테니스 서비스 동작의 운동역학적 분석

이중숙,이훈식 한국운동역학회 2000 한국운동역학회지 Vol.10 No.1

The purpose of this paper is to select 7 male athletes and female athletes of high school, and to compare their active potential differences of trunk muscle according to service motion of tennis. This paper also measures the duration time, and angular velocity of tennis service kinematic variations using Kwon3D(1993) program. When we generalize the change pattern of each variation through normalization process, the results obtained are as follows: 1. In the accumulative distribution rate of trunk muscles in service movement, male athletes show higher muscle active potential in the first service and female athletes show higher muscle active potential in the second service. 2. The ball speed of these athletes after an impact with the racket head is much slower compared with that of the world-famous athletes but of the proper flexsor and extensor of lower limbs, trunk, upper arm, forearm, and racket head are linked properly in sequence, biomechanical efficiency can be obtained in dong powerful service. 3. The angular velocity of wrist joint is much slower compared with that of the world-famous athletes, and this result is thought to be due to improper coordinated movement of the timing and rhythm in upper limb and trunk. 4. The great deviation of angular velocity in elbow joint among male athletes is due to the degree difference of using t he elbow joint. 5. The deviation of angular velocity in shoulder joint is also due to the improper coordinated movement and this keeps athletes from doing powerful service.

Biomechanical Analysis of Injury Factor According to the Change of Direction After Single-leg Landing

김종빈,박상균 한국운동역학회 2016 한국운동역학회지 Vol.26 No.4

Objective: The purpose of this study was to understand the injury mechanism and to provide quantitative data to use in prevention or posture correction training by conducting kinematic and kinetic analyses of risk factors of lower extremity joint injury depending on the change of direction at different angles after a landing motion. Method: This study included 11 men in their twenties (age: 24.6 ± 1.7 years, height: 176.6 ± 4.4 cm, weight: 71.3 ± 8.0 kg) who were right-leg dominant. By using seven infrared cameras (Oqus 300, Qualisys, Sweden), one force platform (AMTI, USA), and an accelerometer (Noraxon, USA), single-leg drop landing was performed at a height of 30 cm. The joint range of motion (ROM) of the lower extremity, peak joint moment, peak joint power, peak vertical ground reaction force (GRF), and peak vertical acceleration were measured. For statistical analysis, one-way repeated-measures analysis of variance was conducted at a significance level of α < .05. Results: Ankle and knee joint ROM in the sagittal plane significantly differed, respectively (F = 3.145, p = .024; F = 14.183, p = .000), depending on the change of direction. However, no significant differences were observed in the ROM of ankle and knee joint in the transverse plane. Significant differences in peak joint moment were also observed but no statistically significant differences were found in negative joint power between the conditions. Peak vertical GRF was high in landing (LAD) and after landing, left 45° cutting (LLC), with a significant difference (F = 9.363, p = .000). The peak vertical acceleration was relatively high in LAD and LLC compared with other conditions, but the difference was not significant. Conclusion: We conclude that moving in the left direction may expose athletes to greater injury risk in terms of joint kinetics than moving in the right direction. However, further investigation of joint injury mechanisms in sports would be required to confirm these findings.

Performance Analysis of Men's 110-m Hurdles using Rhythmic Units

( Sung Hong Hong ),( Jae Kyun Ryu ) 한국운동역학회 2018 한국운동역학회지 Vol.28 No.2

Objective: This study aimed to create a strategic training method to enhance optimal athletic ability using information from 1H to 10H rhythmic units. Method: Top three world class athletes and three national winners of 110-m hurdle finals from the 2010 Daegu International Athletics Competition and 2017 National Athletics Championship, respectively, were selected. To analyze the kinematic variables, Dartfish 9.0 was used for two-dimensional analysis. Results: Regarding the interval time from the start to the finish line, the national athletes took less time during the pure acceleration phase (start to 1H) than the foreign athletes. The horizontal velocity increase was slower after 1H; the national athletes showed a lack of ability to accelerate at the interval phases. Moreover, the hurdle clearance time between phases was longer in the national athletes than in the foreign athletes and lacked consistency. Conclusion: The national athletes lacked the ability to accelerate at the transition, maximum rhythm, rhythm maintenance, and re-acceleration phases and showed a longer hurdle clearance time. If technical improvements and strategic training methods using rhythmic units are applied for hurdling motions, the national athlete's hurdling abilities, performance, and consistency could improve.

Kinematic Analysis of the Technique for 500-m Speed Skaters in Curving

( Joo-ho Song ),( Jong-chul Park ),( Jin-sun Kim ) 한국운동역학회 2018 한국운동역학회지 Vol.28 No.2

Objective: The purpose of this study is to analyze the kinematic characteristics of the national speed skaters in the curve phase of 500-m race. Method: Seven national skaters participated in the study. Race images were acquired using a high - speed camera, and the three-dimensional motion was analyzed. Results: For skaters, whose average velocity in the curve phase is high, the velocity of entry into the straight phase was also fast. The fast skaters showed a larger maximum angle of extension of the knee joints than the relatively slow skaters, and the trunk ROM was smaller. Fast skaters tended to match the timing of the movement of the lower limb with the pelvis, while slow skaters tended to rotate the left pelvis backward. The velocity of the curve phase did not show a clear relationship with stroke time, average trunk angle, and lap time. Conclusion: It is important to skate close to the inner line, keep the trunk ROM below 10 degrees, extend the knee angle to over 160 degrees, and match the movement of the pelvis and lower limb to accelerate in the curve phase. The average velocity of the curves was fast for many athletes, but the competition rankings were low. Therefore, it is possible to improve the performance by optimizing the start technique, the running characteristics of the straight phase, and the physical factors.

Kinematic Analysis of the Technique for 500-m Speed Skaters in Curving

송주호,박종철,김진선 한국운동역학회 2018 한국운동역학회지 Vol.28 No.2

Objective: The purpose of this study is to analyze the kinematic characteristics of the national speed skaters in the curve phase of 500-m race. Method: Seven national skaters participated in the study. Race images were acquired using a high - speed camera, and the three-dimensional motion was analyzed. Results: For skaters, whose average velocity in the curve phase is high, the velocity of entry into the straight phase was also fast. The fast skaters showed a larger maximum angle of extension of the knee joints than the relatively slow skaters, and the trunk ROM was smaller. Fast skaters tended to match the timing of the movement of the lower limb with the pelvis, while slow skaters tended to rotate the left pelvis backward. The velocity of the curve phase did not show a clear relationship with stroke time, average trunk angle, and lap time. Conclusion: It is important to skate close to the inner line, keep the trunk ROM below 10 degrees, extend the knee angle to over 160 degrees, and match the movement of the pelvis and lower limb to accelerate in the curve phase. The average velocity of the curves was fast for many athletes, but the competition rankings were low. Therefore, it is possible to improve the performance by optimizing the start technique, the running characteristics of the straight phase, and the physical factors.

Anterior Cruciate Ligament Injury is Unlikely to Occur when Performing a Stable Weight Lifting Operation

문영진,문제헌 한국운동역학회 2018 한국운동역학회지 Vol.28 No.4

Objective: The purpose of this study was to examine the effect of increase in barbell weight on closely related variable to the anterior cruciate ligament (ACL) injury which are knee joint kinematics, joint load, joint moment, and maximum load attainment point during snatch of the weight lifting. Method: The subjects of the study were 10 male Korean national weight lifting athletes (69 kg 5, 77 kg 5;age: 21.80±3.91 yrs., height: 168.00±4.06 cm, weight: 75.00±4.02 kg, career: 7.8±3.99 yrs., snatch records: 168±4.06 kg). The weight of the barbell during the snatch operation was set at 70%, 75% and 80% of the highest records for each subject studied. Results: The result obtained from the one-way repeated measure ANOVA are as follows: With increased barbell weight, the extension moment of the left knee joint was higher in the 80% condition than the 70%(p<.001). However, other variables were not statistically significant difference. According to the factor analysis of the variables related to maximum load attainment point of the ACL major injury variables, the first subfactor was the internal shear force, the posterior shear force, the abduction moment, and the muscle activity of the VL. The second sub-factor was the extension moment of the knee joint, compressive force, adduction moment, and the third sub-factor was the muscle activity of BF. Conclusion: These results indicate that the possibility of ACL injury can be lowered when performing a stable snatch movement.

Anterior Cruciate Ligament Injury is Unlikely to Occur when Performing a Stable Weight Lifting Operation

( Youngjin Moon ),( Jeheon Moon ) 한국운동역학회 2018 한국운동역학회지 Vol.28 No.4

Objective: The purpose of this study was to examine the effect of increase in barbell weight on closely related variable to the anterior cruciate ligament (ACL) injury which are knee joint kinematics, joint load, joint moment, and maximum load attainment point during snatch of the weight lifting. Method: The subjects of the study were 10 male Korean national weight lifting athletes (69 kg 5, 77 kg 5; age: 21.80±3.91 yrs., height: 168.00±4.06 cm, weight: 75.00±4.02 kg, career: 7.8±3.99 yrs., snatch records: 168± 4.06 kg). The weight of the barbell during the snatch operation was set at 70%, 75% and 80% of the highest records for each subject studied. Results: The result obtained from the one-way repeated measure ANOVA are as follows: With increased barbell weight, the extension moment of the left knee joint was higher in the 80% condition than the 70% (p<.001). However, other variables were not statistically significant difference. According to the factor analysis of the variables related to maximum load attainment point of the ACL major injury variables, the first sub-factor was the internal shear force, the posterior shear force, the abduction moment, and the muscle activity of the VL. The second sub-factor was the extension moment of the knee joint, compressive force, adduction moment, and the third sub-factor was the muscle activity of BF. Conclusion: These results indicate that the possibility of ACL injury can be lowered when performing a stable snatch movement.

체급별 빠른발 돌려차기시 하지분절의 역학적 분석

조필환,정남주 한국운동역학회 2001 한국운동역학회지 Vol.10 No.2

태권도의 차기기술에는 여러 종류가 있지만 그 중에서 빠른발 돌려차기는 경기 시 상당히 빈번히 사용되고 있는 기술 중 하나로 보고되고 있다(김영대, 1997). 빠른발 돌려차기 기술은 상대의 중심을 흐트러 놓고 난 뒤에 다음 기술로 연결할 수 있으며, 또한 첫 공격에 득점을 낼 수 있는 장점을 지니고 있다. 태권도에 관련된 연구들은 경기 시 득점에 관련된 기술사용빈도와 차기기술 동작에 대한 역학적 이해를 위한 분석으로 분리되어 왔다. 특히, 역학적 연구는 대부분이 일반적인 운동학적 변인에 대한 기술(記述)로 한정되어 있어 체급간에 어떠한 차이가 있는지에 대한 결과는 다소 미진한 것으로 판단된다. 따라서 본 연구는 체급별 빠른 발 돌려차기 동작 시 하지분절의 특징을 기술하여 태권도 경기력 향상에 도움을 주고자 한다. 분석결과 다음과 같은 결론을 얻었다. 인체중심의 전진거리와 상승높이가 크다는 것은 인체의 이동속도를 크게할 수 있다는 점에서 상승높이가 적절히 분배되어야 한다. 동작수행 시 대퇴의 최대속도이후 하퇴의 최대속도, 그리고 발의 최대속도로 이어지는 분절의 속도전이가 바람직하게 이루어지고 있었으며 C체급에 비해 A와 B체급이 분절의 속도전이를 보다 효과적으로 수행하는 것으로 나타났다. 체급별로 고관절과 발목관절의 각도는 차기에 적합한 각도를 형성하며 임팩트 시점에 이르고 있으나 무릎관절의 경우 B와 C체급의 신전각도가 임팩트시점에서 작게 나타났다. 체급별 경기에서는 질량이 제한되기 때문에 같은 범위내에서는 속도를 향상시켜야 한다. There are probably kinds of kick technique in Taekwondo and among them it is reported that Parhunbal Dolyeochagi is one of technique frequently used in a great deal. Parhunbal Dolyeochagi has advantages; it is related to other techniques right after scatter the counterpart's C.O.G and player can get points at the first attack. The study of Taekwondo has classified for analysis to make out mechanics on technique using frequency and chagi motion is related to the point in matching. Especially, most of mechanical study is limited to the description of kinematical variables, so the result of the difference among weight is considered to be insufficient. Therefore, this study is to help improve Taekwondo matching power by stating the special feature of low leg segment when performing the Parhunbal Dolyeochagi in each level. The result of the analysis is as stated below. When performing Parhunbal Dolyeochagi, the moving distance and rising altitude should be divided properly, because it is judged to be able to scatter the opponent's ability to defend , for the greatness of the moving distance and rising altitude of the C.O G enables the human body to increase the moving speed. During the action, the velocity transfer of segment which is connected to the highest velocity of thigh, followed by the highest speed of shank, and the highest velocity of foot was performed desirably. Also, compared to weight C, weight A and B seemed to perform the velocity transfer of segment more efficiently. For each weight, the angle of hip joint and ankle joint forms the right angle for kicking, and reaches the impact point. But for the angle of knee joint, the extension angle of weight B and C appeared to be small at the impact point. During at weight matches, the mass is limited, so it is judged that the improvement of the velocity under the same situation is required.

A Review of biomechanical research for Footwear Outsole Stud development in Soccer

Park, Seung-Bum,Seo, Kuk-Woong,Kim, Yong-Jae,Lee, Joong-Sook 한국운동역학회 2003 한국운동역학회지 Vol.13 No.1

본 연구는 축구화 겉창의 스터드개발시 운동역학적 연구가 스터드개발에 어떻게 영향을 끼치었는가를 국외 선행연구문헌을 고찰함으로서 그 과정을 발견하는데 그 목적을 두었다. 지난 70년간 축구화 스터드가 연구개발되는 과정에서 압력분포측정 실험 및 기타 상해유발요인을 분석함으로서 스터드의 형태를 변화시키는 과정에 있어서 축구장 바닥과 축구화 겉창과의 마찰력이 중요한 변수로 작용하였다. 징이 선수들의 미끄럼을 방지하고 순발력을 향상시켜 경기력 향상에 결정적인 도움을 준 것이다. 이후 징박힌 축구화가 보편화하면서 선수들은 공격수냐 수비수냐 또는 잔디 상태에 따라 징의 개수와 길이가 다른 축구화를 신게 되었는데, 그라운드 컨디션에 따라 신발이 개발되었다. 축구화는 징의 종류에 따라 길고 푹신한 잔디(5~7월 잔디)에 신는 SG(soft ground)형, 짧고 단단한 잔디(가을철 잔디)에 적합한 FG(firm groud)형, 인조잔디나 아주 짧은 잔디에 좋은 터프(Turf)형, 맨땅에 쓰는 HG(hard ground)형으로 대별되는데, SG형은 15㎜가 넘는 마그네슘 징을 6개 박는데 순발력과 파워를 극대화하기 때문에 수비수에 어울리는 스타일이다. 짧은 폴리우레탄 징 12개를 다는 FG형은 넓은 그라운드 접촉면을 이루면서도 잔디에 깊게 박히지 않아 유연성을 필요로 하는 공격수와 미드 필더들에게 애용된다. 그라운드 상황이 좋지 않은 곳에서 뛰는 국내 고교, 대학 선수들은 12개의 징이 달린 축구화를 선호한다. 스터드가 많을 수록 그라운드에 닿는 면적이 넓어 안정감도 있고 발목이 꺾이는 현상을 줄여주기 때문이다. 지금까지의 연구현황은 압력분포 및 지면반력실험을 이용한 결과치를 이용하여 새로운 타입의 축구화 스터드의 개발결과를 기존결과와 비교분서하여 상해유발발생요인이 적은 스타일의 스터드를 선호하였다. 이에 향후 연구개발시 운동역학적 연구의 디자인시 상해유발요인분석과 운동역학적 연구결과의 조합을 결과를 비교분석해서 국내에서도 축구화 겉창 스터드 연구개발시 경기력을 향상시키고, 상해유발요인을 감소시킬수 있는 연구디자인이 지속되는 것이 중요하다고 사료된다.

회전하는 탁구공의 비행경로 예측에 대한 연구

한민성,이훈식 한국운동역학회 2006 한국운동역학회지 Vol.16 No.1