• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.152-160
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• 2021

The purpose of this study was to investigate the difference in the number of repetitions and the change in electromyographic response during the maximum speed squat exercise according to the depth conditions and the maximum speed squat exercise according to the time of each depth. Ten men in their 20s were selected as subjects and the maximum speed squat was performed for one minute in three environmental conditions (ground, knee depth, waist depth). We found that the number of repetitions according to the depth of water showed a significant difference, and as a result of the post-mortem comparison, the number of repetitions was higher in the ground condition and the knee depth than in the waist depth. And the muscle activity of rectus abdominis, erector spinae, rectus femoris, biceps femoris was increased during ground squat exercise, activity of all muscle was decreased during knee depth squat exercise, and activity of rectus abdominis, erector spinae, biceps femoris, tibialis anterior, gastrocnemius was decreased during waist depth squat. In conclusion, muscle activity of lower extremities during squat exercise in underwater environment can be lowered as the depth of water is deep due to buoyancy, but muscle activity of trunk muscles can be increased rather due to the effect of viscosity and drag.

• Physical Therapy Rehabilitation Science
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• v.6 no.1
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• pp.33-38
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• 2017

Objective: This study tried to examine the muscle activity of the neck and trunk according to head posture changes during use of laptops. Design: Cross-sectional study. Methods: This study included nineteen young men and women. All subjects maintained each posture while practice typing on laptops for ten minutes with a 5-minute break between each posture. For the neutral head posture, the subjects practiced typing while pulling their chins down towards the Adam's apple and were able to look at their knees while having their external auditory meatus, acromion, and greater trochanter vertical to the ground. For the natural head posture, they practiced typing while balancing their posture between extension and flexion of the cervical vertebrae by themselves without any guidelines. While a forward head posture was created by having their heads face the front horizontal to the rope hanging from the ceiling, they practiced typing with their external auditory meatus located in the place which was 5 cm in front of the vertical plane. The subjects used general word process but practiced typing with accuracy and high speed. Muscle activities were randomly measured using surface electromyography according to each postures. Results: The research result had found that muscle activity with the natural head posture was more significantly reduced than that of the forward head posture in the sternocleidomastoid muscle, upper trapezius, cervical vertebral spinae, and thoracic vertebrae spinae muscles (p<0.05) and that the neutral head posture was more significantly reduced than that of forward head posture in the upper trapezius, cervical vertebral spinae, and thoracic vertebrae spinae muscle activity (p<0.05) with significant increases in lumbar spinae muscle activity (p<0.05). Also, muscle activity with the neutral head posture significantly increased more in the sternocleidomastoid muscle and lumbar spinae than that of the natural posture (p<0.05). Conclusions: Our study results suggest that in order to prevent musculoskeletal pain, the neutral head posture with use of laptops is effective in reducing load to the shoulders and vitalizing the postural muscles.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.421-428
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• 2012

The purpose of this study was to verify the effects of developed assisting wear which maximize trunk(back) muscle's stretch-shortening effect during backswing and downswing for increasing golf ball carrying distance. Design and fabrication of assistive wear were performed based on the results of analyzed data of trunk EMG activity from the golf drive swings of elite professional male golfers during back swing and downswing phases. After the prototype of wear was produced, surface EMG and Flight scope tests were conducted to verify the effectiveness of the wear for increasing distance to the professional golfers. Results indicated that wearing trial showed significant longer carry distance than the non-wearing trial(p<.001). The carry distance of wearing trial showed an average 229 m compared to the non-wearing trial, the average 225 m. The swing with wearing also produced significantly faster ball speed than the trial without wearing(p<.05). Average 245 Km/h and 244 Km/h were produced for the swing with and without wearing trails, respectively. EMG results also indicated that the muscle activity of left psoas was significantly increased for wearing trial during downswing and near the impact. Thus, this may affect positively to increase club head speed. The activity of the left latissimus dorsi was dramatically increased during the final stage of swing. This generates elongation effect for longer follow-through and increased impulse between club and ball so eventually valid assistance to increase carry distance. Therefore, the developed assisting wear was proved to be effective tool for increasing golf ball carry distance with maximizing trunk(back) muscle's stretch-shortening effect during backswing and downswing.

• The Journal of Korean Physical Therapy
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• v.22 no.5
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• pp.25-31
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• 2010

Purpose: The purpose of this study is to provide an efficient and scientific basis for muscle activity (%MVIC) of RA, EO, VL, HS muscles and balance in soccer players through dynamic lumbar stability exercise and static lumbar stability exercise. Methods: This study included 23 soccer players belonging to D University of J province who attended the program for 30 minutes at a time and three times a week for 4 weeks. Of these 13 attended the dynamic lumbar stability exercise (DLSE) program and 10 the static lumbar stability exercise (SLSE) program. The differences between the effects of the dynamic lumbar stability exercise program and static lumbar stability exercise program were analyzed. Results: To increase muscle activity (%MVIC) and balance (WPL), the dynamic lumbar stability exercise program was more effective than was the static lumbar stability exercise program. 1) The %MVIC of trunk muscle (RA &EO) and lower extremitys muscle (VL & HS) increased from before training to after training in the case of the participants who performed the dynamic lumbar stability exercise. 2) The whole path length (WPL) decreased from before the training to after the training. The 2 groups significantly differed in this regard. Conclusion: Dynamic lumbar stability exercise program helps to improve the balancing ability and muscle activity in a soccer players who requires both muscle activity and balance than does any other players.

• PNF and Movement
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• v.14 no.1
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• pp.1-6
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• 2016

Purpose: The purpose of this study was to analyze the effects of proprioceptive neuromuscular facilitation (PNF) patterns on electromyography (EMG) activity in the rectus abdominis, internal abdominal oblique, external abdominal oblique, and erector spinae according to position changes. Methods: Ten healthy adults volunteered to participate in the study. The subjects were required to complete exercises that followed two PNF extremity patterns, namely, an upper extremity extension-adduction-internal rotation pattern and a lower extremity flexion-adduction-external rotation pattern. The exercises were applied in the supine, side-lying, and sitting positions. Repeated measure one-way ANOVA and post-hoc Bonferroni correction were used to determine the influence of the patterns on muscle activity for each muscle, and descriptive statistics were then used to determine the local/global muscle ratios. Results: The upper extremity pattern had a significant effect on the rectus abdominis and erector spinae in the supine position, and on the internal oblique and external oblique in the sitting position (p<0.05). The median value for the internal oblique/rectus abdominis showed a high ratio of 2.05, and a high ratio of 1.01 was shown for the internal oblique/external oblique in the sitting position. The lower extremity pattern had a significant effect on the rectus abdominis in the side-lying position and on the internal oblique, external oblique, and erector spinae in the sitting position (p<0.05). The median value for the internal oblique/rectus abdominis showed a high ratio of 2.83 in the sitting position and a high ratio of 1.30 for the internal oblique/external oblique in the side-lying position. Conclusion: The PNF pattern increases local muscle activation in an unstable position. Therefore, when the pattern is used for intervention purposes, trunk stability and varied position changes should be taken into account.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.71-77
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• 2021

The present study aimed to find out how the trunk muscles, which are mainly used in Cardio-Pulmonary Resuscitation, affect chest compression through plank exercise. Study subjects participated in a 12-week program, and subjects performed only chest compressions for 8 minutes. Regarding their change in a muscle mass by plank exercise, there was a statistically significant difference in the change from 4th to 8th week after the program(p<.01). The muscle activity change had a statistically significant difference from 3rd to 10th week(p<.01). The chest compression depth had a statistically significant difference from 4th to 8th week(p<.01). In addition, insufficient chest relaxation height after compression had a statistically significant difference from 4th to 10th week(p<.01). The chest compression maintenance time had a statistically significant difference from 2nd to 12th week(p<.01). The participants' muscle mass and muscle activity increased more after their participation in plank exercise program than before. All chest compression factors except for chest compression rate brought about positive results.

• Physical Therapy Rehabilitation Science
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• v.8 no.2
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• pp.86-92
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• 2019

Objective: The purpose of this study was to compare the effects of performing squats and kneeling squats on trunk and lower extremity muscle activity in persons with stroke. Design: Cross-sectional study. Methods: Ten persons with stroke (3 male and 7 female) were recruited. The subjects were instructed to randomly perform the 4 different squat conditions: squat with 30 degrees of knee flexion, squat with 60 degrees of knee flexion, squat with 90 degree of knee flexion, and the kneeling squat. During the squat performance, surface electromyograms (sEMG) was used to assess muscle activity of the erector spinae (ES), gluteus maximus (Gmax), gluteus medius (Gmed), and biceps femoris (BF) muscles. Results: Muscle activation of the ES and BF were significantly increased with the kneeling squats compared to the general squats with 30 degrees and 60 degrees of knee flexion (p<0.05), and muscle activation of the Gmax and Gmed were significantly increased with the kneeling squats compared to all other squat conditions (p<0.05). Conclusions: The results suggest that the kneeling squat is an effective exercise to strengthen the proximal muscles of the lower extremities. Rather than applying a difficult general squat to the stroke population, the kneeling squat may be applied as a safer method for training the proximal muscles.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.1-6
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• 2020

The purpose of this study was to investigate the effects of sling and vibrator application of knee push-up plus motion on trunk muscle activities. Ten healthy adult males(age, 23.00±0.45 years; height, 176.60±1.64 cm; body mass, 67.50±1.22 kg; and BMI, 21.65±0.34 kg/㎡) were participated in this study as subjects. Three types' knee push-up plus motions were performed(basic knee push-up plus motion, BKPP; knee push-up plus motion with sling, KPPS; knee push-up plus motion with vibration, KPPV). We measured the right side's trunk muscle activities of the upper trapezius(UT), pectoralis major(PM), serratus anterior(SA), rectus abdominis(RA), and external oblique(EO). The research findings were as follows. UT, PM, SA, RA, and EO muscle activities were greatest during KPPV(p<.001). These results are expected to serve as reference materials for knee push-up plus motion applications in training programs for trunk muscle strengthening.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.1
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• pp.27-36
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• 2020

Background: Exercise in the quadruped position is performed to improve body and shoulder stability. This study examined the muscle activity of the trunk muscles according to the distance of the weight shift when lifting one leg in the quadruped position. Methods: Ten healthy 20 to 40 years old males were tested as subjects. All subjects moved their body weight to 0, 5, and 10cm on the opposite side of the leg lifter while maintaining the quadruped position. The surface electrodes recorded the electromyography data during the one leg lifting. Results: As the weight shift distance was increased, there was a significant difference in muscle activity of both serratus anterior, multifidus and internal oblique muscles (p<.05). Left and right serratus anterior and right internal oblique were most activated when weight shift distance was 0cm (p<.05). Conclusion: Shoulder and lumbar stabilization exercises should be applied in the absence of a weight shift distance during quadruped exercise.

• The Journal of Korean Physical Therapy
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• v.28 no.3
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• pp.205-211
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• 2016

Purpose: This study investigated the influence of muscle activity of the trunk and lower limb during a bridge exercise using a unstable surface and during one-legged bridge hip abduction in healthy adults. Methods: Nineteen healthy participated in this study (12 males and 7 females, aged $29.0{\pm}5.0$). The participants were instructed to perform the bridge exercises under six different conditions. Trunk and lower limb muscle activation, such as the erector spinae (ES), gluteus maximus (GM), external oblique (EO), and internal oblique (IO), was measured using surface electromyography. The six different bridge exercise conditions were conducted randomly. Data analysis was performed by using the mean scores after three trials of each condition. Results: On the ipsilateral side, muscle activity of the IO, EO, and ES during the hip abduction condition (Single-legged hip abduction bridge, Bridge with use of a ball and single-leg hip abduction, Bridge with use of a sling and single-leg hip abduction) was significantly higher than those during Unstable surface (Bridge with use of a ball, Bridge with use of a sling) and General bridging exercise (p<0.05). In the contralateral side, activities of the GM and EO during Single-legged hip abduction bridge, Bridge with use of a ball and single-leg hip abduction and Bridge with use of a sling and single-leg hip abduction was significantly higher than that during Bridge with use of a ball, Bridge with use of a sling and General bridging exercise (p<0.05). Conclusion: This study demonstrated that performing a bridge exercise with use of a sling and single-leg hip abduction had an effect on trunk and gluteal muscle activation. The findings of this study suggest that this training method can be clinically effective for unilateral training and for patients with hemiplegia.