• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.1
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• pp.59-71
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• 2007

The purpose of this study was to study for the change of neural adaptation by muscle contraction force when neuromuscular electrical stimulation(NMES) was applied. Sixteen subjects(8 male, 8 female) without neuromuscular disease volunteered to participate in the study. All subjects were divided into two subgroups: control(no electrical stimulation) group, NMES(50% maximal voluntary isometric contraction) group. NMES training program was performed in the calf muscle over three times a week for 12 weeks. Before and after experiment MVIC of ankle plantar flexor was measured by use of dynamometer. H-reflex and V-wave in tibial nerve were measured. The following results were obtained; MVIC and V/Mmax ratio were significantly increased in the electrical stimulation groups. However, H/Mmax ratio was not changed. It was closely relationship between MVIC and V/Mmax ratio. In this study, the effect of neural adaptation of central neural adaptation was found in this study. Accordingly, NMES means not only a change of muscle fiber and skeletal muscle volume but also a effect of neural adaptation of central neural drive. Also, it was found that there was closely relationship between MVIC and neural adaptation of central neural drive by NMES.

• The Journal of Korean Physical Therapy
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• v.26 no.5
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• pp.280-289
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• 2014

Purpose: This study was conducted in order to determine the stimulation variables which should be considered when neuromuscular electrical stimulation (NMES) is applied for a muscle under the normal innervation to minimize muscle fatigue and increase force-generating ability. Methods: A total of 23 healthy men participated in the study and all subjects were randomly assigned to the 1:1 group, 1:3 group, 1:5 group, and control group with on-off ratio of NMES. The subjects performed a fatigue task, consisting of 10 times of isometric contraction sustained by NMES. NMES using Russian current stimulation was applied to muscle fatigue and divided into three sessions by pulse frequency (10 bps, 30 bps, 90 bps). The EMG was recorded using an MP 100 system from the quadriceps femoris muscle in four groups. Results: The differences of delta MdF and delta MF of between on-off ratio groups of 10 bps, 30 bps, and 90 bps pulse frequencies were very significant (p<0.05). According to the results of post hoc of 10, 90 bps, it was greater in the 1:1 group and the 1:3 group compared with the 1:5 group, and no fatigue was observed in the control group. In 30 bps, it was greater in the 1:1 group compared with 1:3, 1:5, and control group (p<.05). Conclusion: Among NMES variables to minimize muscle fatigue, the larger on-off ratio by pulse frequency showed the lower muscle fatigue. Therefore, on-off ratio needs to be great enough, and will be more efficient with the frequency 30 bps rather than of 10 bps and 90 bps.

• Physical Therapy Korea
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• v.29 no.4
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• pp.269-273
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• 2022

Background: Neuromuscular electrical stimulation (NMES) is used for muscle strengthening. While voluntary muscle contraction follows Henneman et al.'s size principle, the NMES-induced muscle training disrespects the neurophysiology, which may lead to unwanted changes (i.e., declined balance ability). Objects: We examined how the balance was affected by abdominal muscle training with the NMES. Methods: Fifteen young adults (10 males and 5 females) aged between 21 and 30 received abdominal muscle strengthening with NMES for 23 minutes. Before and after the training, participants' balance was measured through one leg standing on a force plate with eyes open or closed. Outcome variables included mean distance (MDIST), root mean square distance (RDIST), total excursion (TOTEX), mean velocity (MVELO), and 95% confidence circle area (AREA) of center of pressure data. Two-way repeated measures analysis of variance was used to test if these outcome variables were associated with time (pre and post) and vision. Results: All outcome variables were not associated with time (p > 0.05). However, all outcome variables were associated with vision (p = 0.0001), and MVELO and TOTEX were 52.4% (45.5 mm/s versus 95.6 mm/s) and 52.4% (364.1 mm versus 764.5 mm) smaller, respectively, in eyes open than eyes closed (F = 55.8, p = 0.0005; F = 55.8, p = 0.0005). Furthermore, there was no interaction between time and vision (F = 0.024, p = 0.877). Conclusion: Despite the different neurophysiology of muscle contraction, abdominal muscle strengthening with NMES did not affect balance.

• Physical Therapy Korea
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• v.29 no.3
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• pp.187-193
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• 2022

Background: Neuromuscular electrical stimulation (NMES) is a physical modality used to activate skeletal muscles for strengthening. While voluntary muscle contraction (VMC) follows the progressive recruitment of motor units in order of size from small to large, NMES-induced muscle contraction occurs in a nonselective and synchronous pattern. Therefore, the outcome of muscle strengthening training using NMES-induced versus voluntary contraction might be different, which might affect balance performance. Objects: We examined how the NMES training affected balance and proprioception. Methods: Forty-four young adults were randomly assigned to NMES and VMC group. All participants performed one-leg standing on a force plate and sat on the Biodex (Biodex R Corp.) to measure balance and ankle proprioception, respectively. All measures were conducted before and after a training session. In NMES group, electric pads were placed on the tibialis anterior, gastrocnemius, and soleus muscles for 20 minutes. In VMC group, co-contraction of the three muscles was conducted. Outcome variables included mean distance, root mean square distance, total excursion, mean velocity, 95% confidence circle area acquired from the center of pressure data, and absolute error of dorsi/plantarflexion. Results: None of outcome variables were associated with group (p > 0.35). However, all but plantarflexion error was associated with time (p < 0.02), and the area and mean velocity were 37.0% and 18.6% lower in post than pre in NMES group, respectively, and 48.9% and 16.7% lower in post than pre in VMC group, respectively. Conclusion: Despite different physiology underlying the NMES-induced versus VMC, both training methods improved balance and ankle joint proprioception.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.3
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• pp.66-71
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• 2006

Some wheelchair users with neuromuscular disorders experience involuntary extensor thrusts, which may cause injuries via impact with the wheelchair, cause the user to slide out of the wheelchair seat, and damage the wheelchair. Knowledge of the human-generated forces during an extensor thrust is of great importance in devising safer, more comfortable wheelchairs. This paper presents an efficient method for identifying human-generated forces during an extensor thrust. We used an inverse dynamic approach with a three-link human body model and a system for measuring human body motion. We developed an experimental system that determines the angular motion of each human body segment and the force at the footrest, which was used to overcome the mathematical indeterminacy of the problem. The proposed method was validated experimentally, illustrating the force-identification process during an extensor thrust.

• PNF and Movement
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• v.5 no.1
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• pp.29-35
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• 2007

Purpose : The purpose of this study was investigated to find the approach in the PNF and TC for frail elder Method : This is a literature study with books, articles, seminal note and books for PNF and TC international course. Result : Neural mechanisms contribute significantly to the gains that occur in the range of motion about a joint with stretching exercises. The participation in a stretch-training program decreases tonic reflex activity and increases flexibility and decreases in force production and muscle activation. Also the stretching-induced decreases may be due to a central nervous system inhibitory mechanism. PNF stretch techniques can increase ROM in older adults. These results may differ from those of studies performed with younger populations because of age-related physiologic changes. TC exercise improves balance control and muscle strength and were associated with reorganized lower extremity neuromuscular patterns. Conclusions : The stretch training program of the PNF and TC contribute to increase the balance and coordination for frail elder. Therefore, The frail elder prevent falling. Further study, The PNF and TC be introduced as the new therapeutic intervention for frail elder.

• PNF and Movement
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• v.20 no.1
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• pp.73-81
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• 2022

Purpose: The aim of this study was to present specific criteria for setting goals for hand rehabilitation by comparing the degree of difference in grip force, coordination, and dexterity between the dominant and non-dominant hand according to gender. Methods: We recruited 100 healthy adults in their 20s and 30s. A handheld digital dynamometer was used to evaluate the grip force of each of the dominant and non-dominant hand, a chopsticks manipulation test was used to evaluate coordination, and the Purdue Pegboard test was used to evaluate agility. Results: In all subjects, the grip force, coordination, and dexterity showed statistically significant difference (p <0.01) between the dominant and non-dominant hand. In the comparison according to gender, both male and female dominant and non-dominant hands showed statistically significant differences in grip force, coordination, and dexterity (p <0.01). In the comparison according to grip force, there was a statistically significant difference between the dominant and non-dominant hand, and men showed stronger result values in both hands compared to women (p <0.01). In the comparison according to coordination, there was no statistically significant difference between the dominant and non-dominant hand in men and women (p >0.05). In the comparison according to dexterity, there was a statistically significant difference between the dominant and non-dominant hand, and women were shown to be faster in performance time with both hands, compared to men (p <0.01). Conclusion: Differences according to gender exist in grip force and dexterity but not coordination, and differences between dominant and non-dominant hand exists across all measurements. The results suggest setting a recovery goal according to dominance and gender during rehabilitation of hand function.

• PNF and Movement
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• v.2 no.1
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• pp.25-33
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• 2004

Purpose : The purpose of this article is to summarize the characteristics of isotonic combination. Method : Some studies of the motor unit activation patterns during isometric, concentric, and eccentric actions, neural strategies in the control of muscle force, and concentric versus combined concentric-eccentric training were reviewed. Results & Conclusions : Eccentric torque may be relatively higher than concentric torque for two potential reasons: 1) stretch responses in the antagonist are not elicited to restrain the motion as can occur concentrically and 2) stretch responses in the agonist may augment eccentric torque production. Concentric-eccentric training has a greater influence on functional capacity than that of concentric training. Both maximal force and average force throughout the motion were significantly higher when the dynamic action was started with preactivation as compared to the mode without preactivation. The peak torques observed during the concentric phase of the eccentric-concentric muscle actions were higher than those noted in the pure concentric contraction.

• PNF and Movement
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• v.8 no.3
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• pp.9-16
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• 2010

Purpose : The purpose of this study was to investigate effects of kinesio taping of thigh muscle on isokinetic muscular function during closed kinetic chain exercise of lower extremity. Methods : Twenty healthy males were participated in this study. The isokinetic muscular function of closed kinetic chain were measured for peak torque, peak torque % body weight, average power, max rep tot work before and after application of kinesio taping on thigh muscles. Results : At $60^{\circ}/s$ peak force and peak force % body weight were significant increased in both extension(p<0.01) and flexion(p<0.001) after applying kinesio taping. At $180^{\circ}/s$ average power was significant increased in both extension and flexion after applying taping(p<0.001). At $240^{\circ}/s$ max rep tot work was significant increased in both extension(p<0.001) and flexion(p<0.05). Conclusion : This study suggests that application of kinesio taping on thigh muscle was more effective to improve isokinetic muscular function in closed kinetic chain exercise of lower extremity.

• PNF and Movement
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• v.7 no.4
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• pp.17-23
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• 2009

Purpose : The objective of this study was conducted to find out treatment of weight bearing joint problems. Method : This is a literature study with books, seminar note and international PNF course books. Result : In joint therapy have to consider that what kind joint mechanics during movement, what kind relation between rotatory component of the force and translatory component of the force, what kind muscles are in the global mobilizer(GM) and local stabilizer(LS). One joint has muscle imbalance between GM and LS. It will make joint surface degenerative change which will make joint pain. Conclusion : Joint therapy is not only joint mobilization but also biomechanics of joint and GM's and LS's role. Total knee of hip joint replacement is not perfect. Before surgery have to be find out problem solving method within the physical medicine.