• 대한물리치료과학회지
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• 제29권3호
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• pp.21-28
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• 2022

Background: Hamstring shortness results in the inappropriate activation of the quadriceps femoris because of the loss of the reciprocal inhibition mechanism. The purpose of this study was to investigate the effects of that activation during lunge exercises on the vastus medialis, vastus lateralis, medial, and lateral hamstrings in participants with hamstring shortness and normal length. Design: Quasi-experimental design Methods: Participants were divided into a hamstring shortness group(n=20) and a hamstring normal length group(n=23), based on a hamstring length test. During lunge exercises, muscle activation of the vastus lateralis, vastus medialis, medial, and lateral hamstrings were measured by electromyography. Results: Each muscle tested was less activated in the hamstring shortness group than in the hamstring normal length group. However, there was no statistically significant difference between the groups (p>.05). Conclusion: Although there was no significant difference between the shortness and normal hamstring groups during short lunge exercise time, longer exercising periods will result in the inappropriate activation of the quadriceps femoris. During lunge exercise, hamstring shortness causes an imbalance activation of quadriceps femoris and hamstring, and continuous hamstring shortness can cause damage on joints of lower limb.

• 한국전문물리치료학회지
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• 제22권1호
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• pp.1-8
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• 2015

The purpose of this study was to compare the change in electromyography (EMG) activity in the gluteus maximus (G-max) and the gluteus medius (G-med) in subjects with and without chronic ankle instability (CAI) during three functional postures. Twenty four females were recruited for this study. Subjects were assigned into two groups: with CAI ($n_1=12$) and without CAI ($n_2=12$). The assessment postures were rotational squat, one leg stand above a gradient and crossed leg-sway. Electromyographic activities of the G-max and the G-med were recorded using surface EMG and was normalized using the maximal voluntary isometric contraction elicited using a manual muscle testing. Independent t-test was used to determine the statistical differences between two groups during the three functional postures. The comparisons of the three posture between two groups were performed using a one-way repeated analysis of variance. A Bonferroni adjustment used for post hoc analysis. The activation of EMG on G-max performing the one leg stand above a gradient and crossed leg-sway in subjects with CAI is significantly higher than normal group (p<.05). The activation of EMG on the G-max during the rotational squat was significantly increased, compared to those of the one leg stand above a gradient and crossed leg-sway (p<.05). The activation of EMG on G-med performing three exercise at CAI is significantly higher than normal group (p<.05). The activation of EMG on the G-med during the crossed leg-sway was significantly increased, compared to the rotational squat (p<.05). This study provides valuable information for clinician who research CAI.

• 대한물리의학회지
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• 제13권1호
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• pp.129-136
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• 2018

PURPOSE: This Study compared the level of activation of the muscles around the shoulder at the time of abduction through Pilates breathing and regular breathing by using quantified biofeedback. METHODS: Experiment was conducted on 25 healthy males and females in the age bracket of 20's~30's as the subjects. The level of activation of muscles displayed at the time of Pilates breathing were measured at intercostal (InC) muscle, transverse abdominis (TrA) muscle, internal oblique (IO) muscle and external oblique (EO) muscle by using surface electromyogram (EMG) and were provided as biofeedback. Moreover, the changes in the level of muscular activation at sternocleidomastoid (SCM) muscle, upper trapezius (UT) muscle and Deltoid (Del) muscle, which are the muscles around the shoulder, at the time of abduction of shoulder during Pilates breathing and regular breathing were measured. RESULTS: When abduction of shoulder is executed through Pilates breathing, the level of muscular activation of UT muscle was $11.56{\pm}7.10%$ at the time of exhaling of Pilates breathing and $17.54{\pm}9.57%$ at the time of exhaling of regular breathing. Del muscle also displayed lowered level of muscular activation at the time of Pilates breathing with $12.88{\pm}5.80%$ during inhaling and $15.14{\pm}5.49%$ during exhaling. CONCLUSION: In conclusion, the results could be interpreted as indicating that the muscle activities of upper trapezius and deltoid muscle were decreased based on Pilates breathing more than those on regular breathing.

• The Journal of Korean Physical Therapy
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• 제33권1호
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• pp.1-6
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• 2021

Purpose: This study examined the effects of heel insoles on the static balance and leg muscle activity and posture control strategy during external perturbation. Methods: Thirty healthy young men participated in the study. The subjects underwent two experimental conditions: 1) no heel insole condition (0cm) and 2) wearing heel insole condition (5cm). The static balance was measured using an I-Balance device, which measured the change in the center of gravity (COG). The onset time of muscle activation and muscle activation of the erector spinae (ES), hamstring (HAM), gastrocnemius (GCM) were measured using surface EMG electrodes to determine the change in posture control strategy during external perturbation. Results: The speed and distance of COG were significantly higher in the wearing heel insoles condition than the no heel insole condition (p<0.05). In addition, significant differences in the onset time of the GCM, HAM, and ES muscle activation were observed when there was no heel insole condition during external perturbation (p<0.017). On the other hand, no significant differences in the onset time of muscle activation were observed between GCM and HAM when wearing the heel insole condition during external perturbation (p<0.017). Moreover, muscle activation of the GCM was significantly higher in the wearing heel insoles condition than the no heel insole condition during external perturbation (p<0.05). Conclusion: These findings suggest that heel insoles may have disadvantages, and increased efforts are needed to maintain balance and change the posture control strategy during external perturbation.

• The Journal of Korean Physical Therapy
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• 제21권1호
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• pp.65-71
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• 2009

Purpose: Numerous investigators demonstrated that adaptative changes were induced by motor skill acquisition in the central nervous system. We investigated the changes of neuroelectric potential following motor learning with serial reaction time task in young healthy subjects, using electroencephalography (EEG). Methods: Twelve right-handed normal volunteers were recruited, who have no history of neurological dysfunction and were given to written the informed consent. All subjects were assigned to flex to extend the wrist joint or flex the thumb for pressing the matched button as quickly and accurately as possible, when one of five colored lights was displayed on computer screen (red, yellow, green, blue, white). EEG was measured, whenfive types simulations ware presented randomly with equal probabilities of 20% in total 200 times at the pre and post test. And they were scheduled for 30 minutes practice session during two consecutive days in the laboratory. Results: The results showed that the reaction time at the post test was significantly reduced, compared to one of the pre test in serial reaction time task. In EEG map analysis, the broaden bilateral activation tended to be changed to the focused contralateral activation in the frontoparietal area. Conclusion: These findings showed that acquisition of motor skill led to product more fast motor execution, and that motor learning could change cortical activation pattern, from the broaden bilateral activation to the focused contralateral activation. Thus we concluded that the adaptative change was induced by motor learning in healthy subjects.

• 한국운동역학회지
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• 제24권3호
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• pp.287-293
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• 2014

The purpose of this study was to investigate the effects of Hoehn-Yahr scale on the activation of lower-extremity muscles during walking. Electromyography (EMG) analysis was carried out on 36 patients with Parkinson's disease in the off phase of the medication cycle. We recorded EMG signals of the tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SOL), rectus femoris (RF), vastus lateralis (VL), semitendinosus (ST) and biceps femoris (BF) using Noraxon 16 channels EMG system during walking at preferred speed. Rectified EMG signals were normalized to reference voluntary contractions (RVC) over a gait cycle at the preferred speed, allowing for an assessment of how the activity was distributed over the gait cycle. Compared to the H & Y Scale 1, H & Y Scale 3 exhibited greater activation of the vastus lateralis during mid-stance and greater activation of the medial gastrocnemius during terminal swing. Compared to the H & Y Scale 1, H & Y Scale 2 and 3 exhibited less activation of the tibialis anterior during initial swing. We conclude that the more Hoen & Yahr Scale increase, the more abnormal lower-extremity muscles activation.

• 한국전문물리치료학회지
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• 제15권1호
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• pp.46-53
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• 2008

The aim of the present study was to determine the effect of proprioceptive neuromuscular facilitation (PNF) leg patterns on the muscle activation of neck flexors. Twenty healthy subjects participated in this study. Each subject performed bilateral asymmetrical PNF leg patterns against manual resistance under four conditions: through the full range of motion toward the right side, left side, and the end range in the right side, left side. Electromyographic (EMG) data was collected from the sternocleidomastoid (SCM) muscles as neck flexors. The root mean square (RMS) value of the SCM was measured and normalized from maximal EMG activity of the SCM. The data were analyzed using the paired t-test and repeated analysis of variance (ANOV A) was used to compare the statistical significance. The results of this study are summarized as follows: Firstly, the RMS values of SCM were significantly higher in all four PNF leg patterns than in the resting condition (p<.05). Secondly, there was no significant difference in muscle activation according to the direction of PNF leg patterns (p>.05). Thirdly, there was no significant difference in muscle activation according to the point of range of the motion of leg patterns (p>.05). It is suggested that PNF bilateral asymmetrical leg patterns have a considerable effect on muscle activation of the SCM, regardless of the range of motion and direction of PNF bilateral asymmetrical leg patterns.

• PNF and Movement
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• 제14권2호
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• pp.113-120
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• 2016

Purpose: The purpose of this study was to compare the intramuscular activation of the scapular stabilizing muscles and the upper trapezius/middle serratus anterior (UT/MSA) ratios during shrug exercise and proprioceptive neuromuscular facilitation (PNF) scapular pattern exercise. Methods: The participants of this study were 13 young adult men who voluntarily consented to participate in this experiment after listening to its purpose and methods. All participants were instructed on maximal voluntary isometric contraction and scapular exercises. The intramuscular activation of the upper trapezius (UT), lower trapezius (LT), middle serratus anterior (MSA), and lower serratus anterior (LSA) muscles while performing scapular exercises in a side-lying position were measured using surface electromyography. To analyze the muscle activation and UT/MSA ratio between the two exercises, a one-way repeated ANOVA was performed. Post-hoc analyses were conducted using Tukey's multiple comparison and analysis. Hamstring flexibility for each group was measured by a passive straight leg raising test. Results: The shrug exercise showed significantly higher UT activation compared to PNF anterior elevation and posterior elevation scapular patterns. The PNF scapular anterior elevation pattern showed significantly higher serratus anterior activation than the shrug exercise. Additionally, the UT/MSA ratios were significantly lower in the PNF scapular anterior elevation pattern than in the two exercises. Conclusion: Although shrug exercise was effective for strengthening UT, the PNF scapular anterior elevation pattern may be effective for strengthening MSA and improving the UT/MSA ratio.

• 대한물리의학회지
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• 제18권1호
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• pp.1-8
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• 2023

PURPOSE: This study analyzed how proprioceptive neuromuscular facilitation (PNF) combined with auricular acupuncture affected the activation of the leg muscles of stroke patients and measured the effects of this combination to provide clinical data. METHODS: The subjects were divided randomly into experimental group I, which received PNF combined with auricular acupuncture, and experimental group II, which received PNF alone. Each group had ten members. A 30-minute intervention was performed four days a week for six weeks. Before the six weeks of intervention, pre-tests were conducted to measure muscle activation in the legs. After six weeks, post-tests were also conducted to measure muscle activation in the legs. RESULTS: Experimental group I showed a statistically significant difference in muscle rectus femoris, muscle biceps femoris, muscle tibialis anterior, and muscle soleus. Experimental group II also showed a statistically significant difference in the muscle rectus femoris, muscle biceps femoris, muscle tibialis anterior, and muscle soleus (p < .05). In a between-group comparison of the changes, a statistically significant difference was observed between the two groups in terms of muscle rectus femoris, muscle biceps femoris, muscle tibialis anterior, and muscle soleus (p < .05). CONCLUSION: Intervention in experimental group I increased the activation of the leg muscles more effectively because auricular acupuncture was applied to various spots on the ear corresponding to the spleen, liver, kidney, pelvis, knee, ankle, and toe. Auricular acupuncture is expected to be used more widely in the future because it is a safe way of stimulating muscle activation.

• 한국전문물리치료학회지
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• 제26권2호
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• pp.1-7
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• 2019

Background: In previous studies, changes in postural alignment were found when the slope was changed during walking. Downhill walking straightens the trunk by shifting the line of gravity backward. Objects: This study investigated the effect of the downhill treadmill walking exercise (DTWE) on thoracic angle and thoracic erector spinae (TES) activation in subjects with thoracic kyphosis. Methods: A total of 20 subjects with thoracic kyphosis were recruited for this study. All the subjects performed the DTWE for 30 minutes. A surface EMG and 3D motion capture system were used to measure TES activation and thoracic angle before and after the DTWE. Paired t-tests were used to confirm the effect of the DTWE (p<.05). Results: Both the thoracic angle and TES activation had significantly increased after the DTWE compared to the baseline (p<.05). An increase in the thoracic angle indicates a decrease in kyphosis. Conclusion: The DTWE is effective for thoracic kyphosis patients as it decreases their kyphotic posture and increases the TES activation. Future longitudinal studies are required to investigate the long-term effects of the DTWE.