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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
Editor in Chief :
Volume & Issues
Volume 21, Issue 5 - Dec 2011
Volume 21, Issue 4 - Dec 2011
Volume 21, Issue 3 - Sep 2011
Volume 21, Issue 2 - Jun 2011
Volume 21, Issue 1 - Mar 2011
Selecting the target year
A Kinematic Analysis of the National Elite Cross-Country Skiers' Double Poling Technique
Choi, Seul-Bi ; Ryu, Jae-Kyun ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 259~268
DOI : 10.5103/KJSB.2011.21.3.259
This study aimed to examine the kinematic characteristics of the national elite cross-country skiers' double poling technique and to provide the quantitative data for better performance. Four male elite cross-country roller skiers skied maximum velocity with Double Pole technique. The cycle characteristics with angles of elbow, hip, and knee joint were analyzed. The results showed that CM velocity of the body was increased with the third cycle, the cycle time and length were also increased. The poling time and recovery time rate showed with 32.79%, 67.44% respectively. The joint angles with elbow, hip and knee were
at pole in event,
at pole out event. Elite skiers should decrease double poling time rate and increase recovery time rate in order to improve the double poling performance. The cycle length and velocity of the double poling should be increased for the better performance. The elbow angle should be minimized at pole in event with maximum extension until pole out event. The hip and knee angles should be increased for the recovery phase.
The Biomechanical Analysis of Two and Half Rotation Technic of Penche in Rhythmic Gymnastics
Seo, Se-Mi ; Ryu, Ji-Seon ; Kim, Tae-Sam ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 269~279
DOI : 10.5103/KJSB.2011.21.3.269
This study was analyzed the characteristics on the stability of posture while conducting a through two and half rotation technic of pench
in rhythmic gymnastics. Two rhythmical gymnastics player(LKH and SSJ) who is a member of the national team were selected, and for obtain the kinematic and kinetic variables were used a ProReflex MCU 240 infrared camera(Qualisys, Sweden) and a Type9286A force platform(Kistler, Switzerland). The mechanical factors were computed by using Visual3D program and Matlab R2009a. During the landing and rotation phase the results showed following characteristics; 1) In medial-lateral and horizontal displacement of the support foot, LKH showed smaller movement than SSJ, but SSJ showed smaller movement than LKH in swing foot. LKH showed bigger movement in medial-lateral axis of COP and vertical axis of COG, but SSJ showed bigger movement in horizontal axis of COP and medial-lateral axis of COG. 2) SSJ showed bigger maximum horizontal and vertical velocity at P1 and P2 than LKH. 3) In the inclination angle of COP and COG, SSJ showed smaller change than LKH, but within medial-lateral tilt of the shoulder, LKH performed rotation motion in horizontal position than SSJ. There was no differences in each force components during rotation, but on landing phase, the results showed a characteristic that SSJ exerted bigger breaking force and vertical force than LKH.
Comparison of Gait Pattern during the Support Phase after Perturbation According to Age
Chun, Young-Jin ; Shin, In-Sik ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 281~288
DOI : 10.5103/KJSB.2011.21.3.281
The purpose of this study was to analyze the difference in reaction patterns during the support phase after perturbation in gait according to different age. A total of 12 subjects participated; 5 elderly and 7 adults(control), to investigate the differences between normal and perturbed gait. The step length didn't change during normal and perturbed gait but was longer in the control group. There was no difference in the step width. When the right foot was perturbed, the control group's left foot speed was faster than the elderly group's which was to maintain stability. The elderly flexed both right and left knees more than the control group. After the perturbation, the elderly group had a larger trunk anterior flexion. With the larger flexion of both legs of the elderly group it shows that the lack of knee flexion strength is a factor, that could cause falling and so a prevention program should focus on strengthening the quadriceps. With the excessive trunk flexion after the perturbation by the elderly group observed, it is suggested that while walking everyday a good routine of walking with an upright posture should be developed.
Characteristic Comparison of Ground Reaction Force of the Taekwondo's Apkubi Motion and the Walking on Older Persons
Bae, Young-Sang ; Kim, Ki-Man ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 289~296
DOI : 10.5103/KJSB.2011.21.3.289
The purpose of this study was to quantify the biomechanical characteristics of the ground reaction force(GRF) during the Taekwondo's Apkubi, one of the basic movement in Taekwondo and the walking. The GRF profiles under the stance foot of Apkubi movement and walking were directly measured in sample of 20 healthy older persons. In the anterior-posterior and vertical direction, the GRF of the Apkubi movement reached to the peak braking force at 10% of the normalized stance time percent and the peak driving force at 90% of stance time, but that of the walking reached to the peak braking force at 20% of stance time and the peak driving force at 80% of stance time. In vertical force, the GRF of the walking showed two peak values, but that of the Apkubi movement seemed three peak values. Moreover the first peak vertical force was significantly(t=6.085, p<.001) greater in the walking(about 1.8 times of body weight) than the Apkubi(about 1.4 times of body weight). The walking velocity was affected significantly(over p<.05) by the braking impulse, the peak braking force and the first peak vertical force. Futhermore the peak braking force in the Apkubi showed a significant effect on the Apkubi's stride length(p<.01). So, we concluded that the braking force after the right touch down, the stance foot on the ground contributed to move the leg forward.
Skeletal Muscle Strength Characteristics in Elderly People and Its Relationship with Body Composition
Choi, Dong-Sung ; Jeon, Justin Y. ; Won, Young-Shin ; Lee, Hae-Dong ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 297~308
DOI : 10.5103/KJSB.2011.21.3.297
The purpose of this study was to investigate the relationship among isometric and isokinetic muscle strength, lean body mass(LBM) and bone mineral density(BMD) in the elderly. Eleven males(age, 70.27
5.78yr; height, 167.36
6.68 cm; weight, 68.34
8.23 kg) and thirteen female(age, 69.77
4.13yr; height, 152.80
4.45 cm; weight, 56.86
7.40 kg) participated in this study. In all subjects, LBM and BMD segments was measured by using Dual-energy x-ray absorptiometry(DEXA, Lunar DPS-DM, U.S.A.). Maximum isometric and isokinetic muscle strength of flexion and extension at the knee and elbow, ankle, trunk joints were measured by using an isokinetic dynamometer(CON-TREX(R) Multi Joint Testing Module, Switzerland). The results of this study showed that isometric and isokinetic muscle strength was significantly higher in extension than flexion. In the male and female, hamstring to quadriceps strength ratio(H:Q ratio) was increased as contraction velocity increased. BMD was correlated significantly with trunk extension in the male, but not in the female. LBM was correlated significantly in the male and female with knee extension strength. This study suggests that in the elderly muscle strength training program should put more weight on extensor muscles of the body.
The Effect of Asymmetric Lower-Extremity Muscle Force of Elementary Students on Dynamic Balance during Walking
Kim, Gun-Soo ; Chae, Woen-Sik ; Yoon, Chang-Jin ; Lee, Haeng-Seob ; Kang, Nyeon-Ju ; Kim, Dong-Soo ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 309~315
DOI : 10.5103/KJSB.2011.21.3.309
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.
The Contribution of Body Segments to the Club Head's Kinetic Energy in the Golf Swing
Chang, Jae-Kwan ; Ryu, Ji-Seon ; Yoon, Suk-Hoon ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 317~325
DOI : 10.5103/KJSB.2011.21.3.317
The purpose of this study was to investigate the contributions of body joints to the kinetic energy of the clubhead in the golf swing. Three dimensional swing analysis was conducted on the seven KPGA golfers. The subjects were asked to swing with 45 inches of driver. The work done by body joints were computed by utilizing the inverse dynamics method. The order of work done by the body joints was lumbar > left hip > right shoulder > left wrist > right wrist > right hip at the first phase. At the second phase, the order of work done by the body joints was trunk > left elbow > right wrist > right shoulder > left wrist > right wrist. At the third phase, the order of work done by body joints was lumbar > right shoulder > left shoulder > left elbow > right wrist > right elbow. The sum of the work done by the body joints was lumbar > shoulder > wrist on the average. The kinetic energy of the club head was 430.11
24.35 J and the subject's swing efficiency was shown as 31.82
4.86% on the average. The contributions of body joints to the kinetic energy of the clubhead was the order of lumbar > upper right shoulder > left elbow > right wrist during the down swing.
Effect of Breathing on Ground Reaction Force and Kinematic Variables dur ing Bending in Korean Dance
Park, Yang-Sun ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 327~334
DOI : 10.5103/KJSB.2011.21.3.327
The objective of this study was to develop a scientific approach for investigating Korean dance in detail, and to examine the intense expressions and various movements, which are based on Danjeon breathing. For the purpose, we analyzed the movement changes and distribution of forces resulting from the switch in movement between exhalation and inhalation while bending, which is the most basic movement in Korean dance. The following conclusions were drawn from this study. In Korean dance, bending with breathing involves less back-and-forth-movement and more up-and-down movement, as compared to bending without breathing; this indicates greater body stability and a wider range of movements while bending with breathing. In addition, less time is required for bending with breathing at the point of switching from exhalation to inhalation, and it involves less movement of the supporting leg; thus, vending with breathing involves faster switching from bending movements to extending movements. While bending, the raised leg goes through a less smooth curve while breathing, which indicates stronger movement of the toes. Bending with breathing requires a greater braking force than bending without breathing, and the vertical force, generated by switching from exhalation to inhalation, is transferred to extending movements using the ground load. The results of this study can be potentially employed to investigate the expressions used in Korean dance on th basis of its principle of forces. Korean dance has evolved into various creative forms, and basic analytical studies of these diverse forms and related breathing methods re required in the future.
The Differences in Patellofemoral Compression Force with Different Height
Cho, Joon-Haeng ; Kim, Kyoung-Hun ; Moon, Gon-Sung ; Lee, Sung-Cheol ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 335~343
DOI : 10.5103/KJSB.2011.21.3.335
Patellofemoral pain syndrome is the most common problem involving the knee, accounting for 25% of knee injuries. Repetitive, overuse activities cause increased force at the patellofemoral joint, resulting in pain during flexion and extension activities. Most research have been conducted in exploring the patellofemoral compressive force in gait, squat and lunges, even though in real cases, possibilities in landing exist. The purpose of this study was to compare the differences in patellofemoral compressive force according to two different height. Sixteen collegiate male students(age: 22.25
3.30 yrs, height: 177.25
4.44 cm, weight: 77.50
8.18 kg) were chosen. The subjects performed drop landings in 45 cm, 60 cm. The findings demonstrated that higher height showed peak knee extension moment, quadriceps contraction force, patellofemoral compressive force with increased VGRF. Regarding the patellofemoral joint compressive force, it increased by quadriceps contraction force with knee flexion during landing, yet, it showed no difference in maximal knee flexion. To minimize patellofemoral joint stress and reduce the likelihood of developing PFPS, we recommend that predesigned quadriceps and hip muscle group strengthening are needed during conditioning and training.
The Effect of Wear ing Spandex Wear with Compression Band on Biomechanical Parameters during a Golf Drive Swing
Chae, Woen-Sik ; Kang, Nyeon-Ju ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 345~352
DOI : 10.5103/KJSB.2011.21.3.345
The purpose of this study was to determine how spandex wear with compressive band affects biomechanical parameters during a golf swing. Nine male golf players, each with at least 6 years golf experienc(handy 4.5
5.4), were recruited as the participants. Eight pairs of surface electrodes were attached to the left and right side of the body to monitor the pectoralis major(PM), external abdominal oblique(AO), erector spinae(ES), and vastus lateralis(VL). This study showed that the angular velocity of the club in EG were increased during the down swing phase but X-Factor and X-factor Stretch were reduced. Average and maximum nEMG (normalized EMG) values of the left AO(external abdominal oblique) were less in EG(experimental group) compared with CG(control group) during the back swing, whereas those of left PM(pectoralis major) in EG were greater than CG. It is more likely that EG performed effectively golf swing without excess muscle activity. Thus, the spandex wear with compressive band played an important role in improving swing performance with injury prevention. This has led to suggestions of the need for further kinetic and kinematic analyses to evaluate its function.
Effects of Exercise-Induced Fatigue and Blocked Vision on Postural Control during Upright Stance
Oh, Hyun-Jin ; Youm, Chang-Hong ; Kim, Tae-Hyeon ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 353~359
DOI : 10.5103/KJSB.2011.21.3.353
The purpose of this study was to investigate the effects of exercise-induced fatigue and blocked vision on postural control during upright stance in elderly women. The study population included 22 women who were aged over 65 years, had no sustained orthopedic damage within the last 6 months, and had been randomly recruited. The results were analyzed with respect to the mediolateral and anteroposterior factors for the center of pressure. The exercise-induced fatigue and the absence of visual information increased the anteroposterior and mediolateral velocity for center of pressure. This means that the elderly women could control their posture through many sways. In conclusion, the exercise-induced fatigue and the blocked vision decreased ability of the postural control in elderly women. Further research on the change of postural control in relation to the types of exercise-induced fatigue and the levels of muscular fatigue is expected.
The Effect of Isometric Hip Adduction and Abduction on the Muscle Activities of Vastus Medialis Oblique and Vastus Lateralis during Leg Squat Exercises
Koh, Eun-Kyung ; Lee, Keun-Hee ; Jung, Do-Young ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 361~368
DOI : 10.5103/KJSB.2011.21.3.361
The purpose of this study was to investigate the effect of isometric hip adduction and abduction on the muscle activities of vastus medialis oblique(VMO) and vastus lateralis(VL) during leg squat exercises. This study consisted of 21 healthy subjects who had no medical history of anterior knee pain or lower extremity disorders. The ball and belt were used to isometrically adduct and abduct the hip joint during the leg squat exercise, respectively. The surface electromyograms of VMO and VL were analyzed, and the findings were used to calculate the VMO:VL ratio during 3 different quadriceps-strengthening exercises(leg squat, LS leg squat with isometric hip adduction, LSHD leg squat with isometric hip abduction, LSHB). The muscle activities of VMO and VL and the VMO:VL ratios were compared using the paired t-test with Bonferroni adjustment. The results showed that the muscle activities of VMO and VL during LSHD were greater than those during LSHB. The VMO:VL ratio was the highest during LSHD. This finding suggests that LSHD using a ball is more effective than LS and LSHB in selectively increasing the muscle activities of VMO. Therefore, we suggest that leg squat exercise with isometric hip adduction using a ball would be useful for maintaining correct patella tracking and for selectively strengthening VMO.
Evaluation of Bio-Mechanical Character istics According to Loading Deviation Methods dur ing Rowing Exercise
Kang, Seung-Rok ; Jung, Gu-Young ; Moon, Dong-An ; Jeong, Jang-Sik ; Kim, Jung-Ja ; Kwon, Tae-Kyu ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 369~382
DOI : 10.5103/KJSB.2011.21.3.369
The purpose of this study was to verify the validation of exercise effect with loading deviation during rowing exercise. We performed evaluation of based physical fitness and joint torque before the experiment for finding muscle unbalance. So we recruited twenty four subjects who have bigger muscle strength in more 20% than average one. Subjects divided two groups. One is dominant upper limbs(DU) and the other was dominant lower limbs(DL). Subjects performed rowing exercise using electric equipment (Robo.gym.Humonic.korea). Exercise is performed four sets a day including 25 times a set, and three days a week. Measurement consist of evaluation of based physical fitness and joint torque using biodex(biodex system3.USA). Evaluation of exercise effect performed each week in joint torque of shoulder, lumbar and knee joint and each month in based physical fitness. Also we adapted 30% of 1RM for muscular endurance and 70% of 1RM for muscle strength as exercise load. The results showed that the difference of maximal peak torque were getting increase significantly during exercise. Also difference of various factor in based physical fitness were getting increase significantly except flexibility and agility. This interpreted that rowing exercise with loading deviation types could provide muscle strength and muscular endurance exercise in same time. These results could be interpret to two ways. One is effect of improving physical fitness for rowing exercise and the other meaned validation of loading deviation in rowing exercise. Our study is going to verify the validation of loading deviation during rowing and we found out that loading deviation could provide muscle strength and muscular endurance exercise for improving muscle unbalance. Our study can be used development of exercise equipment and program for normal people with muscle unbalance. Also that provide effect of whole body exercise to anybody.
Biomechanical Analysis of Lower Limbs on Speed of Nordic Walking
Yang, Dae-Jung ; Lee, Yong-Seon ; Park, Seung-Kyu ; Kang, Jeong-Il ; Lee, Joon-Hee ; Kang, Yang-Hoon ;
Korean Journal of Sport Biomechanics, volume 21, issue 3, 2011, Pages 383~390
DOI : 10.5103/KJSB.2011.21.3.383
In this study, 26 normal subjects were studied to compare the biomechanical Analysis of Lower Limbs on Speed of Nordic Walking. The biomechanical variables were determined by performing three-dimensional gait analysis, and the measurements items were spatial and temporal parameters; vertical ground reaction force; and moments of the hip, knee, and ankle joints. The purpose of this study based on the speed of Nordic Walking to the vertical ground reaction force and joint moments of each were analyzed. Nordic Walking with poles while being whether this weight is reduced to load, not the improvement of muscle activity by identify Nordic walking is to allow efficient. The results of the analysis were follows. The spatial parameters of step length, stride length significantly increased with increase in velocity(p<0.001). The temporal parameters of step time, stride time, the duration of double support use, and the duration of single support use also significantly decreased with increase in velocity(p<0.001), but cadence significantly increased(p<0.01). Analysis of the changes in ground reaction force revealed that vertical ground reaction force significantly increased at the initial contact and the terminal stance and decreased at the mid stance with increase in velocity(p<0.001). Moments of the hip and knee joints significantly in creased with increase in velocity whereas that of the ankle joint did not. Gait analysis revealed that weight-bearing decreased and moments of the hip and knee joints increased with increase in velocity(p<0.01). The results of this study may help people perform Nordic walking efficiently and Nordic walking can be used in the gait training of people with an abnormal gait.