• The Journal of Korean Physical Therapy
• /
• 제18권1호
• /
• pp.53-64
• /
• 2006

Purpose: The present study purposed to examine the effects of massage and stretching on the recovery of muscle contraction force for muscle fatigue caused by sustained isometric contraction. Methods: The subjects of this study Were 64 healthy men and women (women: 30, men: 34). They Were divided into massage group (23), stretching group (21) and rest group (20), and using Biodex System we observed the pattern of changes in maximal voluntary contraction force (MVC) after causing muscle fatigue in quadriceps femoris muscle through sustained isometric contraction. Results: We measured the point of fatigue occurrence by sustained isometric contraction with 50% MVC and changes in isometric contraction force at 0, 10, 20 and 30 minutes after fatigue and compared them according to gender and treatment group. Conclusion: 1. According to the result of measuring the point of time when fatigue occurred, a difference was observed in time to task failure between men and women. It was significantly longer in women. 2. By gender, MVC changed significantly in all time frames in women, but it showed significant increases only at 10 minutes after fatigue in men. 3. In the comparison of MVC among the treatment groups, it showed significant differences among the groups at 10 minutes after fatigue. 4. In the comparison of changes in MVC among the time frames for each group, the rest group showed significant differences in MVC between 0 and 10 minutes after fatigue and between 20 and 30 minutes after fatigue. The massage group showed significant differences in MVC between 0 and 10 minutes after fatigue and between 10 and 20 minutes after fatigue. The stretching group showed a significant difference in MVC between 10 and 20 minutes after fatigue and between 20 and 30 minutes after fatigue.

• 대한물리의학회지
• /
• 제1권1호
• /
• pp.59-66
• /
• 2006

Purpose : The purpose of this study was to investigate the effects of diaphragmatic breathing on activation of lumbar paraspinal muscles of normal healthy people. Diaphragmatic breathing may affect activation of trunk muscles. The assumptions are as follows: the crural diaphragm attatches to the lumbar vertebrae from L1 to L3, the voluntary downward pressurization of the diaphragm increases intra-abdominal pressure, and this increases the stiffness of the spine. Methods : Sixty male college students ranging 19 to 34 years were screened and % maximal voluntary contraction(% MVC) of trunk muscles on the four positions of back extension exercise was compared during the pre and post of inspiration of diaphragmatic breathing. Results : 1. % MVC of right and left erector spinae had the statistically significant difference between pre and post inspiration of diaphragmatic breathing in the dynamic right arm and left leg extension position(p<0.05). 2. % MVC of right and left erector spinae had the statistically significant difference between pre and post inspiration of diaphragmatic breathing in the dynamic left arm and right leg extension position(p<0.05). 3. % MVC of right and left erector spinae had the statistically significant difference between pre and post inspiration of diaphragmatic breathing in the static lying prone extension position(p<0.05). 4. % MVC of right and left erector spinae had the statistically significant difference between pre and post inspiration of diaphragmatic breathing in the static lying on prone position(p<0.05). Conclusion : This study will be used as the purpose of data collection of lumbar paraspinal muscles on diaphragmatic breathing and be introduced as the new therapeutic intervention for management of patients with back pain.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
• /
• pp.394-398
• /
• 1994

The aim of the present study was to determine the influence of vibration frequency and muscle contraction level at constant vibration displacement amplitudes on a commonly observed motor response elicited by local vibratory stimulation, i.e., the Tonic Vibration Reflex (TVR). Vibration was applied to the distal tendons of the hand flexor muscles. Changes in activity of the hand flexor and extensor muscles were analyzed as a function of the vibration frequency (40-200 Hz), displacement amplitude(200.mu.m and 300.mu.m peak-to-peak), and the initial contraction level of the flexor muscles (0%, 10%, and 20% of the maximal voluntary contraction: MVC). The main results indicate that the TVR increases with vibration frequency up to 100-150 Hz and decreases beyond, and the TVR attains its maximum at 10% MVC. It appears that high frequency vibration tends to induce less muscle/tendon stress. Such a result is of particular importance for the design of handheld vibrating tools.

• 한국운동역학회지
• /
• 제15권3호
• /
• pp.51-59
• /
• 2005

To examine the influence of aging on the mechanism of muscle fatigue, we compared the magnitude of central and peripheral fatigue in young and old women before, during and after a sustained submaximaI isometric contraction of elbow flexor muscles. Twelve women (6 young. $20.7{\pm}1.2$ years and 6 old, $68.8{\pm}29$ years) performed a contraction at 20% of maximal voluntary contraction (MVC) torque with their non-dominant arm. The old women were weaker than the young women, however their endurance time for the 20% contraction was longer compared with the young women ($1822{\pm}444$ vs. $1061{\pm}678$ sec, P <. 05). Both groups had a similar reduction in voluntary activation ratio (VA) during and after the fatiguing contraction. However, the old women showed much greater variability in VA before and after the contraction ($91.61{\pm}4.54%$ and $76.70{\pm}19.55\;%$ range of $79{\sim}99$ to $87{\sim}99%$ respectively) compared with the young women ($95.71{\pm}1.86\;%$ and $83.46{\pm}7.57\;%$ range of $39{\sim}75$ to $69{\sim}90%$, respectively). Furthermore, the EMG activity of the elbow flexor muscles and triceps brachii was greater for the old women compared with the young women throughout the fatiguing contraction, indicating different activation strategies with age. Indices of peripheral fatigue including twitch properties, showed that fatigue within the muscle was more rapid for the young women compared with the old women. These results suggest that although old women are weaker than young women, they have greater endurance due to mechanisms within muscle. Furthermore, old women showed great variability in their ability to optimally activate all muscle fiber compared with young women for an isometric contraction.

• The Journal of Korean Physical Therapy
• /
• 제17권3호
• /
• pp.311-327
• /
• 2005

The purpose of this study was to investigate the effects of diaphragmatic breathing on activation of trunk muscles of patients with low back pain. Diaphragmatic breathing may affect activation of trunk muscles. The assumptions are as follows: the crural diaphragm attatches to the lumbar vertebrae from L1 to L3, the voluntary downward pressurization of the diaphragm increases intra-abdominal pressure, and this increases the stiffness of the spine. Diaphragmatic breathing increases intra-abdominal pressure and the increased intra-abdominal pressure may contribute to the lumbar stability. Sixty patients with low back pain were randomly divided into two groups. Experimental group performed diaphragmatic breathing exercise with six breathing positions and control group performed only the breathing positions for five times per week during six weeks. % maximal voluntary contraction(% MVC) of trunk muscles on six breathing positions of experimental and control group was measured according to testing period of pre test, three weeks, and six weeks. The repeated measures of one-way ANOVA were used to analyze % MVC on trunk muscles of experimental and control group according to testing period. The results of this study were as follows: First, % MVC of right and left erector spinae in the right leg extension position indicated the statistically significant difference in experimental group which performed diaphragmatic breathing exercise rather than control group (p<0.05). Second, % MVC of right and left erector spinae in all-four positions indicated the statistically significant difference in experimental group which performed diaphragmatic breathing exercise rather than control group (p<0.05). Third, % MVC of right and left erector spinae, external oblique in the sitting position indicated the statistically significant difference in experimental group which performed diaphragmatic breathing exercise rather than control group (p<0.05). Fourth, % MVC of right and left erector spinae, external oblique in the standing position indicated the statistically significant difference in experimental group which performed diaphragmatic breathing exercise rather than control group (p<0.05). Fifth, % MVC of right and left erector spinae, external oblique in the supine position indicated the statistically significant difference in experimental group which performed diaphragmatic breathing exercise rather than control group (p<0.05). Sixth, % MVC of right and left erector spinae, external oblique in the lying on prone position indicated the statistically significant difference in experimental group which performed diaphragmatic breathing exercise rather than control group (p<0.05). In conclusion, as experimental group performed diaphragmatic breathing exercise according to the period of pre-test, post three weeks, and post six weeks, experimental group showed the greater significant effect on the activation of right, left erector spinae, and external oblique muscle. Diaphragmatic breathing exercise which resulted in activation of trunk muscles can be effective for managing the patients with back pain and should be utilized as the new therapeutic intervention.

• 운동영양학회지
• /
• 제23권1호
• /
• pp.48-54
• /
• 2019

[Purpose] The combined effect of different types of post-exercise treatment has not been fully explored. We investigated the effect of combined cold water immersion (CWI) and compression garment (CG) use after maximal eccentric exercise on maximal muscle strength, indirect muscle damage markers in the blood, muscle thickness, and muscle soreness score 24 h after exercise. [Methods] Ten men performed two trials (CWI + CG and CON) in random order. In the CWI + CG trial, the subjects performed 15 min of CWI (15℃), followed by wearing of a lower-body CG for 24 h after exercise. In the CON trial, there was no post-exercise treatment. The exercise consisted of 6 × 10 maximal isokinetic (60°·s^-1) eccentric knee extensions using one lower limb. The maximal voluntary contraction (MVC) and maximal isokinetic (60°·s^-1) strength during knee extension, as well as the indirect muscle damage markers, were evaluated before exercise and 24 h after exercise. [Results] The maximal muscle strength decreased in both trials (p < 0.001), with no difference between them. The exercise-induced elevation in the myoglobin concentration tended to be lower in the CWI + CG trial than in the CON trial (p = 0.060). The difference in the MVC, maximal isokinetic strength, muscle thickness, and muscle soreness score between the trials was not significant. [Conclusion] CWI followed by wearing of a CG after maximal eccentric exercise tended to attenuate the exercise-induced elevation of indirect muscle damage markers in the blood.

• 대한의용생체공학회:의공학회지
• /
• 제32권4호
• /
• pp.328-335
• /
• 2011

For human factor engineering and wearable robot design, the quantitative assessment of physical workload is needed. Through measuring the surface EMG (sEMG) and analysis, the physical workload in overhead lifting posture is presented in quantitative manner. By normalizing sEMG activities with maximal voluntary contraction (MVC), the inter-subject variability is reduced. In all muscles, %MVC increased as the weight of lifting object increases. In anterior deltoid muscle, the %MVC was 3-4 times higher than the other muscles which imply that this muscle performs the major role in the overhead lifting posture. In fatigue analysis, %MVC and the mean frequency in muscle of anterior deltoid changed markedly when compared with other muscles. Through the suggested procedures and analysis, the physical workload for a specific posture can be represented in quantitative way but the clinical meaning for the value should be investigated further.

• 대한산업공학회지
• /
• 제25권3호
• /
• pp.330-335
• /
• 1999

The goal of the study is to determine the most sensitive parameter to represent the degree of muscle force and fatigue. Various numerical parameters such as the first coefficient of Autoregressive (AR) Model, Root Mean Square (RMS), Zero Crossing Rate (ZCR), Mean Power Frequency (MPF), Median Frequency (MF) were tested in this study. Ten healthy male subjects participated in the experiment. They were asked to extend their trunk by using the right and left erector spinae muscles during a sustained isometric contraction for twenty seconds. The force levels were 15%, 30%, 45%, 60%, and 75% of Maximal Voluntary Contraction (MVC), and the order of trials was randomized. The results showed that RMS was the best parameter to measure the force level of the muscle, and that the first coefficient of AR model was relatively sensitive parameter for the fatigue measurement at less than 60% MVC condition. At the 75% MVC, however, both MPF and the first coefficient of AR Model showed the best performance in quantification of muscle fatigue. Therefore, the sensitivity of measurement can be improved by properly selecting the parameter based upon the level of force during a sustained isometric condition.

• 한국정보통신학회논문지
• /
• 제14권10호
• /
• pp.2317-2323
• /
• 2010

근경직으로 인한 질병을 판단하기 위한 새로운 비침습적 초음파 근경직도 측정 시스템을 검증하기 위해 근경직 발생시 근전도의 변화를 분석하였다. 근경직 유발을 위해 하지 대퇴직근에서 등척성 운동을 실시하였다. 실험 프로토콜에 따라 실험을 반복 실시하였다. 이때 바이오시스템3를 이용하여 무릎관절토크의 크기 및 토크를 실시간으로 측정하였다. 또한 대퇴직근에서 근전도 측정 시스템으로 근전도를 측정하였다. 피검자는 실험 프로토콜에 따라 최초 무릎관절 토크의 최대수의적 등척성수축(MVC : maximal voluntary contraction)을 측정하고,. MVC의 50%에서 -5%로 떨어질때까지 등척성 운동을 지속하였다. 근경직 유발시 근전도 신호를 신호처리 과정을 거쳐 중앙주파수변동과 실효값 변화로 나타내었으며, 이러한 결과가 근경직도 측정 시스템의 결과와 유의함을 보였다.

• 대한인간공학회지
• /
• 제35권5호
• /
• pp.361-370
• /
• 2016

Objective:The aim of this study is to evaluate contributions of individual finger forces associated with various levels of submaximal voluntary contraction tasks. Background: Although many researches for individual finger force have been conducted, most of the studies mainly focus on the maximal voluntary contraction. However, Information concerning individual finger forces during submaximal voluntary contraction is also very important for developing biomechanical models and for designing hand tools, work equipment, hand prostheses and robotic hands. Due to these reasons, studies on the contribution of individual finger force in submaximal grip force exertions should be fully considered. Method: A total of 60 healthy adults without any musculoskeletal disorders in the upper arms participated in this study. The young group (mean: 23.7 yrs) consisted of 30 healthy adults (15 males and 15 females), and the elderly group (mean: 75.2 yrs) was also composed of 30 participants (15 males and 15 females). A multi-Finger Force Measurement (MFFM) System developed by Kim and Kong (2008) was applied in order to measure total grip strength and individual finger forces. The participants were asked to exert a grip force attempting to minimize the difference between the target force and their exerted force for eight different target forces (5, 15, 25, 35, 45, 55, 65, and 75% MVCs). These target forces based on the maximum voluntary contraction, which were obtained from each participant, were randomly assigned in this study. Results: The contributions of middle and ring fingers to the total grip force represented an increasing trend as the target force level increased. On the other hand, the contributions of index and little fingers showed a decreasing trend as the target force level increased. In particular, Index finger exerted the largest contribution to the total grip force, followed by middle, ring and little fingers in the case of the smallest target force level (5% MVC), whereas middle finger showed the largest contribution, followed by ring, index and little fingers at the largest target force levels (65 and 75% MVCs). Conclusion: Each individual finger showed a different contribution pattern to the grip force exertion. As the target force level increase from 5 to 75% MVC, the contributions of middle and ring fingers showed an increasing trend, whereas the contributions of index and little fingers represented a decreasing trend in this study. Application: The results of this study can be useful information when designing robotic hands, hand tools and work equipment. Such information would be also useful when abnormal hand functions are evaluated.