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페달링 시 웨지의 삽입 유무에 따른 족저압의 영역별 비교 연구
배재혁(Jae Hyuk Bae),최진승(Jin Seung Choi),강동원(Dong Won Kang),서정우(Jeong Woo Seo),탁계래(Gye Rae Tack) 한국사회체육학회 2013 한국사회체육학회지 Vol.0 No.52
The purpose of this study was to study effects of inserted wedge on foot pressure during pedaling. Seven cyclists (age: 34.4±4.6year, height: 174.0±4.2cm, weight: 84.6±6.2kg) participated in 10 second maximal tests with and without wedges by their condition of varus or valgus. Movement of the knee joint was obtained through 3D motion analysis system (Motion analysis Corps., USA), and foot pressure were measured by F-scan System (Tekscan Inc., Boston, USA). Foot pressure was analyzed by contact area, contact pressure, peak contact pressure, contact force and peak contact force of 4 regions such as toe, forefoot, midfoot and rear-foot. CV(coefficient of variation) of mediolateral trajectory of the knee and CV of mediolateral COP(center of pressure) of foot pressure, which is closely related with lower limb vertical alignment, were analyzed. Results showed that CV of mediolateral trajectory of the knee and CV of COP at forefoot were significantly decreased with inserted wedge (p<.05). There were no significant differences in CV of COP at toe, midfoot and rearfoot. Contact pressure, peak contact pressure, contact force, and peak contact force at the forefoot were signifi-cantly increased after inserting wedges (p<.05) and there was no significant difference in contact area at the forefoot after inserting wedges. Contact area and contact force at the midfoot were significantly decreased with wedge(p<.05). However, there was no significant differences in contact pressure and peak contact pres-sure at the midfoot. There were no significant differences in foot pressure at toe and rearfoot with wedges. It could be concluded that inserted wedges made increasing effects of contact pressure, peak contact pressure, contact force, peak contact force of the forefoot by decreasing the variability of the knee and COP of foot pressure. Inserting wedges by considering rider`s physical characteristics will help vertical alignment of lower limb and the resulting vertical alignment will do positive effects on the prevention of injuries and efficiency of force transmission to the pedal.
사이클 페달링 시 페달반력 효율성을 고려한 적정 안장높이 결정방법
배재혁 ( Jae Hyuk Bae ),서정우 ( Jeong Woo Seo ),강동원 ( Dong Won Kang ),최진승 ( Jin Seung Choi ),탁계래 ( Gye Rae Tack ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.4
The purpose of this study was to compare two saddle height determination methods by the effectiveness of pedal reaction force. Ten male subjects (age: 24.0±2.4 years, height: 175.1±5.4 cm, weight: 69.3±11.1 kg, inseam: 77.8±4.5 cm) participated in three minutes, 60 rpm cycle pedaling tests with the same load and cadence. Subject`s saddle height was determined by 25° knee flexion angle (K25) when the pedal crank was at the 6 o`clock position (knee angle method) and 97% (T97), 100% (T100), 103% (T103) of trochanter height (trochanteric method). The RF (resultant force), EF (effective force), and IE (index of effectiveness) were compared by measuring 3D motion and 3-axis pedal reaction force data during 4 pedaling phases (phase1: 330°-30°, phase2: 30°- 150°, phase3: 150°-210, phase4: 210°-330°). Results showed that there were significant differences in EF at phase1 between T97 and K25, in EF at phase4 between T100 and T103, in IE at total phase between T97 and K25, between T100 and T103, in IE at phase1 & phase2 between T97 and K25. There was higher IE in the K25 than any other saddle heights, which means that K25 was better pedaling effectiveness than the trochanteric method. Therefore it was suggested the saddle height as 103.7% of trochanter height that converted from K25.
배재혁 ( Jae Hyuk Bae ),최진승 ( Jin Seung Choi ),강동원 ( Dong Won Kang ),서정우 ( Jeong Woo Seo ),탁계래 ( Gye Rae Tack ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.3
The purpose of this study was to develop an electric riding machine for cycle fitting to control riding posture easily, to measure frame size quantitatively, and to overcome disadvantages of the traditional systems. The electric riding machine consisted of actuator, load controller, and display & control unit. The actuator unit by BLDC(BrushLess Direct Current) motor drives the saddle height up and down, the crank forward and backward, the handlebar up and down, and the handlebar forward and backward. The load controller unit controls loads by Eddy current controller with electromagnet and aluminum circular plate. The display & control unit consisted of frame size controller and display panel which shows top tube length(485~663mm), head tube length(85~243mm), seat tube length(481~671mm), and seat tube angle(62.7~76.4˚). The range of frame size control for developed electric riding machine did not have difference compared to traditional commercial systems, but quantitative and precise control with 0.1 mm length and 0.1° angle was possible through digital measurement. Unlike traditional commercial systems, frame size control was possible during riding through motor driven method, thus fitting duration decreased. It is necessary for further improvement to have feedback from users. It is believed that developed electric riding machine can help to develop domestic fitting system.
최대 및 최대하 페달링 시 무릎각도법을 이용한 사이클 안장높이 결정에 대한 기초연구
최진승(Jin Seung Choi),배재혁(Jae Hyuk Bae),강동원(Dong Won Kang),신윤호(Yoon Ho Shin),이주학(Joo Hack Lee),탁계래(Gye Rae Tack) 한국사회체육학회 2013 한국사회체육학회지 Vol.0 No.53
The purpose of this study was to identify the applicability of the knee angle method during submaximal (SUB) and maximal (MAX) pedaling, and to compare with the movement of hip and ankle joint. Six cyclists(age: 34.6±5.6years, height: 174.2±5.7cm, weight: 84.8±7.6kg, career: 15.8±9.2years) participated in this experiment. 3D motion analysis system was used to acquire the movement of lower limb. Using these motion data, hip, knee and ankle joint angle were calculated. To compare SUB and MAX pedaling pattern, knee joint angle, minimum angle and range of motion (ROM) of each joint were used. Result showed that the knee angle method can be applied regardless of changes of cadence, in other words, both knee angles were in the range from 25° to 35° suggested by knee angle method. There were significant differences in the timing of minimum ankle joint of MAX and those of SUB, but those were not directly related to the changes of the knee joint angle. To clarify those causes, it is necessary to perform further study using ankle strategy for improving pedaling and preventing injury.
단신 : 페달링 시 정량적인 동적 피팅을 위한 실시간 평가 시스템
이주학 ( Joo Hack Lee ),강동원 ( Dong Won Kang ),배재혁 ( Jae Hyuk Bae ),신윤호 ( Yoon Ho Shin ),최진승 ( Jin Seung Choi ),탁계래 ( Gye Rae Tack ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.2
In this study, a real-time evaluation system for quantitative dynamic fitting during pedaling was developed. The system is consisted of LED markers, a digital camera connected to a computer and a marker detecting program. LED markers are attached to hip, knee, ankle joint and fifth metatarsal in the sagittal plane. Playstation3 eye which is selected as a main digital camera in this paper has many merits for using motion capture, such as high FPS (Frame per second) about 180FPS, 320×240 resolution, and low-cost with easy to use. The maker detecting program was made by using Labview2010 with Vision builder. The program was made up of three parts, image acquisition & processing, marker detection & joint angle calculation, and output section. The digital camera`s image was acquired in 95FPS, and the program was set-up to measure the lower-joint angle in real-time, providing the user as a graph, and allowing to save it as a test file. The system was verified by pedalling at three saddle heights (knee angle: 25, 35, 45o) and three cadences (30, 60, 90 rpm) at each saddle heights by using Holmes method, a method of measuring lower limbs angle, to determine the saddle height. The result has shown low average error and strong correlation of the system, respectively, 1.18±0.44o, 0.99±0.01o. There was little error due to the changes in the saddle height but absolute error occurred by cadence. Considering the average error is approximately 1°, it is a suitable system for quantitative dynamic fitting evaluation. It is necessary to decrease error by using two digital camera with frontal and sagittal plane in future study.
사이클 페달링 시 안장높이에 따른 하지관절 각도와 근육활성화의 상관관계
서정우 ( Jeong Woo Seo ),최진승 ( Jin Seung Choi ),강동원 ( Dong Won Kang ),배재혁 ( Jae Hyuk Bae ),탁계래 ( Gye Rae Tack ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.3
The purpose of this study was to investigate the effects of different saddle heights on lower-limb joint angle and muscle activity. Six elite cyclists(age: 32.2±5.2 years, height: 171.0±3.5 cm, weight: 79.7±5.6 kg, cycle career: 13±6.2 years) participated in three min. submaximal(90 rpm) pedaling tests with the same load and cadence based on saddle heights where subject`s saddle height was determined by his knee flexion angle when the pedal crank was at the 6 o`clock position. Joint angles(hip, knee, ankle joints) and the activity of lower limb muscles(biceps femoris(BF), vastus lateralis(VL), tibialis anterior(TA) and gastrocnemius medial(GM)) were compared by measuring 3D motion and electromyography(EMG) data. Results showed that there were significant differences in minimum hip & knee joint angle and range of motion of hip and knee joint between saddle heights. Onset timing and integrated EMG of only BF among 4 muscles were significantly different between saddle heights. Especially there was a negative relationship between minimum hip joint angle and onset timing of BF in most subject, which means that onset timing of BF became fast as the degree of bending of the hip joint became larger by saddle height. Optimal pedaling will be possible through increased amount of muscle activation due to the appropriate burst onset timing by proper pedaling posture with adjusted saddle height.
사이클 페달링 시 웨지를 이용한 하지 수직정렬이 무릎 궤적 및 페달링 파워, 속도에 미치는 영향
최진승(Jin Seung Choi),강동원(Dong Won Kang),배재혁(Jae Hyuk Bae),서정우(Jeong Woo Seo),탁계래(Gye Rae Tack) 한국사회체육학회 2012 한국사회체육학회지 Vol.0 No.48
This paper evaluated quantitative effects of vertical alignment of leg on knee trajectory, pedaling power and speed during pedaling. In general, traditional cycle fittings consisted of optimization of frame size using cyclist`s body size (static fitting) and pedaling efficiency using vertical leg alignment (dynamic fitting) during pedaling. Though both fitting methods were adopted in this study, static fitting was used for all test conditions thus the effects of dynamic fitting were evaluated. Fifteen male subjects (height 172.9 cm, weight 65.2 kg, age 25.3 years) were participated in this study. For the comparison of pedaling performance between before and after fitting, two min. submaximal pedaling tests with constant pedaling load were conducted. Results showed that the range of motion of medio-lateral direction at the knee, which represented pedaling trajectory, and the coefficient of variance of pedaling power were decreased significantly. From these results, it is believed that dynamic fitting showed positive effects such as increased pedalling kinematic stability and kinetic efficiency. Further study is necessary to evaluate the effects of the dynamic fitting through enough subjects with considering pedaling force and muscle activation.
사이클 안장 높이 증가가 대퇴 외측광근과 대퇴이두근의 길이 및 활성화 패턴에 미치는 영향
최진승 ( Jin Seung Choi ),강동원 ( Dong Wan Kang ),서정우 ( Jeong Woo Seo ),배재혁 ( Jae Hyuk Bae ),탁계래 ( Gye Rae Tack ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.4
The purpose of this study was to investigate the effects of increased saddle height on the length and activity pattern of vastus lateralis (VL) and biceps femoris (BF) muscle. To compare the effects of increased saddle height, Preferred (self-selected height of subject) and High saddle height (approximately 5 % higher saddle height than self-selected) were used. Seven elite cyclists (career: 16.1±8.5 years) participated in 3 min. sub-maximal pedaling tests under the same cadence (90 RPM) and pedaling power (150 W). Hip and knee joint angles, and the length and activity of VL and BF were compared by measuring 3D motion and electromyography (EMG) data. Results showed that there were significant differences in peak extension timing of the hip joint angle and the range of motion of the hip and knee join between different saddle heights. Although there were significant differences in muscle length of both muscles with increasing saddle height, the timing and amount of muscle activity differed only at the CF. These findings suggest that the timing and amount of bi-articular muscle activity (i.e. BF) can be altered by changing the saddle height. For practically applying these results, further study is necessary to evaluate the effects of various cadence and the pedaling power with various saddle heights.