골프 어프로치 스윙 시 거리변화와 성공,실패에 따른 EMG 차이 분석

이경일 ( Kyung Ill Lee ),유문석 ( Moon Seok You ),홍완기 ( Wan Ki Hong ) 한국운동역학회 2015 한국운동역학회지 Vol.25 No.1

Objectives : The purpose of this study was to compare differences in muscle activities according to distance changes, and success or failure in relationto approaches during a round of golf in order to obtain basic data on golf swings· Methods : To achieve our research goal, we asked eight professional golfers playing for the Korea Professional Golfers` Association (height: 1·76 ±0·05 m, weight: 73·87 ± 9·21 kg, career duration: 12·87 ± 4·48 yr) to perform approach swings at distances of 30, 50, and 70 m· Results : No differences were observed in the muscle activity of the extensor carpi radialis that were caused by the distance changes· In addition, wefound that the wrist extensors seemed unaffected by the increase in approach distance· Also, we found that the powers of the approach shots were drivenby efficient movements rather than by the strength of the arms· We confirmed that when the distance of the approach increased, the golfers shouldperform their back-swing tops and follow-through right from the right to the left pelvic limb· To achieve successful approach swings despite distancechanges, golfers should first work on the activity of the erector spinae to prepare for rotatory power in the P1 section· Moreover, golfers should increasethe activity of the erector spinae on the left when they need to deal with the distance improvements in the P2 and P3 sections· Conclusion : In the light of the discussion above, we may infer that despite approach distance changes during a round of golf, ideal swings can berealized by consistent activities of the wrist extensor muscles and improved performances of the pelvic limb muscles· Furthermore, this study suggeststhat golfers should improve the consistency of muscle activities in all the other body parts to achieve the ideal swing·

중량물 취급 보행 시 하지의 역학적 정렬에 따른 생체역학적 변화 분석

이경일 ( Kyung Ill Lee ),이철갑 ( Chul Gab Lee ),송한수 ( Han Soo Song ),홍완기 ( Wan Ki Hong ) 한국운동역학회 2015 한국운동역학회지 Vol.25 No.2

Objective: Walking with a Material handling is an activity frequently undertaken by agricultural workers in Korea, due to the nature of their work. This study aimed to investigate differences in biomechanical variables according to the mechanical alignment of the lower limbs when walking with a heavy load, and to use this as basic data in the design of various working environments to reduce the skeletomuscular burden on the knee joint. Method: The study subjects comprised of 22 right-foot dominant adult men and women aged between 20 and 23 years. The subjects were divided into a varus or valgus group according to the mechanical alignment of the lower limb by using radiographic findings. The subjects walked without any load and with a load of 10%, 20%, or 30% of their body weight held in front of them. The Kwon3d XP program was used to calculate biomechanical variables. Results: The flexion/extension moment of the knee joint showed a decreasing trend with increased load, irrespective of the mechanical alignment of the lower limb, while the varus group did not show normal compensatory action when supported by one leg at the point of maximum vertical ground reaction force. In addition, in terms of the time taken, subjects showed no difficulties in one-foot support time up to 20%/BW, but at 30%/BW, despite individual differences, there was an increase in single limb. The increased load resulted in a decrease in the ratio of standing phase to ensure physical stability. The valgus group showed a trend of increasing the stability of their center of mass with increasing load, through higher braking power in the early standing phase. Conclusion: In conclusion, although there was no statistical difference in biomechanical variables according to the mechanical alignment of the lower limbs, the varus group showed a more irregular walking pattern with a Material handling than the valgus group, partially proving the association between lower limb alignment and walking with a Material handling.

보행 시 농작업 종사자들의 슬관절 퇴행성 등급에 따른 지면반력 특성 분석

이경일 ( Kyung Ill Lee ),이철갑 ( Chul Gab Lee ),홍완기 ( Wan Ki Hong ),김민 ( Min Kim ) 한국운동역학회 2015 한국운동역학회지 Vol.25 No.4

Objective : This study was conducted with an aim to use it as basic data for developing assistive devices, such as insoles that can suppress the progress of degenerative diseases and strategies, to improve early degenerative diseases by assessing walking characteristics of farm workers who were classified as KL-grade in the perspective of motor mechanics. Method : 38 male and female adults who complained of knee joint pain for more than six months were selected, and they were classified according to KL-grade. KL-grade was assessed by an orthopaedic specialist and an occupational environment health specialist. Filming equipment (FX-1, CASIO, Japan) and a ground reaction force system (AMTI OR6, AMTI, USA) were used to identify ground reaction force characteristics, and WOMAC was used for a pain rating scale. Results : There was a difference between the right and left side (axis-X) according to KL-grade, and when the grade was higher, the internal ground reaction force was also higher. Changes in COP were not affected by KL-grade of the knee joint, but it tended to increase as the grade increased. There were differences in the time required for limb support while walking according to the grades, and when the grade was higher, walking was more inefficient with long braking force and short propulsion forces. Also, pain rating scale, the right and left side, and COP changes while in support phase were related. Conclusion : There was a partial, statically significant difference in KL-grade and ground reaction force occurring during the support phase, and there were differences in ground reaction forces according to the grades of degenerative arthritis in the knee joint, indicating that this study is worthy as basic data for future studies.

드롭랜딩 시 발목테이핑 유형에 따른 운동역학적 차이 분석

이경일 ( Kyung Ill Lee ),홍완기 ( Wan Ki Hong ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.1

The purpose of this study was to compare and analyze kinetic variables of lower limbs according to types of ankle taping in drop landing. For this, targeting seven male basketball players (average age: 20.8±0.74 yrs, average height: 187.4±3.92 cm, average weight: 79.8±7.62 kg) with no instability of ankle joints, the drop landing motion was conducted according to three types of inelastic taping (C-type), elastic taping (K-type), and no treatment (N-taping). Based on the result, the next conclusion was reached. First, the effect of taping for the players with stable ankles was minimal and the high load on ankle joints offset the fixing effect of inelastic taping. Thus the inelastic taping for the players with stable ankles did not have an effect on the control of dorsal flexion during one-foot landing. Second, increasing angular velocity by increasing the movable range of knee joints disperses impact forces, yet inelastic taping restricted the range of knee joint motion and at the same time increased angular velocity, adding to a negative effect on knee joints. Third, inelastic taping induced inefficient motion of Lower limbs and unstable impact force control of ankle joints at the moment of landing and produced maximum vertical ground reaction force, which led to an increase of load. Therefore, inelastic ankle taping of players whose jump actions occur very often should be reconsidered. Also, it is thought that this study has a great meaning in proving the problem of inelastic taping related to knee pain with unknown causes.