내림 경사로 보행 시 전족부 탈-부착형 아웃솔의 각도 및 형태 변화가 하지 근활성도에 미치는 영향

이행섭 ( Haeng-seob Lee ),정재후 ( Jae-hu Jung ),채원식 ( Woen-sik Chae ) 한국스포츠정책과학원(구 한국스포츠개발원) 2017 체육과학연구 Vol.28 No.2

[목적] 본 연구의 목적은 내림 경사로 보행 시 발 전족부 탈-부착형 아웃솔의 각도 및 형태 변화가 하지근골격계에 미치는 영향에 있다. [방법] 본 연구에 참여한 연구 대상자는 근골격계에 질환이 없는 K대학교남학생 15명(나이: 23.5±2.1 yrs, 키: 175.7±4.6 cm, 몸무게: 651.9±55.5 N)을 선정하였으며, 피험자는 전족부 탈-부착 아웃솔의 각도(5°, 10°, 20°) 및 형태(Type-A, Type-B)에 따른 아웃솔을 착용하여 무작위순으로 보행하였다. 근전도 자료 수집을 위해 유선 근전도기기(QEMG8, Laxtha Inc. korea, sampling frequency = 1,024 Hz, gain = 1,000, input impedance > 1012 Ω, CMRR > 100 dB)를 사용하였다. 내림 경사로 보행 시 전족부 탈-부착형 아웃솔의 각도 변화가 하지 근육과 척추기립근의 근활성도에 미치는 영향을 분석하기 위해 좌측 척추기립근, 왼쪽 하지의 대퇴직근, 내측광근, 외측광근, 대퇴이두근, 전경골근, 외측비복근, 내측비복근에 표면전극을 부착하였다. 통계 처리는 아웃솔의 두 가지 형태(A, B)와 세 가지각도(5°, 10°, 20°) 변화가 근활성도 어떠한 영향을 미치는지 분석하기 위해 반복측정을 통한 이원배치분산분석(two-way ANOVA with repeated measure)을 실시하였다. 이 때 유의 수준은 p<.05로 하였고 Mauchly의 구형성을 만족하지 않을 경우 Greenhouse-Geisser로 검정하였다. 상호작용 효과가 통계적으로 유의하지 않을 경우 사후검정(post-hoc test)은 bonferroni를 통해 다중비교를 하였으며, 상호작용 효과가 통계적으로 유의할 경우 단순 주 효과(simple main effect)를 알아보기 위해 집단간 변인인 아웃솔의 형태는 일원분산분석(one-way ANOVA)으로 검증하였고, 집단내 변인인 아웃솔의 각도는 대응표본 t-검증(pairedt-test)을 실시하였다. [결과] 본 연구의 결과 IDLS 구간에서 대퇴직근의 경우 B형태의 아웃솔은 10° 아웃솔이 5° 아웃솔과 비교하여 대퇴직근의 근육활동이 통계적으로 유의하게 증가하였다. 5° 아웃솔에서 A형태가 B형태보다 대퇴직근의 근육활동이 통계적으로 유의하게 증가하였고, 20° 아웃솔에서도 A형태가 B형태보다 대퇴직근의 근육활동이 통계적으로 유의하게 증가하였다. [결론] 이러한 결과는 B형태 아웃솔이 A형태 아웃솔보다 신체의 균형과 안정성을 높이는 것으로 판단되며, 과도한 전족부 말단부의 높이는 불안정성을 증가시키는 것으로 사료된다. 5°-B 아웃솔은 내림 경사로 보행 중 안정성 향상과 인체 중량 부하에 따른 동작 제어에 가장 유용성 있는 아웃솔로 판단되지만 아웃솔 착용이 입각기 말의 발의 이지 동작과 이지 후, 하지 근육의 원활한 근육 활동을 통한 적절한 힘 분배에 있어서는 효용성이 떨어진다고 판단된다. [Purpose] The purpose of this study was to evaluate the effect of detachable forefoot outsole on muscle activity of the lower extremity during downhill walking. [Methods] Thirteen male university students (age: 23.5±2.1 yrs, height: 175.7±4.6 cm, weight: 651.9±55.5 N) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked down 20° ramp with forefoot`s design for the detachable outsole`s angle(5°, 10° and 20°) and type(A and B). To assess the myoelectric activities of selected muscles, six of surface EMG(QEMG8, Laxtha Inc. korea, sampling frequency = 1,024 Hz, gain = 1,000, input impedance > 1012 Ω, CMRR > 100 dB) electrodes with on-site pre-amplification circuitry were attached to ES, RF, BF, TA, LG, and MG. For each dependent variable, two-way ANOVA with repeated measures was used to determine whether there were significant differences among forefoot`s design for the detachable outsole`s angle and type (p<.05). When correlation effect was not statistically significant, post hoc analyses were performed using the multiple comparison through bonferroni, and if correlation effect was statistically significant, one-way ANOVA was performed as for the form of outsole which is an inter-group variable in order to find out simple main effect, and the paired t-test was performed to find out the angle of outsole, which is an intra-group variable. [Results] In IDLS phase, In terms of Rectus Femoris, 10°-B outsole showed statistically higher muscle movement than 5°-B, 5°-A outsole showed statistically higher muscle movement than 5°-B, 20°-A outsole showed statistically higher muscle movement than 20°-B. Among these outsoles, [Conclusion] 5°-B outsole was found to the most useful outsole for improving stability and controlling the bodily movement due to the body weight load when walking down the ramp.

고등학생의 성별에 따른 수직점프 유형별 운동역학적 분석

이행섭 ( Haeng Seob Lee ),주명덕 ( Myung Duck Ju ) 한국운동역학회 2006 한국운동역학회지 Vol.16 No.4

내리막 보행시 발 전족부 부착형 아웃솔의 각도 변화가 척추기립근과 하지근의 근활성도에 미치는 영향

이행섭 ( Haeng Seob Lee ),채원식 ( Woen Sik Chae ),정재후 ( Jea Hu Jung ),김동수 ( Dong Soo Kim ),임영태 ( Young Tae Lim ),장재익 ( Jea Ik Jang ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.2

The purpose of this study was to evaluate the effect of angle change of forefoot`s adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over -20o ramp. Thirteen male university students (age: 25.4±3.9 yrs, height: 176.2±5.1 cm, weight: 717.4±105.0 N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site preamplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over 0o and 20o ramp with three different forefeet`s EVA outsole (0, 10, 20o) in random order at a speed of 1.2±0.1 m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in 20o shoes compared to 0o and 10o ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot`s adhesive outsole, indicating that the increment of shoes` angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in 20o outsole compared to 0o and 10o ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

배드민턴 포핸드 헤어핀 동작 시 숙련 정도에 따른 손가락 압력 및 운동학적 변인 비교 분석

이행섭 ( Haeng Seob Lee ),채원식 ( Woen Sik Chae ),정재후 ( Jea Hu Jung ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.4

The purpose of this study was to compare and analyze the finger pressure and kinematic variables in the forehand hairpin net shot between skilled elite players and less skilled recreational players. Eight elite players (age: 18.1±0.8 yrs, height: 176.8±1.5 cm, weight: 640.9±48.6 N) with minimum of 6 years of experience and eight recreational players (age: 27.9±1.6 yrs, height: 177.1±6.1 cm, weight: 820.5±62.8 N) with less than one year experience were recruited in this study. For each trial being analyzed, four critical instants were identified from the video recordings: Right heel contact1 (E1), Right toe-off (E2), Right heel contact2 (E3), and Shuttlecock impact (E4). Each hairpin net shot was broken into consecutive phases: E1~E2 (Right Landing Phase: RLP), E2~E3 (Sliding Step Phase: SSP), and E3~E4 (Impact Phase: IP). Temporal parameters, Shuttlecock speed, linear and angular kinematics of body segments, and finger pressures were computed for this study. The results showed that the finger pressure of the ring finger and the middle finger for the skilled group during an impact had significantly greater than those of unskilled group. It is possible that all fingers were not used in the same manner when the racket was gripped in forehand hairpin. The result also suggested that the ring finger and the middle finger pushed the racket from top to bottom while having the mid-phalanx and proximal phalanx of index finger as an axis.

내림 경사로 보행시 배낭 무게에 따른 하지 움직임의 운동역학적 분석

채원식 ( Woen Sik Chae ),이행섭 ( Haeng Seob Lee ),정재후 ( Jae Hu Jung ),김동수 ( Dong Soo Kim ) 한국운동역학회 2015 한국운동역학회지 Vol.25 No.2

Objective: The purpose of this study was to conduct biomechanical analysis of varying backpack loads on the lower limb movements during downhill walking over -20° ramp. Method: Thirteen male university students (age: 23.5±2.1 yrs, height: 175.7±4.6 cm, weight: 651.9±55.5 N) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked over 20° ramp with four different backpack weights (0%, 10%, 20% and 30% of body weight) in random order at a speed of 1.0±0.1 m/s. Five digital camcorders and two force plates were used to obtain 3-d data and kinetics of the lower extremity. For each trial being analyzed, five critical instants were identified from the video recordings. Ground reaction force, loading rate, decay rate, and resultant joint moment of the ankle and the knee were determined by the inverse dynamics analysis. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among four different backpack weight conditions ( p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results: The results of this study showed that the medio-lateral GRFs at RHC in 20% and 30% body weight were significantly greater than the corresponding value in 0% of body weight. A consistent increase in the vertical GRFs as backpack loads increased was observed. The valgus joint movement of the knee at RTO in 30% body weight was significantly greater than the corresponding values in 0% and 10% body weight. The increased valgus moment of 30% body weight observed in this phase was associated with decelerating and stabilizing effects on the knee joint. The results also showed that the extension and valgus joint moments of the knee were systematically affected by the backpack load during downhill walking. Conclusion: Since downhill walking while carrying heavy external loads in a backpack may lead to excessive knee joint moment, damage can occur to the joint structures such as joint capsule and ligaments. Therefore, excessive repetitions of downhill walking should be avoided if the lower extremity is subjected to abnormally high levels of load over an extended period of time.

드롭 착지동작 시 마우스가드 착용이 운동역학적 변인에 미치는 영향

채원식 ( Woen Sik Chae ),이규복 ( Kyu Bok Lee ),정재광 ( Jae Kwang Jung ),이행섭 ( Haeng Seob Lee ),김동수 ( Dong Soo Kim ),정재후 ( Jae Hu Jung ) 한국운동역학회 2013 한국운동역학회지 Vol.23 No.4

The purpose of this study was to determine the biomechanical effect of wearing the mouthguard on the lower limb during drop landing. Nine male university students who have no musculoskeletal disorder were recruited as the subjects. Linear velocity, angular velocity, vertical GRF, loading rate, joint moment, and lower extremity muscle activity were determined for each subject. For each dependent variable, paired t-test was performed to test if significant difference existed between with mouthguard (WM) and without mouthguard (WOM) conditions (p<.05). The results showed that linear velocity, angular velocity, vertical GRF and loading rate were no significant difference between the two groups. The inversion moment of the ankle joint was increased in WM compared to WOM. Average IEMG values from BF, TA, and LG in WM were significantly greater than corresponding values in WOM during IP phase. This indicates that wearing mouthguard played a vital role in muscle tuning for maintaining joint stability of the lower limb and preventing injury.

하지 근력의 좌우 비대칭성이 초등학생의 보행 동적안정성에 미치는 영향

김건수 ( Gun Soo Kim ),채원식 ( Woen Sik Chae ),윤창진 ( Chang Jin Yoon ),이행섭 ( Haeng Seob Lee ),강년주 ( Nyeon Ju Kang ),김동수 ( Dong Soo Kim ) 한국운동역학회 2011 한국운동역학회지 Vol.21 No.3

The purpose of this study was to evaluate the effect of asymmetric muscle force in lower extremity on dynamic balance during walking. Sixteen elementary students(age: 12.3±0.7 yrs, height: 149.4±9.7 cm, weight 40.6±7.8 kg) who have no musculoskeletal disorder were recruited as the subjects. Temporal parameters, M-L inclination angle of XCoM-CoP, M-L and A-P CoP, loading rate, and decay rate were determined for each trial. For each dependent variable, a independent-sample t-test was performed to test if significant difference existed between each conditions(p<.05). The displacement of antero-posterior COP during RTO-LHC1 in SG was siginificantly smaller than corresponding value in AG. In contrast, the displacement of medio-lateral COP during RTO-LHC1 in SG was greater than those of AG. It seems that imbalance of muscle force may result in increasing the medio-lateral stance in order to minimize the instability. We found that the asymmetric muscle force in the lower extremity may be a reason for the awkward control of impact force.

휴대전화 파지방법이 엄지손가락의 운동학적 변인과 근활성도에 미치는 영향

김동수 ( Dong Soo Kim ),채원식 ( Woen Sik Chae ),정재후 ( Jae Hu Jung ),이행섭 ( Haeng Seob Lee ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.3

The purpose of this study was to determine whether there are significant differences in kinematic variables and muscle activities of the thumb between two smartphone holding techniques. Twelve right handed university students(age 25.4±3.9 yrs, height 176.2±5.1 cm, weight 75.8±11.4 kg, hand length 19.2±1.1 cm) who have no musculoskeletal disorder were recruited as the subjects and had experience in using a smartphone for more than one year. Maximum joint angle, angular velocity, muscular activities were determined for each trial. For each dependent variable, paired t-test was used to determine whether there were significant differences between one hand (OH) and two hands ([TH], ρ<.05). The results of this study showed that there were no significant differences between OH and TH in the maximum joint angle of the thumb. The angular velocity of each joint was not statistically significant between OH and TH. The statistical analysis revealed that the main effect of the smartphone holding conditions was significant in the peak normalized muscular activities of FDI and APL. Although smartphone holding technique doesn``t affect on mobility and movement of the thumb joint, it may affect on active degree of the thumb and the upper extremity in directly and indirectly.

탄소나노튜브 인솔 착용에 따른 드롭 착지 동작의 생체역학적 분석

채원식 ( Woen Sik Chae ),정재후 ( Jae Hu Jung ),이행섭 ( Haeng Seob Lee ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.4

The purpose of this study was to determine the biomechanical effect of wearing carbon nanotube-based insole on cushioning and muscle tuning during drop landing. Twenty male university students(age: 21.2±1.5 yrs, height: 175.4±4.7 cm, weight: 70.2±5.8 kg) who have no musculoskeletal disorder were recruited as the subjects. Average axial strain, average shear strain, inversion angle, linear velocity, angular velocity, vertical GRF and loading rate were determined for each trial. For each dependent variable, a one-way analysis of variance(ANOVA) with repeated measures was performed to test if significant difference existed among different three conditions(p<.05). The results showed that Average axial strain of line 4 was significantly less in CNT compared with EVA and PU during IP phase. The average shear strain was less in CNT compared with EVA and PU during other phases. The inversion angle was increased in CNT compared with EVA and PU during all phase. In linear velocity, angular velocity, vertical GRF and loading rate, there were no significant difference between the three groups. This result seems that fine particle of carbon nanotube couldn`t make geometric form which can absolve impact force by increasing density through eliminating voids of forms, Thus, searching for methods that keep voids of forms may play a pivotal role in developing of insole. This has led to suggestions the need for further biomechanical analysis to these factors.

2011 대구 세계육상선수권 대회에 참가한 한국 남자 창던지기 선수와 입상자들의 3차원 운동학적 비교 분석

채원식 ( Woen Sik Chae ),윤창진 ( Chang Jin Yoon ),임영태 ( Young Tae Kim ),이행섭 ( Haeng Seob Lee ),김동수 ( Dong Soo Kim ) 한국운동역학회 2011 한국운동역학회지 Vol.21 No.5

The purpose of this study was to compare selected kinematic variables between male medalists and a Korean male javelin thrower at the IAAF World Championships, Daegu 2011. The three medalists and one Korean javelin thrower that participated in the Championships were videotaped using three high-speed cameras (300 frames/s, EX-F1 Exilim, Casio, Japan), The results showed that the release and attitude angles of the Korean male javelin thrower (KMJT) were greater than that of the medalists, whereas the attack angle of the KMJT was smaller than that of the medalists. This study also found that the KMJT clearly had a lower release height than the medalists. As a possible adaptation of his physique to the skill, the KMJT used a small trunk inclination angle and produced greater inclination angles at his upper extremities. These results may be linked to an increase in the release angle of the KMJT. There were some difference between the KMJT and the medalists in terms of the length and duration of the delivery phase. In harmony with the shorter length of the delivery phase, its duration was shorter for the KMJT in comparison to the medalists. Because the delivery stride is considered to be a primary generator of endpoint speed, this decrease in the delivery phase time would decrease the javelin velocity at release. The amount of time taken in the delivery phase may be a critical factor to enhance a javelin thrower`s performance. Thus, rhythmic movement training specifically designed for the KMJT will help him attain an optimal throwing position.