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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Sport Biomechanics
Journal Basic Information
Journal DOI :
Korean Society of Sport Biomechanics
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Volume & Issues
Volume 18, Issue 4 - Dec 2008
Volume 18, Issue 3 - Sep 2008
Volume 18, Issue 2 - Jun 2008
Volume 18, Issue 1 - Mar 2008
Selecting the target year
Mechanical Analysis of the Force on Landing 3 Type Curves(Ellipse, Circle, Brachistochrone) of Halfpipe
Lee, Un-Hak ; Kim, Kew-Wan ; Park, In-Ho ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 1~19
DOI : 10.5103/KJSB.2008.18.4.001
This research is to analyze the force on landing 3 Type of Halfpipe Curves(Ellipse, Circle, Brachistochrone) based on the mechanical calculation of normal force on a sloping surface. Jumping off a platform on a bard horizontal surface, the flexing of the legs, the softness of the snow, the angle of the landing surface, initial velocity and the forward motion of the snowboarder can contribute to reducing the force on landing. But halfpipe is significantly determined by the curvature of surface. It is definitely verified that the Brachistochrone curve is more safety than others. However currently using the Ellipse curve is mostly safe too. If we consider the efficiency of construction, we can easily think there is no use of another curves except normal ellipse curved halfpipe. It would better that geometrically verity curved halfpipe should be designed for improving fluent skills to snowboarders. This methode of research can be a model of scientifical research on sports safety how can sportsman reduce critical injury by designing optimal halfpipe facilities and manual.
Alterations in the Neuro-Mechanical Properties of Human Ankle Dorsiflexor after Maximum Eccentric Exercise
Lee, Hae-Dong ; Kim, Seung-Jae ; Kawakami, Yasuo ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 21~30
DOI : 10.5103/KJSB.2008.18.4.021
The purpose of this study was to investigate changes in mechanical properties of human tibialis anterior following eccentric exercise. Healthy subjects (n
The Kinematic analysis of the third Hurdling motions of The 110m Hurdles Elite
Lee, Jung-Ho ; Park, Young-Jin ; Ryu, Jae-Kyun ; Kim, Jong-In ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 31~39
DOI : 10.5103/KJSB.2008.18.4.031
The purposes of this study were to compare and analyze the world elite hurdler and the domestic hurdler 3-D kinematic and kinetic techniques about hurdling motion in the 110m hurdles. After analyzing variables in the 110m hurdle run the following conclusions were obtained; In a preparation phase, the domestic hurdler came out running more 0.13m then world elite hurdler from grounding to taking off in the height of center of gravity and the distance by 1.04m. In a flight phase, the domestic hurdler came out taking off 0.33m less then world elite hurdler from taking off to flight peak in the height of center of gravity and the distance by 1.63m. In a flight peak phase, domestic hurdler came out landing more 0.37m then world elite hurdler by 159m. More over, during the hurdling, the horizontal velocity of center of gravity came out decreasing from taking off to landing with domestic hurdler by 0.75m/s. the take off percentage and the landing percentage is 53:47. In a acceleration phase, domestic hurdler came out going slower 0.54m/s than world elite hurdler from landing in the horizontal velocity of center of gravity by 8.78m/s.
Acute Effect of Isokinetic Muscle Strength Related to the Static Stretching of Knee Joint
Lim, Seung-Geon ; Kim, Chang-Guk ; Lee, Yun-Seob ; Han, Jin-Tae ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 41~47
DOI : 10.5103/KJSB.2008.18.4.041
The purpose of this study was to provide foundations for proper stretching method not to lose muscle strength caused by shrink of muscle for preventing injury and improving performance when we make training programs. This study compared and analyzed isokinetic variables related to the static stretching frequency of knee joint extensor by isokinetic instruments applied to normal adults. 45 normal adults are randomly sampled into 3 different groups. All the measured variables were processed with SPSS and, means and standard deviations at each angle speed were calculated. The difference of means between before and after stretching of each groups were processed by paired t-test. One-way ANOVA and after test(Duncan) This study was able to see that stretching decrease acute isokinetic muscle strength High frequency stretching group showed more efficient decrease of muscle strength than low frequency stretching group. As a result, making training program for a game requiring strong muscle strength should consider proper stretching method not to lose muscle strength.
Elastic Resistance Exercise for the Elderly on the Magnitude of Frequency and Variability of Ground Reaction Force Signals during Walking
Seo, Se-Mi ; Ryu, Ji-Seon ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 49~57
DOI : 10.5103/KJSB.2008.18.4.049
The purpose of this study was to determine the effects of 12-week elastic resistance exercise for the elderly on the magnitude of frequency and variability of ground reaction force signals. To this aim, total 12 elderly women aged in their 70 were participated in this study and asked to do a 12-week elastic resistance exercise program. FFT(fast Fourier Transform) was used to analyze the frequency domain analysis of the ground reaction forces`s signals and an accumulative PSD (power spectrum density) normalized by support phase of walking was calculated to reconstruct the certain signals. To estimate the gait stability between the before and after exercise, values of variability were determined in a coefficient of variance. The magnitude of frequency and variability analysis for media-lateral signal revealed significantly less after exercise (p<.05). In contrast, variability of this signal`s frequency that have used to evaluate the local stability during walking exhibited significantly greater after exercise(p<.05). In summary, magnitude frequency and variability of media-lateral ground reaction force`s signal were significantly changed after a 12-week elastic resistance exercise.
Comparison of Plantar Foot Pressure and Shift of COP among Level walking, Stairs and Slope Climbing
Han, Jin-Tae ; Kim, Kyoung ; Lim, Seung-Geon ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 59~65
DOI : 10.5103/KJSB.2008.18.4.059
The purpose of this study was to investigate the shift of COP pathway and the plantar foot pressure among level walking and stairs and ramp climbing in young and elderly people. Plantar foot pressure was measured by MatScan system(Tekscan, USA). Statistical analysis was used One-way ANOVA to know the characteristics of peak plantar pressure during walking with different the facilities. In young adults, COP pathway during stairs climbing was slightly shorten and trended to abduct at forefoot. COP pathway during ramp climbing was also shorten but trend to adduct at forefoot. Peak plantar pressure of 2-3 metatarsal head and heel during ramp climbing was more decreased than level walking. In elderly people, COP pathway during stairs climbing was more shorten and abducted than leve walking and COP pathway during ramp climbing was more unstable than level walking. Peak plantar pressure of first metatarsal head increased at stair climbing and decreased at ramp climbing. That of second metatarsal head and heel was more decreased at ramp climbing. Conclusionally, Peak plantar pressures of each foot region generally increased and more changed during ramp climbing.
Kinematic Analysis on the Mogul Short Turn Motion in Interski
Joo, Hyun-Sik ; Park, Jong-Hoon ; Lee, Gye-San ; Kim, Won-Kyoung ; Park, Jong-Chul ; Back, Jin-Ho ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 67~76
DOI : 10.5103/KJSB.2008.18.4.067
The purpose of this study was to analyze differences in kinematic variables for mogul short turn motion between superior and inferior group, so that it can explore more effective mogul short turn motions. To meet the goals, this study selected total 10 ski players who would participate in mogul short turn event of the National Technical Ski Championship 2007, so that it could analyze kinematic variables by way of 3D motion analysis using DLT method. As a result, this study came to the following conclusions; For total and phase-specific duration, it was found that superior group took shorter time than inferior group. Superior group`s Center of Mass was stands for more high value in up-down movement skill than inferior group. However right-left movement scale was less than them. In this reason, superior group was made a straight descent at the same time made a fast front-rear velocity. In the part of up-down movement velocity show that move slowly in the drop-in phase while increased in the bump-up phase. It is show that superior group was less tinny than inferior group include joint angle and knee joint angle. However leaning angle of trunk and the body inclination angle were more high figured than inferior group. Leaning angle of lower limbs also showed high figure at the center mogul. Lastly, In the part of body torsion angle show that superior group was high figure direction of right turn in the drop-in phase while in bump-up phase, made a high figure direction of left turn.
A Case Study of Tkatchev stretched Motion by Technical Feedback in Horizontal Bars
Back, Jin-Ho ; Son, Won-Il ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 77~87
DOI : 10.5103/KJSB.2008.18.4.077
This study is to formulate strategy for subject who are selected as national team in horizontal bars event in apparatus gymnastics. For this, skill training program was applied to players for 8 weeks. Then it was analyzed by using 3D motion Analysis system to seek the difference between before and after using the program. There were decisive demerit element K`s first try for Tkatchev stretched movement from low elevation and crooked body while elevating. Not only, the location of his center of mass is far and low and there was some concern in his landing due to bended his hip-joint, but also, it exposed weak point in retro-action followed technique. Thus, to overcome that weak point, the subject repeated practices on following; when preparing for Tkatchev stretched movement at downward for big spin, make sure extend shoulder angle faster, make sure Tap movement is short and concise using hip-joint angular while delaying Tap timing for folding the body, and moreover, while backlashing the body, used shoulder joint angle wide to pull up the body. As a result, the speed of vertical upward did rut increase when separation from the bar. However, height of elevation increased that the leg would rut hit the horizontal bar even straight up the hip-joint. Therefore, the movement itself provided magnificent motion and even helped decrease the demerits.
Functional Evaluation of Tennis Shoes Using Foot-Pressure Distribution
Park, Seung-Bum ; Lee, Joong-Sook ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 89~97
DOI : 10.5103/KJSB.2008.18.4.089
The purpose of this study was to analyze the foot-pressure distribution of Tennis Shoes for assessing their functionality. 10 university male students (shoe size: 265mm) who had no history of injury in the lower extremity and a normal gait pattern participated in this study. Four types of tennis shoes, most popular in Korea (A, B, C & D company), were selected and tested. Using the PEDAR-X system and PEDAR-X insoles, 4 different motion stages were analyzed for the foot-pressure distribution: (a) straight running; (b) c-cut(
left turn running; (c) forehand stroke; and (d) backhand stroke. Results revealed that in all stages, there were no statistically significant differences among the types of shoes; however, descriptive statistics indicated that functionality of shoe types was somewhat different depending on the type of stages. The order in functionality found was C>A>B>D.
The Comparative Analysis on the Kinematic Variables according to the Types of Stance in the Dead-lift of Snatch Events of Junior Weight Lifters
Chung, Nam-Ju ; Kim, Jae-Pil ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 99~107
DOI : 10.5103/KJSB.2008.18.4.099
The aim of this study was to provide fundamental data in training to improve athletes` competitiveness through the comparative analysis of kinematic variables according to the types of stance. For this study, the subjects selected 4 Junior Weight lifters. Subjects performed two type(8-type and 11-type) Dead-lift and their performance was sampled at 60frame/sec. using four high-speed digital video cameras. After digitizing images from four cameras, the two-dimensional coordinates were used to produce three-dimensional coordinates of the 15 body segments(20 joint makers and 2 bar makers). And the results were as follows. 1. As for the time required for stances, 8-type motion was faster than 11-type motion. 2. As for the body-center shift in stances, 8-type motion was bigger than 11-type motion in back and forth motion shift, and 11-type motion was bigger than 8-type motion in right and left, up and down motion shift. 3. As for the speed of a body-center and a babel, 8-type motion was faster than 11-type motion. 4. As for the motion-trace of a babel in stances, 8-type motion was bigger than 11-type in back and forth, right and left motion and 11-type motion was bigger than 8-type in up and down motion. 5. As for the body-angles in stances, 8-type motion was bigger than 11-type in the stance angle, and 11-type motion is bigger than 8-type in the angles of a coxa, a knee and an ankle. As a result of the comparative analysis between 8-type and 11-type stance of Junior Weight lifters dead-lift, both were generally similar in variables, but 8-type motion was more stable than 11-type in aspects of time, speed, center shift, angle change.
Estimation of Energy Expenditure of Walking and Running Based on Triaxial Accelerometer and Physical Information
Kang, Dong-Won ; Choi, Jin-Seung ; Mun, Kyung-Ryoul ; Tack, Gye-Rae ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 109~114
DOI : 10.5103/KJSB.2008.18.4.109
The purpose of this study was to estimate the energy expenditure simply and practically during physical activities. The physical activity is quantified by the integration of the accelerometer signals obtained from the triaxial accelerometer attached at the waist level of the human body. To find a relationship between energy expenditure and accelerometer data, 6 male and 5 female subjects walked and ran on the treadmill with speeds of 1.5, 3.0, 4.5, 6.0, 6.5, 7.0, and 8.5 km/hr. Each subject performed walking at the speed lower than 6.0 km/hr and running at the speed higher than 6.5 km/hr. Actual energy expenditure was determined by a continuous direct gas analyzer. Two predictive equations of walking and running mode for energy expenditure which includes gender, body mass index(BMI) and data from accelerometer were developed using multiple regression analysis. The correlation coefficients and coefficients of determination between the estimated and measured energy expenditure were R
The Effects of Trunk Stabilization Exercise on the Isometric Muscle Power and Muscle Activation in Chronic Low Back Pain
Kim, Hyoung-Su ; Hyong, In-Hyouk ; Kim, Eun-Young ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 115~124
DOI : 10.5103/KJSB.2008.18.4.115
The purpose of this study was to know influenced on the change of Oswestry back pain disability index(OBPDI), isometric muscle power(IMP), muscular activation with chronic low back pain(CLBP) patients after Trunk Stabilization Exercise. Intervention was provided 6 weeks(5 days a week). Muscular activation was measured during IMP(Muscles : transversus abdominis : TA, internal obliqus : IO, external obliqus : EO, rectus abdominis : RA and erector spinae: ES). The results were as follows. 1. OBPDI about the MBE and the SE groups had effective decrease pain and disability. 2. IMP of intervention after the MBE and the SE groups had effective improve muscle power. 3. Muscle activation during IMP of intervention after was : TA, IO, RA had increase in the MBE and the SE groups. EO muscle activation during IMP of intervention after had increase only MBE groups. This shows that the MBE and the SE groups had effective increase because it has effective improve muscle power. Therefore, this study shows ￡hat trunk stabilization exercise program influenced on the change of OBPDI, IMP, muscular activation with CLBP patients.
The Comparative Analysis of EMG Activities on the Lower Limb Muscles during Power Walking and Normal Walking
Gi, Se-Joon ; Chae, Woen-Sik ; Kang, Nyeon-Ju ; Jang, Jae-Ik ; Yoon, Chang-Jin ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 125~133
DOI : 10.5103/KJSB.2008.18.4.125
The purpose of this study was to compare EMG activities on the lower limb muscles during power walking and mormal walking. Seventeen subjects who have no known musculoskeletal disorders performed walking exercise at a cadence of 140 beats/min. After surface electrodes were attached to rectus femoris, vastus medialis, vastus lateralis, biceps femoris, tibialis anterior, medial gastrocnemius, averageed IEMG and peak IEMG, were measured. The result showed that the power walking did influence the averaged IEMG and peak IEMG. The EMG activity of the quadriceps during power walking was significantly higher than the corresponding values in normal walking during most phases. The averaged IEMG and peak IEMG of gastrocnemius muscles at the end of the double limb stance increased significantly when going from normal walking to power walking. The results indicate that power walking had greater effect on EMG activities on the lower limb muscles and demonstrate that the wide range of benefits can be obtained from power walking in respect to health and fitness. This study suggests that power walking has the potential to improve aerobic fitness and assist in weight management.
A Biomechanical Research for Incorates a Rounded Sole with a 20 Degree Heel Lift in Functional Shoes
Lee, Joong-Sook ; Park, Sang-Kyoon ; Park, Seung-Bum ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 135~142
DOI : 10.5103/KJSB.2008.18.4.135
The primary innovation in the new footwear is a heel lift of
which is proposed to improve posture and balance as well as increase shock absorption. The purpose of this research was to compare the movement, forces and muscle activity between the new shoes and standard athletic footwear during standing and walking. Nine healthy subjects participated in this study. Data were collected at two times: 1) when the subjects first wore the new walking shoes and 2) after the subjects wore the shoes for 6 hours a day for two weeks. 1. During standing. the movement of the center of pressure is increased approximately 60% when wearing the new walking shoes compared to a control shoe. 2. During walking. the ankle is approximately
more dorsiflexed during landing due to the 200heel lift in the new walking shoes. The knee compensates slightly by flexing approximately
more. 3. As a result of the changes in the walking movement, the ground reaction forces are applied more quickly, although the peak magnitudes do rut change. 4. The resultant joint moments at the ankle and knee joints decrease from 21-60% with the largest reductions occurring during landing. In conclusion, the new footwear change the movement, showing a more upright stance. Also, the new footwear reduce joint loading at the joint during the landing and weight acceptance phase of walking. However, the influence of the new footwear is immediate and does rut change after wearing the shoes for two weeks.
Muscle Activity in T-ball Swing with Down Syndrome`s Children
Han, Ki-Hoon ; Lim, Bee-Oh ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 143~149
DOI : 10.5103/KJSB.2008.18.4.143
The purpose of this study was to investigate the muscle activities of pectoralis major, upper serratus, lat dorsi, anterior deltoid, rhomboids, infraspinatus, and posterior deltoid using Noraxon 8 channels EMG system during T-ball swing in children with Down syndrome. Five Down syndrome, one healthy children, and one baseball adult player were participated in the study. Down syndrome`s children showed higher muscle activity than one healthy children and one baseball adult player during address to backswing and backswing to impact swing phase. While Down syndrome`s children showed lower muscle activity than one healthy children and one baseball adult player during impact to follow swing phase. The strength of the pectoralis major and upper serratus muscle may help to improve T-ball swing movement during impact to follow swing phase.
Kinematic Analysis on Stroke in Wheelchair Table Tennis of Spinal Cord Injured Athletes and a Comparative Study with Abscission Athletes -Case Study of Medalists of Beijing 2008 Paralympics-
Moon, Gun-Pil ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 151~159
DOI : 10.5103/KJSB.2008.18.4.151
In this research, kinematic comparative analysis was performed on strokes of abscission and spinal cord injured athletes who participated in 2008 Beijing Paralympics wheelchair table tennis games. Strokes of all situations were collected under real match-like conditions. Among those, three major forehand stroke motions and backhand stroke motions were drawn Data collected by 9 infrared cameras were expressed in angular motions using graphic program LabVIEW7.0. As a result, forehand stroke of spin handicap athlete from analyzed images, the rotations of the trunk happened with the rotations of shoulder and the flexion extensions of elbow nearly at the same time. According to these results, insufficient turning force or speed of rackets is recompensed using flexion. backhand stroke of spin handicap athlete from analyzed images, the rotations of the trunk, the flexion extensions of the elbow and the flexion extensions of the shoulder were lined up on the prolongations of ping-pong balls. Forehand stroke of abscission athletes was done by outward rotation of the arm using backswing and inner rotation. As for backhand stroke, backswing was made by inner rotation in the spin of shoulder and waist. And after the backswing, impact was formed in wide outer rotation towards the ball.
A Kinetic Analysis of the Lower Extremity during Walking on Three Different Stair width in Healthy Adults
Jun, Hyun-Min ; Ryu, Ji-Seon ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 161~169
DOI : 10.5103/KJSB.2008.18.4.161
The purpose of this study was to investigate kinetic variables of the lower extremity during walking on three different stair widths in healthy adults. Ten healthy college-aged adults(
) recruited for this study. Each stairs with the same height and length(l8cm and 90cm) under the Korean Constructional Law but three different widths(26cm, 31cm and 36cm) were conducted for this study. One force plate(9286AA, Kistler Co.) was put on third stairs. One-way ANOVA was performed to find the stair width effects during stair walking and the following findings ware obtained. There was significantly decreased in ankle resultant joint moment at Pull-Up phase(p<.05) and, significantly increased in knee extension moment during mid-stance phase as stair width increase(p<.05), but there was no significance in ankle resultant joint moment was found at Forward Continuance Phase in Ascending Stair Walking and There was significantly increased in ankle resultant joint moment as stair width increase during mid-stance phase(p<.05) and no significance in knee and hip resultant moments among the stair width in descending stair walking.
Electromyographic Analysis of a Uphill Propulsion of a Bicycle by Forward.Backward Pedaling
Shin, Eung-Soo ; Kim, Hyun-Joong ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 171~177
DOI : 10.5103/KJSB.2008.18.4.171
This work intends to investigate the effects of pedaling directions on the muscle actions during the bicycle`s uphill propulsion. A test rig was developed that consists of a bicyle with a special planetary geartrain, a height-adjustable treadmill, a rear-wheel support and a magnetic brake. A three-dimensional motion analysis was performed for measuring kinematic characteristics of the forward backward pedaling and the electromygraphy(EMG) measurements were simultaneously performed for estimating the muscle actions of the leg. In this work, four muscles are considered including Gastrocnemius muscle(GM), Vastus lateralis(VL), Tibialis anterior(TA) and Soleus(SOL) while the uphill slope is varied from
. Raw EMG signals were first processed through the root-mean-square(RMS) averaging and then ensemble curves were derived by averaging the EMG RMS envelopes over 50 consecutive cycles. Results show that both the kinemactic characteristics and the muscle actions are significantly affected by the pedaling direction. The crank speed of the forward pedaling is higher but the difference in speed is reduced as the slope is increased. The ensemble curves of the :ac signals clearly exhibit some differences in their patterns, peak values and the corresponding locations with respect to the crank angle. The peak values of most EMG signals are higher for the forward pedaling regardless of the slope magnitude. However, the averages of the EMG signals are not observed to have a similar relationship with the pedaling direction, which seems to be affected by several factors such as less experience of the participants` backward pedaling. inappropriate bicycle design for the backward pedaling. These limitations will be further considered in future work.
The Process of the Interjoint and Intersegmental Coordination of Side Kick Motion in Taekwondo
Yoon, Chang-Jin ; Chae, Woen-Sik ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 179~189
DOI : 10.5103/KJSB.2008.18.4.179
The purpose of this study was to investigate interjoint and intersegmental coordination of lower segments in skill process. For the investigation, we examined the difference of resultant linear velocity of segments and angle vs angle graph. Novice subjects were 9 male middle school students who have never been experienced a taekwondo. We analyzed kinematic variables of Side Kick motion through videographical analysis. The conclusions were as follows. 1. Examining the graph of novice subjects` maximal resultant linear velocity of the thigh, shank, and foot segment, as it gets closer to the end of the training, the maximal resultant linear velocity in each segment increases which can be assumed to be a result of the effective momentum transfer between adjacent segments. 2 This research showed a sequential transfer from trunk, to thigh, and then to shank as it gets closer to the end of learning at intersegment angular velocity, and it also showed pattern of throwlike motion and pushlike motion. 3. In three dimension of flexion-extension, adduction-abduction and internal-external rotation of the thigh and shank segment, the angle-angle diagram of knee joint and of hip joint showed that dynamic change was indicated at the beginning of learning but stable coordination pattern was indicated like skilled subject as novice subjects became skilled.
The Kinematic Analysis on the 300m Starting Motion of Korean National Male In1ire Roller Skaters
Kim, Kab-Sun ; Kim, Dong-Hyun ; Seol, Han-Soo ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 191~199
DOI : 10.5103/KJSB.2008.18.4.191
The purpose of this study was to analyze movement of inline skate players at inline roller skate T300m start so that we can find effective starting movement, and provide basic and scientific materials in improving performance of inline roller skaters for T300m inline roller skating. In doing so, five Korean national representative inline skaters who elected in 2008 Korean National Inline Roller Skating Cup were taped during the cup and analyzed through 3D viewing in terms of their starting movement Conclusions of the analysis were as follows: First, the better the record of starting phase is the shorter average of contact time on track. Second, to improve starting speed, players raised their body just like running instead of lowering them when gliding. players could shorten their strike and moved faster in order to accelerate, and it was more effective to speed up when they quickly switched from running to gliding. Third, the five country-representative players speeded up by bending their knees to a greater degree in order to improve stability. And then the most effective way was believed to minimize track connection of skating at starting in each phase.
The Kinetic Analysis K-study of Roche Technique in Horse Vaulting
Yeo, Hong-Chul ; Ryu, Jae-Kyun ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 201~207
DOI : 10.5103/KJSB.2008.18.4.201
The purpose of this study was to examine the Roche technique performed by three male subjects in 2003 Taegu World Students Game. Conclusions are as followed. If the angular momentum was increased to counter-clockwise on voulting, the momentum acted like an interrupting factor of body spinning force. The biggest body angle was at VTD phase and the smallest was at BTO phase. At the phase of contacting on vaulting board and taking off from the vaulting board, the biggest personal angle difference between VTD and BTO was found. As the Roche technique was needed not only to fly high but also to increase body spinning rate, the projection angles of Roche technique were showed smaller than those of Cuervo technique. The angular velocity was peak during 2 times forward turn phase. The angular momentum was influenced by angular velocity from BTO and VTD phase.
Analysis of Impulse Force and Kinematic Variable to the University Male`s Triple Jumpers
Ryu, Jae-Kyun ; Yeo, Hong-Chul ;
Korean Journal of Sport Biomechanics, volume 18, issue 4, 2008, Pages 209~216
DOI : 10.5103/KJSB.2008.18.4.209
The purposes of this study were to describe the techniques used by the university male`s triple jumpers and to examine the characteristics of the kinematic and the kinetic factors of the three phases of a triple jump. The subjects were the five finalists with 16.70m over in the triple jump at the 2003 World Student Games. After analyzing the kinematic and the kinetic data during the whole triple jump, the following findings are obtained. The heights of the center of gravity of takeoff and touchdown for the three phases of the triple jump were medium-law-high pattern and the same height pattern as hop and step, respectively. Mean values for the average forces exerted on the subjects ranged from 0.6 to 0.7 times body weight to the horizontal direction and about 2.8 to 3.0 times body weight to the vertical direction.