Joong-Sook Lee

The effects of elbow joint angle changes on elbow flexor and extensor muscle strength and activation.

[Purpose] This research investigated the relationship between elbow joint angle and elbow flexor and extensor strength and activation, taking into consideration the length-tension tension curve of the muscle. [Subjects] There were 30 research subjects in total, 15 male and 15 female college students from Busan S University who had no functional disabilities that might affect measurement of muscle strength and muscle activation, and none had they experienced any damage in their upper extremities or hands. [Methods] The elbow joint angles were positioned at angles of 56°, 70° and 84°, and then muscle strength and activation were compared. Repeated measures ANOVA was used for statistical analysis, and the paired t-test was used to identify the difference between each angle. We used the SPSS for windows (ver. 21.0) statistical software and a significance level of α=0.05. [Results] The results showed that muscle strength and activation of the biceps was highest when the joint was placed at 56°. On the other hand, for the triceps, the result was highest when the joint angle was placed at 84°. [Conclusion] The tests confirmed that muscle strength and activation were highest at the joint angle at which the muscle was stretched to 20% more than the resting position in concentric contraction.

The influence of soccer cleat design on resultant joint moments

Footwear traction has previously been associated with lower extremity injury such as ankle and knee sprains. Recent changes in soccer shoe cleat design such as the introduction of bladed cleats have the potential to dramatically affect footwear traction. Therefore, the purpose of this study was to determine how soccer cleats of different designs and traction influence resultant ankle and knee joint moments during soccer movements. Two traditional soccer cleat designs and one bladed cleat design were compared to a standard running shoe as the control condition. Translational and rotational traction of the shoes on artificial turf were measured using a Stewart platform. Ankle and knee joint moments were quantified on a group of 12 recreational soccer players while performing cutting and turning movements at 4.0 m s−1 on the same artificial turf. All soccer shoes had significantly higher rotational traction than the running shoe but there were no significant differences between cleat designs. The bladed cleat design had significantly higher translational traction than the traditional cleat designs. As a result, the bladed cleat design that was tested appears effective at decoupling translational and rotational traction characteristics of soccer shoes, which could potentially be beneficial in reducing injuries. There were no significant differences in resultant ankle and knee joint moments between the shoes during the cutting movement. During the turning movement, the cleated shoes had significantly higher ankle and knee rotation moments than the control running shoe. Thus, increased rotational traction increases ankle and knee joint loading which in turn could lead to a greater incidence of injury, however, it is important to note that this was only true during a rotational movement.

The Effects of Abdominal Hollowing in Lower-limb PNF Pattern Training on the Activation of Contralateral Muscles.

[Purpose] The purpose of this study was to determine the effects of abdominal hollowing during lower-limb proprioceptive neuromuscular facilitation (PNF) training on the activation of contralateral muscles. [Subjects] Twenty male college students without symptoms or signs of muscular or nervous disease participated in this experiment after signing a consent form. [Methods] All the subjects were measured with electromyography (EMG) in a muscle activation test before and after abdominal hollowing. In the PNF program, the lower-limb pattern of PNF training, was maintained for 5 seconds, followed by a 2-minute break. This was repeated three times. The resting time between sets was 30 minutes. Surface EMG (Keypoint, Medtronic Inc., USA) was used for the measurements, and the highest value of three measurements was used in the analysis. [Result] The results revealed a significant change in the muscular activation of the opposite-side lower limbs. The muscular activations of the vastus lateralis, tibialis anterior, semitendinosus and gastrocnemius were increased significantly after the abdominal hollowing. [Conclusion] The findings suggest that abdominal hollowing in PNF pattern training can be effective at promoting muscular activation of the contralateral muscles. To promote muscular activation of the opposite side in lower-limb PNF pattern training, abdominal hollowing should be considered to improve the effect of PNF pattern training.

The Effects of the Height and the Quality of the Material of Popular Heel-up Insole on the Mean Plantar Foot Pressure during Walking

This study determined the effects of the height and the quality of the material of popular heel-up insole on mean plantar foot pressure during walking. Seven healthy college students who are studying at S university in Busan were as participants in this study. After sufficiently explaining about the research to the subjects before the experiment, mean plantar foot pressures were examined using F-Scan Pressure Measure System 5.23 for the gait with shoes inserted insole and the data were compared among the height and the quality of material of insoles. In the result, there was a difference significantly in the mean plantar foot pressure followed the height of insoles both left and right. Especially, mean plantar foot pressure in left indicated significantly lower in 3 cm and 5 cm insoles than in 0 cm and 1 cm insoles. Also mean plantar foot pressure in right showed significantly lower in 3 cm and 5 cm insoles than in 0 cm, and indicated significantly lower in 5 cm insoles than in 1 cm and 3 cm insoles. The mean plantar foot pressure followed the quality of the material of insoles were different significantly. In left, the mean plantar foot pressure of urethane poly-acetyl insole was lower significantly than urethane poly-acetyl inserted air insole, power-gel insole and jelly insole. And the mean plantar foot pressure of urethane poly-acetyl insole was lower significantly than power-gel insole and jelly insole in right. We showed that 3 cm and 5 cm insoles in the height of insoles and Urethane poly-acetyl insole in the quality of material were suitable to reduce a fatigue which is felt in plantar foot during the walking.

Gender Differences in Electromyography of the Lower Extremity during Golf Driver Swing

본 연구에서 KPGA소속 프로골퍼 5명, KLPGA소속 프로골퍼 5명 총 10명을 대상으로 골프 드라이브 스윙시 내측광근, 외측광근, 전경골근, 비복근의 근전도 분석을 통하여 운동역학적 요인을 비교분석하였으며, 그 결과 다음과 같은 결론을 얻었다. 성별에 따른 근 활동전위 차이는 어드레스부터 백스윙탑까지 구간에서 남성의 오른쪽 비복근이 가장 높게 나타났고, 백스윙탑에서 임팩트까지 구간에서 여성의 오른쪽 전경골근이 가장 높게 나타났으며, 모든 구간과 국면에서 남성의 경우 왼쪽 하지근이 주동근이었고, 여성의 경우 오른쪽 하지근이 주동근으로 나타났으며, 통계적으로 유의한 차이가 있는 것으로 나타났다. 남자의 경우 백스윙탑에서 임팩트 구간까지 체중을 이동시키면서 왼쪽 전경골근이 주동근으로 활동하는 것으로 판단되며, 여성의 경우 오른쪽 무릎을 왼쪽 무릎 쪽으로 밀어주는 동작에서 오른쪽 외측광근과 전경골근이 주동근으로 나타났다. 따라서 남성의 경우 왼쪽 외측광근과 전경골근을, 여성의 경우 오른쪽 외측광근과 전경골근을 발달시킬 수 있는 트레이닝을 수행한다면 비거리와 방향성을 향상시킬 수 있을 것으로 판단된다. 【This study was to investigate gender differences in muscle activities on tibialis anterior muscle, gastrocnemius and vastus medialis obliqus and outside and prime mover, antagonist and assistance mover during golf drive swing by electromyography. Ten healthy professional golfers (KPGA(n)=5, KLPGA(n)=5) volunteered in this experiment. All statistical analyses were performed using SPSS. Statistical differences were assess using t-test (p】

Effects of 12-Week Complex Training Program on Foot-Pressure Patterns of the Elderly Women

The purpose of this study was to investigate the effects of 12-week complex training program on foot pressure patterns of the elderly women. The training program consisted of aerobic exercise and muscular training for 12 weeks. Two stages of walking were given to the participants before and after treatment: (a) straight walking; and (b) turn at while walking. Data related to foot-pressure distribution(FPD) while walking were collected from each stage and analyzed. Results indicated that in both stage of walking, the mean of the foot pressure(FP) was significantly reduced after the participation in the program. Results also revealed that in all stages, the patterns of the FPD and the center of pressure(COP) were widely lower and more stable. Based on the results of this study, it was concluded that participating in a 12-week complex program bas impact on the gait patterns of the elderly women, reducing the foot pressure on their shoes.

The Effects of Active Scapular Protraction on the Muscle Activation and Function of the Upper Extremity

[Purpose] The purpose of this study was to determine the effects of adjusting the scapula into its ideal position through active scapular protraction on the muscle activation and function of the upper extremity. [Subjects] Twenty female college students aged 19–21 without any physical or functional disability were the subjects of this study. They had no history of injury to their upper extremities or hands. [Methods] After the initial measurements the experimental group was asked to perform active scapular protraction; then, their grip strength and muscle activation were measured again. Every action was maintained for 5 seconds and repeated 3 times. The mean values of the measurements were analyzed. A resting of 1 minute was given between each action. [Results] The results revealed a significant change in the experimental group’s grip strength after active scapular protraction had been performed. The surrounding muscles of the scapula, such as the serratus anterior, upper trapezius, flexor carpi ulnaris, flexor carpi radialis and palmaris longus, showed significant changes in muscle activation after active scapular protraction. The muscles of the upper extremity also showed significant changes after active scapular protraction. [Conclusion] The adjustment of scapula into its ideal position through active scapular protraction increased the activations of the muscles surrounding the shoulder joint and improved the function of the upper extremity.

Utilization of Sport Biomechanics for the Correct Posture Exercise Program (Centering in Female Middle School Students)

The purpose of this study was to investigate the degree of improvement of scoliosis, muscle function and VAS between the exer- cise group and the control group after conducting correct posture exercise program with 20 female students diagnosed with scoli- osis through PAPS in M middle school for 12 weeks. The conclusion was as follows. Cobbs angle in exercise group was changed from 11.6°ae2.5°ý to 7.3°ae2.0°ý which was statistically significant difference (p<.001). However, the change in Cobbs angle was not significant in control group, hence there was no statistically significant difference. The limber back strength was changed from 45.9°ae8.7 kg to 51.6°ae14.9 kg and sit-up was changed from 13.7°ae5.1 times to 12.9°ae5.3 times in exercise group, but they were not statistically significant. Control group also showed no statistically significant change in back strength and sit-up. The degree of VAS was changed from 7.3°ae1.6 to 3.3°ae2.4 which was a statistically significant difference (p<.01) in exercise group. How- ever, there was no statistically significant difference in control group. Consequently, correct posture exercise program was con- sidered to be effective for the reduction of Cobbs angle and degree of VAS for middle school female students with scoliosis. Therefore the correct posture exercise program can be recommended for youth scoliosis to improve and prevent the body imbal- ance and ultimately for the health of the youths.

Analysis of Plantar Foot Pressure according to Insole Types during Treadmill Gait

Objective : The purpose of this study was to analyze the foot-pressure distribution of 2D(2 dimensional form) & 3D(3 dimensional form; a customized arch-fit for posture correction) insoles for assessing their biomechanical functionality. Background: Recently there has been increased interest in both foot health and foot pain patients. Analysis of the plantar pressure was often used to solve the problems of the foot displayed by such people as rheumatoid arthritis patients. Method : Subjects who participated in this study were 17 female university students who had no previous injury experience in lower limbs and a normal gait pattern. The shoe size of all subjects was 240 mm. Two models of insoles of 2D(typical flat insole 2 dimensional form) and 3D(special production 3 dimensional form) were selected for the test. Using the Pedar-X system and Pedar-X insoles, 4.0 km/h of walking speed, and a compilation of 50 steps walking stages were used to analyze foot-pressure distribution. Results : Results of the foot-pressure distribution and biomechanical functionality on each insole were as follows; analyses of mean plantar pressure, maximum plantar pressure, maximum vertical GRF, and plantar pressure curve shape all showed overall low plantar pressure and GRF. Conclusion : This can be evaluated as an excellent insole for low levels on the plantar pressure and GRF. Therefore, it is possible to conclude that according to this analysis the 3D Customized Arch-fit Insole was better than 2D insole on the basis of these criteria.

Effects of combined exercise on changes of lower extremity muscle activation during walking in older women

[Purpose] The purpose of this study was to demonstrate the effects of combined exercise for a period of 12 weeks on the changes in lower extremity muscle activation during walking in older women. [Subjects] The subjects of this study were 22 elderly women who were 65 years of age or older and living in B-City. The subjects had no nervous system or muscular system diseases that might affect walking in the previous two years. [Methods] Muscle activation was measured by using surface EMG (QEMG-8, Laxtha, Daejeon, Republic of Korea). The subjects were asked to walk on an 8 m of footpath at a natural speed. In order to minimize the noise from the cable connecting the EMG measuring instrument to the electrodes, tape was used to affix the electrodes so that they would not fall off the subjects. The EMG data were analyzed by using the RMS. [Results] Muscle activation of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius was increased significantly after combined exercise for 12 weeks. However, no increase was observed in the left biceps femoris. [Conclusion] It was demonstrated that our exercise program, which includes aerobic walking exercises, senior-robics, and muscle strengthening exercises using elastic bands, is very effective for reorganizing the normal gait pattern in the cerebral cortex and improving muscle strength.