• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.59-63
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• 2021

Objective: Through comparative analysis of muscle activity for whole-body vibration, walking and running movements, it is to verify the training effect of whole-body vibration exercise in terms of amount of exercise and muscle activity characteristics. Method: Flat ground walking and slope walking (10 degrees) at a speed of 5 km/h, flat ground running and slope running (10 degrees) at a speed of 11 km/h for running were performed on treadmill, and squats were maintained at 12 Hz, 20 Hz, and 29 Hz conditions on Whole body vibration exercise equipment (Galileo). Muscle activity was analyzed through EMG analysis device for one minute for each condition. Results: The Anterior Tibialis and Erector Spinae show greater exercise effect in whole-body vibration than walking and running. The Rectus Femoris, Biceps Femoris, and Gluteus Maximus have the best effect of exercise in flat running. Whole-body vibration exercise showed greater muscle activation effect as the frequency increased, and exercise effect similar to walking during the same exercise time. Conclusion: The amount of exercise through Whole-body vibration exercise was similar to that of walking exercise, and the Anterior Tibialis and Erector Spinae shows better exercise effect than walking and running.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.57-67
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• 2022

The demand for personal training (PT), through which high exercise effects can be achieved within short-term, has recently increased. PT can achieve an exercise amount improvement effect, only if accurate postures are maintained upon performing PT, and exercise with inaccurate postures can cause injuries. However, research is insufficient on exercise amount comparisons and judging exercise accuracy on PT. This study proposes an exercise accuracy measurement algorithm and compares differences in exercise amounts according to exercise postures through experiments using a respiratory gas analyzer. The exercise accuracy measurement algorithm acquires Euler anglesfrom major body parts operated upon exercise through a motion device, based on which the joint angles are calculated. By comparing the calculated joint angles with each reference angle in each exercise step, the status of exercise accuracy is judged. The calculated results of exercise accuracy on squats, lunges, and push-ups showed 0.02% difference in comparison with actually measured results through a goniometer. As a result of the exercise amount comparison experiment according to accurate posture through a respiratory gas analyzer, the exercise amount was higher by 45.19% on average in accurate postures. Through this, it was confirmed that maintaining accurate postures contributes to exercise amount improvement.

• Journal of the Korean Society of Clothing and Textiles
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• v.48 no.5
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• pp.991-1005
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• 2024

This study developed functional leggings to guide correct posture for women not trained in the squat exercise technique. Through in-depth interviews, we developed four types of functional leggings that prevent unskilled women from rotating their legs inward or outward, both improper squat forms. These functional leggings include two types of design variables: MD(medial direction design), which turns the lower extremities inward; LD(lateral direction design), which turns the lower extremities outward; and two types of variables according to material. The angles of each part of leggings during the squat movement were measured, and subjective sensations by women were evaluated, including control leggings CD(control design) without rotation function. There was no difference in the adduction and abduction angles depending on the type of functional leggings. However, at the rotation angles of the hip joint (p=0.005), femur (p=0.016), and tibia (p=0.000), the MD leggings rotated inward regardless of the material. Further, the LD leggings rotated outward regardless of the material. The developed functional leggings had an excellent subjective sense of ease of movement, pressure, and preference, thus the developed functional leggings were appropriate while guiding squat posture.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.184-184
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• 2011

선로의 레일은 재료적인 특성과 현장의 많은 주변 요소에 의한 불확실성이 매우 높은 시스템으로 결함의 위험이 상존한다. 결함 발생과 조치에 따라 영업손실로 이어지므로 레일 결함 발생과 동시에 적절한 조치가 요구된다. 따라서 레일결함 발생 시 레일교환시기를 파악하는 것이 선로관리비용을 줄일 수 있으며 레일교환에 대한 신속한 판단을 위함 관리기준을 정립하는 것이 요구된다. 현재 국내에서 고속선의 경우 관리 기준이 있으나, 일반철도는 없는 실정이다. 본 연구는 차후 일반철도 180km/h 속도상승을 계획하고 있는 현 시점에 국외 관리기준을 분석하여 결함관리기준을 정립에 기여하고자 한다. 국내의 경우, 2004. 4. 1 프랑스 기술을 전수받아 개통한 고속선은 프랑스 레일관리기준을 적용한 "레일손상 등급별 관리기준"을 제정하여 레일관리를 시행하고 있다. 국외의 경우, INNOTRACK프로젝트 안에서 관련된 다른 IM(Infrastructure Managers, 사회기반시설 관리자들)에게 최근의 활동과 변화의 이해를 제공하기 위해서, 선택된 결함들의 최소조치들의 조사가 Network Rail, OBB, Prorail, Banverket 그리고 DB에서 수행되고 있으며 UIC 지침에도 포함되고 있다. 모든 최소조치 원칙은 초음파나 육안에 의해 발견된 길이나 초음파 또는 와류탐상기(eddy current system)를 이용한 깊이에 대한 제한(limits)을 준다. 또한 침목과 이음매 또는 용접부에 관한 위치에 관한 결함의 제한이 있다. 명시된 기간은 즉각적일 수도 있으며, 보통 속도 제한이나 비상 죔쇠(Clamps)같은 경감시키는 수단에 적용될 수 있으며, 또는 더 긴 기간이 될 수도 있다. 더 긴 기간들은 수리나 레일 교체를 통하여 선로로부터 결함이 제거되어야 하는 최대의 시간이다. 본 연구에서는 Transverse Breaks, Squats, Head Checks 3가지 결함 유형에 대해 각 국에서 사용하는 최소 조치를 비교하여 분석하였다. 분석결과, 유럽에서는 레일결함에 대하여 깊이 있는 연구를 통하여 관리기준을 정하여 관리하고 있으며 이에 따라 상세하고 구체적인 레일 관리가 가능하므로 효율적이며 안전성이 제고되는 것으로 판단된다. 차후 일반철도의 180km/h 속도상승을 계획하고 있는 현 시점에서 국내철도 일반선 여건에 적합한 레일결함관리기준을 정립하기 위한 추가적인 연구가 필요할 것으로 판단된다.

• Physical Therapy Korea
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• v.23 no.4
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• pp.9-15
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• 2016

Background: Squatting is one of the best functional exercises to strengthen the quadriceps muscle in independent gait and activities of daily living. Although the use of a gym ball during squat exercise is the most common way of strengthening the vastus medialis oblique (VMO) muscle, published data on this subject are limited. Objects: The purpose of this study was to compare the sequential muscle activation of the VMO and vastus lateralis (VL) muscles during squat exercise using a gym ball at different knee flexion angles. Methods: Forty healthy adults were randomly divided into experimental (squat exercise using a gym ball) and control (squat exercise alone) groups, in which squats were performed at $45^{\circ}$ and $90^{\circ}$ knee flexion. Electromyographic (EMG) activity data were collected over 10 seconds under the 2 angles of knee flexion ($45^{\circ}$ and $90^{\circ}$). Results: There was significant group and time interaction effect for VMO and VL muscle activation at $45^{\circ}$ knee flexion. This was similarly demonstrated at $90^{\circ}$ knee flexion. No significant group main effect and time main effect for VMO and VL muscle activation were noted at $45^{\circ}$ knee flexion, respectively. In contrast, there was significant group main effect and time main effect for VMO and VL muscle activation at $90^{\circ}$ knee flexion. These significant differences were demonstrated through two-way analysis of variance over repeated measurements, suggesting that the EMG activity of the VMO muscle during squatting with a gym ball showed remarkable improvement compared to that of the VL muscle. Conclusion: This research suggests that squat exercise using a gym ball may be more beneficial in improving the activity of VMO than of the VL muscle at both $45^{\circ}$ and $90^{\circ}$ of knee flexion, respectively. We highly recommend squat exercises with a gym ball for selective strengthening of the VMO muscle in knee rehabilitation.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.271-279
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• 2020

Squats and lunges are important exercises for strengthening the trunk and lower body among various free weight exercises. It should be achieved safe and effective excise through establishing of theoretical basis for exercise posture and standard movement. Therefore, it's necessary to develop the exercise model in order to prepare the scientific countermeasures for the prevent injuries and error movement through optimal exercise movement. For this purpose, it is effective to use appropriate instruments for motion compensation according to the optical motion and error motion. In this paper, we develop a motion model analysis system based on dynamic motion through the four-point load cell for dynamic motion analysis. Proposed analytical method, the optimal and the error motion numerical data is obtained through the dynamic motion analysis. And we verified that dynamic movement is simplified to establish the motion modeling according to the classification motion and the numerical quantification data for analyzing.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.93-103
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• 2016

PURPOSE: The purpose of this study is to determine the effect of therapeutic exercise on pain, range of motion and strength, and balance ability in a patient with an anterior ankle impingement (AAI). METHODS: A-32-year-old male presented limited ankle motion and pain with forced dorsiflexion at both ankle joints. In response, a therapeutic exercise program consisted of ankle joint mobilization, strength exercises using an elastic band, and proprioceptive exercises including semi-squats and a one-legged standing exercise with open and closed eyes. The program was performed for 40 min/day, twice per week, for 8 weeks. Pain, range of motion (ROM), and muscle strength (ankle dorsiflexion, plantarflexion, inversion, and eversion), as well as a one-legged standing test of both ankles, were measured before and after 4 and 8 weeks of therapeutic exercise. RESULTS: VAS decreased in both ankles after 8 weeks of exercise, respectively, compared to baseline levels. Range of motion and strength increased in both ankles for dorsiflexion, plantarflexion, inversion, and eversion after 8 weeks of exercise compared to baseline levels. In addition, the ability to perform a one-legged standing test with eyes opened and closed improved in both legs after 8 week of exercise compared to baseline levels. CONCLUSION: These results suggest that therapeutic exercise improves pain, ROM, muscle strength, and balancing ability in patients with AAI.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.371-376
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• 2018

The purpose of this study is to clarify the effects of whole-body vibration and to provide scientific basis for effective exercise by analyzing the differences in lower extremity muscle activation according to squat position during whole body vibration. In this study, muscle activation during whole-body vibration was measured in 10 healthy males in their 20s with no orthopedic conditions during standing posture, deep squat, half squat, and heel raise squat. Muscle activation was compared by measuring the root mean square (RMS) with electromyography electrodes attached to lateral gastrocnemius, tibialis anterior, vastus lateralis, and biceps femoris. The vibration intensity was applied in combinations of the volumes of 50 and 80 and the frequencies of 10, 25, and 40 Hz in each posture. The results showed that there were differences in muscle activations of external gastrocnemius, tibialis anterior, and vastus lateralis among the position(p<.05). The heal raise squat was found to have a high muscle activation effect.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.2
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• pp.97-107
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• 2020

Purpose : The purpose of this study is to investigate the effect of squat exercise using a ball on the gap between knees and Q angle of a subject with a genu-varum, and to prove the effect, to provide a clinical basis for developing into a knee correction exercise program. Methods : As a result of posture measurement through GPS, 26 female with genu-varum with a knee length of 5 cm or more were studied. The group was randomly assigned to 13 squat exercise group using ball (experimental group) and 13 general squat exercise groups (control group). The experimental group placed the ball between both knees in a position where the distance between both feet was slightly wider than the shoulder width on a flat support surface, and fixed the ball, and then squat with the start signal. The control group squats without a ball. Each group performed three sets of exercise three times a week for six weeks. Before their exercise, after three and six weeks, EMG, GPS, digital goniometer measurement, the vastus medialis (VM), the vastus lateralis (VL), and the Q-angle were measured in the squat exercise posture. EMG was measured in squat exercise posture. Results : The distance between the knees was reduced. EMG is activated in group A, the group B experimental results showed the high activity of the VL. Q-angle had increased. But the experimental group increased more than the control group. Conclusion : We have confirmed through our experiments that the distance interval between the knees during squat exercises using a ball can be reduced. Furthermore, it would also be helpful to ensure the treatment of genu-varum.

• Physical Therapy Korea
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• v.24 no.1
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• pp.79-85
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• 2017

Background: The wall squat is considered an effective exercise because it can reduce the knee load and prevent excessive lumbar movement. However, the relationship between wall squat performance and strength of knee extensors and hip extensors remained unclear. Objects: The purpose of this study was to compare the strengths of the knee extensors and hip extensors between groups with low and high wall squat performance. Method: Nineteen males (low performance group: 9 subjects, high performance group: 10 subjects) participated in this study and performed wall squats. The subjects who were performing less than 30% of the average wall squat count were classified into the low wall squat performance group (less than or equal to 4 times) and the subjects who performed more than 30% of the average wall squat count were classified into the high wall squat performance group (greater than or equal to 8 times). Knee extensor and hip extensor strength were measured with a strength measurement system. An independent t-test was used to compare the strengths of the knee extensors and hip extensors between the groups with low and high wall squat performance. Results: The ratios of knee extensor and hip extensor strength to bodyweight were greater in the high wall squat performance group than in the low wall squat performance group (knee extensors: p<.001; hip extensors: p=.03). In the high- and low-performance groups, the ratios of knee extensor strength to bodyweight were $42.74{\pm}5.72$ and $30.76{\pm}8.54$, respectively, and the ratios of hip extensor strength to bodyweight were $31.95{\pm}10.61$ and $20.66{\pm}11.25$, respectively. Conclusion: Our findings suggest that knee extensor and hip extensor strength are needed for high wall squat performance. Thus, exercise to increase the knee and hip extensors strength can be recommended to improve squat performance.