973 research outputs found
Effect of a 6-week yoga intervention on swing mechanics during the golf swing:a feasibility study
Recent evidence suggests that participating in physical conditioning programmes can improve golf performance, however, the effectiveness of a yoga intervention has yet to be investigated. The aim of the current study was to investigate the effectiveness of a six-week yoga intervention on golf swing mechanics. Ten male golfers participated in the laboratory-based-study. Golf swing mechanics were collected from two testing sessions, before and after the six-week yoga intervention, using the Vicon motion capture system. Following the six-week yoga intervention, significant changes were observed between the yoga and control group in X-Factor (P ≤ 0.05) and a medium effect (d ≥ 0.50) observed. No significant changes (P > 0.05) and no effect (d < 0.20) were observed in the X-Factor stretch. Significant changes (P ≤ 0.05) and a medium effect (d > 0.50) were observed for the pelvis rotations following the yoga intervention, however, no differences were observed in torso rotations or hand velocities (P > 0.05). The findings of this feasibility study suggest that yoga may be a promising intervention in helping to improve golf swing mechanics, however, future research is required to confirm the effect of the use of yoga during the golf swing due to the sample size
BIOMECHANICAL SIMILARITIES OF LONGSWINGS AT VARYING SPEEDS AND THE KOVACS ACTION
INTRODUCTION: Low movement variability in the backward longswing has been partly attributed to external competitive constraints (Irwin & Kerwin, 2005). However, a number of high level skills (e.g. Gienger, Deff, Kovacs) derive from variations in the longswing action. If movement variability is viewed as having a functional role (Bartlett et al., 2007) then variability in the longswing might be beneficial to subsequent skill acquisition. This study aims to determine whether variations in the speed of longswing can induce movements thatare more similar to movements associated with a high level skill, in this case the Kovacs
INSTEP SOCCER KICK TECHNIQUE AND PERFORMANCE THROUGH AN ANALYSIS OF MOVEMENT VARlABILlN
The purpose of this study was to investigate the structure of movement variability (MV) for hit and missed instep kicks using the uncontrolled manifold (UCM) analysis. University soccer players (n=1 1 ) performed a maximal instep kick at a target 11 metres (m) away. Hit and missed kicks were analysed using the UCM method. Dependent measures for UCM analysis were UCM variability measures and strength of synergy across six performance variables. Clear differences were noted between hit and missed kicks based on the UCM analysis. The UCM analysis provided a powerful tool for showing clear differences between hit and missed kicks and suggest that accurate kicking performance could be dependent on the structure of MV within the human motor system
PERFORMANCE RELATED TECHNIQUE FACTORS IN OLYMPIC SPRINT KAYAKING
A sprint kayaking specific deterministic model was used to identify key performance related technique factors using data from 12 international-level kayakers. There was large variability in the strength of the between-factor relationships across the group. The pull phase was split into 3 components with the 1st phase contributing the most to increases in boat velocity and the 3rd phase causing a decrease in velocity. The propulsive impulse had the largest influence on velocity, but the magnitude of the impact was moderated by blade slip. Large propulsive impulses in the 3rd phase of the pull were associated with larger decreases in velocity. The results show that the model can be used to identify key technique factors on an individual level, although the use of the model should be confirmed on additional kayakers before being used in an applied setting by practitioners
KINEMATICS OF WOMEN'S SPRINT CANOEING TECHNIQUE
Little is known about the biomechanics of sprint canoeing, especially for women's canoeing, and a quantitative kinematic description of the motion would help coaches to develop valid technique coaching models. Five highly-trained female canoeists were filmed at 150 Hz while undertaking a 50 s maximal effort on a canoe ergometer, whose trolley motions were taken to represent those of the boat. Selected boat, body and paddle kinematics were evaluated at three key stroke cyde events (Contact, Paddle Vertical, and End of Drive) and their patterns monitored across the stroke cycle. While no clear trends between the kinematics and power output emerged, a range of strategies were identified and the data represent an initial step in the construction of detailed technique models that can be used to evaluate and monitor individual athletes
THE EFFECT OF STEP WIDTH CONTROL ON LOAD CARRIAGE ECONOMY
The purpose of this study was to assess the influence of step width on load carriage economy. Fifteen healthy volunteers (age = 25 ± 3 years; stature = 1.78 ± 0.07 m; body mass = 73.6 ± 10.1 kg) completed three trials in a randomised order. Each trial differed by load carriage method and involved walking on a force-instrumented at 3km.h-1 with 0, 3, 12 and 20 kg. This protocol was then repeated with step width controlled to each participant’s preferred unloaded width. Relative load carriage economy was measured using the Extra Load Index (ELI). Load carriage economy was significantly worse in the head loading method compared to the other two method with step width uncontrolled (p = 0.02) and controlled (p = 0.02). For the trials where step width was uncontrolled, there was a significant difference in step width from unloaded walking between the different loading methods (p = 0.01) but no significant difference between load mass (p = 0.39). There was no difference in ELI between preferred and controlled step widths. Based on the data presented here, moderate alterations in step width caused by load carriage do not appear to influence load carriage economy
The SNARE Protein Syntaxin 3 Confers Specificity for Polarized Axonal Trafficking in Neurons.
Cell polarity and precise subcellular protein localization are pivotal to neuronal function. The SNARE machinery underlies intracellular membrane fusion events, but its role in neuronal polarity and selective protein targeting remain unclear. Here we report that syntaxin 3 is involved in orchestrating polarized trafficking in cultured rat hippocampal neurons. We show that syntaxin 3 localizes to the axonal plasma membrane, particularly to axonal tips, whereas syntaxin 4 localizes to the somatodendritic plasma membrane. Disruption of a conserved N-terminal targeting motif, which causes mislocalization of syntaxin 3, results in coincident mistargeting of the axonal cargos neuron-glia cell adhesion molecule (NgCAM) and neurexin, but not transferrin receptor, a somatodendritic cargo. Similarly, RNAi-mediated knockdown of endogenous syntaxin 3 leads to partial mistargeting of NgCAM, demonstrating that syntaxin 3 plays an important role in its targeting. Additionally, overexpression of syntaxin 3 results in increased axonal growth. Our findings suggest an important role for syntaxin 3 in maintaining neuronal polarity and in the critical task of selective trafficking of membrane protein to axons
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