• Physical Therapy Korea
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• v.23 no.4
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• pp.55-62
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• 2016

Background: The functioning of the serratus anterior (SA) muscle is essential to normal scapulohumeral rhythm during forward flexion (FF) of the shoulder. Also, SA weakness and overuse of the upper trapezius (UT) is observed in patients with shoulder dysfunction and trapezius myalgia. We designed a combination exercise involving FF and scapular protraction with resistance (CFFSP) to activate the SA muscle and to deactivate the UT muscle. Objects: The purpose of this study was to determine whether or not CFFSP would be more effective in activating the SA muscle than FF alone and FF with scapular protraction (FFP). Methods: Nineteen subjects (12 men and 7 women) participated in this study and performed FF, FFP, and CFFSP at $120^{\circ}$. Surface electromyography was applied to the SA, UT, and pectoralis major (PM) muscles, as was one-way analysis of variance (ANOVA) with repeated measures. Statistical significance was set at .05. Bonferroni adjustment was used to counteract the problem of multiple comparisons, with a statistical level of significance of .017 (.05/3). Results: A statistically significant difference was found in relation to the three positions for the SA muscle (p<.001) and the SA/UT ratio (p=.005) using ANOVA. Significantly different results, depending on the position, were also demonstrated using the Bonferroni post-hoc test for the SA muscle ($FF=28.27{\pm}16.20$, $FFP=45.66{\pm}15.81$, and $CFFSP=62.4{\pm}27.21$) and for the SA/UT ratio ($FF=3.04{\pm}2.14$, $FFP=3.61{\pm}2.38$, and $CFFSP=5.95{\pm}3.01$). Significant differences between the three positions was not found regarding the average amplitude of SA/PM muscle ratio (SA/PM: p=.060). Conclusion: We recommend the use of CFFSP to strengthen the SA muscle at $120^{\circ}$.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.107-113
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• 2007

The purpose of this study were to investigate the effects of knee brace on the knee muscular neuro-biomechanical variables during the rebound in female highschool basketball players. Twelve high school female ($17.9{\pm}0.8years$) basketball players rebound jumped for maximal vertical height to sufficiently stress the anterior cruciate ligament with and without knee brace. Kinematic data were collected to estimate the knee flexion, abduction angles and jump height. The EMG data from the biceps femoris and rectus femoris was used to estimate the ratio of quadriceps muscle activity. Female athletes with knee brace showed more reduced the knee abduction angle and the ratio of quadriceps muscle activity at foot contact phase than without knee brace. In conclusion, Female athletes with brace reduced knee anterior cruciate ligament loads.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.1
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• pp.57-67
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• 2006

Musculoskeletal neck dysfunction syndromes are common in outpatient musculoskeletal pain practice. The underlying musculoskeletal and neurologic causes of pain are variable. In the management of these patients, it is important to accurately identify and treat these pain generators to optimize patient outcome. It is the purpose of this review to discuss three main categories of functional anatomy, the role of superficial/deep muscular system and the scientific evidence for optimal physical therapy intervention for cervical dysfunction. Specifically there is evidence of lowered microcirculation in the upper trapezius muscle, morphological signs of disturbed mitochondrial function which appears to be limited to type I fibers and an increased cross-sectional area of type I muscle fibers despite a lower capillary to fiber area ratio. In acute neck pain syndrome, changes in muscle activity of painful muscles may result from segmental and supraspinal inhibitory effects. Muscle activation is closely related to the control of joint movements and postures and it is difficult to separate the influence of the two components. Both the altered muscle recruitment patterns and altered kinematics appear to be a poor adaptation for pain of the head - neck region, as they are likely to result in increased compressive loading in the cervical spine, affecting muscles, articular structures such as zygapophyseal joints, connective tissues and neural tissues which are all peripheral generators of referred pain. The rectus capitus posterior minor muscle shows that it is one of the most important muscles of the suboccipital region. In this article, i reviewed the anatomy, neurophysiology, function and dysfunction as well as the treatment of cervical dysfunction.

• Physical Therapy Rehabilitation Science
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• v.9 no.1
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• pp.18-24
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• 2020

Objective: The purpose of this study was to compare the activities of the abdominal muscles according to trunk stabilization exercises using Swiss ball in normal individuals. Design: Cross-sectional study. Methods: Ten healthy university students participated in this study. The subjects were required to complete the following three exercise positions: Exercise position 1, sitting on a Swiss ball and lifting the legs; Exercise position 2, pushing to a plank position from an ending position; and Exercise position 3, push-up posture with the legs on a Swiss ball. Changes in the trunk muscle activities were estimated using Biometric electromyography (EMG). Activities of the dominant side internal oblique muscle (IOM) and external oblique muscle (EOM) were estimated in all participants. The maximal voluntary isometric contraction (MVIC %) was measured to standardize the EMG signals for the IOM and EOM during maximum resistance when sitting up with each shoulder pointing towards the contralateral pelvis with knees bent and both arms crossed on the chest for 5 seconds. Results: There was a significant difference in the activity of the internal and external oblique muscles between Exercises 1 and 2 and Exercises 1 and 3 (p<0.05). Furthermore, the IOM/EOM activity ratio was the greatest during Exercise 3 and the smallest during Exercise 1. IOM and EOM activities were the greatest during Exercise 2 with greater EOM activity. Conclusions: In future studies, it will be necessary to investigate muscle activities by supplementing the above-mentioned limitations during the stabilization exercise. The results of this study may be used as a basis for controlling the intensity and frequency of exercise while prescribing trunk stabilization exercises.

• Physical Therapy Korea
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• v.26 no.4
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• pp.29-34
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• 2019

Background: The serratus anterior is one of the most important muscle for maintaining good scapular alignment in the shoulder joint. The pectoralis major and upper trapezius may also compensate for weak serratus anterior muscles. The push-up plus exercise has been identified as the optimal exercise for maximum activation of the serratus anterior. Objects: The purpose of this study was to examine differences in surface electromyography (EMG) activity of upper trapezius, pectoralis major, and serratus anterior muscles during push-up plus exercises on variously angled surfaces in subjects with winged scapula. Methods: Sixteen subjects with winged scapula (male=5, female=11) volunteered for this study. The subjects performed push-up plus exercise on four different tilt angles, namely $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$. EMG activities in the serratus anterior, upper trapezius, and pectoralis major muscles during performance of push-up plus exercise were measured in all subjects. Data were processed from repeated measures one-way analysis of variance. Results: There was significant difference in the muscle activity of the serratus anterior on the different surface angles (p<.05). The results of the post-hoc analysis showed significantly greater serratus anterior muscle activity on a surface at a $0^{\circ}$ angle than at others tilt angles (p<.05). There was also significant difference in the ratio of serratus anterior to upper trapezius and serratus anterior to pectoralis major across the four surfaces (p<.05), and post-hoc analysis showed significantly greater values on the $0^{\circ}$ surface than on other tilts (p<.05). Conclusion: This study found that performing push-up plus exercises on a flat surface with $0^{\circ}$ and $30^{\circ}$ tilt angle achieves high activation of the serratus anterior muscle for selective strengthening. It can also take into account the sequential application, which is first performed at a $30^{\circ}$ and at a $0^{\circ}$ tilt angle for and effective but not excessive muscle activation.

• Physical Therapy Korea
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• v.24 no.4
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• pp.1-10
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• 2017

Background: Flexion-relaxation phenomenon (FRP) was a term which refers to a sudden onset of myoelectric silence in the erector spinae muscles of the back during standing full forward flexion. Hamstring muscle length may be related to specific pelvic and trunk movements. Many studies have been done on the FRP of the erector spinae muscles. However, no studies have yet investigated the influence of hamstring muscle flexibility on the FRP of the hamstring muscle and lumbopelvic kinematics during forward bending. Objects: The purpose of this study was to examine the flexion-relaxation ratio (FRR) of the hamstring muscles and lumbopelvic kinematics and compare them during forward bending in subjects with different hamstring muscle flexibility. Methods: The subjects of two different groups were recruited using the active knee extension test. Group 1-consisted of 13 subjects who had a popliteal angle under $30^{\circ}$; Group 2-consisted of 13 subjects who had a popliteal angel above $50^{\circ}$. The kinematic parameters during the trunk bending task were recorded using a motion analysis system and the FRRs of the hamstring muscles were calculated. Differences between the groups were identified with an independent t-test. Results: The subjects with greater hamstring length had significantly less lumbar spine flexion movement and more pelvic flexion movement. The subjects with greater pelvic flexion movement had a higher rate of flexion relaxation during full trunk bending (p<.05). Conclusion: The results of this study suggest that differences in hamstring muscle flexibility might cause changes in people's hamstring muscle activity and lumbopelvic kinematics.

• Journal of Korean Medicine Rehabilitation
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• v.15 no.2
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• pp.45-54
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• 2005

Objectives : This study aims to confirm the importance of behavior habit and exercise, especially leg exercise in obese. Methods : Out of 2247 people, we divided 1125 people in normal group(BMI<25) and 122 people in obese group($BMI{\geq}25$). We measured each arm, leg, abdomen muscle circumference and right and left water difference using BLA. We Investigated whether ratio of leg muscle circumference to arm and abdomen has differences by statistics between each groups. And analyzed correlation with BMI. We also investigated right and left water distribution difference of two group's limbs and the correlation with BMI. Statistical analysis was performed by using SPSS program. Results : 1. In obese group, ratio of leg muscle circumference to arm and abdomen is significantly lower than normal group(P<0.001). 2. Ratio of leg muscle circumference to arm and abdomen were negatively correlated with BMI(r-0.461, r=0.462, P<0.001). And partial correlation coefficient controlled for age and sex is -0.528, -0.632(P<0.001). 3. In the case of women, there was right and left water distribution difference as statistical in leg. In the case of Obese, the difference is serious. Conclusions : These results suggest that exercise and activity of lower limbs is more needed in the field of obesity treatment and prevention.

• PNF and Movement
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• v.21 no.3
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• pp.291-298
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• 2023

Purpose: This study aimed to suggest an effective exercise for treating anterior cruciate ligament (ACL) and hamstring injuries based on the dynamic control ratio (DCR) for the hamstring and quadriceps during eccentric hamstring exercises. Methods: Twenty-four healthy participants participated in this study. The participants performed three eccentric hamstring exercises, including the Nordic exercise, the supine leg curl, and single-leg deadlifts. During the eccentric hamstring exercises, the vastus medialis oblique (VMO), vastus lateralis (VL), biceps femoris (BF), and semitendinosus (ST) were measured using surface electromyography. Results: The DCR was significantly lower during the supine leg curl and single-leg deadlift than during the Nordic exercise (p < 0.05). The activity of the VMO and VL was significantly greater during the supine leg curl than during the Nordic exercise and the single-leg deadlift (p < 0.05). VL activity was significantly higher during the single-leg deadlift than during the Nordic exercise (p < 0.05). ST activity was significantly higher during the supine leg curl and Nordic exercise than during the single-leg deadlift (p < 0.05). BF activity was significantly higher during the supine leg curl than during the Nordic exercise and single-leg deadlift (p < 0.05). Finally, the BF showed significantly higher activity during the Nordic exercise compared to during the single-leg deadlift (p < 0.05). Conclusion: Based on the DCR ratio and quadriceps activity, the supine leg curl should be introduced early in rehabilitation for ACL injuries.

• PNF and Movement
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• v.19 no.2
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• pp.215-223
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• 2021

Purpose: This study aimed to compare the contraction ratios of the abdominal muscles and the preferential activation ratios of the transversus abdominis muscle (TrA) during the abdominal drawing-in maneuver (ADIM) in the hook-lying, sitting, and standing positions. Methods: This study included 30 healthy participants. The thicknesses of the TrA, internal oblique muscle (IO), and external oblique muscle (EO) were measured at rest and during the ADIM in the hook-lying, sitting, and standing positions using B-mode ultrasound imaging. The contraction ratios of these muscles and the preferential activation ratios of the TrA were calculated for each position. Results: The contraction ratio of the TrA and preferential activation ratio of the TrA during the ADIM in the hook-lying position were significantly higher than those in the sitting and standing positions (p < 0.05). The contraction ratio of the TrA during the ADIM in the sitting position was significantly higher than that in the standing position (p < 0.05). Conclusion: The hook-lying position tended to facilitate TrA activity better than the sitting position. Furthermore, the sitting position tended to facilitate TrA activity better than the standing position. These findings suggest that the ADIM in the hook-lying position should be implemented before that in the sitting position and that the ADIM in the sitting position should be implemented before that in the standing position.

• Physical Therapy Rehabilitation Science
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• v.13 no.1
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• pp.53-70
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• 2024

Background: The conventional deadlift is a popular exercise for enhancing trunk, core, and lower extremity strength. However, its use in sports medicine is constrained by concerns of lumbar injuries, despite evidence supporting its safety and rehabilitative benefits. To optimize muscle activation using resistive bands in variable resistance therapy, we explored their feasibility in the deadlift. Design: Comparative experimental design Methods: Surface electromyography recorded muscle activity in the trunk and lower extremities during lifting, with normalization to the isometric Floor Lift using Maximal Voluntary Contraction. Kinematics were measured using inclinometer sensors to track hip and trunk sagittal plane angles. To prevent fatigue, each subject only used one of the three pairs of bands employed in the study. Results: Our study involved 45 healthy subjects (mean age: 30.4 ± 6.3 years) with similar baseline characteristics, except for years of lifting and strength-to-years-of-lifting ratio. Various resistance band groups exhibited significantly higher muscle activity than conventional deadlifts during different phases. The minimal resistance band group had notably higher muscle activity in the trunk, core, and lower extremity muscles, particularly in the end phase. The moderate resistance band group showed increased muscle activity in the mid-and end-phases. The maximum resistance band group demonstrated greater muscle activity in specific muscles during the early phase and overall higher activity in all trunk and lower extremity muscles in the mid and end phases of the deadlift (p<0.05). Conclusion: Our findings provide valuable insights into muscle activation with various resistance bands during deadlift exercise in clinical and gym settings. There appears to be a dose-response relationship between increased resistance bandwidth, external load, myoelectric activation, and range.