• 한국운동역학회지
• /
• 제28권1호
• /
• pp.37-43
• /
• 2018

Objective: The aim of this study was to analyze muscle activation of the lower extremities as a function of changes of the center of pressure (CoP) of the foot during squats in order to provide quantitative information to trainers who would like to teach correct movements for developing muscles. Method: Ten men with over three years of weight training experience participated in this study (age: $26.1{\pm}0.8yrs$, height: $171.2{\pm}3.9cm$, body mass: $71.1{\pm}5.7kg$, 60%RM: $84{\pm}9kg$, career: $4.0{\pm}0.7yrs$). The participants were instructed to perform a squat in each of 3 conditions, with different CoP's (the front, middle, and rear of the foot). Results: The position of the CoP showed significant differences according to instructions in both the eccentric and concentric contraction phases (p < .05). The range of movement of the hip and ankle joints showed significant differences corresponding to changes of the CoP position (p < .05). The rectus femoris and gluteus maximus muscle showed significant differences for different CoP positions only in the concentric contraction phase, while the gastrocnemius and anterior tibialis were significantly different in both the concentric and eccentric contraction phase (p < .05). Conclusion: When the target muscle of squat training is the gastrocnemius, the CoP should be located in the front of the foot for effective muscle training. When the target muscles of squat training are the gluteus maximus and quadriceps femoris, the CoP should be located on the rear of the foot.

• 한국정밀공학회지
• /
• 제28권6호
• /
• pp.670-677
• /
• 2011

This study is to estimate the joint torques without torque sensor using the EMG (Electromyogram) signal of agonist/antagonist muscle with Neural Network Back Propagation Algorithm during the elbow motion. Command Signal can be guessed by EMG signal. But it cannot calculate the joint torque. There are many kinds of field utilizing Back Propagation Learning Method. It is generally used as a virtual sensor estimated physical information in the system functioning through the sensor. In this study applied the algorithm to obtain the virtual senor values estimated joint torque. During various elbow movement (Biceps isometric contraction, Biceps/Triceps Concentric Contraction (isotonic), Biceps/Triceps Concentric Contraction/Eccentric Contraction (isokinetic)), exact joint torque was measured by KINCOM equipment. It is input to the (BP)algorithm with EMG signal simultaneously and have trained in a variety of situations. As a result, Only using the EMG sensor, this study distinguished a variety of elbow motion and verified a virtual torque value which is approximately(about 90%) the same as joint torque measured by KINCOM equipment.

• PNF and Movement
• /
• 제22권1호
• /
• pp.151-158
• /
• 2024

Purpose: The present study investigated how variations in diagonal exercises affect shoulder muscle activity, examining changes in neuromuscular activation during scapular and shoulder diagonal patterns of exercises. Furthermore, we explored whether the exercise phase affects muscle activation. Methods: Sixteen asymptomatic male participants were recruited. Four diagonal pattern exercises (scapular anterior elevation, posterior elevation, flexion-adduction-external rotation, flexion, abduction-external rotation), and two exercise phases (concentric and eccentric) were administered. Surface electromyography data were collected. Results: Upper trapezius activity was significantly higher during the concentric phase of scapular posterior elevation exercises compared with the others (p<0.05). The serratus anterior, anterior deltoid, and infraspinatus activities were significantly higher during shoulder diagonal pattern exercises compared with the scapular diagonal pattern exercises (p<0.05). Except for the lower trapezius, muscular activities during the concentric phase were significantly greater compared with the eccentric phase (p<0.05). Conclusion: The current study suggests that the diagonal pattern of exercise may contribute to selective strengthening of the shoulder complex muscles and that the form of exercise should be tailored to the subject. It also suggests that diagonal exercises with concentric contractions tend to be more beneficial than eccentric contractions for overall muscle recruitment, but the effects vary for specific diagonal patterns.

• 한국체육학회지인문사회과학편
• /
• 제54권5호
• /
• pp.769-780
• /
• 2015

이 연구는 고령자의 근육수축양식 및 손상정도에 따른 염증물질, 면역적격세포 및 골수유래 전구세포의 변화를 검증하는데 그 목적이 있다. 연구대상은 최근 6개월간 저항성운동 프로그램을 실시하지 않은 65세 이상의 고령자 20명을 신장성운동 집단(ECC, n=10)과 단축성운동 집단(CON, n=10)으로 분류하였다. 모든 피험자는 팔꿈치 굽힘근의 1차 신장성운동(ECC 1) 및 단축성운동(CON)을 실시하였고, ECC는 4주후에 재차 2차 신장성운동(ECC 2)을 6회 10세트, 세트 사이에 2분의 휴식시간을 적용하여 실시하였다. 골격근손상 지표(ROM, VAS, CK), 염증물질(TNF-α, IL-1, IL-6), 면역적격세포(CD3+, CD4+, CD8+, CD19+), 골수유래 전구세포(CD34+) 및 백혈구수는 운동전, 운동 직후, 운동 시기의 2, 24, 48, 72 및 96시간 후에 각각 측정하였다. 주요결과는 다음과 같다. 고령자의 골격근손상 지표(ROM, VAS)는 CON(근육수축양식) 및 ECC 2(손상정도)와 각각 비교해서 ECC 1에서 손상이 크게 증가하였다(p<.05). IL-6 및 TNF-α는 CON 및 ECC 2와 각각 비교해서 ECC 1의 24, 48 및 72시간 후에 유의하게 높게 나타났다(p<.05). 호중구수는 CON 및 ECC 2와 각각 비교해서 ECC 1의 2시간 후에 유의하게 높게 나타났다(p<.05). 이 연구에서는 고령자에서도 근육수축양식은 단축성운동보다 신장성운동에서, 또한 손상정도는 2차 신장성운동보다 1차 신장성운동에서 보다 크게 손상이 발생하였다는 사실을 확인하였다. 특히 IL-6와 TNF-α 및 호중구수는 근손상 정도와 밀접한 관련성이 있다는 것이 시사되었다.

• The Journal of Korean Physical Therapy
• /
• 제11권1호
• /
• pp.137-141
• /
• 1999

Proprioceptive neuromuscular facilitation(PNF), pelvic patterns are very important for orthopaedic and neurologic patient. It is an essential treatment techniques for motor developmental disorder. CVA, lumbar disk, muscle weekness and pain control of lumbar, pelvic and lower extremity, Pelvic patterns of PNP has 4 different type of basic pattern. each of them is combinding of movement plane and functional movement. Biomechanically most of PNF patterns are a concentric contraction with third-class lever. But the movement pattern have a technique of combination of isotonic that should make a eccentric contraction with second-class lever.

• 한국안전학회지
• /
• 제15권1호
• /
• pp.153-160
• /
• 2000

Occupational cumulative traumas (CTDs) are becoming one of leading ailments in industrialized worl $d^{(1.2)}$. The degree of muscle fatigue is important parameter to understand cause of occupational cumulative trauma disorders. To quantify degree of muscle fatigue, muscle EMG activity was measured during isometric and dynamic contractions(repetitive concentric/eccentric muscle contraction) and its analyzed data, such as RMS, median frequency, and median power were compared when the muscle was fresh and exhausted. When muscle become fatigue, it was observed that median frequency decreased and median power and RMS increased However, based on overall prolonged observation, median frequency increased and median power and RMS decreased. Therefore it was concluded that shifting patterns of RMS, median frequency, and median power values can be used as parameter to evaluate degree of muscle fatigue even in dynamic muscle contraction.

• The Journal of Korean Physical Therapy
• /
• 제11권3호
• /
• pp.65-69
• /
• 1999

Proprioceptive neuromusculat facilitation(PNF), scapular patterns are very important for orthopaedic and neurologic patients. It is an essential treatment techniques for motor developmental disorder, CVA, cervical disk, frozen shoulder and pain control of cervical, shoulder girdle and upper extremity. Scapular patterns of PNF has 4 different type of pattern. each of them in combining of movement plane and functional movement. Biomechanically, most of PNF patterns are a concentric contraction with third-claw lever. But the movement pattern have a technique of combination of isotonic that should make a eccentric contraction with second-claw lever.

• The Journal of Korean Physical Therapy
• /
• 제16권3호
• /
• pp.205-216
• /
• 2004

The purpose of this study is to find application of combination of insotonic(CI) in clinical approach. This is a literature study with books and clinical experience. CI was developed after Margaret Knott that is very useful in clinically. CI has two lever system. It has class II lever system for eccentric contraction and class III lever system for concentric contraction. Therefore it make two different contraction that is not only magnitude of motion and speed increase of motion but also biomechanical advantage. Application of CI has much variety by patient position and treatment position. Especially, it is very effectable on mat activities and training for mid stance period. CI apply in supine position on treatment table, mat or high mat activities, bridging activities, all fourth activities and sit on chair activities. CI apply serially with different techniques. These are rhythmic initiation, dynamic reversal, approximation, rhythmic stabilization and replication.

• 대한물리의학회지
• /
• 제3권4호
• /
• pp.255-260
• /
• 2008

Purpose : This study was performed to find out the influence of the change on proprioception and coordination of the lower limb by experimentally induced paraspinal muscle fatigue, Methods : Twelve subjects(6 males, 6 females) with no history low back and lower limbs problem volunteered for this study. Subjects were pre-tested proprioception and coordination using the MR-FSS(Mornitored Rehab Functional Squat System). And then the subjects performed isometric paraspinal muscles contraction for induced muscle fatigue. Muscle fatigue was defined surface EMG(MP 150). After isometric contraction, the subjects were post-tested using the MR-FSS. Results : In comparison of coordination, deviation of concentric coordination was increased(from $0.50{\pm}0.13cm$ to $0.67{\pm}0.21$)(p<0.05) and deviation of eccentric coordination was also increased(from $0.51{\pm}0.15cm$ to $0.70{\pm}0.26cm$)(p<0.05). And deviation movement of proprioceptive test was increased(from $4.98{\pm}1.80cm$ to $5.69{\pm}1.98cm$), but there was no significant different(p>0.05). Conclusion : Fatigue of paraspinal muscles was decreased concentric and eccentric coordination of the lower limb.

• 한국운동역학회지
• /
• 제30권1호
• /
• pp.111-119
• /
• 2020

Objective: The purpose of this study is to apply exercise learning effect to various subjects through training effect and information accumulation based on verification of the effect on dumbbell curl exercises applied with virtual reality. Method: To analyze the effect on the dumbbell curl exercise in the virtual environment, a total of 20 persons with 10 males and 10 females who does not have orthopedics diseases were selected. The dumbbell weight of the subjects was set to a weight of 70% strength of 1RM. At this time, the virtual environment situation was set to four types; presence/absence of virtual environment, preferred colors, and unfavorable colors to perform dumbbell curl exercise. The anaysis of muscle activity was conducted by adhering four surface electrodes (Biceps Brachii, Triceps Brachii, Brachioradialis Muscle, Extensor Carpi Radialis Longus Muscle) on the right upper limbs. Independent sample t-test using SPSS (24.0) program was carried out to analyze average values and standard deviations for each variable depending on the presence/absence of virtual environments and changes in color (preferred colors, unfavorable colors) and the level of significance was set to a=.05. Results: In the eccentric contraction, males showed high muscle activity in the Biceps Brachii under virtual reality. On the other hand, females had high muscle activity in the Biceps Brachii in the absence of virtual reality. Also, in case of a change of colors in the virtual environment, females had the high muscle activity in the unfavorable color in the eccentric contraction. Conclusion: During the dumbbell curl exercise, results of different exercises present depending on gender. When males put VR on and performs a basic dumbbell curl exercise, the effect of Biceps presents Brachii for them while exercising in unfavorable colors. However, since it is the basic research data of muscle exercise using virtual reality, it is necessary to verify whether or not it is effective for myopachynsis through long-term training rather than unity.