• PNF and Movement
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• v.22 no.2
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• pp.243-255
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• 2024

Purpose: Although foot muscle imbalance has been confirmed in patients with hallux valgus deformity, there is insufficient information on how corrective taping affects muscle activity and contraction rate of the foot muscles. The purpose of this study was to confirm the effectiveness of Mulligan taping as a treatment method for hallux valgus deformity by examining changes in muscle activity and contraction rate when Mulligan taping with inelastic tape was applied to these patients. Methods: Thirty-two patients with hallux valgus deformity were randomly divided into two groups, experimental and control. In the experimental group, Mulligan taping with inelastic tape was applied to correct the hallux valgus angle of the big toe, and in the control group, placebo taping was performed in which inelastic tape was applied in a straight line without modifying the angle of the big toe. Muscle activity and muscle contraction rate were measured before and after the intervention, and changes were compared and analyzed. Results: In the experimental group where Mulligan taping was applied, the muscle activity and muscle contraction rate of the abductor hallucis muscle significantly increased after the intervention (P < 0.05). On the other hand, the muscle activity and muscle contraction rate of the adductor hallucis muscle and tibialis posterior muscle significantly decreased (P < 0.05). There was no significant difference in muscle activity and muscle contraction rate in the control group, where placebo taping was applied (P > 0.05). Conclusion: Mulligan taping significantly changed muscle activity and contraction rates compared to placebo taping. By correcting the position of the big toe, the activity and contraction rate of the abductor hallucis muscle increased, while the activity and contraction rate of the adductor hallucis muscle and tibialis posterior muscle decreased. Therefore, Mulligan taping is considered an intervention that can prevent symptom worsening and enhance foot function by improving muscle imbalance in patients with hallux valgus deformity.

• PNF and Movement
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• v.1 no.1
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• pp.19-25
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• 2003

Objectives: The purpose of this article is to summarize the effect of stretch stimulus on muscle contraction facilitation. Methods : Some studies of the stretch reflex. ${\gamma}-motor$ system, and the effect of stretch stimulus on muscle activation were reviewed. Results : To facilitate muscle contraction, before the movement is started, the prime mover is in stretched position. The patient must be instructed to occur voluntary muscle contraction after quick stretching. It elicits the functional stretch reflex to produce a more powerful and functional contraction. The intensity of muscle contraction depends on two ways. One is firing rate of ${\alpha}-motor$ neuron by sensory information from the periphery induced in stretched position and stretch reflex. The other is excitation level of the cortical motor area and the corresponding motor neurons. Conclusions: To activate central nervous system and to increase firing rate of ${\alpha}-motor$ neuron. the therapist should apply quick stretch for the patient with stretched position and the patient should make voluntary muscle contraction.

• The Korean Journal of Physiology
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• v.1 no.1
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• pp.67-72
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• 1967

Present paper is attempted to introduce the phenomenon of 'after contraction' in isolated cardiac-muscle. Papillary muscles were removed from cat right ventricle and were used as a preparation. The muscle strip was Placed in tissue bath which is kept in steady temperature of around $25^{\circ}C$ and was perfuced by Tyrode solution, saturated with 95% $O_2$ and 5% $CO_2.$ under the condition of high calcium (8.2-10.0 mM/l), low sodium (72.4-70.0 mM/l) perfusion with the administration of epinephrine (1-2 mg/l) into tile tissue bath normally triggered muscle contraction was followed by oscillatory, repetitive contractions - after contraction. The phenomenon of after contraction was augumented by decrease in tissue bath temperature and by increase in number of preceding beats and in driving rate. Authors were able to maintain the phenomenon in prominent and steady state giving proper experimental conditions such as fixed bath temperature (ranged from $22^{\circ}C\;to\;27^{\circ}C$), suitable driving rate (20 per minute in average) and perfusion of high calcium, loll sodium and 1-2 mg/l of epinephrine. In some preparations, the strength of after contraction (second contraction) reached up-to 80% of normally triggered contraction and five repetitive contractions were observed as largest number of after contractions. Intracellular action potential measured in the muscle which was beating regulary showing steady after contraction revealed no oscillating after potential in most parts of the muscle but in few cases oscillating changes of after potentials were detectable. In electrogram of the muscle preparation recorded by means of contact electrode prominent, oscillating after potentials were observable when the recorder was set at highest sensitivity. It still is not clear that whether after contraction is the phenomenon which corresponds to those changes in action potential, oscillating after potential, of the muscle preparation. Possible mechanism of the phenomenon of after contraction relating with after potential changes was proposed. Detailed results obtained from further studies on after contraction and concrete discussion on the phenomenon will be reported by authors.

• Physical Therapy Korea
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• v.11 no.3
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• pp.85-90
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• 2004

The purpose of this study was to find the difference in muscle firing rate between each muscle according to the knee angle with the quadriceps femoris which is a representative action muscle of the lower extremity. Seven normal healthy subjects were recruited. The median frequency (MDF) of muscle contraction was recorded from vastus lateralis, vastus medialis, and rectus femoris muscles using the surface EMG, in 5 seconds, during maximal isometric knee extension. The data were analyzed by the two-way repeated ANOVA. The results of the study were as follows: 1) median frequency of muscle contraction was significantly higher at the vastus lateralis, vastus medialis, and rectus femoris in descending order. 2) median frequency of muscle contraction was significantly higher at the $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ in descending order. Consequently, muscle recruitment at the knee decreases the EMG activity of the lengthened muscle. This study suggests that the change in EMG activity at different muscle lengths resulted in affecting the muscle firing rate during the knee extension.

• Journal of International Academy of Physical Therapy Research
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• v.3 no.2
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• pp.422-428
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• 2012

The present study purposed to examine the effects of transcutaneous electrical nerve stimulation, self-stretching and functional massage on the recovery of muscle contraction force for muscle fatigue caused by sustained isotonic contraction. The subjects of this study were 45 healthy students. They were divided into transcutaneous electrical nerve stimulation group(n=15), self-stretching group(n=15) and functional massage group(n=15), and using Primus RS. We observed the pattern of changes in maximal voluntary isometric contraction force(MVIC) after causing muscle fatigue in quadriceps femoris muscle through sustained isotonic contraction. Maximal voluntary isometric contraction force(MVIC) were greatly increased after transcutaneous electrical nerve stimulation, self-stretching and functional massage. In the comparison of recovery rate of muscle contraction force for muscle fatigue caused by sustained isotonic contraction among the treatment groups, it did not show any significant differences. However, it showed that each treatment may be effective in recovery of muscle fatigue caused by sustained isotonic contraction.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.269-281
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• 1995

To study the characteristics of EMG power spectrum of masticatory muscles during sustained isometric contraction and recovery at various contraction times, the author analysed the EMG signals of anterior temporal and masseter muscles before, during, and after sustained isometric contraction at 50% level of maximum voluntary contraction (MVC) for 15,30,60 seconds. Twelve normal subjects were included in this study. The author came to following conclusions from the results. 1. MMF of anterior temporal muscle in the contraction period was significantly higher than that of masseter muscle during sustained isometric contraction regardless of isometric contraction times (p<0.05). 2. MMF in the contraction period decreased as the contraction time increased during sustained isometric contraction in both temporal and masseter muscles(p<0.05). 3. SMF in the contraction period increased as the contraction tie increased during sustained isometric contraction in both temporal and masseter muscles(p<0.01). 4. MMF in the first part of recovery period (20 seconds) decreased as the contraction time increased during sustained isometric contraction(p<0.05). However, MMF in the later parts of recovery period (20-120 seconds) showed no significant differences. 5. MMF of anterior temporl muscle in the recovery period was significantly higher than that of masseter muscle after sustained isometric contraction regardless of isometric contraction times (p<0.05). 6. The recovery rate of MF reached 100% in 100 seconds after the isometric contraction regardless of isometric contraction times.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.1046-1053
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• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1497-1505
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• 2010

The present study was performed to investigate the effect of aging on muscular activity of older subjects under the condition of fixed load muscle contraction. SEMG signals were recorded from old (46 women) and young (45 women) groups performing sustained isometric elbow flexion contraction with a fixed load during 30 seconds. Linear regression and mean square error (MSE) analysis with four characteristic variables (ARV, RMS, MDF, MNF) were used to compare the age-related difference (of local muscle fatigue and fluctuation of the amplitude and frequency) in the SEMG signal. The main results can be summarized as follows: During sustained muscle contraction with a fixed load: i) the MSE values of amplitude (ARV, RMS) and frequency (MDF, MNF) variables were more than 30% higher for the young than for the old adults; ii) the measures of local muscle fatigue (slope of the MDF and MNF) indicated greater fatigue in the old; and iii) the rate of increase of the SEMG amplitude was higher for the young than the old.

• Women's Health Nursing
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• v.10 no.3
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• pp.244-251
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• 2004

Purposes: This study was to examine the effects of postpartum exercise on pressure of the pelvic muscle contraction, body composition and physical fitness of postpartum mothers. Method: A nonequivalent pre-test, post-test control group study was conducted. Fifty-two postpartum mothers(experimental group, 26; control group, 26) admitted to a postpartum ward in a Busan mother-baby clinic were recruited. Data was analyzed using mean, $x^2$-test, and t-test by SPSS 10.0. Result: Body fat mass(t=-3.196. p= .002), body fat rate (t=-3.831, p= .000), and fat distribution(t=-3.026, p= .004) of body composition increased significantly in the experimental group after the postpartum exercise as compared with the control group. After an 8 week exercise program, the pressure of the pelvic muscle contraction in the experimental group was significantly higher than in the control group(t=3.329, p=.002). In the change of physical fitness, grip strength of the hand, back muscle strength, and trunk flexion forward were not significantly changed, but trunk backward extension in the experimental group significantly increased(t=1.950, p=.050). Conclusion: Postpartum exercise affects pelvic muscle contraction, body composition, and physical fitness of the postpartum mother.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.139-146
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• 2016

PURPOSE: The purpose of this study was to determine the effect of craniocervical flexion exercise with masticatory muscle contraction in patients with neck pain. Patients with neck pain also experience muscle weakness and limitation of activities of daily living. Craniocervical flexion exercise with masticatory muscle contraction may increase the thickness of the deep cervical flexor muscles, thereby reducing pain and limitations on activities of daily living. METHODS: Twenty-six volunteers participated in this study. The subjects were randomly divided into an experimental group (n=13) and a control group (n=13). Both groups performed craniocervical flexion exercise using a pressure biofeedback unit; the experimental group performed craniocervical flexion exercise with masticatory muscle contraction for 20 minutes, 3 times a week for 4 weeks. Assessment tools included ultrasonography for measurement of muscle thickness and the Neck Disability Index for the level of pain and function. RESULTS: The rate of change in muscle thickness in both groups significantly increased (p<.05), with a significantly greater increase in the experimental group than in the control group (p<.05). The Neck Disability Index score significantly improved (p<.05) in both groups, with significantly greater improvement in the experimental group compared with the control group (p<.05). CONCLUSION: These results suggest that craniocervical flexion exercise with masticatory muscle contraction can be effective in increasing muscle thickness and improving the Neck Disability Index score in patients with neck pain.