Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. However, during exercise, excessive activation of the posterior deltoid compared to the infraspinatus causes the humeral head to move anteriorly in an abnormal position. Many researchers have emphasized selective activation of the infraspinatus during shoulder external rotation exercise. Objects: This study aims to delineate the optimal exercise method for selective activation of infraspinatus by investigating the muscle activities of the infraspinatus and posterior deltoid according to the four shoulder exercise methods and two forearm positions. Methods: Thirty healthy individuals participated in this study. The participants were instructed to perform shoulder external rotation exercises following four exercise methods: sitting external rotation (SIER); standing external rotation at 90° abduction (STER); prone external rotation at 90° abduction (PRER); side-lying external rotation (SLER), and two forearm positions (neutral, supinated). The electromyography (EMG) signal amplitude was measured during each exercise. Surface EMG signals were recorded from the posterior deltoid, infraspinatus, and biceps brachii. Results: EMG results of the infraspinatus and posterior deltoid in PRER, were significantly higher than that of the other exercises (p < 0.01). The EMG ratio (infraspinatus/posterior deltoid) in SIER was significantly higher than that of the other exercises. EMG activation of the posterior deltoid in SIER, PRER, and SLER was significantly higher in neutral than in supinated (p < 0.01). Furthermore, the EMG of the infraspinatus in SIER was significantly higher in neutral than in supinated (p < 0.01). The EMG ratio (infraspinatus/ posterior deltoid) in SIER was significantly higher in neutral than in supinated (p < 0.05.) Contrarily EMG ratios in PRER and SLER were significantly higher in supinated than in neutral (p < 0.05). Conclusion: The results show that clinicians should consider these exercise methods and forearm positions when planning shoulder external rotation exercises for optimal shoulder rehabilitation.

The purpose of this study was to investigate the effect of the two different types of chairs on trapezius muscle activation during dictation tasks. Seventeen university students, each of whom were within standard deviation of the mean Korean standard body size, voluntarily participated in this study. Surface electromyography was used to collect electrical signals from both the upper and lower trapezius muscles. Amplitude Probability Distribution Function (APDF) was performed to analyze the muscle activity. The findings of this study were 1) The backrest-point height of the auditorium chair and the height, length and width of the connected desk were shorter than what was suggested by the KS. Another difference was that the auditorium chair had a bigger angle of the backrest compared to the classroom chair. 2) Regarding within-subject effect the sole statistically significant difference was found between activation of the upper trapezius muscle. The upper trapezius muscle's %RVC in the APDF 10th-50th-90th percentile was statistically higher for participants sitting in the auditorium chair than for participants sitting in the classroom chair (p<.05). 3) There was an interaction effect between the 'two chair-types' and the 'two muscle-sides' in the APDF 10th-50th percentile (p<.05). 4) There was an interaction effect between the 'two chair-types' and the 'three gaze-direction' in the APDF 90th percentile (p<.05). The findings of this study indicated that maintaining a writing posture for a prolonged period of time in an auditorium chair significantly increased the left upper trapezius muscle activation compared to a classroom chair.

큰고랭이(Scirpus tabernaemontani)와 세모고랭이(Scirpus triqueter)는 외떡잎식물 벼목 사초과의 여러해살이풀로서 한국·일본·중국 동북부·사할린·유럽등지에서 자라며 연못이나 호수의 얕은 물속에서 무리 지어 자란다. 석창포(Acorus gramineus)는 외떡잎식물 천남성목 천남성과의 여러해살이풀로서 산지나 들판의 냇가에서 자란다. 속새목 속새과의 속새(Equisetum hyemale)는 습진곳을 좋아한다. 이들 수생식물들은 수질정화에도 큰 역할을 수행하고 있다. 최근 웰빙바람을 타고 실내공기정화의기능과 습도조절의 기능을 가진 식물에 대한 관심이 증가됨에 따라 이러한 역할을 수행할 수 있는 식물자원의 수집이 필요하다. 이에 본 실험은 실내 도입가능성이 높은 큰고랭이외 3종 식물들의 양액처리에 따른 생육차이를 알아보았다. 공시식물은 2007년 12월 마사토에 식재하여 20℃에서 생육시켰으며, 양액은 Hyponex 1000배액을 담수상태가 되도록 처리하였다. 식재 후 15일 간격으로 3개월간 생육조사를 하였다. 큰고랭이의 초장은 45일 후 약 30cm 증가하였으며, 양액처리 효과는 뚜렷하지 않았고, 줄기수와 뿌리수 역시 처리간 차이를 보이지 않았다. 세모고랭이, 석창포, 속새 역시 처리간 생육 차이를 보이지 않았으며 앞으로 양액농도 처리에 대한 효과를 조사, 비교할 예정이다.