• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.63-72
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• 2020

Objective: The purpose of this study was to investigate meta-analysis on the effects of exercise therapy and physiotherapy on pain in korean patients with chronic low back pain. Method: Meta-analysis was performed on the type and method of treatment. A total of 23 experimental studies were coding into 31 individual studies, into types, methods, visual analogue scale (VAS), each pre/post value of the effect size was calculated by meta-analysis. Results: Sling exercise, stretching, thermal therapy, kinesio-taping, lumbar stabilization exercise, electrotherapy is large effect size (ES ≥ .08). In addition, big effects occurred in order of treatment period is more than 9 weeks, three times a week. Conclusion: Our results indicated that persistent treatment of chronic back pain is the most effective method of self-sufficiency rather than temporary relief.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.97-105
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• 2011

The purpose of this study was to investigate the kinetic factors of Stefan holm's take-off motion and provide the technical data. Collected data of the subject(height: 181 cm, weight: 71 kg, record: 230 cm) were used for the last two strides and take-off phase. The results were as follows: The vertical impulse force was 2044.8 N which was 2.49 times and the anterior-posterior impulse force was -1306.4 N which was 1.88 times of the subject's weight. The take-off leg angular velocities($\omega_x,\;\omega_y$) were switched drastically from clockwise to count clockwise direction between two-step touchdown and take-off. The highest jerk of the take-off foot was 368.97 m/s3 during the two step take-off and the take-off foot made an impact to the ground with 1225.07 m/s3 during the one step touchdown.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.387-393
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• 2013

The purpose of this study was to investigate the difference of kinematic factors acting in the body during a normal swing and a swing taken with an intention to increase driving distance by female pro golfers. Female pro golfers may increase driver clubhead speed and improve driving distance through maintaining a large X-factor angle during backswing and delaying the uncocking period by rapidly shifting the weight to the left foot during downswing.

• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.149-155
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• 2017

Objective: The purpose of this study was to investigate the effects of three visual conditions (eyes opened, eyes closed, and wearing of a head mounted display [HMD]) on single-leg standing through kinematics and kinetic analysis. Method: Twelve college students (age: $24.5{\pm}2.6years$, height: $175.0{\pm}6.4cm$, weight: $69.2{\pm}5.1kg$) participated in this study. The study method adopted three-dimensional analysis with six cameras and ground reaction force measurement with one force plate. The analysis variables were coefficient of variation (CV) of the center of body mass, head movement, ground reaction force, and center of pressure, which were analyzed using one-way analysis of variance with repeated measures according to visual conditions. Results: In most cases, the results of this study showed that the CV was significantly higher in the order of HMD wearing, eyes closed, and eyes opened conditions. Conclusion: Our results indicated that body sway was the largest in the HMD wearing condition, and the risk of falling was high owing to the low stability.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.9-16
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• 2007

The purpose of this study was to analyze the effects of after aquatic exercise on gait in the Falls Experienced elderly. There were one group : Fall Experienced Elderly Women(n=8). They were tested on their gait (Elapse time of each phase, Stance time of limb, Stride length, Velocity of segment). we took video and analyzed their movement using Ariel Performance Analysis System and compared gait parameters. For data analysis, mean and standard deviation scores were calculated, and correspondence sample t-test and pearson's correlation analysis were used. First, after exercise is short than before exercise on Elapse time of each phase, fall-experience subjects showed meaningful total time. Second, after exercise is short than before exercise on Stance time of limb and Stride length, fall-experience subjects showed meaningful Stride length. Third, after exercise is fast than before exercise on Velocity of segment.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.107-113
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• 2007

The purpose of this study were to investigate the effects of knee brace on the knee muscular neuro-biomechanical variables during the rebound in female highschool basketball players. Twelve high school female ($17.9{\pm}0.8years$) basketball players rebound jumped for maximal vertical height to sufficiently stress the anterior cruciate ligament with and without knee brace. Kinematic data were collected to estimate the knee flexion, abduction angles and jump height. The EMG data from the biceps femoris and rectus femoris was used to estimate the ratio of quadriceps muscle activity. Female athletes with knee brace showed more reduced the knee abduction angle and the ratio of quadriceps muscle activity at foot contact phase than without knee brace. In conclusion, Female athletes with brace reduced knee anterior cruciate ligament loads.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.127-139
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• 2007

The purpose of this study was to examine the pitching ability of baseball player by analysing the effect of elastic resistance exercise and pilates exercise on EMG. Five out of currently active highschool baseball player performed 5 times a week of elastic resistance exercise and pilates for 8 weeks, each for 100 minutes. They demonstrated significant increase in EMG after 8 weeks of exercise. Especially, in extensor carpi radialis brevis and flexor carpi radialis of fore arm, they demonstrated significant increase of inning figure after exercise. These results suggested that elastic resistance exercise and pilates exercise can improve pitching ability of baseball player according to inning.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.129-138
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• 2006

The motion of a spinning table-tennis ball is investigated in both theory and experiment. The equation of motion of spinning table-tennis ball is made using aerodynamics and calculated by C++ program In theoretical part, gravity, drag force and lift force are regarded as main force. Velocity, angular velocity, mass and Drag and lift coefficients are considered as a independent variable. Experiments are made by a digital stroboscope, a digital camera and a mirror, and snap multi-exposed images were took as a dependent result In experimental part, both magnitude and direction of velocity and angular velocity are changed in each situation. The predicted three-dimensional trajectories of spinning balls are compared with experimental trajectories. As a result the theoretical trajectories were predicted within 10% of experimental trajectories.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.55-63
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• 2006

The purpose of this study was to investigate the effects of vibration exercise using surface electromyography. Seven male collegiate wrestlers were participated in this study. Each subject stood on the platform and the vibration was induced for 1min. WEMG8 EMG system was used to record muscle activity from Vastus lateralis, Biceps Femoris, Tibialis Anterior, and Gastrocnemius. The EMG data were sampled for 30 sec. during non-vibration and vibration half squat position, respectively. The raw data were band pass filtered to remove noise and full wave rectified Paired sample t-test were performed to see the differences of maximum and average EMG between non-vibration and vibration trials. The results indicated that vibration produced much more muscle contraction than that of non-vibration trial for all selected muscles even though the significant difference was found only from Biceps Femoris. This phenomenon was due to the individual differences so care must be taken to evaluate vibration intensity and position before personal training.

• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.99-115
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• 2004

In order to Know the correct swing methods in golf swing it is important to understand the whole swing path but also the concept of swing plane. But, most amateur golfers don't Know the concept of swing plane well. Therefore this study was trying to make a good material that makes the concept of swing plane easy to understand. A good swing motion data was obtained from a professional golfer using the three-dimensional DLT method. This swing motion was divided into 10 phases and evaluated using the concept of swing plane. The result of the analyze show a good matches between the path of the club and swing plane. This result was summarized as a 3 dimensional graphics to provide a good material to teach the golf swing well.