• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.2
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• pp.33-37
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• 2010

Purpose : We investigated the effects of the insole types on lower leg muscle activation during treadmill walking. The three insole types investigated for this study were normal insole, medial wedge insole, and viscoheel. Methods : Participants were assigned into three groups. People with foot transformation were excluded from this study. Each participant walked for ten minutes. The first day we applied a normal insole. On the second day, a medial wedge insole was applied. Finally, on the last day a viscoheel was applied. After walking on a treadmill for ten minutes, we measured muscle activation in lower leg muscles (gastrocnemius and tibialis anterior). Surface electromyography (EMG) was used to measure muscle activity. The data were analyzed using one-way analysis of variance (ANOVA) with repeated measures to determine the statistical significance. Results : The results of this study were summarized as follows. While walking on the treadmill, root mean square (RMS) values of the gastrocnemius when the viscoheel was applied were significantly lower than the other insole types. There was no significant difference for the RMS values for the tibialis anterior using viscoheel. The normal insole and viscoheel insole were significantly different in a post hoc analysis. However, there was no significant difference for normal insole and medial wedge insole. Conclusion : Using a viscoheel insole decreases muscle activity of the lower leg. Therefore, in conclusion, the viscoheel insole type reduces the load on the lower leg during walking.

• Journal of Korean Medicine Rehabilitation
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• v.27 no.2
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• pp.1-8
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• 2017

Objectives Ethanol is a potent inhibitor of muscle protein synthesis. Muscle mass is regulated by the balance between rates of protein synthesis and protein breakdown. Both acute and chronic alcohol consumption inhibits synthesis to a greater extent than degradation. Protein synthesis is more intensely decreased in type II fibers than in type I fibers. Apoptosis has been shown to occur frequently in a variety of tissues in response to chronic alcohol feeding. Increased muscle fiber apoptosis has been shown in alcoholics with myopathy. Pueraria radix has been used for many disorders such as fevers, gastrointestinal disorders, muscle aches, allergies, respiratory problems, skin problems, high blood pressure, migraine headaches, lowering cholesterol and treating chronic alcoholism. We therefore tested the hypothesis that oral treatment with Pueraria radix could reduce the ethanol-induced muscle atrophy. Methods Young male Sprague-Dawley rats were orally given 25% ethanol (5 ml/kg, body weight) daily with Ethanol for 4 weeks. Normal group was similarly administrated with saline. The Rats of Pueraria radix treated group (EtOH+PR) were orally administrated Pueraria radix water extract, and rats of EtOH group were given with the vehicle only. After 4 week, the morphology of gastrocnemius and plantaris muscles were assessed by hematoxylin and eosin staining. The immunoreactivities of pre-apoptotic BAX and anti-apoptotic Bcl-2 proteins were also measured. Results The muscles from rats of EtOH group represented a significant reduction in average cross section area compared to Normal group. EtOH+PR group had increased fiber compared to the EtOH group. Moreover, to investigate the ethanol-induced muscular apoptosis, the immunohistochemical analysis of Bax and Bcl-2 was carried out. The treatment with Pueraria radix (EtOH+PR) significantly decreased BAX expression and increased Bcl-2 expression 4 weeks after ethanol administration when compared with Normal group. Conclusions These results suggest that Pueraria radix water extract has protective effects on chronic alcohol induced myopathy.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.37-43
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• 2018

Objective: The aim of this study was to analyze muscle activation of the lower extremities as a function of changes of the center of pressure (CoP) of the foot during squats in order to provide quantitative information to trainers who would like to teach correct movements for developing muscles. Method: Ten men with over three years of weight training experience participated in this study (age: $26.1{\pm}0.8yrs$, height: $171.2{\pm}3.9cm$, body mass: $71.1{\pm}5.7kg$, 60%RM: $84{\pm}9kg$, career: $4.0{\pm}0.7yrs$). The participants were instructed to perform a squat in each of 3 conditions, with different CoP's (the front, middle, and rear of the foot). Results: The position of the CoP showed significant differences according to instructions in both the eccentric and concentric contraction phases (p < .05). The range of movement of the hip and ankle joints showed significant differences corresponding to changes of the CoP position (p < .05). The rectus femoris and gluteus maximus muscle showed significant differences for different CoP positions only in the concentric contraction phase, while the gastrocnemius and anterior tibialis were significantly different in both the concentric and eccentric contraction phase (p < .05). Conclusion: When the target muscle of squat training is the gastrocnemius, the CoP should be located in the front of the foot for effective muscle training. When the target muscles of squat training are the gluteus maximus and quadriceps femoris, the CoP should be located on the rear of the foot.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.11-21
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• 2007

The purpose of this study was to examine the differences of kinematics and muscle activities depending on the changes of angle approaching balls during backhand drive in squash. The results are as follows. Stride time took the longest at AD2 and step lengths were the biggest at AD1 of left foot contact and right foot contact and AD2 of impact and follow-through. The center of gravity and the speed of racket head were the highest at AD3 and at AD2. Angle of shoulder joint were the biggest at AD1 of left foot contact, right foot contact and impact and AD3 of follow-through. Angle of elbow joint were the biggest at AD3 of left foot contact, right foot contact and follow-through and AD2 of impact. Angle of pelvis joint were the biggest at AD2 of left foot contact, AD1 of right foot contact and AD3 of impact and follow-through. Angle of knee joint were the biggest at AD2 of left foot contact, AD1 of right foot contact and AD3 of impact and follow-through. Angle of ankle joint were the biggest at AD1 of left foot contact and AD3 of right foot contact, impact and follow-through. According to the analysis results of triceps brachii, latissimus dorsi, brachioradialis muscle and flexor carpi ulnaris muscle activities were high at AD1 of all phases. Analysis results of vastus lateralis, vastus medialis, tibialis anterior and gastrocnemius medial muscle activities were high at AD2 of phase1 and phase3. Those of vastus lateralis, vastus medialis and tibialis anterior, gastrocnemius medial were high at AD3 of Phase 2 and AD1 of phase2.

• PNF and Movement
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• v.12 no.4
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• pp.209-215
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• 2014

Purpose: This study aims to understand the effect of balance training on ankle muscle activity and static balance in stroke patients. Methods: The subjects were composed of 12 patients who were admitted with chronic stroke in H, K, and R hospitals located in Gangwon-do from August to October 2014. This study conducted balance training on the subjects for 20 min a session, twice a day, five times a week for six weeks. This study measured the surface electromyogram (EMG) of the paretic side's tibialis anterior and medial gastrocnemius for muscle activity. Static balance was measured as a TETRAX stability index. The measurements were conducted before the experiment and six weeks after. The result was statistically analyzed using paired t-test at the significance level of 0.05. Result: Muscle activity of the paretic side's tibialis anterior and medial gastrocnemius did not show a significant difference in the comparison between pre- and post-balancing training. However, the stability index showed a significant difference (p<0.05) between standing with eyes open (NO) and standing on a sponge with eyes open (PO). Conclusion: Although balance training did not affect the muscle activity of chronic stroke patients, it had an effective influence on the stability index. That is, balance training was effective at the functional level, but it did not change the structure level in terms of the ICF evaluation standard. Balance training becomes more effective when it is applied in relation to task.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.311-319
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• 2020

Objective: The purpose of this study was to examine of this study is to study the effect of squat exercise on muscle activation in a sling device using various types of ropes and to propose an effective sling exercise method for strengthening the lower extremity strength. Method: 20 adult male subjects (age: 25.2±2.4 yrs, height: 176.5±3.2 cm, weight: 77.2±4.5 kg) participated in this study. In the experiment, a total of four squats were conducted: squat [SE], sling squat using inelastic rope [IR], sling squat using elastic rope [ER], and sling squat using two elastic ropes [TER]. Squats were performed 5 times for each condition, and a 60-second break was given for each condition to minimize muscle fatigue. The activation of biceps brachii, rectus femoris, gastrocnemius, and tibialis anterior muscles was measured. Results: It was found that the activation of all muscles was the lowest during the squat exercise [SE]. During the sling squat using inelastic rope [IR], the muscle activation of the biceps brachii was the highest. During the sling squat using elastic rope [ER], the activation of the rectus femoris, gastrocnemius, and tibialis anterior muscles was found to be the highest. In the sling squat using two elastic ropes [TER], most of the muscle activation was similar to that of the sling squat using inelastic rope [IR]. Conclusion: Our results of the experiment, it was found that sling squat exercise using elastic rope had a positive effect on the activation of all muscles. It is thought that performing a squat exercise under moderate weight load and unstable conditions, such as sling squat exercise using elastic rope, can increase the muscle activity of the lower limbs and perform more effective exercise effect than performing a conventional squat exercise under stable conditions. In the future, if research is conducted not only on adult men, but also on various ages and patients, it will be able to provide positive help in improving balance, stability and stamina through squat exercise.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.31-36
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• 2022

Objective: The purpose of this study was to investigate muscle activation according to the four strap lengths in the TRX plank exercise to provide scientific and accurate data on effective training methods. Method: Twenty healthy men who had at least 6 months of weight training experience and could fully adjusted plank exercise, were participate in this study (age: 25.2 ± 3.7 yrs., height: 174.2 ± 3.9 cm., weight: 71.2 ± 9 kg). To pursue the study purpose, surface electrodes were attached to trunk muscles (pectoralis major, rectus abdominis, external oblique, internal oblique, erector spinae, latissimus dorsi) and lower extramity muscles (gluteus maximus, rectus femoris, gastrocnemius), and the muscle activity was measured using 11-channel electromyography equipment. In order to verify the muscle activation according to the four strap lengths during TRX plank exercise, an one-way ANOVA with repeated measure was used with statistical significance level set at as α=.05. Results: First, there were statistically significant differences in pectoralis major, rectus abdominis, external oblique, internal oblique, and erector spinae among TRX strap lengths. Second, there were statistically significant differences in gluteus maximus, rectus femoris, and gastrocnemius among TRX strap lengths. Third, even though no statistically significant difference found in latissimus dorsi, but increased muscle activation tendency was showed as the length of the strap increased. Conclusion: From the results of this study, it may be possible that TRX exercise prevent injuries and improve lower extremity muscle as well as trunk muscles by setting appropriate length of strap.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.4
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• pp.497-503
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• 2013

PURPOSE: The purpose of this study was to investigate the change of triceps surae activation during heel raise test in standing among knee flexion angles($0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$). METHODS: Twenty healthy individuals performed unilateral plantarflexion in standing with $0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$ knee flexion. Activity of medial gastrocnemius(MG), lateral gastrocnemius(LG), soleus(Sol) was recorded with surface electromyography(EMG). RESULT: The muscle activations induced the four different positions were compared and results showed that was significant difference MG and LG while the angle increase from $0^{\circ}C$ to $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$ but Sol did not show significant differences in every angle. CONCLUSION: This study suggest that $30^{\circ}C$ knee flexion is required to induce a significant mechanical disadvantage of gastrocnemius.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4459-4466
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• 2011

The purpose of this study was to compare the lower extremity muscle activities according to the different longitudinal arch and treadmill inclination and to provide basic data on treadmill walking exercise. The selected 17 subjects who had not lower extremity injury and ROM limitation were recruited in this study. The longitudinal arch was divided into normal foot and flat foot. The inclinations of the treadmill were $0^{\circ}$, up hill $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, down hill $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$. The electromyography was used to analyze the muscle activity of rectus femoris, biceps femoris, tibialis anterior, gastrocnemius lateralis and medialis. There were significant differences between the inclination $0^{\circ}$ and down hill $15^{\circ}$. There was no interactive effect of treadmill inclination on the longitudinal arch. The activity difference of lower extremity muscle was not conspicious. There existed the interactive effect between the longitudinal arch and muscle activity. The contrast test within subjects showed positively in the rectus femoris and gastrocnemius medialis, biceps femoris and gastrocnemius medialis. The different longitudinal arch did not influence on the effect(p>.05). There was significant difference between the normal foot and the flat foot. So it is necessary to carry out the long term study.

• The Journal of Korean Physical Therapy
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• v.21 no.1
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• pp.35-40
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• 2009

Purpose: The purpose of this study was to investigate change of muscle activities during level walking, stairs and ramp climbing in old adults. Methods: Twelve old adults were recruited and agreed this study. Muscle activity was measured by MP150 system (BIOPAC System Inc., Santa Barbara, USA). Statistical analysis was used one-way ANOVA to know the difference according to gait conditions (level walking, stairs and ramp ascending) Results: In stance phase, muscle activities of low extremities with old adults were generally significant difference in ramp ascending. In swing phase, rectus femoris and biceps femoris activity in old adults generally more increased during stairs ascending and tibialis anterior and gastrocnemius activity in old adults generally increased during ramp ascending. Conclusion: These results indicate that stair and ramp climbing is different muscle recruit pattern to level walking.