5954 research outputs found
Sort by
DIFFERENCES IN TEMPORAL VARIABLES AND THEIR EFFECT ON KINETICS IN HIGH SCHOOL PITCHERS WITH HIGH AND LOW PITCH VELOCITIES
Get PDFThe purpose of this study was to compare temporal parameters between high and low velocity high school (HS) pitchers and investigate the influence these parameters have on both pitch speed and upper extremity kinetics. 30 healthy right-handed HS male pitchers with no recent injuries, and clearance to play were included. A 3D motion analysis system was used. Analysis included 15 kinetic and 35 temporal variables. Statistical tests conducted in SPSS. Correlation strength was interpreted as weak, moderate, or strong. High velocity and low velocity throwers showed differences in the timing to progress through the pitching cycle and these temporal variables showed separate relations to pitch speed and kinetics
THE PREDICTIVE MODEL OF INTERVAL TIME BASED ON PACING STRATEGY IN A 400 M HURDLES RACE
Get PDFThe purpose of the present study was to verify the reliability of the prediction equation for interval time (the times between hurdles) established from the hierarchical model in the 400 m hurdles. From 155 data samples of previous studies (record range: 47.42–50.99s), regression equations were established to predict each interval time throughout the race (model #1), during the first and latter halves (model #2) and during the first, middle, and last parts (model #3). Leave-one-out cross-validation was used to avoid overtraining for each regression equation. Models #2 and #3 showed better goodness of fit and generalization for each interval time compared to model #1. These hierarchical models are found to be more reliable compared to the non-hierarchical model. The hierarchical model will help to set the pace distribution to achieve the athlete’s target records accurately
THE RELATIONSHIP BETWEEN STRIDE MECHANICS AND SHOULDER DISTRACTION FORCE IN COLLEGIATE SOFTBALL PITCHERS
Get PDFThe purpose of this study was to determine the relationship between stride mechanics and shoulder distraction force in softball pitchers. Sixty-three collegiate softball pitchers (age: 20.1 ± 1.3 yrs, height: 173.3 ± 7.4 cm, weight: 79.7 ± 11.7 kg) participated and threw three maximal effort fastballs for a strike. Kinematic data were collected using an electromagnetic tracking system with a sampling frequency of 100 Hz. Regression analysis revealed a significant positive relationship between stride length and shoulder distraction force [R2 = .11; F (1, 61) = 7.345, p = .009], where stride length accounted for 11% of the variation in shoulder distraction force. Specifically, shoulder distraction force increased by .94 N/kg for every 10% increase in stride length normalized as a percentage of body height
THE ASSOCIATION BETWEEN STATIC FOOT POSTURE AND PEAK PATELLAR TENDON FORCE DURING SINGLE-LEG LANDINGS: PRELIMINARY FINDINGS
Get PDFPatellar tendinopathy is particularly prevalent in jumping-sport athletes and develops due to chronic overloading without appropriate load modification. Pronated and supinated foot postures have been suggested to be associated with the development of the injury. This study aimed to investigate the association between static foot posture, measured using the Foot Posture Index (FPI), and peak patellar tendon force during single-leg drop landings. Kinetic and kinematic data were collected during a single-leg landing task and used to estimate peak patellar tendon force. There was no statistically significant association between FPI and peak patellar tendon force during landing (p = 0.910). Further research investigating how foot posture may affect lower limb loading during landing is required to inform pre-screening and rehabilitation protocols for jumping sport athletes
LOWER LIMB STABILIZATION STRATEGIES OF DART ATHLETES AT DIFFERENT LEVELS
Get PDFThe purpose of the study was to understand lower limb stabilization strategies during the acceleration phase of dart throwing in athletes at different levels. Multi-Axis Force Plates and 3D Motion Capture were adopted to collect data. Six male darts athletes, including three elite athletes and three sub elite athletes, throw darts to hit Bull\u27s Eye abiding the rules of the World Darts Federation. The study shows that during acceleration phase, the ground reaction force of elite athletes changes substantially, while the change of ground reaction force of sub elite athletes was relatively small. Significant difference of the change in the front foot ground reaction force (GRF) on a vertical axis is reached (p\u3c0.05). The cause may be because the elite players use greater GRF transition from rear foot and front foot than sub elite players. On the contrast, sub elite athletes are still in the stage of integration, thus lower limb movement is minimized in order to stabilize the throw
RESTING-STATE FUNCTIONAL CONNECTIVITY CORRELATES OF ATTENTIONAL BIAS IN AN EMOTIONAL FREE VIEWING PARADIGM: AN EYE-TRACKING INVESTIGATION
Get PDFThreat detection, the process of searching complex environments for harmful stimuli, represents a vastly important job that promotes the biological fitness of the organism. Decades of experimental evidence suggests individuals either diagnosed, or at risk for, affective disorders display altered patterns of attentional engagement (hypervigilance or maintenance) with external stimuli; referred to as attentional biases. To date, the extent to which underlying neural mechanisms drive attentional biases, both in affective disorders as well as unselected populations, remain to be resolved. Thus, using eye-tracking and a passive emotional free viewing task, this study set to clarify resting-state network contributions from three large scale brain networks: frontoparietal, default mode, and salience networks. Results indicate participants displayed significant biases to negative/threat stimuli, and these attentional biases toward threat were associated with positive and negative connectivity between nodes within the three networks. Notably these were the lateral parietal cortex, medial prefrontal cortex, lateral prefrontal cortex, anterior insula, amygdala, and superior frontal gyrus. Attentional biases to negative/threat were not associated with stress, anxious, or depressive symptomatology measured by self-report. Lastly, eye-movement measures were found to be largely reliable, in contrast to those derived from response time indices. Main implications from the study suggest eye-movement measures should be further adopted due to their superior psychometric reliability, and further studies should target these brain structures for further analysis of their contributions to these biases
The Possible Role for Basigin Receptor Function in The Induction of Matrix Metalloproteinase Expression in Human Endometrial Stromal Cells
Get PDF10-15% of couples worldwide are affected by infertility. The leading cause of infertility is implantation failure. Molecular communication in precise time and space between an implanting embryo and a receptive uterus is essential for successful implantation. Basigin has been shown to have vital functions within the implantation process. Basigin is best known for inducing the expression of matrix metalloproteinases. Basigin has been shown to induce MMP expression in vitro in human endometrial stromal cell lines (HESC). Understanding how basigin induces matrix metalloproteinases within normal cellular conditions will help researchers understand how these signaling cascades flow in the framework of implantation. In order to do this, I attempted to characterize a basigin knock-out cell line using CRIPSR/cas9 in human endometrial stromal cells. Sixteen potential candidate clones were screened for the knock-out using PCR and western blotting. I determined that the donor plasmid was inserted into the genomes, but not in the intended location. Upon western blotting, all clones contained basigin protein expression. This could be due to basigin being a key gene in cell regulatory processes. Soluble basigin was then used to stimulate wildtype HESC lines for 0, 6, or 24 hours to characterize MMP protein expression and activation using immunoblotting and zymography. I found the highest expression fold changes in MMP-1, -2, and -9 at 6 hours, and MMP-2 at 24 hours. Zymography showed no difference in time. Future work is recommended to pinpoint peak protein expression for MMPs in HESCs following soluble basigin stimulation