Purpose The purpose of this study was to identify the lower extremity muscles length change according to the increase of the weight during snatch. Also, through the muscle contraction velocity analysis, it is necessary to identify muscles that require rapid muscle contraction. Methods The subjects were 10 national weight-lifters. Their mean age was 29 ± 3.84 yrs, body weight 71.3 ± 16.04 kg, height 1.63 ± 0.07 m, and the highest recorded height 128 ± 36.30 kg. Experiments were performed during the snatch to 70%, 80%, and 90% of the individual highest records. The analysis variables were the lower extremity angle, angular velocity, muscle length and muscle contraction velocity and were calculated by biomechanical modeling. Statistical analysis was performed with a repeated measure with one-way ANOVA to analyze the difference between the increase weight (70%, 80%, 90% of peak) and the dependent variable (angel, angular velocity, muscle length and muscle contraction velocity). Results According to the results of the study, there was no statistical difference in angle, angular velocity and muscle length with increasing weight. However, in the comparison of the muscle length, muscle length of the vastus medialis, vastus lateralis, biceps femoris, rectus femoris were statistically higher than other muscles. Also muscle contraction velocity of the rectus femoris, biceps femoris, vastus medialis, vastus lateralis, rectus femoris were statistically higher than other muscles. Conclusion In the snatch, the dominant muscles were the muscles around the femur, and the co-contraction of biceps femoris and great adductor muscles would contribute to improve the performance.
The purpose of the study was to investigate the relationship between the different kinematical variables with respect to the records and techniques performed by the participants during the 2011 Daegu IAAF World Championships Men's Pole Vault Event. Subjects chosen for the study were 8 male athletes who were selected for men's pole vault finals (highly skilled group) and 7 athletes who scored lowest record (skilled group) from the men's pole vault qualifying round. Personal best record of the each subjects were chosen to perform two dimensional (2D) and three dimensional (3D) video analyses. The data were obtained at 60 Hz with the use of five video cameras and digitizing was performed. Kinematical variables were calculated after smoothing the data using 2nd order Low-Pass Butterworth filter at cut-off frequency of 10 Hz and Independent samples t-test was performed to test any differences between two subject groups. The results: during the run-up stage, the horizontal velocity rate of the number of steps and run-up phase was obtained higher in highly skilled group than skilled group. During the take-off phase, deceleration in the horizontal velocity rate was observed in highly skilled group than skilled group. Distinct technical characteristics of distant and lower take-off of the take-off angle (angle of pole support) were also observed in highly skilled group than skilled group. During the pole bending and releasing phase, horizontal velocity was generally higher in highly skilled group than skilled group. It is considered that highly skilled group was able to jump higher as the vertical velocity during the pole bending as well as release phase was much higher in comparison to the skilled group.
In this paper, we tried to find out the difference of CoM displacement, CoM velocity and Foot-pressure between draw motion and takeout motion in curling’s delivery motion. To do this, we experimented for 10 female athletes of curling national team(all athletes are in her 20th~30th ages) to carry out draw motion and takeout motion from backline to near hogline in state of speed limit. The limited speed was 3.80~3.90 sec for draw and 2.97~3.07 sec for takeout. From the experiments, we obtained the result like followings. 1. Draw motion is more increase than takeout motion in displacement of horizontal direction of CoM displacement. 2. Takeout motion is more increase than draw motion in displacement of vertical direction of CoM displacement. 3. Takeout motion is faster than draw motion in both of horizontal and vertical direction of CoM max. velocity. 4. Takeout motion is higher than draw motion in pressure of fore-foot and mid-foot of foot-pressure 5. Draw motion is higher than takeout motion in pressure of fore-foot and mid-foot of foot-pressure These result means that the characteristics of techniques for draw motion and takeout motion is differ from each other and it is necessary to take different training protocol individually to enhance athletes’s performance. And further research will contains another things like that the pursuit of curling stone’s rut by various delivery techniques
