• Journal of the military operations research society of Korea
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• v.8 no.1
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• pp.77-98
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• 1982

Experiments have been performed for estimating the individual muscle capabilities of the biceps brachii and the quadriceps femoris muscle. The surface EMG has been recorded on the bellies of the biceps brachii and the quadriceps femoris muscle during isometric contractions at $50\%,\;75\%,\;and\;100\%$ MVC. The rectified EMG amplitudes of the maximum voluntary contraction (MVC) were in the range of $2.8\~3.0\;mV\;and\;6.9\~7.2\;mV$ the biceps brachii and the quadriceps femoris, respectively. In the biceps brachii, Type S motor units were recruited in the range of $41\~49\%$ MVC; and Type F motor units were recruited in the range of $51\~59\%$ MVC, In the quadriceps femoris, Type S, Type SF, and Type F motor units were recruited in the ranges of $31\~38\%,\;33\~48\%$, and $21\~29\%$ MVC respectively.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.1-10
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• 2017

PURPOSE: This study assessed the effect of the pelvic compression belt on the electromyographic activity of erector spinae (ES), internal oblique (IO), rectus femoris (RF), and biceps femoris (BF) after bridge exercise with pelvic belt compression in subjects with lumbar instability. METHODS: Forty subjects with lumbar instability volunteered for this study. We asked them to perform the bridge exercise while wearing a pelvic belt compression for 30 minutes five times weekly over a six week period. The pelvic compression belt was adjusted just below the anterior superior iliac spines with stabilizing pressure using elastic compression bands during bridge position. Surface electromyographic data were collected from the erector spinae (ES), internal oblique (IO), rectus femoris (RF) and biceps femoris (BF). RESULTS: After the six week intervention, the experimental group improved significantly. Muscle activation significantly decreased in the erector spinae, rectus femoris, and biceps femoris, and increased in the internal oblique muscle in bridge position while wearing a PCB (P <.01). CONCLUSION: Our findings suggest that the bridge exercise with pelvic belt compression is helpful to reduce activation in superficial muscles and lower extremity muscles such as erector spinae (ES), rectus femoris (RF), biceps femoris (BF) and increase activation in deep trunk muscle such as the internal oblique (IO).

• Journal of Korean Physical Therapy Science
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• v.26 no.3
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• pp.37-43
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• 2019

Purpose: The purpose of this study is to determine the effect of load and speed of treadmill exercise impact on muscle activity and muscle strength. Design: Randomized controlled trial. Methods: The study was conducted for 12 female student from G University. Treadmill exercise was divided into four groups (ULS, LLS, UHS, LHS). Results: 1) There was significant difference in muscle activity of tibialis anterial, medial head of gastrocnemius, rectus femoris, biceps femoris muscle in ULS, UHS (p<0.05). 2) There was significant difference in muscle activity of tibialis anterial, medial head of gastrocnemius, rectus femoris, biceps femoris muscle in LLS, LHS (p<0.05). 3) There was significant difference in muscle activity of tibialis anterial, medial head of gastrocnemius, rectus femoris, biceps femoris muscle in ULS, LLS (p<0.05). 4) There was significant difference in muscle activity of tibialis anterial, medial head of gastrocnemius, rectus femoris, biceps femoris muscle in UHS, LHS (p<0.05). 5 There was significant difference in muscle strength in LHS (p<0.05). Conclusion: Exercising with high speed and load has more influence on the muscle activity and muscle strength of the lower extremities.

• Physical Therapy Rehabilitation Science
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• v.10 no.4
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• pp.487-492
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• 2021

Objective: This study aimed to identify the effects of assuming two types of posture (standing and kneeling) during squat exercise on lower body muscle activity. Design: Cross-sectional study Methods: Twenty-five healthy adults (18 men and 7 women) were instructed to perform the squat exercises while assuming two types of posture (standing and kneeling). EMG (Electromyography) data (% maximum voluntary isometric contraction) were recorded three times from the rectus femoris (RF), gluteus maximus (GMax), gluteus medius (GMed) and biceps femoris (BF) of participant's dominant side and the mean values were analyzed. Results: During the squat exercise with all postures, there was statistically significant difference on rectus femoris, gluteus maximus, gluteus medius, and biceps femoris muscle activity (p<0.05). The results showed that, there was significantly greater rectus femoris, gluteus medius, and biceps femoris muscle activity in standing posture than in kneeling position (p<0.05). However, the gluteus maximus muscle activity was significantly greater with kneeling posture compared to standing posture (p<0.05). Conclusions: With standing posture, it is showed that rectus femoris, gluteus medius, and biceps femoris muscle activity was greater than kneeling position. While the gluteus maximus muscle activity with standing posture was less than with kneeling posture. Therefore, it is considered that this study can be used as a selective indicator of exercise posture for strengthening specific muscle or weakness caused by paralysis.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.77-84
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• 2015

Objective : The purpose of this study was to analyze the effects of lower limb muscle activity on postural stability and ground type in elderly women subjects. Method : Forty two subjects participated in the experiment (high group - age: $74.29{\pm}4.13yr$, height: $152.44{\pm}5.54cm$, weight: $57.43{\pm}6.16kg$, BMI: $24.77{\pm}2.99$, low group - age: $77.67{\pm}5.16yr$, height: $151.40{\pm}3.93cm$, weight: $60.92{\pm}6.40kg$, BMI: $26.59{\pm}2.57$). Wireless EMG with eight channels was used. Ground types were classified as flat and cushion. Results : In the double-support phase, left and right rectus femoris, left biceps femoris, left and right tibialis anterior, and left gastrocnemius did not show a significant difference in postural stability according to ground type. However right biceps femoris and gastrocnemius showed higher muscle activity in the elderly women group with lower postural stability. In the single-support phase, left and right rectus femoris, right biceps femoris, and left and right tibialis anterior did not show a significant difference in postural stability according to ground type. In addition, left biceps femoris had higher muscle activity in the elderly women group with lower postural stability. Left gastrocnemius had higher muscle activity in the elderly women group with higher postural stability and right gastrocnemius had higher muscle activity in the elderly women group on cushion ground. Conclusion : In a dynamic postural stability and cushion ground, biceps femoris and gastrocnemius muscle activity were high. As a result, biceps femoris and gastrocnemius muscle strengthening exercise on cushion ground could be beneficial in the prevention of falling.

• Physical Therapy Korea
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• v.6 no.2
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• pp.32-42
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• 1999

This study was conducted to identify the effects of high-heel shoes on EMG activities of rectus femoris and biceps femoris in 28 healthy women. Subjects were composed of experimental group (wearing high-heel shoes) and control group (wearing low-heel shoes). Two groups participated in three conditions standing (bare foot wearing athletic shoes and 7.5 cm height shoes). In high-heel shoes condition, EMG activities of rectus femoris of control group were significantly lower than that of biceps femoris of experimental group, but EMG activities of both muscles of experimental group did not should significant difference. In bare foot standing condition, EMG activities of rectus femoris of experimental group were significantly lower than that of biceps femoris but EMG activities of both muscles of control group had no significant difference. These results showed that hamstring lengthening effects was produced when wearing high-heel shoes because the external knee extension moment was increased. In the short term, high-heel shoes effect on the increase of the biceps femoris activities by spindle reflex, but in the long term, the normal amplitude of the same muscle activities by Golgi tendon organ reflex.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.2
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• pp.1-9
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• 2020

PURPOSE: This study examined the effects of different external loads on the muscle activities around the hip during prone hip extension with knee flexion (PHEKF) exercise in healthy young men. METHODS: Sixteen healthy adult males participated in the study. A pressure biofeedback unit was used to provide feedback to the participants during the abdominal drawing-in maneuver (ADIM) with PHEKF. Sandbags (0 kg, 1 kg, 2 kg, and 3 kg) were used to provide external resistance. The quadriceps was contracted to maintain knee flexion 90° against resistance. Each resistance condition using a sandbag weight was given in random order. Surface electromyography (sEMG) was used to measure the electrical activity of the gluteus maximus, biceps femoris, and erector spinae during PHEKF. RESULTS: The muscle activity of the gluteus maximus was highest with the 3 kg resistance and lowest with 0 kg (F = 128.46, P = .00). The muscle activities of the biceps femoris and erector spinae were highest with 0 kg and lowest with 3 kg (F = 29.49, P = .00). The muscle activity rate of the gluteus maximus/biceps femoris was highest with 3 kg and lowest with 0 kg (F = 37.49, P = .00). CONCLUSION: The activity of the gluteus maximus was increased using a higher external weight load during PHEKF, while the activity of the biceps femoris decreased. These findings suggest that an external weight is needed during hip extensor exercise to strengthen the gluteus maximus and inhibit the biceps femoris.

• PNF and Movement
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• v.21 no.3
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• pp.309-317
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• 2023

Purpose: This study set out to investigate the effects of prone hip extension with knee flexion (PHEKF) exercises according to external load on the thickness of the gluteus maximus (Gmax) and biceps femoris (BF). Methods: Twenty-three healthy men participated in this study. All subjects randomly practiced PHEKF under the burden of external loads created by sandbags (0 kg, 1 kg, and 2 kg). Rehabilitative ultrasound imaging (RUSI) was used to measure the thickness of the Gmax and BF during the PHEKF with different external loads. Results: The thickness of the Gmax was highest during the 2 kg resistance exercise and lowest at 0 kg. The thickness of the Gmax was significantly increased at 1 kg and 2 kg compared to 0 kg and significantly increased at from 1 kg to 2 kg (p < 0.05). The thickness of the biceps femoris was highest at 0 kg and lowest at 2 kg. The thickness of the biceps femoris muscle was significantly reduced at 1 kg and 2 kg compared to 0 kg (p < 0.05), but there was no significant difference between 1 kg and 2 kg (p > 0.05). Conclusion: The thickness of the Gmax was increased by applying PHEKF with a higher external load, whereas the muscle thickness of the biceps femoris decreased. These results suggest that the application of external loads during PHEKF exercises may be an effective method for selective strengthening of the Gmax.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.9 no.1
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• pp.35-39
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• 2011

Purpose : The purpose of this study was to determine changes in muscle activity due to elastic taping at the rectus femoris, biceps femoris and tibialis anterior muscles using surface electromyography analysis. Methods : In this study 10 healthy university students in the Department of Taekwondo Studies were screened and individuals with a history of previous injury or surgery to their nerve, muscle, and skeletal systems, such as paresthesia and motor disorder, were excluded. Subjects were taped over the rectus femoris, biceps femoris, and tibialis anterior and their muscle activities were analyzed using the surface electromyography method during maximal voluntary isometric contraction. Results : The results of this study were as follows: muscle activities indicated a significant increase after elastic taping than before at the rectus femoris, biceps femoris, and tibialis anterior muscle. These results lead us to the conclusion that muscle activity were influenced by elastic taping at the rectus femoris, biceps femoris, and tibialis anterior muscles. Conclusion : The results of this study show that muscle activity can be improved by elastic taping at the lower limbs. These results suggest that elastic taping of muscles in the lower extremities has the capability to increase muscle activity in the body.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.31-46
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• 2002

The purpose of this research is to provide scientific training guides and the basis for preventing injuries in performing tango backward walk by comparing the effects the height and shape of a heel will have on leg muscles and determining the difference between skilled and unskilled dancers through EMG analysis according to different types of shoes Total eight female athletes were selected for this research. Four with six years of professional dancing experience and another four with one year of dance sports experience. Utilizing the EMG system, rectus femoris, biceps femoris, anterior tibialis, gastrocnemius were measured under different heights (0cm, 5cm, 7cm, 9cm) and shapes (flat, fine, wide) of a heel. Experiments were conducted calculating EMG peak value and muscle load ration under different types of shoes in order to analyze the EMG of leg muscles and Erector Spinae when performing tango backward walk. The result was as follows: 1. The EMG peak value of leg muscles showed significant difference under different heights of a heel in anterior tibialis(p<.001) and gastrocnemius(p.<01) in case of skilled dancers, and in biceps femoris(p.<01) in case of unskilled dancers. 2. The EMG peak value of leg muscles showed significant difference under different shapes of a heel in anterior tibialis(p<.001) and gastrocnemius(p<.001) in case of skilled dancers, and showed no significant difference in case of unskilled dancers. 3. The muscle load ration of leg muscles showed different degrees of muscle contribution between skilled and unskilled dancers. The muscle load ration was in the order of anterior tibialis, rectus femoris, biceps femoris, and gastrocnemius in case of skilled dancers and anterior tibialis, gastrocnemius, biceps femoris, and rectus femoris in case of unskilled dancers.