• 한국운동역학회지
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• 제31권3호
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• pp.214-219
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• 2021

Objective: The aim of this study was to evaluate the differences in muscle activity of hamstring muscle depending on the position of the feet during Swiss ball hamstring curl exercise. Method: Total of 15 male participants with no history of hamstring muscle injuries and musculoskeletal disorders in the past 6 months were participated in this study (Age: 29.27 ± 4.96 yrs, Height: 173.47 ± 5.18 cm, Body mass: 75.47 ± 12.50 kg). The muscle activation of semitendinosus and biceps femoris with four different feet positions including neutral stance, internal rotation, external rotation, and wide stance were measured during a Swiss ball hamstring curl exercise. For the analysis, the Swiss ball exercise movement comprised of 3 events (90°→ 0°→ 90°) based on the knee angle and 2 phases relative to the mechanism of muscle contraction (eccentric/concentric contraction). To pursue the study goal, an one-way ANOVA with repeated measures was performed with statistical significance as α = 0.05. Results: There was no statistically significant feet position effect found during the Swiss ball hamstring curl with eccentric contraction phase (p>.05). It is, however, semitendinosus showed an enhanced muscle activation in concentric contraction phase, displaying the highest muscle activity in wide stance and the lowest in external rotation (p<.05). Conclusion: Our findings suggest that this exercise can be beneficial in selectively training the semitendinosus. In other words, Swiss ball hamstring curls performed in wide stance strengthens semitendinosus, which improves the stability of knee and are effective in preventing knee injuries and reinforces rehabilitation.

• Journal of Animal Science and Technology
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• 제63권1호
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• pp.149-159
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• 2021

This study examined the effects of different wet-aging times on the physicochemical characteristics and microbial profile of longissimus lumborum (LL) and biceps femoris (BF) muscles from Korean native black goat (KNBG) meat. The water holding capacity (WHC), pH, cooking loss, shear force, meat color, free amino acid, total bacteria, and coliform count of KNGB meat were analyzed at 0, 5, 10, and 15 days of wet-aging at 4℃ under vacuum packaging. The results showed that different wet-aging times led to significant pH variations between the muscles throughout the aging period. The wet-aging time did not affect the WHC and cooking loss in meat from the LL muscle. In the BF muscle, however, meat wet-aged for five days had a significantly higher WHC and less cooking loss than meat aged for 0, 10, and 15 days. The meat from the LL muscle wet-aged for five days produced tenderer meat (low shear force value) than the unaged meat (p < 0.05). Moreover, the color was similar in the LL muscle regardless of the number of aging days. In the BF muscle, the redness (a*) was higher in the meat wet-aged for 15 days compared to that aged for 0, 5, and 10 days (p < 0.05). Regardless of the muscles, an increase in wet-aging time led to an increase in the total free amino acids contents in both muscles (p < 0.05). On the other hand, the tasty/bitter amino acid ratio was significantly higher for five days of wet-aged meat than 10 and 15 days of aging from the BF muscle. In addition, regardless of the muscles, the total bacteria and coliform counts were significantly lower for five days of wet-aged meat than 10 and 15 days of aging (p < 0.05). Therefore, chevon wet-aged for five days is an optimal aging period under vacuum packaging that fortifies meat quality with a minimal microbial negative defect.

• 한국운동역학회지
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• 제30권4호
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• pp.311-319
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• 2020

Objective: The purpose of this study was to examine of this study is to study the effect of squat exercise on muscle activation in a sling device using various types of ropes and to propose an effective sling exercise method for strengthening the lower extremity strength. Method: 20 adult male subjects (age: 25.2±2.4 yrs, height: 176.5±3.2 cm, weight: 77.2±4.5 kg) participated in this study. In the experiment, a total of four squats were conducted: squat [SE], sling squat using inelastic rope [IR], sling squat using elastic rope [ER], and sling squat using two elastic ropes [TER]. Squats were performed 5 times for each condition, and a 60-second break was given for each condition to minimize muscle fatigue. The activation of biceps brachii, rectus femoris, gastrocnemius, and tibialis anterior muscles was measured. Results: It was found that the activation of all muscles was the lowest during the squat exercise [SE]. During the sling squat using inelastic rope [IR], the muscle activation of the biceps brachii was the highest. During the sling squat using elastic rope [ER], the activation of the rectus femoris, gastrocnemius, and tibialis anterior muscles was found to be the highest. In the sling squat using two elastic ropes [TER], most of the muscle activation was similar to that of the sling squat using inelastic rope [IR]. Conclusion: Our results of the experiment, it was found that sling squat exercise using elastic rope had a positive effect on the activation of all muscles. It is thought that performing a squat exercise under moderate weight load and unstable conditions, such as sling squat exercise using elastic rope, can increase the muscle activity of the lower limbs and perform more effective exercise effect than performing a conventional squat exercise under stable conditions. In the future, if research is conducted not only on adult men, but also on various ages and patients, it will be able to provide positive help in improving balance, stability and stamina through squat exercise.

• 한국운동역학회지
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• 제32권1호
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• pp.24-30
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• 2022

Objective: The purpose of this study was to determine the factors of successful and unsuccessful movements through the analysis of kinematics and muscle activity of the Free Aerial Cartwheel on the balance beam. Method: Subjects (Age: 22.8 ± 2.4 yrs., Height: 158.7 ± 5.0 cm, Body mass: 54.1 ± 6.4 kg, Career: 13 ± 2.4 yrs.) who were currently active as female gymnasts participated in the study. They had no history of surgical treatment within 3 months. Subject criteria included more than 10 years of professional experience in college and professional level of gymnastics and the ability to conduct the Free Aerial Cartwheel on the Balance Beam. Each subject performed 10 times of Free Aerial Cartwheel on the balance beam. One successful trial and one unsuccessful trial (failure) among 10 trials were selected for the comparison. Results: It was found that longer time required in case of unsuccessful trial when performing the Free Aerial Cartwheel on the balance beam compared with successful trial. It is expected to be the result of movement in the last landing section (i.e. phase 5). In addition, it was found that the center of gravity of the body descends at a high speed to perform the jump (i.e. phase 2) in order to obtain a sufficient jumping height when the movement is successful while the knee joint is rapidly extended to perform a jump when movement fails. In the single landing section after the jump (i.e. phase 4), if the ankle joint rapidly dorsiflexed after take-off and the hip joint rapidly flexed, so landing was not successful. Conversely, in a successful landing movement, muscle activity of the biceps femoris was greatly activated resulting no shaking in the last landing section (i.e. phase 5). Conclusion: In order to succeed in this movement, it is necessary to perform a strong jump after rapidly descending the center of gravity of the body using the force of the biceps femoris muscle. Further improvement of the skills on the balance beam requires the analysis of the game-like situation with continuous research on kinematic and kinematic analysis of various techniques, jumps, turns, etc.

• The Journal of Korean Physical Therapy
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• 제35권1호
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• pp.13-18
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• 2023

Purpose: The purpose of this study was to investigate the effects of posterior oblique sling activation on the muscle activities of the gluteus maximus (GM), multifidus (MF), and biceps femoris (BF) during three different prone hip extension exercises in healthy male individuals. Methods: Twenty healthy subjects participated in this study. An electromyography device was used to measure the muscle activities of the GM, MF, and BF. Each subject was asked to perform three different prone hip extensions as follows: [1) Prone hip extension with knee flexion + hip abduction 30°; PHE1, 2) Prone hip extension with knee flexion + hip abduction 30° and shoulder abduction 125°; PHE2, 3) Prone hip extension with knee flexion + hip abduction 30° and shoulder abduction 125° with 1kg loading; PHE3, in random order. A one-way repeated measures analysis of the variance and a Bonferroni post hoc test were used to analyze the results. The statistical significance was set at α=0.01. Results: The muscle activity of the GM was significantly different between the three positions (P_adj<0.01). The muscle activity of the GM was significantly greater during PHE3 compared with PHE1 and PHE2 (P_adj<0.01). The BF muscle activity was significantly lower during PHE3 compared with PHE1 and PHE2 (P_adj< 0.01). There was no significant difference in the muscle activity of the MF (P_adj<0.01). The ratio of the muscle activity (ratio=GM/BF) during PHE3 was significantly greater compared to PHE1 and PHE2 (P_adj< 0.01). Conclusion: The GM activity and GM/BF ratio during the PHE3 exercise were significantly greater compared to that during PHE1 and PHE2. Therefore, the PHE3 exercise could be recommended as a selectively effective GM activation exercise while decreasing the muscle activity of the BF.

• Journal of Animal Science and Technology
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• 제65권3호
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• pp.511-518
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• 2023

This study examined the association between functional sequence variants (FSVs) of myosin heavy chain 3 (MYH3) genotypes and collagen content in a Landrace and Jeju native pig (JNP) crossbred population. Four muscles (Musculus longissimus dorsi, Musculus semimembranosus, Musculus triceps brachii, and Musculus biceps femoris) were used for the analysis of meat collagen content, and the same animals were genotyped for the FSVs of the MYH3 gene by using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). Three FSVs of MYH3 genotypes were identified and had genotype frequencies of 0.358, 0.551, and 0.091 for QQ, Qq, and qq, respectively. QQ animals for the FSVs of the MYH3 genotypes showed higher collagen content in their M. longissimus dorsi (p < 0.001), M. semimembranosus (p < 0.001), M. triceps brachii (p < 0.001), and M. biceps femoris (p < 0.001) than qq homozygous animals. After the validation of this result in other independent populations, the FSVs of MYH3 genotypes can be a valuable genetic marker for improving collagen content in porcine muscles and can also be applied to increase the amount of collagen for biomedical purposes.

• 한국전문물리치료학회지
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• 제31권1호
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• pp.18-28
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• 2024

Background: Lateral instability of the ankle is one of the most common causes of musculoskeletal ankle injuries. The peroneus longus (PL) and peroneus brevis (PB) contribute to ankle stability. In early rehabilitation, isometric exercises have been selected for improvement of ankle stability. To effectively train the peroneal muscles during eversion, it is important to consider ankle and body posture. Objects: This study aimed to compare activation of the PL, PB, and biceps femoris (BF) muscles during eversion in different ankle postures (neutral [N], plantarflexed [PF]) and body postures (sitting and side-lying). Methods: Thirty healthy individuals with no history of lateral ankle sprains within the last 6 months were included in the study. Maximal isometric strength of eversion and muscle activation were measured simultaneously. Muscle activation at submaximal eversion was divided by the highest value obtained from maximal isometric eversion among the four postures (percent maximal voluntary isometric contraction [%MVIC]). To examine the differences in muscle activation depending on posture, a 2 × 2 repeated measures analysis of variance (ANOVA) was conducted. Results: There were significant interaction effects of ankle and body postures on PL muscle activation and evertor strength (p < 0.05). The PL muscle activation showed a significantly greater difference in the side-lying and PF conditions than in the sitting and N conditions (p < 0.05). Evertor strength was greater in the N compared to the PF condition regardless of body posture (p < 0.05). In the case of PB and BF muscle activation, only the main effects of ankle and body posture were observed (p < 0.05). Conclusion: Among the four postures, the side-lying-PF posture produced the highest muscle activation. The side-lying-PF posture may be preferred for effective peroneal muscle exercises, even when considering the BF muscle.

• 한국정보전자통신기술학회논문지
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• 제17권2호
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• pp.108-112
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• 2024

회내족은 넙다리두갈래근의 활성화를 증가시키거나 근피로 또는 과사용증후군(overuse syndromes)을 초래한다. 본 연구에서는 회내각(pronation angles)이 20° 이상인 회내족 피험자를 대상으로 회내각과 근피로지수와의 관계를 파악하는 것이다. 나이 범위가 15-61세인 12명의 피험자가 실험에 참여하였으며, 30초 동안 4.5 km/h의 속도로 트레드밀 보행시 넙다리두갈래근의 근전도를 측정하여 근피로지수인 중앙주파수와 저주파수 대역 크기의 기울기를 산출하였다. 본 연구에 참여한 피험자로부터 산출한 두 가지 근피로지수와 회내각 사이의 관계가 정상인과 유사할 것이라는 가정 하에 실험한 결과, 근피로지수와 회내각 사이의 유의한 상관성을 얻을 수 있었다 (r>0.60; p<0.05).

• 대한물리의학회지
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• 제3권4호
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• pp.215-224
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• 2008

Purpose : The purpose of this study was to evaluate the effects of the Hahoe mask dance on the gait and muscle activity in the elderly who lived at a elderly welfare facility. Methods : Dancing group was consisted of 20 subjects(over 70 years). The time of measurement was assigned in pre measurement, after 1 month, after 2 months. Subjects was received the Hahoe mask dance for three times a week during 8 weeks. The control group was consisted of 20 the elderly (similar age) who didn't received dancing. Assessment of gait function included the gait velocity, step time, stride, step length, it was analyzed in activity for 4 muscles (rectus femoris, biceps femoris, tibialis anterior, and lateral gastrocnemius). Results : Activities for muscles of control group was decreased in rectus femoris, bieps femoris, however, those of experimental group was increased significantly(p<.05). While control group showed decrease in the gait velocity per second (p<.05), experimental group showed statistically significant increase(p<.05). Control group had a significant long time than that of control group in gait time of right and left foot(p<.05). Control group was a little longer than control group in stride time of right and left foot(p<.05). Step length for control group was shorter than that for experimental group both foots(p<.05). Conclusion : In conclusion, this study confirmed that activities for 4 muscles by EMG have showed significant increases, so we will use a programme of muscle improvement in elderly community welfare faculty. We recommend that further research should explore the degree of muscle activity by larger sample sizes and longer follow-up periods.

• 대한관절경학회지
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• 제4권1호
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• pp.25-31
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• 2000

후외측 회전 불안정성은 정확한 손상 기전에 대하여 논란이 많은 복잡한 손상으로 올바른 진단과 치료가 어려운 것으로 알려져 있다. 저자들은 Modified Clancy 술식으로 치료한 후외측 회전 불안정성 재건술의 임상결과를 후방십자인대 손상 여부에 따라 비교 분석하고자 한다. 방법 : 후외측 회전 불안정성 단독 손상 환자 (group I) 21예와 후방십자인대 손상을 동반한 후외측 회전불안정성 손상 환자 (group II) 25명을 대상으로 후방십자인대 손상은 일절개법을 이용하여 관절경적 재건을 하였으며, 후외측 회전 불안정성은 Clancy 변형 술식을 이용하였다. 이들의 임상적 결과를 비교 분석하였다. 결과 : 모든 예에서 수술 전 reverse pivot shift test 양성이었으나 수술 후 43례에서 음성으로 측정되었다. 수술 전 측정한 external rotation thigh foot angle test는 I군과 II군에서 모두 건측에 비해 증가되어 있었고 통계학적으로 의미 있는 차이를 보였다. 수술 후 양군 모두 $10^{\circ}$이하의 측정치를 나타내었다. 평균 40.3개월 (24-99개월) 추시 관찰 기간 중 평균 Lysholm knee score와 Hospital For Special Surgery knee ligament score는 양군에서 모두 90점보다 높은 점수를 나타내었고 두 군 사이의 차이는 통계학적으로 의미 없는 것으로 평가되었다. 술 후 합병증으로 3예에서 전환 대퇴 이두건 파열이 발생하여 재수술을 시행하였다. 결론 : Clancy 변형 술식은 장경 인대의 손상을 줄이며 대퇴 이두건을 등척점으로 전환함으로 정상 운동범위 회복을 가능하게 한다는 장점이 있다. 본 연구 결과 Clancy 변형 술식을 이용한 후외측 회전 불안정성 재건은 I군과 II군에서 모두 만족스러운 결과를 얻었으며 대퇴 이두건 부착부의 유착이 없는 경우 Clancy 변형 술식은 단독 또는 동반 손상을 가진 후외측 회전 불안정성 재건술에 좋은 방법이라고 사료된다.