Jooho Song

The Kinematical Comparative Analysis Between Spring Shoe and General Shoe

The purpose of the study is to examine the effect of the spring shoe through the comparison of spring shoe to general shoe. For this, 12 healthy females in the age from 20 to 30 years participated in the E.M.G. experiment with testing kinematic variables. Results indicated that there was significant differences in angle of ankel between the general and spring shoe. Specifically, the spring shoe showed a bigger angle of take on and a smaller angle of take off in walking than the general shoe. This mesns that the spring shoe does not have a significant effect to produce efficient and smooth walking. In addition, the spring shoes revealed a bigger rear-foot angle than the general shoe in the evaluation of rear-foot control function. This means that the rear-foot control function of the spring shoe is low compared to trhe general shoe. Meanwhile, there is no significant differences in angle of knee and angle of Achilles tendon between both shoes. In an analysis of E.M.G., the significant differences were found in gastrocnemius muscle, anterior tibial musculi, musculi rectus femoris, biceps muscle of thigh between both the general and spring shoe groups by the section. In the case of gastrocnemius muscle, the spring shoe showed a low muscle production of anterior tibial musculi than the general shoe. This is a result from structural nature of the sole of a foot of the spring shoe. The spring shoe performs a rolling movement through slightly large pronation toward front-foot from rear-foot in supprt time before taking-off of toe and the power for this movement is mainly produced from musculi rectus femoris.

A Kinematic Analysis of Snatch Technique in Weight-Lifting

This study analyzed snatch technique in weight-lifting performed by female gold, silver, and copper medalists at the 75kg level in the 2002 Pusan Asian Games and obtained the following conclusions. 1. KSH used more extensor in the waist than those in ankles, knees, or hip joints during the second pull, So further training is required to manifest both each of joints and waist extensor effectively and thus for the line from shoulders through barbell to hip joints to form a smooth vertical pattern. 2. Contrary to those in other countries, Korean athlete KSH tended to be swift in starting but slow in the second pull section, showing less effectiveness in movement during the second pull; therefore, they must try to exert a swift movement in lockout. 3. KSH showed slowdown in the speed, which was a factor interfering with performance during second pull, despite the great maximum speed of moving barbell. It is important to use barbell sufficiently not to reduce the speed of vertical movement but rather to keep the speed increasing. 4. KSH, who kept doing inefficient movements such as failure to perform swift lockout after lifting the heel at the maximum angle of lower limbs, needs to reduce this meaningless extension of ankles, knees, or hip joints to exert energy effectively.

A Kinematic Analysis on Clear & Drop Motion of Badminton

The purpose of this study was to present the basic data on improving the skills for 3 junior high school national badminton players in clear and drop motion through the 3-dimensional image analysis. Therefore, the results of this study are as follows: 1. In the duration times per phase, subject C relatively showed a similar time between clear and drop motion. Accordingly, C took a more effective motion than A and B. 2. In the velocities of racket head, subject A and C showed similar changes relatively. However, in case of subject B, the velocity was decreased before back swing(E2) and increased until impact(E3). 3. Regardless of clear and drop motion, the changing phases of joint angle for wrist and elbow showed similar changes comparatively. 4. In the angles of upper body, clear motion was average 85.0 degree and drop one was average 80.7 degree during the impact(E3). Hence, it showed that drop motion hit the ball bowing the upper body more than clear one. 5. In the angles of racket head, clear motion was average 87.7 degree and drop one was average 85.6 degree during the impact(E3). Consequently, drop motion was impacted forward more than clear one.

Kinematics of the running-like sprint start in long-track speed skating

Abstract The purpose of this study was to investigate the kinematics of the sprint start in long-track speed skating. Video recordings of 11 world-class long-track speed skaters (5 men and 6 women) were made during an ISU 500-m World Cup race held in February 2016. Video recordings were analysed with KWON3D XP 4.0. Analysis revealed that male skaters changed to gliding technique at fifth stroke while female skaters adopt gliding technique at sixth stroke. Although statistically not significant, male skaters showed greater difference (amplitude) in hip (mean difference = 4.43, SD = 12.11), knee (mean difference = 7.01, SD = 15.12) and ankle (mean difference = 16.68, SD = 27.76) angles between at the time of the CONTACT and the OFF compared to female skaters. Male skaters also showed greater pushoff angles compared to female skaters. These greater angles of male skaters were associated with quicker time to transition point therefore this might explain why male skaters are able to use gliding technique earlier than female skaters leading to superior performance.

Differences in Rectus Femoris Activation Among Skaters Wearing Fabric Speed Skating Suits with Different Levels of Compression

In a speed skating simulation study, Saetran (2008) reported that different race suits could produce a difference of 3 seconds in a 1,500-m race. Given that the difference between the first and second place in the 1,500-m final at the 2014 Sochi Winter Olympics was only 0.003 seconds (Lee et al., 2014), the small effect of the suit and apparatus can have a major impact on the outcome of a race. Thus, the importance of sportswear is receiving increasing attention (Brownlie et al., 2004). As scientific and differentiated equipment reduces friction, improves motor efficiency, and has a positive impact on athletic ability, active athletes consider their personal equipment and clothing to be important, and are quick to adopt innovative, proven equipment if it could help them achieve even slightly better results. Recently, race suits for athletes have focused on the development of functional clothing that reduces muscle fatigue by limiting the size of large muscle movements during exercise. Compression clothing improves athletic performance, and alleviates post-exercise muscle pain and tissue damage. Kraemer et al. (2010) and Doan et al. (2003) reported that even simple compression stockings contribute to reducing fatigue (Berry & McMurray, 1987) and improving muscle power (Done et al., 2003). Takarada (2002) implemented blood flow restriction training in the lower limb and reported a 15% improvement in muscle strength and a 10% increase in cross-sectional muscle area. Based on the observation that compression reduces edema, and improves venous and lymphatic return, Chatham and Thomas (2013) suggested that compression improved muscle strength by increasing blood circulation. However, Ebersole (2006) found no significant differences in peak torque, total work, or peak power at different levels of compression. Thus, opinions vary on the effectiveness of compression clothing. Moreover, it has not been clearly demonstrated that compression is effective in improving athletic performance. Nevertheless, compression clothing is receiving attention worldwide from elite athletes, both in intense competitions and leisure sports (Fu et al., 2012). Efforts have been made to develop samples or products that can improve athletic performance through compression clothing. Therefore, based on a functional coated fabric applied to the femoral region of speed skating suits (developed as part of a nationally funded project to develop textiles, led by the Korea Evaluation Institute of Industrial Technology), the present study analyzed how different levels of compression affected the maximum power and activation of the rectus femoris, which produces the most power during racing, with the aim of assisting the future manufacture of speed skating suits. Korean Journal of Sport Biomechanics 2016; 26(4): 421-426 http://dx.doi.org/10.5103/KJSB.2016.26.4.421 http://e-kjsb.org eISSN 2093-9752 ORIGINAL

Trend Complex Analysis of Exercise Content on the Rings Final in the Korea Cup 2014

The purpose of the study was to perform trend analysis of the exercise content i.e. element difficulty distribution scores, element group distribution scores obtained by the athletes during 2014 Korea Cup International Gymnastic finals. The conclusion drawn from the analysis are as follows: Firstly in terms of tournament technical difficulty value, Korean athletes showed characteristics of reliance on swing element rather than strength hold element which could actually secure higher difficulty scores. Secondly, skill acquisition of higher difficulty value is demanded by taking advantage of familiar characteristics from the swing element i.e. Jonasson and Roll bwd. Slowly with str. arms and body to swallow (2s.). Thirdly, development of sensory training and strengthening exercise program are essential to enhance strength hold technique.