test

The aortic-femoral arterial stiffness gradient demonstrates good between-day reliability

In a healthy cardiovascular system, arterial stiffness progressively increases from the elastic aorta to the muscular conduit arteries of the periphery. This stiffness gradient permits a gradual attenuation of the forward pressure wave into a smooth consistent blood flow and prevents the transmission of pulsatile forces to the microcirculation and endorgans [1]. However, aging and lifestyle factors may disrupt these beneficial phenomena [2]. In particular, the aorta tends to stiffen, whereas changes in lower-limb arterial stiffness, for example, are less marked [2]. These differential changes in stiffness lead to a reversal of the stiffness gradient, increasing forward pressure transmission, and contributing to end-organ damage [1, 3]. A recent study reported that the stiffness gradient between aortic and lower-limb arterial stiffness provided prognostic information beyond the carotid-femoral pulse-wave velocity (cfPWV), a criterion measure of arterial health [4]. This measure provides a promising opportunity to gain meaningful insight into the hemodynamic integration of the vascular system. However, a measurement must have acceptable precision (reliability) to be of value in clinical and research settings. Therefore, the objective of this study was to estimate the between-day reliability of the aortic-femoral arterial stiffness gradient (af-SG)

The Importance of Velocity Acceleration to Flow-Mediated Dilation

The validity of the flow-mediated dilation test has been questioned due to the lack of normalization to the primary stimulus, shear stress. Shear stress can be calculated using Poiseuille's law. However, little attention has been given to the most appropriate blood velocity parameter(s) for calculating shear stress. The pulsatile nature of blood flow exposes the endothelial cells to two distinct shear stimuli during the cardiac cycle: a large rate of change in shear at the onset of flow (velocity acceleration), followed by a steady component. The parameter typically entered into the Poiseuille's law equation to determine shear stress is time-averaged blood velocity, with no regard for flow pulsatility. This paper will discuss (1) the limitations of using Posieuille's law to estimate shear stress and (2) the importance of the velocity profile—with emphasis on velocity acceleration—to endothelial function and vascular tone

The Importance of Velocity Acceleration to Flow-Mediated Dilation

The validity of the flow-mediated dilation test has been questioned due to the lack of normalization to the primary stimulus, shear stress. Shear stress can be calculated using Poiseuille's law. However, little attention has been given to the most appropriate blood velocity parameter(s) for calculating shear stress. The pulsatile nature of blood flow exposes the endothelial cells to two distinct shear stimuli during the cardiac cycle: a large rate of change in shear at the onset of flow (velocity acceleration), followed by a steady component. The parameter typically entered into the Poiseuille's law equation to determine shear stress is time-averaged blood velocity, with no regard for flow pulsatility. This paper will discuss (1) the limitations of using Posieuille's law to estimate shear stress and (2) the importance of the velocity profile—with emphasis on velocity acceleration—to endothelial function and vascular tone