• Physical Therapy Rehabilitation Science
• /
• v.13 no.3
• /
• pp.304-314
• /
• 2024

Objective: This study aimed to investigate the association of explosive strength with muscle mass and muscle function measured using traditional methods such as peak torque (PT) and joint angular velocity (PAV). Design: Cross-sectional study Methods: Twenty-nine healthy adults (14 males and 15 females) participated in this study. Body mass index and appendicular skeletal muscle index (ASMI) were measured using bioelectrical impedance analysis. The explosive strength of the knee extensors was evaluated by measuring the rate of torque development (RTD) and rate of velocity development (RVD). RTD was analyzed by dividing it into early (0-50 ms) and late (100-200 ms) muscle contraction phases. In addition, PT and PAV were measured as traditional methods for assessing muscle function. Results: According to regression analysis, PAV accounts for 24.7% and 66.9% of the variance of RTD 0-50 (p=0.006) and RVD (p<0.001), respectively. On the other hand, ASMI (p=0.035) and isometric PT (p=0.001) explained 49.2% of the RTD 100-200. Conclusions: Early RTD is mainly predicted by PAV, which is thought to be a result of muscle fiber type. Therefore, PAV presents the possibility of an alternative method to evaluate explosive performance. Late RTD seems to be related to ASMI or isometric PT. The findings of this study are expected to contribute to musculoskeletal rehabilitation and evaluation in that they revealed factors contributing to early and late muscle contraction.

• Journal of the Korean Society of Physical Medicine
• /
• v.10 no.1
• /
• pp.71-82
• /
• 2015

PURPOSE: The aim of this study is to compare changes in the thickness of the gluteus medius muscle fiber between chronic low back pain(clbp) with gluteus medius weakness and healthy subject. METHODS: Ultrasound imaging was used to measure in the thickness of each fiber of the gluteus medius muscle based on maximal muscle contraction during abduction motion of the hip joint in a healthy group (11 subjects) and a chronic CLBP group (21 subjects). An independent t-test was performed to analyze the difference of thickness in each fiber of the gluteus medius muscle and the rate of changes in the fibers in the two groups. RESULTS: The fiber thickness changes in the gluteus medius muscle were significantly lower for the posterior fiber in the CLBP group compared to the healthy group (p<0.01). The changes in rate of difference of thickness the posterior part of the gluteus medius muscle was significantly lower in the CLBP group than in the healthy group (p<0.05). CONCLUSION: The findings of this study CLBP patients with weakness of the gluteus medius muscle that lower for the posterior fiber's difference of thickness and rate of change in the CLBP group compared to the healthy group. Indicate that rehabilitation of CLBP patients with weakness of the gluteus medius muscle should consider the functions of posterior fiber of the gluteus medius muscle.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.2 no.2
• /
• pp.1-12
• /
• 2004

The purpose of this study was to determine the effect of muscle fatigue by neuromuscular electrical stimulation(NMES). Using Biodex System 3PRO(Biodex Medical Systems Inc, USA), experiment was conducted as to the normal group(I) composed of fifteen adults and the patient group(II) composed of fifteen patients with spastic hemiplegia. As to each group, maximal tolerated intensity(MTI) and maximal tolerated isometric contraction(MTIC) in electric currents yielded by low rate(20 pps) and high rate(100 pps) neuromuscular electrical stimulation and the aspects of decrease and restoration of the isometric contraction were examined, and their strength decrement index(SDI) and strength recovery index(SRI) were also calculated. 1. As for MTI in NMES, the MTI of the group II was higher than that of the group I in both low rate and high rate NMES. In comparison within group, MTI of group II was significantly higher in high rate NMES rather than in low rate NMES(p<0.05). 2. In comparison of MTIC between groups, the group I showed higher in both low rate and high rate NMES. In comparison within group, MTIC of group II was significantly higher in high rate NMES rather than in low rate NMES(p<0.01). 3. As for SDI, both groups showed highest SDI in high rate NMES, but no significant differences could be observed. 4. As for SRI, both groups showed significantly low SRI in low rate NMES(p<0.01, p<0.05), and comparison between groups showed no significant differences could be observed. These result lead us to the conclusion that muscle fatigue was influenced by frequency, high rate NMES was lower at SDI and higher at SRI on compare to low rate NMES, therefor, a further studies concerning electrical stimulation should consider differences each frequency in response to treatment.

• Archives of Pharmacal Research
• /
• v.10 no.2
• /
• pp.80-87
• /
• 1987

To get a better insight into the exxistence and the role of a Na-Ca exchange mechanism in smooth muscle, the effect of Na substitution with sucrose on tension development, cellular Ca uptake and $^{45}Ca$ efflux was investigated using isolated cat ileal longitudinal muscle strips. Experimental results were summarized as follows;1) Exposure of the cat ileal longitudinal muscle to Na-free solution induced a contraction, and the magnitude of the contraction increased after incubation of the muscle strips with ouabain ($2{\times10^{-}5}$M) for 1hr. 2) Cellular Ca uptake in Na-free solution increased with an increase in Na content of the Na-loading media, and a linear relationship existed between tissue Na content and cellular Ca uptake for 10 min 3) After tissues were equilibrated in PSS containing $^{45}Ca$ for 2hr, cellular Ca uptake decreased with rising the external Na concentration. 4)Removal of medium Na or inhibition of the Na-K pump decreased the rate of $^{45}Ca$ efflux. These results strongly suggested that Na substitution increases cellular Ca uptake and decreases the rate of $^{45}Ca$ efflux via a Na-Ca exchange mechanism.

• The Journal of Korean Medicine
• /
• v.23 no.1
• /
• pp.100-111
• /
• 2002

Objectives : In order to obtain the clinical type of facial palsy sequelae and try to make the treatment protocols for each, I observed patients who visited Gunpo-Wonkwang oriental medicine center with Bell’s palsy sequelae that were treated over three months. Methods : I make the value standard of muscle paralysis, contraction, synkinesis and acquired the results as follows. Results and Conclusions : 1. The distribution of age and sex was as follows : females of 41-50 years were the most common demographic, females of 51-60 years and males of 31-40 years were the second, males of 51-60 years were the third, females of 21-30 years and males of over 60 years were the fourth, and males of 41-50 years were the fifth. 2. The distributions of period of disease were as follows : 3-6 months was the most, 12-18 months was the second, 6-12 months and over 24 months was the third, and 18-24 months was the fourth. 3. The sequelae distributions of disease were as follows. In the group of 3-6 months, 12 persons (80%) showed palsy and atrophy, 10 persons (66.6%) showed synkinetics. In the group of over 6 months, all patients showed muscle palsy, muscle atrophy and synkinetics. All groups showed lower sensitivity of muscles, but the group of 18-24 months and the group of over 24 months showed more. Tinnitus was shown by the groups of 12-18 months and 3-6 months. Facial muscle pain was shown by the group of3-6 months only, Crocodile's tear was shown by the groups of 18-24 months and over 24 months. 4. The total palsy rates of sequela patients and palsy rates by muscle for disease period were as follows. The total palsy rate was 27.94%; the palsy rates for the group of 6-12 months and the group of over 24 months was lower than the total palsy rate. The rates of the groups of 3-6, 12-18, 18-24 months were higher than the total palsy rate. The palsy rate of zygomatic minor, levator labii superior muscle was higher than the total palsy rate for all groups. 5. Synkinetics manifestation rates by disease period were as follows. Total synkinetics manifestation rate was 73.81 %; the manifestation rate of the group of 6-12 months was lower than total synkinetics manifestation rate. For the groups of 12-18, 18-24, and over 24 months it was more than the total synkinetics manifestation rate. The group of over 24 months, total synkinetics induced by orbicularis oculi muscle and orbicularis oris muscle. 6. Facial muscle atrophy rates by disease period were as follows. Total atrophy rate was 5.26%; in the groups of 6-12, 18-24, over 24 months, the atrophy rates were higher than the total atrophy rate. The groups of 3-6 and 12-18 months showed lower than the total atrophy rates, while the atrophy of the levator palpebrae superioris muscle and levator palpebrae inferioris muscle was higher than in other groups.

• The Korean Journal of Physiology
• /
• v.23 no.1
• /
• pp.99-108
• /
• 1989

The effects of prostaglandin $(PGF_{2{\alpha}})$ on the contractility of vascular smooth muscle were investigated in the helical strip of the rabbit aorta. The aortic strip was immersed in the phosphate-buffered Tyrode's solution which was equilibrated with 100% $O_{2}$ at $35^{\circ}C$ and its isometric tension was measured. The contraction was induced by $(PGF_{2{\alpha}})$, norepinephrine (NE), or potassium (40 mM) in the nomal Tyrode's solution (1 mM, $Ca^{2+}$) or $Ca^{2+}-free$ Tyrode's solution. Effects of verapamil and phentolamine on the contraction were also observed. The aortic strip began to contract at the concentration of $5\;{\mu}g%$ and reached the maximal contraction at the concentration of $150\;{\mu}g%$ $(PGF_{2{\alpha}})$. The maximal contraction was corresponded respectively to $52.2{\pm}3.0%$ and $81.5{\pm}3.5%$ of maximal contraction by NE $(1{\times}10^{-5}M)$ and 40 mM $K^{+}$. And the maximal contractions by $(PGF_{2{\alpha}})$ or NE were induced at the concentration of about 1 mM $Ca^{2+}$. $(PGF_{2{\alpha}})$ induced the contraction of aortic strip even after induction of contraction by 40 mM $K^{+}$ and the contraction by $(PGF_{2{\alpha}})$ was not blocked by the ${\alpha}-receptor$ blocker, phentolamine. And the contraction by the $(PGF_{2{\alpha}})$ was inhibited partially by a verapamil at the concentration of $1{\times}10^{-5}M$ and the contraction began to increase at the concentration of $1{\times}10^{-4}M$ verapamil. Whereas the contraction by NE was completely blocked by verapamil. Though both the $(PGF_{2{\alpha}})$ and NE induced the contraction in the $Ca^{2+}-free$ Tyrode's solution, the peak tension was not maintained. But the rate of tension decline was lower in the contraction by $(PGF_{2{\alpha}})$ than in that by NE. The verapamil did not inhibit the contraction by $(PGF_{2{\alpha}})$ in the $Ca^{2+}-free$ Tyrode's solution and increased the contraction at the concentration of above $1{\times}10^{-4}M$. The NE-induced contraction in the $Ca^{2+}-free$ Tyrode's solution was inhibited completely by a verapamil. From the above results it is suggested that the contraction induced by $(PGF_{2{\alpha}})$ results from the promotion of the both $Ca^{2+}$ influx and the intracellular $Ca^{2+}$ release by different way from NE.

• The Korean Journal of Pharmacology
• /
• v.12 no.1
• /
• pp.45-55
• /
• 1976

The effect of positive inotropic agents on the contractile properties of myocardial muscle were studied in the cat papillary muscle preparation. For the purpose, the effects of ouabain $(1{\times}10^{-6}g/ml)$, norepinephrine (0.05r/m1) and Aconiti tuber butanol fraction (AF(5), $1{\times}10^{-4}$, $5{\times}10^{-4}$, $1{\times}10^{-3}$, $2{\times}10^{-3}g/ml$) on the contractile dynamics of the papillary muscle preparation isolated from right ventricle of cat were observed in terms of the characteristics of isometric twitch and the lengh-tension relation, the force-velocity relation and the load-extension relation of the series elastic component of contractile model of A.V. Hill. All the studied inotropic drugs similary increased the rate and the intensity of the developed isometric tension, while shortened the time from onset of contraction to peak tension and the total duration of contraction. In the afterloaded simultaneous isotonic and isometric contraction, they also similary increased the maximal velocity of shortening accompanied with the increasing the maximum developed force. In the load-extension relation all the drugs, however, had no appreciable influence on the properties of the series elastic component. Increasing the concentration, Aconiti tuber butanol fraction produced more pronounced effect on all the studied parameters of isometric and isotonic contraction of cat papillary muscle preparation. From the aspect of contractile dynamics, it seemed that the positive inotropic effect of ouabain, norepinephrine and Aconiti tuber butanol fraction are similary achieved through an influence on the behavior of the contractile component only.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.2 no.3
• /
• pp.25-35
• /
• 2004

The purpose of this study was compared to MTICs(maximal tolerated isometric contraction), decrement and recovery. For this, using isokinetic exercise analysis device(Biodex Medical Systems Inc., Biodex System 3PRO, USA), low rate(20 Hz) and high rate(100 Hz) NMES(neuromuscular electrical stimulation) were applied to the quadriceps muscles of fifteen patients with spastic hemiplegia caused by lesions in the central nervous system. The results were as follows: 1. It was shown to fast decrement in the middle of phase at low rate NMES and to slow decrement of MTIC response at high rate NMES(p<.01). 2. It was shown to fast recovery at high rate NMES and to slow recovery at low rate NMES in recovery tendency of MTIC(p<.01). These conclusions suggest that NMES of high rate caused to slow fatigue and fast recovery different from low rate NMES.

• Physical Therapy Korea
• /
• v.1 no.1
• /
• pp.75-82
• /
• 1994

The purpose of this study is to determine cardiovascular reponses to concentric, eccentric and isometric exercise applied to the knee extensor muscle group. Exercise types studied were concentric, eccentric and isometric. The subjects were sixty healthy male volunteers who had no hypertension or cardiac disease. Heart rate, systolic and diastolic blood pressure were recorded prior to starting exercise. The subjects also performed 10RM on right lower extremity. A N-K table was used for three exercises to right knee extensors. Each exercise was selected randomly and applied to each subject 10 times in a 10 second. After each exercise, heart rate, systolic and diastolic blood pressure were recorded immediately. Findings were as follows concectric contractions had a greater effect on the increase of systolic blood pressure and heart rate than eccentric or isometric contractions. Diastolic blood pressure is influenced only by isometric contractions. Eccentric contractions have less effect on the increase of systolic blood pressure and heart rate than concentric or isometric contractions. We hope that the results of this experiment can be adapted to exercise programs for patients with cardiac disease.

• Journal of the Ergonomics Society of Korea
• /
• v.14 no.1
• /
• pp.9-23
• /
• 1995

The objectives of the study were twofole: (1) to investigate effects of rhythmic contraction and sustained contraction methods on recovery rate of isometric endurance capacity and (2) to compare aptterns of muscle recruitment of both arms observed during each contraction period. In the experiment, each of two subjects performed five successive rhythmic or sustained isometric contractions at 50% MVC with both arms to the point of fatigue, which was the failure to maintain the required tension. In making the contractions, the subjects stood erect with upper arms held at an angle of approximately 90 .deg. to the forearm. The interval between the successive contractions was kept constant at 3, 7, 20, or 40 minutes. Regardless of the contraction methods, the recovery rate was least at the shortest interval and was highest at the longest interval. However, a statistical analysis showed that the recovery rates for the rhythmic contractions were significantly lower than those for the sustained contractions throughout 4 different intervals. Furthermore, as the frequency of the rhythmic contractions per min, increased 4 to 6 times, the recovery rate of isometric endurance capacity decreased. From an EMG anglysis, recruitment pattern of the muscules of both arms was found to be common between two different contraction methods. The biceps muxcles of the upper arms played a major role in exerting 50% MVC, while the brachioradialis muscles of the forearms acted as synergists. As the contraction proceeded, the role of the biceps muscles as a prime mover lessened due to the fatigue. Then, the brachioradialis muscles exerted more strength to sustain 50% MVC. The implications of these finding were discussed.