The purpose of this study was to compare the change in electromyography (EMG) activity in the gluteus maximus (G-max) and the gluteus medius (G-med) in subjects with and without chronic ankle instability (CAI) during three functional postures. Twenty four females were recruited for this study. Subjects were assigned into two groups: with CAI (n1=12) and without CAI (n2=12). The assessment postures were rotational squat, one leg stand above a gradient and crossed leg-sway. Electromyographic activities of the G-max and the G-med were recorded using surface EMG and was normalized using the maximal voluntary isometric contraction elicited using a manual muscle testing. Independent t-test was used to determine the statistical differences between two groups during the three functional postures. The comparisons of the three posture between two groups were performed using a one-way repeated analysis of variance. A Bonferroni adjustment used for post hoc analysis. The activation of EMG on G-max performing the one leg stand above a gradient and crossed leg-sway in subjects with CAI is significantly higher than normal group (p<.05). The activation of EMG on the G-max during the rotational squat was significantly increased, compared to those of the one leg stand above a gradient and crossed leg-sway (p<.05). The activation of EMG on G-med performing three exercise at CAI is significantly higher than normal group (p<.05). The activation of EMG on the G-med during the crossed leg-sway was significantly increased, compared to the rotational squat (p<.05). This study provides valuable information for clinician who research CAI.

The purpose of this study was to determine the effects of warm-up and cool-down exercises on pain and muscle activation of delayed onset muscle soreness after intense exercise. Delayed onset muscle soreness was caused by the eccentric exercise in the elbow flexor muscle of the non-dominant upper limb. Forty-four subjects volunteered to participate in this study and were randomly assigned to one of the following groups: warm-up and cool-down group, only warm-up group, only cool-down group, or control group with no intervention. The level of perceived pain using the visual analogue scale and electromyographic activation change in maximal voluntary isometric contraction were measured 4 times at the following times: 10 min, 24 hr, 48 hr, and 72 hr after the exercise. The results revealed the main effect between the groups and interaction effect between the group and measurement session (p<.05). The warm-up and cool-down group showed most favorable results with respect to reduced perceived pain level and increased muscle strength in most measurement sessions, and the only warm-up group showed significantly more decreased pain level than the control group at 24 hr and 48 hr and more increased muscle activation than the cool-down group at 48 hr (p<.05). However, there were no significant differences in pain level and muscle activation between the only cool-down group and control group at all measurement sessions (p>.05). The findings suggest that the warm-up exercise performed before an intense exercise had beneficial effects on the symptoms of delayed onset muscle soreness, whereas cool-down exercise performed after the intense exercise did not.

목적 : 본 연구는 머리 각도에 따른 목뿔위근육의 활성 정도를 확인하여 임상에서 삼킴 기능 증진을 위한 치료적 적용시 목뿔위근육들이 보다 활성화 되는 자세를 확인하고 이를 치료에 적용하기 위하여 시행되었다. 연구 방법 : 대전광역시 OO대학교에 재학중인 학생들을 대상으로 실험참가 대상자들을 모집하여, 지원자 중 무작위로 39명의 학생(남 24명, 여 15명)들을 선정하여 실험을 진행하였다. 프랑크포트 수평면이 지면과 수평이 되는 각도를 기준으로 머리각도 중립 자세(head flexion 0°)를 설정하였으며, 방사선 촬영을 통하여 머리각도 15°하방, 머리각도 15°상방 상태를 확인한 후, 각각의 상태(머리 중립 0°, 머리 굴곡 15°, 머리 신전 15°)에서 3회씩(1회 삼킴 후 10초 휴식) 마른 삼킴과 젖은 삼킴을 시도하였다. 결과 : 마른 삼킴과 젖은 삼킴 모두에서 중립시보다 머리 각도를 15°굴곡하였을 경우 목뿔위근육들이 보다 활성화되는 것을 알 수 있었다. 이에 반하여 머리 각도를 15°신전하여 삼킴을 시도하였을 경우에는 통계적으로 유의할만한 결과를 보이지 않았다. 결론 : 머리를 굴곡시킨 자세에서 삼킴을 유도하는 것이 좀더 목뿔위근육을 활성화시키고 목뿔의 가동성을 높여, 보다 안전한 식이를 위한 방법으로 제안될 수 있을 것이다.

This study is performed to investigate the difference of the spinal stability system with and without low back pain. There were 9 participants with low back pain and 9 asymptomatic subjects to be recruited, they were measured thoracic and lumbar curvature, trunk muscle activation in upright sitting postures and slump sitting, back muscle endurance, and lumbar proprioception. Spinal curvature and surface electromyography of 4 trunk muscles were measured in an upright sitting postures and slump sitting in 18 subjects. The result of the study was that there were significant differences between the groups in spinal curvature (p<.05), significantly higher external oblique activity and less internal oblique in the low back pain group than the healthy subjects (p<.05), and significantly less proprioception in the low back pain group (p<.05). But there was not a significant difference between the trunk muscle endurance groups. According to the result, the low back pain group had greater thoracic extension and higher global muscle activity in the upright sitting posture and less proprioception. This study was useful to suggest postural training for normal muscle activation, selective muscle strengthening to prevent chronic deterioration, and helpful in making a treatment plan to indicate a synthetic care method that includes increasing proprioception.

The aim of the present study was to determine the effect of proprioceptive neuromuscular facilitation (PNF) leg patterns on the muscle activation of neck flexors. Twenty healthy subjects participated in this study. Each subject performed bilateral asymmetrical PNF leg patterns against manual resistance under four conditions: through the full range of motion toward the right side, left side, and the end range in the right side, left side. Electromyographic (EMG) data was collected from the sternocleidomastoid (SCM) muscles as neck flexors. The root mean square (RMS) value of the SCM was measured and normalized from maximal EMG activity of the SCM. The data were analyzed using the paired t-test and repeated analysis of variance (ANOV A) was used to compare the statistical significance. The results of this study are summarized as follows: Firstly, the RMS values of SCM were significantly higher in all four PNF leg patterns than in the resting condition (p<.05). Secondly, there was no significant difference in muscle activation according to the direction of PNF leg patterns (p>.05). Thirdly, there was no significant difference in muscle activation according to the point of range of the motion of leg patterns (p>.05). It is suggested that PNF bilateral asymmetrical leg patterns have a considerable effect on muscle activation of the SCM, regardless of the range of motion and direction of PNF bilateral asymmetrical leg patterns.

This study was designed to determine the effects of different widths in the base of support (BOS) on trunk and lower extremity muscle activation during upper extremity exercise. Twenty-seven healthy male subjects volunteered for this study. Exercises were performed for a total of 10 trials with a load of 10 repetitions maximum (10 RM) for each of the various widths of BOS (10 cm, 32 cm, 45 cm). The width of a BOS is the distance between each medial malleoli when a subject was in a comfortable standing position. Electromyography was used to determine muscle activation. Surface bipolar electrodes were applied over the tibialis anterior, medial gastrocnemius, biceps femoris, rectus femoris, gluteus maximus, upper rectus abdominis, and elector spinae muscle. Electromyographic (EMG) root mean square (RMS) signal intensity was normalized to 5 seconds of EMG obtained with a maximal voluntary isometric contraction (MVIC). The data were analyzed by atwo-factor analysis of variance (ANOVA) with repeated-measures () and Bonferroni post hoc test. The results were as follows: (1) There were significant differences in the width of the BOS (p=.006). (2) The post hoc test showed significant differences with the BOS between 10 cm and 32 cm, between 10 cm and 45 cm and between 32 cm and 35 cm (p=.008, p=.003, p=.011). (3) There was no interaction with the BOS and muscle. (p=.438) There were no significant differences in the muscle activation (p=.215).

본 연구는 슬관전 신전 직전에 수행된 선행 슬관절 굴곡이 슬관절 신전근의 최대 근력발생 및 근육 활성도(activation)에 미치는 영향을 알아보기 위하여 실시되었다. 16명의 정상인이 Cybex II 등속운동기구에서 3가지 다른 운동 속도(, , )와 2가지 다른 근육 활성 조건(선행부하가 없는 조건과 선행부하 조건)에서 슬관절의 최대 신전을 수행하였다. 연구대상자들에게 선행부하 없는 조건에서는 슬관절 굴곡 상태에서 까지 최대 신전을 수행하도록 하였

목적: 본 연구의 목적은 의식적인 체간 근육의 동시 활성화(co-activation) 조건과 1RM(repetition max)의 50%, 65%, 80%의 부하 수준에서 바벨 백 스쿼트(barbell back squat)를 수행하였을 때, 척추 분절의 자유도의 변화 양상을 관찰하는 것이다. 방법: 이를 위하여 본인 체중의 1.8∼2배 이상으로 바벨 백 스쿼트를 수행할 수 있는 4명의 연구 참여자들에게 실험 조건에 따른 운동학적 자료를 수집한 뒤 주성분 분석(principal component analysis)을 사용하여 척추의 자유도를 정량화하였다. 결과: 전체 분산의 95% 이상을 설명할 수 있는 주성분의 개수(5개)를 기준으로 백 스쿼트의 하강 구간에서 의식적인 활성에 따라 통계적으로 유의미한 차이를 보였으며 상승 구간에서는 부하 조건에 따라 유의미한 차이를 보였다. 결론: 백 스쿼트의 하강 구간 동안 의식적인 체간 근육의 동시 활성화에 의해 척추 분절의 자유도가 제한될 수 있으며 상승 구간에서는 부하 수준에 따라 차이가 발생할 수 있다.

The electrical muscle stimulator (EMS) based human machine interface (HMI) free to mechanical constraint and muscle fatigue problems are proposed for force feedback in a virtual reality. The device was designed to provide force feedback up to 4.8 N and 2.6 N each to the thumb and forefingers. The main objective of the HMI is to make unnecessary mechanical structures to attach on the hand or fingers. It employs custom EMSs and an interface arranged in the forearm. In this work, major muscle groups such as extensor pollicis brevis (EPB), extensor indicis proprius (EIP), flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) are selected for efficient force feedback and controlled individually. For this, a human muscular-skeletal analysis was performed and verified. The validity of the proposed multi-channel EMS based HMI was evaluated thorough various experiments with ten human subjects, interacting with a virtual environment.