• The Journal of Korean Physical Therapy
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• v.22 no.5
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• pp.57-61
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• 2010

Purpose: The purpose of this study was to identify the effect of active foot arch support on the muscles of lower extremity electromyographic activity during squat exercise in persons with pronated foot. Methods: The study subjects were 16 persons with pronated foot. They have no history of surgery in lower extremity and trunk and limitation of range of motion or pain when performing squat exercise. Each subject was measured the navicular drop (ND) to determine the pronated foot. And then the subjects were asked to perform three repetitions of a $90^{\circ}$ knee flexion squat in both conditions which are 1) preferred squat and 2) squat with active foot arch support. Results: Paired t-test revealed that squat with active foot arch support produced significantly greater EMG activities in abductor hallucis (p=0.00), proneus longus (p=0.03) and gluteus medius (p=0.04) than preferred squat. But the EMG activities of tibialis anterior, vastus medialis oblique and vastus lateralis were not showed significantly different between the both squat conditions. Conclusion: The findings of this study suggest that active foot arch support during squat increase the activities of lower extremity muscles which are the abductor hallucis, proneus longus and gluteus medius. Also, the abductor hallucis which is one of the planter intrinsic muscle and peroneus longus play a role in support of the foot arch and active foot arch support induced the increase of the activity of gluteus medius. Therefore active foot arch support can change the lower extremity biomechanics as well as passive foot support such as foot orthotics and taping.

• Korean Journal of Applied Biomechanics
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• v.22 no.2
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• pp.159-171
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• 2012

The purpose of this study was to provide information about kinematic variables of the gliding and delivery motion of Hyung-Keun Lee, a high school shot putter who was ranked 1st at the 2011 National Sports Festivals. Three-Dimensional motion analysis using a system of 4 video cameras at a sampling frequency of 60 Hz was conducted during shot-putting events at the 2011 National Sports Festivals. During the gliding and delivery phase of the player the results showed following characteristics; 1) The gliding technique types of the player appeared to be the short-long technique as the gliding and stance length ratio were $42.3{\pm}3.87$ % and $57.7{\pm}3.87$ %, respectively. In addition, the trajectory of shots during the gliding and delivery phase showed different trajectory patterns with "S-shaped" type of elite players due to the deviation from a central axis of the APSS (athletic-plus shot system). 2) The horizontal velocity of COG made from gliding should maintain the velocity during transition and release phase, but the player showed a small momentum for a gradual decrease of velocity. 3) Therefore, the player requires to adjust an appropriate ratio between gliding and stance length with a strong muscle power at the trunk, throwing arm, and the lower extremity during gliding and delivery phase.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.161-171
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• 2011

The purpose of this study was to identify biomechanical characteristics of glide and delivery motion of In-Sung Hwang, player who is a member of the national team among the finalists in the men's shot put at the 2010 National Sports Festivals. Three-Dimensional motion analysis using a system of 3 video cameras at a sampling frequency of 60 Hz was performed for this study. During the glide and delivery phase the results showed following characteristics; 1) The glide type was suitable for the short-long technique, but the trajectory of shot at the glide and delivery phase showed a different trajectory pattern with "S-shaped" type of elite players due to many deviating from central axis of the APSS(athletic-plus shot system). 2) Left knee was more flexed during failed trials compared to successful trials but COG was higher. Therefore, the player showed less stability of COG as he may not get enough breaking force at the left foot. 3) Furthermore, it would be required to have strong muscle power at the trunk, throwing arm, and the lower extremity in order to achieve maintain a low projection angle of the release.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.2
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• pp.286-291
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• 1997

The purpose of this study is to examine the effect of clothing habits wearing cool or warm in daily life on motor ability. A group of ten healthy young females were divided into a cold (C) group and a warm (W) group. From autumn to winter, C group was advised to wear cool clothing, and W group, warm Clothing. The subject's physical fitness were tested in October, initial stage of the clothing training and March of the following year, final stage of the training. The measurements were taken after the subjects rested in a thermoneutral room conditioned at 23$\pm$2$^{\circ}C$ over 1 hour. The test items were weight, skinfold thickness, grip strength (right, left), back-lift strength, vertical jump, sit-ups, Irosmax, side step test, single-foot standing test with eyes closed, and standing trunk flexion. Changes in motor ability of each group between initial stage and final stage of the training were compared. 1. Muscle strength, part of the motor revelation capacity, showed no significant change in the both ,Troops. On the other hand, strength and power showed a decrease in the both groups and C group showed a sharp decrease. 2. Muscular endurance and cardio-pulmonary fitness, part of the motor continuation capacity, were increased after the training and the degree of increase was great in C group. 3. C group showed significant increase in motor coordination capacity including agility, balance, and flexibility after the training, while Wgroup showed significant increases only in balance. 4. Weight and skinfold thickness as a part of the physique showed no significant change.

• The Korean Journal of Pain
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• v.29 no.1
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• pp.18-22
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• 2016

Background: The interscalene brachial plexus block is widely used for pain control and anesthetic purposes during shoulder arthroscopic surgeries and surgeries of the upper extremities. However, it is known that interscalene brachial plexus block is not appropriate for upper limb surgeries because it does not affect the lower trunk (C8-T1, ulnar nerve) of the brachial plexus. Methods: A low approach, ultrasound-guided interscalene brachial plexus block (LISB) was performed on twenty-eight patients undergoing surgery of the upper extremities. The patients were assessed five minutes and fifteen minutes after the block for the degree of block in each nerve and muscle as well as for any complications. Results: At five minutes and fifteen minutes after the performance of the block, the degree of the block in the ulnar nerve was found to be $2.8{\pm}2.6$ and $1.1{\pm}1.8$, respectively, based on a ten-point scale. Motor block occurred in the median nerve after fifteen minutes in 26 of the 28 patients (92.8%), and in all of the other three nerves in all 28 patients. None of the patients received additional analgesics, and none experienced complications. Conclusions: The present study confirmed the achievement of an appropriate sensory and motor block in the upper extremities, including the ulnar nerve, fifteen minutes after LISB, with no complications.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.11
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• pp.1794-1805
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• 2009

This study investigates the influence of slit positions on the microclimate temperature/humidity of garments. To design the slits, a market survey was performed to indicate the method to apply the slits, in addition to a literature survey about muscles and body surface variation through body movements. Based on the survey, three positions of slits were selected, shoulder slit, lowback slit, and midback slit, a slit width of 1cm and length to 30cm was used. The results showed that microclimate temperatures/humidity on the back according to the slit positions were in the order of, lowback, midback, and the shoulder. The lowback slit showed the highest effect on the temperature/humidity of a front trunk. Lowback slits affected on localized areas of the glutaeus maximus, erector spinae, and latissimus dorsi. Midback slits affected the back muscle and deltoid. Shoulder slits showed a more significant effect on the localized area of the deltoid versus other localized areas. In the subjective sensations, the lowback slit was cooler, dryer, and more comfortable than the other slits. For the subjective sensations by fabric characteristics, the slit positions correlated at |r|${\geq}.8$ and were significant at p<.001 The results show that the lowback slit has a superior air exchange effect and thermoregulation qualities.

• Physical Therapy Rehabilitation Science
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• v.9 no.3
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• pp.197-200
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• 2020

Objective: The purpose of this study was to develop and investigate the feasibility of a sit-to-stand assistive chair using a pneumatic cylinder. Design: Cross-sectional study. Methods: The sit-to-stand assistive chair was developed to assist the sit-to-stand movement by rising up of the chair by a pneumatic cylinder. After the user is seated on the chair, if the pneumatic cylinder pulls the seat plate when standing up, the spring of the pneumatic cylinder, which has been stretched, assists in rising the rear end of the seat plate so that the user can stand conveniently and comfortably. A feasibility test was performed in 10 heathy adults. The electromyographic muscle activation of the trunk and lower extremity muscles was analyzed, which included the erector spinae, rectus abdominis, quadriceps, tibialis anterior, gastrocnemius when standing up from sitting using the developed chair and standing up without using the developed chair. Results: As a result, the sit-to-stand assistive chair using a pneumatic cylinder was developed. In the feasibility test, the use of the developed chair had a decrease in rectus abdominis, quadriceps, tibialis anterior activation compared to those who did not use the device in the healthy adults. Conclusions: The sit-to-stand assistive chair using a pneumatic cylinder may be helpful to reduce the activation of the rectus abdominis, quadriceps, tibialis anterior muscles when performing a sit-to-stand movement. Through the results, the efficacy of the sit-to-stand assistive chair can be confirmed. In the future, further studies are warranted to investigate for the safety and efficacy of its use in the elderly population or those who are disabled.

• Journal of the Ergonomics Society of Korea
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• v.30 no.5
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• pp.597-603
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• 2011

Objective: The objective of this study was to compare one-hand and two-hands lifting activity in terms of biomechanical stress for the range of lifting heights from 10cm above floor level to knuckle height. Background: Even though two-hands lifting activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting are also very common at the industrial site and forestry and farming. Method: Eight male subjects were asked to perform lifting tasks using both a one-handed as well as a two-handed lifting technique. Trunk muscle electromyographic activity was recorded while the subjects performed the lifting tasks. This information was used as input to an EMG-assisted free-dynamic biomechanical model that predicted spinal loading in three dimensions. Results: It was shown that for the left-hand lifting tasks, the values of moment, lateral shear force, A-P shear force, and compressive force were increased by the average 43%, as the workload was increased twice from 7.5kg to 15.0kg. For the right-hand lifting task, these were increased by the average 34%. For the two-hands lifting tasks, these were increased by the average 25%. The lateral shear forces at L5/S1 of one-hand lifting tasks, notwithstanding the half of the workload of two-hands lifting tasks, were very high in the 300~317% of the one of two-hands lifting tasks. The moments at L5/S1 of one-hand lifting tasks were 126~166% of the one of two-hands lifting tasks. Conclusion: It is concluded that the effect of workload for one-hand lifting is greater than two-hands lifting. It can also be concluded that asymmetrical effect of one-hand lifting is much greater than workload effect. Application: The results of this study can be used to provide guidelines of recommended safe weights for tasks involved in one-hand lifting activity.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.413-420
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• 2013

Objective: The objective of this study was to compare one-hand and two-hands lowering activity in terms of biomechanical stress for the range of lowering heights from knuckle height to 10cm above floor level. Background: Even though two-hands lifting/lowering activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting/lowering are also very common at the industrial site and forestry and farming. Method: Eight male subjects were asked to perform lowering tasks using both a one-handed as well as a two-handed lowering technique. Trunk muscle electromyographic activity was recorded while the subjects performed the lowering tasks. This information was used as input to an EMG-assisted free-dynamic biomechanical model that predicted spinal loading in three dimensions. Results: It was shown that for the left-hand lowering tasks, the values of moment, lateral shear force, A-P shear force, and compressive force were increased by the average 6%, as the workload was increased twice from 7.5kg to 15kg. For the right-hand lowering task, these were increased by the average 17%. For the two-hands lowering tasks, these were increased by the average 14%. Conclusion: Even though the effect of workload on the biomechanical stress for both one-hand and two-hands lowering tasks is not so significant for the workload less than 15kg, it can be claimed that the biomechanical stress for one-hand lowering is greater than for two-hands lowering tasks. Therefore, it can be concluded that asymmetrical lowering posture would give greater influence on the biomechanical stress than the workload effect for one-hand lowering activity. Application: The result of this study may be used to provide guidelines of recommended safe weights for tasks involved in one-hand lowering activity.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.213-218
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• 2018

Objective: The purpose of this study was to examine the effect of the core muscle strength enhancement of the elderly on 8 weeks training using the core exercise equipment for the elderly on the ability to control the whole-body center of mass in posture stabilization. Method: 16 females (10 exercise group, 6 control group) participated in this study. Exercise group took part in the core strength training program for 8 weeks with total of 16 repetitions (2 repetitions per week) using a training device. External perturbation during standing as pulling force applied at the pelvic level in the anterior direction was provided to the subject. In a UCM model, the controller selects within the space of elemental variables a subspace (a manifold, UCM) corresponding to a value of a performance variable that needs to be stabilized. In the present study, we were interested in how movements of the individual segment center of mass (elemental variables) affect the whole-body center of mass (the performance variable) during balance control. Results: At the variance of task-irrelevant space, there was significant $test^*$ group interactions ($F_{1,16}=7.482$, p<.05). However, there were no significant main effect of the test ($F_{1,16}=.899$, p>.05) and group ($F_{1,16}=1.039$, p>.05). At the variance of task-relevant space, there was significant $test^*$ group interactions ($F_{1,16}=7.382$, p<.05). However, there were no significant main effect of the test ($F_{1,16}=.754$, p>.05) and group ($F_{1,16}=1.106$, p>.05). Conclusion: The results of this study showed that the 8 weeks training through the core training equipment for the elderly showed a significant decrease in the $Vcm_{TIR}$ and $Vcm_{TR}$. This result indicates that the core strength training affects the trunk stiffness control strategy to maintain balance in the standing position by minimizing total variability of individual segment CMs.