• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.209-218
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• 2013

This study was to perform the kinetic analysis of forward $1\frac{1}{2}$ somersault on the platform diving. Six men's diving players of the Korea national reserve athletes participated in this study. The variables were analyzed response time, velocity, center of mass (COM), angle, center of pressure (COP) and ground reaction force (GRF) of motion. For measure and analysis of this study, used to synchronized to 4 camcorder and 1 force plate, used to the Kwon3D XP (Ver. 4.0, Visol, Korea) and Kwon GRF (Ver. 2.0, Visol, Korea) for analyzed of variables. The results were as follows; Time factor were observed in maximum knee flexion depending on the extent of use at phase 1 of take-off to execute the somersault. This enabled the subject to secure the highest possible body position in space at the moment of jumping to execute the somersault and prepare for the entry into the water with more ease. Regarding the displacement of COM, all subjects showed rightward movement in the lateral displacement during technical execution. Changes in forward and downward movements were observed in the horizontal and vertical displacements, respectively. In terms of angular shift, the shoulder joint angle tended to decrease on average, and the elbow joints showed gradually increasing angles. This finding can be explained by the shift of the coordinate points of body segments around the rotational axis in order to execute the half-bending movement that can be implemented by pulling the lower limb segments toward the trunk using the upper limb segments. The hip joint angles gradually decreased; this accelerated the rotational movement by narrowing the distance to the trunk. Movement-specific shifts in the COP occurred in the front of and vertical directions. Regarding the changes in GRF, which is influenced by the strong compressive load exerted by the supporting feet, efficient aerial movements were executed through a vertical jump, with no energy lost to the lateral GRF.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1066-1069
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• 2002

Dynamic postural control varies with the environmental context, specific task and intentions of the subject. In this paper, dynamic postural control against forward-backward perturbations of a platform was estimated using tri-axial accelerometers and a force plate. Ten young healthy volunteers stood upright in comfortable condition on the perturbation system which was controlled by an AC servo motor. With anterior-posterior perturbations, movements of ankle, knee and hip Joints were obtained by tri-axial accelerometers. and ground reaction forces with corresponding displacements of the center of pressure(CoP) by the force plate. The result showed that the ankle moved first and the trunk forward, which implies that the mechanism of the dynamic postural control in forward-backward perturbations, occurred in the procedure of the ankle, the knee and the hip. Knee flexion and hip extension in the period of acceleration, constant velocity and deceleration phase is very important fur the balance recovery. These responses depends on the magnitude and timing of the perturbation. From the present study the accelerometry-system appears to be a promising tool for understanding kinematic accelerative In response to a transient platform perturbation. A more through understanding of balance recovery mechanism may aid in designing methods for reducing falls and the resulting injuries.

• Physical Therapy Korea
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• v.23 no.2
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• pp.57-66
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• 2016

Background: For the treatment of forward head posture (FHP) and forward shoulder posture, methods for strengthening scapular retractors and deep cervical flexors and stretching pectoralis and upper cervical extensors are generally used. No study has yet assessed whether suboccipital release (SR) followed by cranio-cervical flexion exercise (CCFE) (SR-CCFE) will result in a positive change in the shoulders and neck, showing a "downstream" effect. Objects: The purpose of this study was to investigate the immediate effects of SR-CCFE on craniovertebral angle (CVA), shoulder abduction range of motion (ROM), shoulder pain, and muscle activities of upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) and LT/UT and SA/UT muscle activity ratios during maximal shoulder abduction in subjects with FHP. Methods: In total, 19 subjects (7 males, 12 females) with FHP were recruited. The subject performed the fifth phase of CCFE immediately after receiving SR. CVA, shoulder abduction ROM, shoulder pain, muscle activities of UT, LT, and SA, and LT/UT and SA/UT muscle activity ratios during maximal shoulder abduction were measured immediately after SR-CCFE. A paired t-test and Wilcoxon signed-rank test were used to determine the significance of differences in scores between pre- and post-intervention in the same group. Results: The CVA (p<.001) and shoulder abduction ROM (p<.001) were increased significantly post-versus pre-intervention. Shoulder pain was decreased significantly (p<.001), and LT (p<.05) and SA (p<.05) muscle activities were increased significantly post- versus pre-intervention. The LT/UT muscle activity ratio was increased significantly post- versus pre-intervention (p<.05). However, there was no significant change in UT muscle activity and SA/UT muscle activity ratio between pre- and post-intervention (p>.05). Conclusion: SR-CCFE was an effective intervention to improve FHP and induce downstream effect from the neck to the trunk and shoulders in subjects with FHP.

• 한국체육학회지인문사회과학편
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• v.53 no.2
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• pp.531-540
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• 2014

The purpose of this study was to investigate the differences between two inflatable kayak by recording performance related variables during the kayak forward stroke motion. A total of 5 elite high school kayak players were recruited to participate while their kinematics and muscle activations were recorded while performing inside their high school swimming pool. Boat velocity, boats swaying angle, the average angular velocity and were used to evaluate the boats performance. The player's trunk rotational range of motion, knee flexion-extension angle range of motion, maximum trunk rotation angle, the knee flexion-extension angular velocity, and the upper and lower limb muscle activations were calculated and analyzed for the player's efficiency evaluation. There were no significantly different variables for the player's kinematics and their muscle activations for the two conditions. The B kayak was significantly faster than the A kaya. In addition there were no significant differences between the remaining variables for the two kayaks. In conclusion, the B kayak was faster than the A kayak, but neither of the kayaks had an influence on the player's performance variables.

• Clinics in Shoulder and Elbow
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• v.26 no.2
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• pp.126-130
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• 2023

Background: Arm swing plays a role in gait by accommodating forward movement through trunk balance. This study evaluates the biomechanical characteristics of arm swing during gait. Methods: The study performed computational musculoskeletal modeling based on motion tracking in 15 participants without musculoskeletal or gait disorder. A three-dimensional (3D) motion tracking system using three Azure Kinect (Microsoft) modules was used to obtain information in the 3D location of shoulder and elbow joints. Computational modeling using AnyBody Modeling System was performed to calculate the joint moment and range of motion (ROM) during arm swing. Results: Mean ROM of the dominant elbow was 29.7°±10.2° and 14.2°±3.2° in flexion-extension and pronation-supination, respectively. Mean joint moment of the dominant elbow was 56.4±12.7 Nm, 25.6±5.2 Nm, and 19.8±4.6 Nm in flexion-extension, rotation, and abduction-adduction, respectively. Conclusions: The elbow bears the load created by gravity and muscle contracture in dynamic arm swing movement.

• Women's Health Nursing
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• v.10 no.3
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• pp.244-251
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• 2004

Purposes: This study was to examine the effects of postpartum exercise on pressure of the pelvic muscle contraction, body composition and physical fitness of postpartum mothers. Method: A nonequivalent pre-test, post-test control group study was conducted. Fifty-two postpartum mothers(experimental group, 26; control group, 26) admitted to a postpartum ward in a Busan mother-baby clinic were recruited. Data was analyzed using mean, $x^2$-test, and t-test by SPSS 10.0. Result: Body fat mass(t=-3.196. p= .002), body fat rate (t=-3.831, p= .000), and fat distribution(t=-3.026, p= .004) of body composition increased significantly in the experimental group after the postpartum exercise as compared with the control group. After an 8 week exercise program, the pressure of the pelvic muscle contraction in the experimental group was significantly higher than in the control group(t=3.329, p=.002). In the change of physical fitness, grip strength of the hand, back muscle strength, and trunk flexion forward were not significantly changed, but trunk backward extension in the experimental group significantly increased(t=1.950, p=.050). Conclusion: Postpartum exercise affects pelvic muscle contraction, body composition, and physical fitness of the postpartum mother.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.181-189
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• 2005

To know the proper impact posture and changes for the various clubs, changes of impact variables according to the change of golf club length was investigated. Swing motions of three male low handicappers including a professional were taken using two high-speed video cameras. Four clubs iron 7, iron 5, iron 3 and driver (wood 1) were selected for this experiment. Three dimensional motion analysis techniques were used to get the kinematical variables. Mathcad and Kwon3D motion analysis program were used to analyze the position, distance and angle data in three dimensions. Major findings of this study were as follows. 1. Lateral position of the head remained more right side of the target up to 3.5cm compared to the setup as the length of the club increased. 2. Left shoulder raised up to 5cm and right shoulder lowered up to 2.5cm compared to setup. The shoulder line opened slightly (maximum 11 degrees) to the target line. 3. Forward lean angle of the trunk decreased up to 4 degrees (more erected) compared to setup. 4. Side lean angle of the trunk increased compared to setup and increased up to 16 degrees as the club length increased. 5. The pelvis moved to the target line direction horizontally and opened up to 31 degrees. Right hip moves laterally to the grip position at the setup. 6. Flexion of the left leg maintained almost constantly but the right leg flexed up to 11 degrees compared to setup. 7. Left arm is straightened but the right arm flexed about 20degrees compared to straight. 8. Center of the shoulders were in front of the knees and toes of the feet. 9. Hands moved to the left (8.7cm), forward (5.7cm) and upward (11.6cm) compared to the setup. This is because of the rotation of pelvis and shoulders. 10. Shaft angle to the ground was smaller than the lie angle of the clubs but it increased close to the lie of the clubs at impact.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1548-1556
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• 2014

The study was conducted to analyze the effect of Playing Exercise Program on body composition and physical fitness on mentally handicapped. The subjects participated research were 12 male and 7 female who were mentally handicapped. P.E.P. was applied once a week for 120 minutes in total for 10 weeks. Pre-Post test for body composition (weight, body fat percentage, body fat mass, muscle mass, cell mass) and Physical Fitness (muscular endurance, strength; hand strength, back strength, flexibility; trunk flexion forward) were conducted to analyze the effects. For obtaining the statistics, SPSS 18.0 was used and mean and standard deviation were calculated. T-test was performed to differentiate performance ability and to compare the effect of P.E.P. on body composition and physical fitness for 10 weeks and the statistical level of significance was set to p<.05. The result obtained showed significant difference for only muscle mass in body composition variable. Moreover when analyzing physical fitness variable, there were significant differences in back strength, grasping left and right hand, trunk flexion forward and muscular endurance. Therefore, it can be concluded that the P.E.P. was effective for mentally handicapped. And the program can be utilized as effective energy consumption program and can contribute to preventing adult diseases.

• The Journal of Korean Academy of Sensory Integration
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• v.11 no.1
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• pp.29-37
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• 2013

Objective : The purpose of this study was to investigate the effect of 8 weeks complex exercise program on height, body composition, and physical fitness in elementary school children. Method : The experimental group had 11 children (male=6, female=5) who belong to Seong-Nam Community Welfare Center in Gyeonggi-Do. All children received 50 minutes of complex exercise program 2 times a week for total of 8 weeks. In-body 520 were measured initially to serve as baseline data for height, and body composition. To determine the impact on physical fitness, Primus RS Power Track II commander Sit-up Trunk forward flexion measurement was also done. Repeat measurements of In-body520 Primus RS Power Track II Commander Sit-up Trunk forward flexion were done after 8 weeks. Results : There was significant increase in height, skeletal muscle mass, body fat percentage, lower limbs strength, and muscular endurance after the complex exercise program. There was, however, no significant difference in upper limbs strength, and flexibility after the program. Conclusions : These results indicate that the complex exercise program used in this study was very effective in producing significant benefits in height, body composition, and physical fitness in elementary school children. There would be better objective results if the control group and various environmental factors are considered in the future research.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.37-44
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• 2016

The aim of the present study was to compare the strength, balance, and flexibility across two age groups (older adults vs. young adults). The isokinetic muscle function, ankle ROM, trunk forward flexibility, stability, and antropometric data for the elderly and 46 university students were collected. The results indicated that male older adults possessed relatively low flexibility (2.97cm) among the groups and showed better stability in the right foot than in the left foot and $35^{\circ}$ of plantar flexion ROM, which was not in the normal range. Their peak strength at the knee joint was below 50% of their counterpart. They revealed a hamstring deficit of 18.55%, ankle eversion deficit of 23.08%, and ankle inversion deficit of 19.19%. The results indicated that female older adults possessed comparable flexibility compared to female young adults. The reciprocal muscle strength ratio of both knees was under 50%, and the deficit was 14.32% (extension) and 19.73% (flexion). The ankle plantar flexion peak torque was approximately 62% (left) and 73% (right) of WS's. The ankle dorsi flexion deficit was 25.05% and the plantar flexion was 26.86%. The eversion deficit was 19.97% and the inversion was 21.09%. These results will be significant in establishing an elderly fitness enhancement program and policy.