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논문검색은 역시 페이퍼서치

한국운동역학회지검색

Korean Journal of Sport Biomechanics


  • - 주제 : 예체능분야 > 체육학
  • - 성격 : 학술지
  • - 간기: 계간
  • - 국내 등재 : KCI 등재
  • - 해외 등재 : -
  • - ISSN : 1226-2226
  • - 간행물명 변경 사항 :
논문제목
수록 범위 : 26권 2호 (2016)

Effects of Fatigue Induction on Ground Reaction Force Components, Postural Stability, and Vertical Jump Performance in Taekwondo Athletes

( Seung Hyun Hyun ) , ( Young Pyo Kim ) , ( Che Cheong Ryew )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 143-151 ( 총 9 pages)
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초록보기
Objective: The purpose of this study was to investigate the effect of fatigue induction on ground reactionforce (GRF) components, postural stability, and vertical jump performance in Taekwondo athletes.Method: Ten Taekwondo athletes (5 men, 5 women; mean age, 22.30 ± 2.62 years; mean height, 174.21 ±9.20 cm; mean body weight, 67.28 ± 12.56 kg) participated in this study. Fatigue was induced by a shortperiod of strenuous exercise performed on a motorized treadmill. The analyzed variables included verticaljump performance, static stability (mediolateral [ML], center of pressure [COP], anteroposterior [AP] COP,ΔCOPx, ΔCOPy, and COP area), postural stability index values (ML stability index [MLSI], AP stability index[APSI], vertical stability index [VSI], dynamic postural stability index [DPSI]), and GRF components (MLforce, AP force, peak vertical force [PVF], and loading rate). To analyze the variables measured in this study,PASW version 22.0 was used to calculate the mean and standard deviation, while a paired t-test was usedto evaluate the pre- versus post-fatigue results. Pearson``s correlation coefficients among variables were alsoanalyzed. The statistical significance level was set at α = .05.Results: Vertical jump performance decreased significantly after the induction of fatigue, while AP COP,ΔCOPx, COP area, APSI, VSI, and DPSI increased significantly. PVF and loading rate increased significantlyafter the induction of fatigue, while the postural stability variables (AP COP, ΔCOPy, COP area, APSI, VSI,DPSI) were similarly correlated with GRF components (PVF, loading rate) after fatigue was achieved (r= .600, R2 = 37%).Conclusion: These results suggest that the induction of fatigue can decrease postural stability and exerciseperformance of Taekwondo athletes during training and competition sessions.

Effects of Joint Mobilization on Foot Pressure, Ankle Moment, and Vertical Ground Reaction Force in Subjects with Ankle Instability

( Na Mi Yoon ) , ( Yeon Soon Seo ) , ( Yang Hoon Kang )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 153-159 ( 총 7 pages)
4,000
초록보기
Objective: The purpose of this study was to investigate the effects of joint mobilization on foot pressure,ankle moment, and vertical ground reaction force in subjects with ankle instability.Method: Twenty male subjects (age, 25.38 ± 3.62 yr; height, 170.92 ± 5.41 cm; weight, 60.74 ± 9.63 kg;body mass index (BMI), 19.20 ± 1.67 kg/m2) participated and underwent ankle joint mobilization. Weightbearingdistribution, ankle dorsi/plantar flexion moment, and vertical ground reaction force were measuredusing a GPS 400 and a VICON Motion System (Oxford, UK), and subsequently analyzed. SPSS 20.0 forWindows was used for data processing and paired t-tests were used to compare pre- and post-mobilizationmeasurements. The significance level was set at α = .05.Results: The results indicated changes in weight-bearing, ankle dorsi/plantar flexion moment, and verticalground reaction force. The findings showed changes in weight-bearing distribution on the left (pre 29.51± 6.31 kg, post 29.57 ± 5.02 kg) and right foot (pre 32.40 ± 6.30 kg, post 31.18 ± 5.47 kg). There weresignificant differences in dorsi/plantar flexion moment (p < .01), and there were significant increases invertical ground reaction forces at initial stance (Fz1) and terminal stance (Fz2, p < .05). Additionally, therewas a significant reduction in vertical ground reaction force at midstance (Fz2, p < .001).Conclusion: Joint mobilization appears to alter weight-bearing distribution in subjects with ankle instability,with resultant improvements in stability.

Comparison of Lower Extremity Kinematics and Kinetics during Downhill and Valley-shape Combined Slope Walking

( Jiyoung Jeong ) , ( Choongsoo S. Shin )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 161-166 ( 총 6 pages)
4,000
초록보기
Objective: The purpose of this study was to determine the knee and ankle joint kinematics and kinetics bycomparing downhill walking with valley-shape combined slope walking.Method: Eighteen healthy men participated in this study. A three-dimensional motion capture systemequipped with eight infrared cameras and a synchronized force plate, which was embedded in the slopedwalkway, was used. Obtained kinematic and kinetic parameters were compared using paired two-tailedStudent``s t-tests at a significance level of 0.05.Results: The knee flexion angle after the mid-stance phase, the mean peak knee flexion angle in the earlyswing phase, and the ankle mean peak dorsiflexion angle were greater during downhill walking comparedwith valley-shape combined slope walking (p < 0.001). Both the mean peak vertical ground reaction force(GRF) in the early stance phase and late stance phase during downhill walking were smaller than thosevalues during valley-shape combined slope walking. (p = 0.007 and p < 0.001, respectively). The mean peakanterior GRF, appearing right after toe-off during downhill walking, was also smaller than that of valleyshapecombined slope walking (p = 0.002). The mean peak knee extension moment and ankle plantar flexionmoment in late stance phase during downhill walking were significantly smaller than those of valleyshapecombined slope walking (p = 0.002 and p = 0.015, respectively).Conclusion: These results suggest that gait strategy was modified during valley-shape combined slopewalking when compared with continuous downhill walking in order to gain the propulsion for lifting thebody up the incline for foot clearance.

Relationship between Attenuation of Impact Shock at High Frequency and Flexion-Extension of the Lower Extremity Joints during Downhill Running

( Ji Seon Ryu ) , ( Suk Hoon Yoon ) , ( Sang Kyoon Park )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 167-174 ( 총 8 pages)
4,000
초록보기
Objective: The purpose of this study was to determine the interrelationship between ranges of motion ofthe knee and ankle joints on the sagittal plane and the attenuation magnitude of impact shock at highfrequency (9~20 Hz) in the support phase during downhill running.Method: Fifteen male heel-toe runners with no history of lower extremity injuries were recruited for thisstudy (age, 25.07 ± 5.35 years; height, 175.4 ± 4.6 cm; mass, 75.8 ± .70 kg). Two uniaxial accelerometers weremounted to the tuberosity of tibia and sacrum, respectively, to measure acceleration signals. The participantswere asked to run at their preferred running speed on a treadmill set at 0°, 7°, and 15° downhill. Sixoptical cameras were placed around the treadmill to capture the coordinates of the joints of the lowerextremities. The power spectrum densities of the two acceleration signals were analyzed and used in thetransfer function describing the gain and attenuation of impact shock between the tibia and the sacrum.Angles of the knee and ankle joints on the sagittal plane and their angle ranges were calculated. ThePearson correlation coefficient was used to test the relationship between two variables, the magnitude ofimpact shock, and the range of joint angle under three downhill conditions. The alpha level was set at .05.Results: Close correlations were observed between the knee joint range of motion and the attenuationmagnitude of impact shock regardless of running slopes (p<.05), and positive correlations were foundbetween the ranges of motion of the knee and ankle joints and the attenuation magnitude of impact shockin 15° downhill running (p<.05).Conclusion: In conclusion, increased knee flexion might be required to attenuate impact shock duringdownhill and level running through change in stride or cadence while maintaining stability, and strongand flexible ankle joints are also needed in steeper downhill running.

Age-related Changes in Multi-finger Synergy during Constant Force Production with and without Additional Mechanical Constraint

( Yang Sun Park ) , ( Hyun Joon Kwon ) , ( Kyung Koh ) , ( Jae Kun Shim )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 175-181 ( 총 7 pages)
4,000
초록보기
Objective: The aim of this study was to investigate age-related changes of multi-finger synergy during aconstant force production task with and without an additional mechanical constraint.Method: Fourteen elderly subjects (age: 78.50 ± 4.63 yrs, height: 157.29 ± 8.97 cm, weight: 65.13 ± 6.93 kg)and 14 young subjects (age: 21.13 ± 1.35 yrs, height: 171.57 ± 8.43 cm, weight: 70.29 ± 16.77 kg) participatedin this study. The subjects were asked to place their index and middle fingers on two force transducersfixed on a small non-moving teeterboard and produce 10 N by pressing the sensors while watching forcefeedback on a computer screen under the no additional constraint condition (NAC). The subjects alsoperformed the same task with an additional mechanical constraint (AC) where the subjects were asked tobalance a teeterboard that could be rotated by finger forces. An uncontrolled manifold approach was usedto calculate within-trial and between-trial multi-finger synergy indices, variance in uncontrolled subspace(VUCM), and variance in subspace orthogonal to UCM subspace (VORT). Two-way repeated measured ANOVAwas performed with the within-factor of task condition (with and without an additional constraint) andthe between factor of groups (elderly and young).Results: The elderly group showed significantly increased within-trial VORT in AC compared with NAC (p< .05) while the young group showed no significant difference between AC and NAC. There was nosignificant group difference for within-trial VUCM. Between-trial VORT remained unchanged between groupsand conditions. However, between-trial VUCM for the elderly group significantly decreased in AC as comparedto NAC, along with no significant difference for the young group. For multi-finger synergy, there was nosignificant group difference of within-trial synergy. However, between-trial synergy for the elderly groupsignificantly decreased in AC as compared to NAC (p < .05).Conclusion: Our results indicate that aging decreased consistency (i.e., ability to perform the task on amoment-to-moment basis) with an additional mechanical constraint. In addition, aging was associatedwith decreased multi-finger synergy on a trial-to-trial basis.

A Correlational Study of Biomechanical Variables and Aesthetic Artistry in Grand Pas de Chat

( Jung Eun Jung ) , ( Kyung Ill Lee )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 183-190 ( 총 8 pages)
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초록보기
Objective: The objective of this study is to present a scientific basis for ballet dancer training methods byanalyzing the relationships between subjective assessment of the ballet movement ``Grand pas de chat`` andkinematic and electromyographic factors.Method: The subjects were 14 professional dancers with 15 years of experience on average. Four camerasand a wireless electromyogram were used to examine kinematic factors, and the filmed videos were analyzedby 3 experts for subjective assessment.Results: Although no differences in kinematic factors were found between the excellent dancer group andthe non-excellent dancer group divided based on the experts`` assessment, some difference was found inelectromyographic factors, especially in relation to the gastrocnemius muscle, rectus femoris muscle, anderector spinae muscle. A relationship between subjective assessment and kinematic and electromyographicfactors was found, and factors such as right-side rectus femoris activation, time required, left-side gastrocnemiusactivation, and front-back displacement affected subjective assessment.Conclusion: This study showed a relationship between subjective assessment and kinematic andelectromyographic factors. To receive higher scores in subjective assessment, it is necessary to extend thehang time by using the lower limb muscles. The findings of this study also indicate the necessity of weighttraining in order to improve dancing techniques.

The Immediate Effects of Ankle Restriction Using an Elastic Band on Ground Reaction Force during a Golf Swing

( Kyungock Yi ) , ( Okja Kim )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 191-195 ( 총 5 pages)
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초록보기
Purpose: The purpose of this study was to analyze the immediate effects of ankle restriction with an elasticband on ground reaction force during a golf swing.Method: There were five subjects who were teaching pros with an average golf score of 75. A force platform(9281B, Switzerland) was used. The independent variable was the presence of an elastic band. The dependentvariables were three-dimensional ground reaction forces to analyze the transfer of momentum with thetiming, control and coordination of the three forces. A paired t-test within subject repeated measure designwas used via an SPSS 20.0.Results: Wearing an elastic band around one``s ankles significantly makes shorter time differences betweenthe moment of cross anterior / posterior forces and vertical force and median value of anterior / posteriorforces during the backswing, between medial and lateral maximum and anterior / posterior force from thetop of the back swing to the mid down swing, and creates an anterior / posterior maximum force.Conclusion: Wearing an elastic band around one’s ankles affects control and coordination between threedimensional forces, and anterior force power according to each phase of the golf swing.

The Kinematic Factors of Physical Motions During Air Pistol Shooting

( Min Soo Kim )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 197-204 ( 총 8 pages)
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초록보기
Objective: The purpose of this study was to analyze the kinematic factors of motion during air pistolshooting.Method: This study aimed to investigate changes in forces during movement and determine the factorsthat affect changes in force during the first, middle, and last periods of shooting an air pistol. Two groundreaction force systems (force platform), SCATT (a shooting training system), and EMG (electromyogram)to measure the action potentials in the muscles of the upper body were used in this study. Four universityair pistol players (age: 19.75 years, height: 175.50 cm, body mass: 69.55±11.50 kg, career length: 6.25±6years) who are training to progress to a higher rank were enrolled.Results: In terms of the actual shooting results, the mean score in the middle section was 42.48±1.74points, higher than those in the first and the last periods when using SCATT. The gunpoint moved 13.48mm more vertically than horizontally in the target trajectory. With respect to action potentials of musclesmeasured using EMG, the highest action potentials during the aiming-shooting segments, in order higherto lower, were seen in the trapezius (intermediate region), trapezius (superior region), deltoid (lateral), andtriceps brachii (long head). The action potentials of biceps brachii and brachioradialis turned out to be highduring grasping motion, which is a preparatory stage. During the final segment, muscle fatigue appearedin the deltoid (lateral), biceps brachii (long head), brachioradialis, and trapezius (intermediate region). Interms of the ground reaction force, during the first period of shooting, there was a major change in theoverall direction (left-right Fx, forward-backward Fy, vertical Fz) of the center of the mass.Conclusion: The development and application of a training program focusing on muscle groups withhigher muscle fatigue is required for players to progress to a higher rank. Furthermore, players can improvetheir records in the first period if they take part in a game after warming up sufficiently before shooting inorder to heighten muscle action potentials, and are expected to maintain a consistent shooting motioncontinuously by restoring psychological stability.
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Purpose: The aim of this study was to analyze biomechanical factors and PMT (premotor time) of bodymuscles between elite college and amateur baseball players during the baseball batting motion.Method: Kinematic and electromyographic data were obtained for 10 elite college baseball players and 10amateur baseball players who participated in this study. All motion capture data were collected at 200 Hzusing 8 VICON cameras and the PMT of muscles was recorded using a Delsys Trigno wireless system. Thepeak mean bat speed and the peak mean angular velocities of trunk, pelvis, and bat with PMT of 16 bodymuscles were computed. These kinematic and PMT data of both groups were compared by independentt-tests (p < .05).Results: The pelvis, trunk, and bat showed a sequence of angular velocity value during baseball batting.The PMTs of right tibialis anterior, left gastrocnemius, external oblique, and erector spinae were significantlydifferent between the two groups.Conclusion: The PMT of body muscles was related to the shifting of body and rotation of the pelvis andthe trunk segment, and this action can be considered the coordinated muscle activity of the lower andupper body.

Effects of ProBody Massage on Body Alignment and Plantar Pressure Balance in Middle-aged Men with Musculoskeletal Diseases

( Se Jin Oh ) , ( Joong Sook Lee )
한국운동역학회|한국운동역학회지  26권 2호, 2016 pp. 213-220 ( 총 8 pages)
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초록보기
Objective: The purpose of this study was to investigate the effect of an 8-week ProBody massage programon body alignment and plantar pressure balance in middle-aged men with musculoskeletal diseases.Method: The subjects of this study were 20 middle-aged men with musculoskeletal diseases in B MetropolitanCity who participated in an 8-week ProBody massage program conducted twice a week. Physical characteristics(height, weight, and body mass index), body alignment, and plantar pressure were assessed before andafter the experiment.Results: The 20 middle-aged men with musculoskeletal diseases who underwent the ProBody massageprogram showed positive changes in physiological characteristics, body alignment, and plantar pressurebalance.Conclusion: Consequently, the 8-week ProBody massage program was suggested to be effective forimproving and preventing postural imbalance in middle-aged men with musculoskeletal diseases. TheProBody massage program could also be utilized to improve the body alignment and plantar pressurebalance in middle-aged women with musculoskeletal diseases.
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