• Physical Therapy Rehabilitation Science
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• 제11권2호
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• pp.253-258
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• 2022

Objective: This study aimed to determine the effect of internal abdominis pressure(normal, hollowing and bracing) on trunk muscle activity during one leg bridge exercise. Design: Cross-sectional study. Methods: Thirteen healthy adults (9 men and 4 women) were instructed to perform Internal abdominal pressure(IAP) control(Normal, Hollowing, Bracing) during one leg bridge. Electromyography (EMG) data (% Maximum Voluntary Isometric Contraction, MVIC) were recorded three times on both sides of the participant's Internal Oblique(IO), Effector Spinae(ES), and Multifidus(MF) muscles and the average value was analyzed. Results: As a result, Abdominal bracing one leg bridge (BOLB) group and Abdominal hollowing one leg bridge (HOLB) group showed significantly increased muscle activation of bilateral internal oblique, erector spinae and multifidus activation compared to the Normal one leg bridge (NOLB) group (p<0.05). Abdominal hollowing one leg bridge (HOLB) group had a significant difference in bilateral Internal oblique muscle activation in compared to the NOLB group (p<0.05). Conclusions: Bilateral internal oblique, erector spinae, and multifidus muscles activation in healthy adults at one leg bridge exercise showed greater activation at abdominal bracing. Therefore, in this study, IAP control can be used as an indicator of choice to the dysfunction with trunk muscle weakness and corrective exercise subject's situation when the goal is to activate the trunk muscles by performing one leg bridge.

• 한국전문물리치료학회지
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• 제17권2호
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• pp.1-9
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• 2010

To develop effective training methods for strengthening a weakened quadriceps femoris muscle in hemiplegic patients, we examined the effects of maximal isometric contraction of the nonparalyzed knee joint on the electromyographic activities of the paralytic muscle. An electromyogram (EMG) was used to record the electromyographic activities of the paralytic quadriceps femoris muscle in 27 hemiplegic patients. The maximal isometric contraction was measured for each subject to normalize the electromyographic activities. The maximal isometric extension and flexion exercises were randomly conducted when the knee joint angles of the nonparalyzed knees were $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$. The patients were encouraged to maintain maximal isometric contractions in both knee joints during each measurement, and three measurements were taken. A one-minute rest interval was given between each measurement to minimize the effects of muscle fatigue. An average from the three values was taken as being the root mean square of the EMG and was recorded as being the maximal isometric contraction. The electromyographic activity obtained for each measurement was expressed as a percentage of the reference voluntary contraction, which was determined using the values obtained during the maximal isometric contraction. The results of this study are summarized as follows: First, when the knee joint angle of the nonparalyzed knee was $0^{\circ}$, the electromyographic activities of the paralytic medial aspect of rectus femoris were related to measurement by a maximal isometric flexion exercise than by an extension exercise (p<.05). Second, when the knee joint angle of the nonparalyzed knee was $90^{\circ}$, the electromyographic activities of the paralytic lateral aspect of rectus femoris were related to measurement by a maximal isometric flexion exercise than by an extension exercise (p<.05). The results show that myoelectrical activities of paralytic quardriceps were not related to measurement angles and exercise directions of the nonparalized knee joint. Studies on various indirect intervention to improve muscular strength of patients with nervous system disorders of the weakened muscle should be constantly conducted.

• 한국전문물리치료학회지
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• 제21권3호
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• pp.1-10
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• 2014

The aim of this study was to investigate the effect of hip external rotation angle on pelvis and lower limb muscle activity during prone hip extension. Sixteen healthy men were recruited for this study. Each subject performed an abdominal drawing-in maneuver (ADIM) in a prone position, and extended the dominant hip at three different hip external rotation angles ($0^{\circ}$, $20^{\circ}$, $40^{\circ}$) with a $30^{\circ}$ hip joint abduction. Activity of the gluteus maximus (G Max), gluteus medius (G Med), and hamstring (HAM) and the G Max/HAM and G Med/HAM ratios were determined with surface electromyography (EMG). The EMG signal was normalized to 100% maximum voluntary isometric contractions (MVICs) and expressed as %MVIC. Data were analyzed by one-way repeated analysis of variance (alpha level=.05) and the Bonferroni post hoc test. Significant differences in G Max and G Med muscle activity were noted among the three different hip external rotation angles. G Max muscle activity increased significantly at both $40^{\circ}$ (p=.006) and $20^{\circ}$ (p=.010) compared to a $0^{\circ}$ hip external rotation angle. G Med muscle activity increased significantly at $20^{\circ}$ (p=.013) compared to a $40^{\circ}$ hip external rotation angle. The G Max/HAM activity ratio increased significantly at both $40^{\circ}$ (p=.004) and $20^{\circ}$ (p=.014) compared to a $0^{\circ}$ hip external rotation angle. The G Med/HAM activity ratio increased significantly at $20^{\circ}$ (p=.013) compared to a $40^{\circ}$ hip external rotation angle. In conclusion, $40^{\circ}$ and $20^{\circ}$ hip external rotation angles are recommended to increase G Max activity, and $20^{\circ}$ hip external rotation is advocated to enhance G Med muscle activity during prone hip extension with ADIM and $30^{\circ}$ hip abduction in healthy subjects.

• 대한의용생체공학회:의공학회지
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• 제33권2호
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• pp.98-103
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• 2012

The purpose of this study was to compare premotor time(PMT) and electro-mechanical delay(EMD) between sitting and standing posture. Twenty four healthy young subjects(12 women and 12 men) participated in this study. Subjects were instructed to perform maximal, voluntary, isometric contraction of ankle muscle(tibialis anterior and gastrocnemius muscles) in reaction to auditory stimulus. PMT and EMD, calculated from stimulus, EMG and torque profile were compared between sitting and standing postures. As statistical analysis, paired t-test was performed to assess difference between sitting and standing posture. In both tibialis anterior and gastrocnemius muscles, EMD was found to be significantly longer for standing than sitting. However, PMT in standing posture was longer than that in sitting posture only in gastrocnemius muscles. These result indicate that increased reaction time, particularly, increased EMD of ankle muscles in standing posture may be caused by co-contraction of ankle muscles for postural control in standing posture.

• 대한인간공학회지
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• 제31권2호
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• pp.281-289
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• 2012

Objective: The purpose of this study is to evaluate the potential risk of shoulder muscle at particular working postures in sitting. Background: The cause of shoulder pain needs to be specifically studied in relation with particular shoulder postures to prevent shoulder MSDs in workplace. Method: In this study MVC, fatigue and subjective workload were investigated depending on the change of shoulder posture. An experiment was designed to evaluate the six shoulder muscles at nine shoulder postures including the combination of 30(adduction), 0, 30(abduction) degrees and 60, 90, and 120 degrees of shoulder flexion. Surface electrodes were attached to the middle trapezius, inferior middle trapezius, anterior deltoid, posterior deltoid, serratus anterior and teres major. Thirteen subjects participated in the experiment. Dependent variables were RPE (rating of perceived exertion), MVC(maximum voluntary contraction) and MPF(mean power frequency) shift by EMG (electromyography). Results: The middle trapezius and inferior middle trapezius were not significantly fatigued at all postures. The decline of MPF slope was less than 10% at all postures. The anterior deltoid was significantly fatigued all postures. The decline of MPF slope was more than 10% at all postures. The posterior deltoid was significantly fatigued 30 degrees of adduction and 90 degrees of flexion. And, neutral and 30 degrees of abduction postures were fatigued more than 90 degrees of flexion. The serratus anterior was significantly fatigued except for 30 degrees of adduction and 60 degrees of flexion posture. The teres major was significantly fatigued except for neutral and 60 degrees of flexion, 30 degrees of abduction and 60 degrees of flexion posture. Conclusion: It was found that a certain muscle was fatigued fast at particular posture compared to other muscles, which would mean that a certain shoulder muscle at particular posture could be easily exposed to the risk of musculoskeletal disorders than other muscles. Application: It is expected that the result can be applied to design workplace using shoulder muscles.

• 대한물리의학회지
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• 제11권3호
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• pp.65-72
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• 2016

PURPOSE: The purpose of this study is to determine the differences between the muscle activity of cranio-cervical flexion and extension muscles according to the types of tools used through a short-term intervention of cranio-cervical static stabilization exercises using small tools. METHODS: A total of fifteen male and female adults in their 20s who showed forward head posture in the overall body posture measurement system participated in this study. Each subject performed cranio-cervical static stabilization exercises about flexion and extension while using a sling, a foam roller, a TOGU ball, and without tools separately, and the muscle activity of the sternocleidomastoid muscle, scalenus anterior and splenius capitis was measured. Each value was measured for 10 seconds a total of three times. The maximum voluntary isometric contraction value was computed using the average during the middle four seconds. RESULTS: Cranio-cervical flexion exercises using various tool types, the average activity of the sternocleidomastoid and scalenus anterior muscles was significantly higher when applying the TOGU ball (p<.05). According to the results of implementing cranio-cervical flexion exercise using various tools, the maximum muscle activity of the sternocleidomastoid muscle was significantly higher for the TOGU ball (p<.05). CONCLUSION: Based on these results, the provision of an unstable surface using small tools rather than a stable surface is recommended as an exercise scheme for proprioceptive stimulation in a forward head posture. Particularly, we recommend using the TOGU ball for the provision of an unstable surface to increase the muscle activity of the sternocleidomastoid muscle and scalenus anterior.

• 전기학회논문지
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• 제65권4호
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• pp.678-683
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• 2016

The study aim was to investigate a comparison of muscle activity fatigue between maximal and submaximal strength gains during the bench press in men. It was hypothesized that maximal voluntary contraction (%MVC) would similar gains between maximal and submaximal strength gains during the bench press, but median frequency (MDF) would increase in maximal compared with submaximal exercise. Employing a randomized, counterbalanced crossover design, 12 men were asked to perform maximal repetitions and submaximal repetitions (concentric: 1-s, eccentric: 1-s, 2-s/repetition) to failure with a load of 85% of 1RM for the bench press, with a 3-minute recovery between the sets. Each subject was tested for the number of repetitions and sets, total work in bench press. Surface electromyography (EMG) was recorded from the pectoralis major, deltoid anterior, and triceps brachii for %MVC and MDF. Total work was significantly higher in the submaximal repetition exercise than that the maximal repetition exercise (p<.05). Muscle fatigue of pectoralis major, deltoid anterior and triceps brachii were significantly smaller in the submaximnal repetition exercise than that the maximal repetition exercise (p<.05, respectively). However, muscle activity of pectoralis major, deltoid anterior, and triceps brachii were not significantly different between exercises. Our study showed that a smaller muscle fatigue in submaximal repetitions, despite higher in total work and a similar in muscle activity were observed. These results suggest that submaximal repetitions during the bench press would be enhanced intensity and/or volume compared with maximal repetitions exercise.

• 대한통합의학회지
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• 제4권3호
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• pp.17-25
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• 2016

Purpose : This study attempts to examine the effect of the balance exercise on the unstable surfaces for the vital capacity in healthy adults. Methods : A total of 13 subjects was randomly divided into a breathing exercise training group (n=7) and a breathing and balance exercise training group (n=6). Changes in vital capacity and respiratory muscle activity were measured before and after the intervention. The intervention was performed three times a week for four weeks. Forced vital capacity (FVC), forced expiratory volume at one second (FEV1) and maximal voluntary ventilation (MVV) were used as measurement tools for the vital capacity test. Electromyography (EMG) was also used to examine respiratory muscle activity. Result : The breathing exercise training group showed significant improvement in terms of FVC, FEV1 and external oblique (EO), and transverse abdominis/internal oblique (TrA/IO) of MVV. The breathing and balance exercise training group showed significant improvement in terms of FVC, MVV and EO, TrA/IO of FVC and rectus abdominis (RA), EO, and TrA/IO of MVV. However, in comparing changes in vital capacity and respiratory muscle activity before and after the training, the breathing exercise training group and the breathing and balance exercise training group showed a significant difference in terms of MVV. Conclusion : This study is as a preliminary study to find out the relation between a balance exercise and a vital capacity, it is considered to require a further study with several revisions of subjects, duration and time for an intervention.

• PNF and Movement
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• 제15권2호
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• pp.167-176
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• 2017

Purpose: This study investigated the effect of core and abdominal muscle-strengthening exercises on muscle activity in the lower extremity on unexpected perturbation. Methods: Twenty subjects were randomly divided into the core exercise group (n=10) or the abdominal muscles strengthening group (n=10). The two groups performed their exercises during three sessions a week for a total of four weeks. The muscle activity in the lower muscles (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) was assessed using surface electromyography (EMG) and normalized maximal voluntary isometric contraction (MVIC) before and after the exercises. Results: An increase in the tibialis anterior activity after the core and abdominal muscles strengthening exercises was found after four weeks. A significant difference in the pre- and post-exercise was found. The gastrocnemius muscle activity increased in the core exercise group more than the abdominal muscles strengthening group. However, the difference was not significant. Conclusion: The results of this study suggest that the core and abdominal muscles strengthening exercises increased the tibialis anterior muscle activity. It is expected to help make more balance ability that affect who has abdominal muscles weakness.

• 한국전문물리치료학회지
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• 제11권1호
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• pp.19-25
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• 2004

The purpose of this study was to investigate the effects of backrests of varying degrees ($90^{\circ}$, $100^{\circ}$, $110^{\circ}$) on three abdominal muscles (upper rectus abdominis, external oblique, internal oblique) and back extensor activation during lower extremity exercise. The three different conditions during bilateral knee extention exercise were: (1) leaning on a chair with a $90^{\circ}$ backrest, (2) leaning on a chair with a $100^{\circ}$ backrest, (3) leaning on a chair with a $110^{\circ}$ backrest. Fifteen healthy muscle subjects (mean age=24.2 years [SD=2.96], mean height=175.6 cm [SD=7.46], mean weight=69.1 kg [SD=7.36]) with no history of neuromusculoskeletal disease voluntarily participated in this study. Electromyography was used to collect muscle activation, and the muscle activation was expressed as a percentage of maximal voluntary isometric contraction (%MVIC). Repeated one-way analysis of variance (ANOVA) was used to determine the statistical significance. The results were as follows: (1) upper rectus abdominis, external oblique, internal oblique activation measured significantly lower. (2) measured significantly lower when lower degree.