• Physical Therapy Korea
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• v.9 no.2
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• pp.33-42
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• 2002

The purpose of this study was to compare the onset times of muscle activities and the order of muscle firing in hamstring gluteus maximus, and lumbar erector spinae muscle during active hip extension between subjects with low back pain (LBP) and healthy subjects. Thirty subjects, 15 with LBP and 15 healthy subjects, participated in this study. Electromyographic activity was recorded during active hip extension in prone and standing position. Relative onset times of these muscle activities were determined. Similar muscle firing order in hamstring, gluteus maximus, and lumbar erector spinae muscle showed in both groups and positions. However, the onset time of gluteus maximus was significantly later in prone and standing active hip extension in subjects with LBP than in healthy subjects. The onset time of lumber erector spinae muscle activity was significantly delayed in subjects with LBP in standing active hip extension, The delayed onset times of gluteus maximus and lumbar erector spinae muscles' activities were probably related to LBP. Further studies are needed to identify whether the delayed onset times of gluteus maximus and lumbar erector spinae muscle activities are the contributing factors to LBP.

• Journal of Korean Physical Therapy Science
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• v.19 no.4
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• pp.41-46
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• 2012

Background : The purpose of this study was to investigate the electromyographic(EMG) amplitude of the gluteus medius muscle bilaterally at various hip angles and motions(flexion, extension and abduction). Methods : Thirty young with a mean(SD) age of 21.03(1.69) years performed hip motions(flexion, extension and abduction) while the surface EMG activity of the gluteus medius muscles was recorded bilaterally. Subjects were instructed to use the right lower limb during moving 3 different direction. Differences in EMG amplitudes in according with movement direction and angle were assessed by use of paired t-test analyses of variance for the right and left lower extremities. The alpha level was set at .05. Results : Gluteus medius muscle EMG activities in the both side were significantly greater for abduction at angles of 30 degrees than those for other motions at other angles. Conclusion : Hip abduction at angles of 30 degrees on the standing position may be effective in activating the gluteus medius muscle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.43-44
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• 2009

• Physical Therapy Korea
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• v.13 no.2
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• pp.70-76
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• 2006

The purpose of this study was to investigate the effects of hip extension velocity (7.5 degree/second, 30 degree/second) on the relative onset time of the gluteus maximus in relation to the hamstring during hip extension in prone position. Thirteen healthy male subjects (mean age=22.6 years [SD=1.8], mean weight=73.4 kg [SD=10.3], mean height=176.1 cm [SD=6.3]) voluntarily participated in this study. Electromyographic data was collected on the gluteus maximus and hamstring to determine onset time. Statistical analyses were performed with the paired t-test. The results showed that the onset time of the hamstring was significantly faster than that of the gluteus maximus in both fast and slow hip extension velocity. The gluteus maximus began contraction .079 seconds later following the contraction of the hamstring. The onset time of the hamstring was significantly faster in fast hip extension velocity compared with slow hip extension velocity. In conclusion, it was determined that the onset time of the gluteus maximus was faster with fast hip extension velocity compared with slow hip extension velocity. There was a statistically significant difference between the onset times of the gluteus maximus and hamstring in relation to the two velocities (p<.05). Further study is needed to examine whether the velocity of hip extension can influence the onset time in a similar fashion in patients with low back pain.

• Physical Therapy Korea
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• v.29 no.4
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• pp.249-254
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• 2022

Background: The lateral step down (LSD) is a form of stair negotiation used by the elderly because it requires less movement of the lower extremity. Although it is necessary to study the amount of pelvic drop and the strength of a hip abductor during LSD for intervention, limited studies have investigated the relationship between the amount of pelvic drop and strength of a hip abductor during LSD in elderly people. Objects: This study aimed to determine the relationship between the amount of pelvic drop on an unsupported leg and the strength of the hip abductor during LSD in the elderly. Methods: Thirty elderly people (male: 17, female: 13) were recruited. Subjects performed the LSD task, and the evaluator measured and the amount of pelvic drop on an unsupported side. Also, the isometric strength of the hip abductor was measured in a supine position. Results: We found significant relationships between the strength of the hip abductor and the amount of pelvic drop (r = -0.386). The average hip abductor strength normalized by body weight was 1.06 N/kg (max: 1.99, min: 0.52) and the average contralateral pelvic drop (CPD) angle was 4.16° (max: 15.3, min: 0). Conclusion: Our results indicated that the strength of the hip abductor had a moderate correlation with the CPD during a LSD in the elderly. Hip abductor weakness could translate into altered movement of the pelvis.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.9 no.1
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• pp.39-52
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• 2003

The test for internal and external rotation of hip joint, was donet from September 2 to 9, 2002, with the participation of 50 male/female university students who are in a normal health condition. Results are : 1. When applying the external rotation of 45 degrees angle ; 1) In a sitting position, for male it results in an increase of 5 degrees on right and left sides each. 2) In a sitting position, for female there is no change on both right and left sides. 3) In a supine position, for both male and female it results in an increase of 5 to 10 degrees on right and left sides each. 4) In a prone position, for male it results in an increase of 5 degrees on the left side only. 5) In a prone position, for female it results in an increase of 5 to 10 degrees on right and left sides each. 2. When applying the internal rotation of 45 degrees angle ; 1) In a sitting position, for male it results in a decrease of 5 degrees on right and left sides each. 2) In a sitting position, for female there is no change on both right and left sides. 3) In a supine and prone position, there is no change for male. 4) In a supine position, for female it results in an increase of 5 to 10 degrees on right and left sides each. 5) In a prone position, for female it results in an increase of 5 degrees on right and left sides each.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.155-164
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• 2007

This study is to find out effective defensive type by analysis on differences among three different defence types of the body lock technique in the ground wrestling. The subjects are 5 athletes who are in 60kg weight class. To get the kinematic analysis seven ProReflex MCU-240(Motion Capture Unit), infrared rays cameras, which was produced by Qualisys, were used to get a two-dimensional coordinate. Following are the analysis result from kinematic factors such as time element, speed element and angular element. 1. During position of ground wrestling, the average necessary time until defender's hip joint touches the mat for Phase1 was $0.34{\pm}0.14sec$ at side position was the shortest space of time out of three types, and Phase2 was $0.21{\pm}0.02sec$ at front position was the shortest space of time out of three types. Moreover, side defence position was the shortest for total average necessary time with $0.78{\pm}0.05sec$. 2. The movement change for hip joint was $57.21{\pm}20.17cm$ for front, $43.35{\pm}7.13cm$ for rear, and $18.67{\pm}10.24cm$ for side at Phase1 and $42.08{\pm}17.56cm$ for side, $16.61{\pm}6.34cm$ for front, and $1.48{\pm}1.29cm$ for rear at Phase2. 3. Movement speed of hip joint at defensive type were most effective in success and fail rate at Phase 1 and its frontal average speed was fastest with $1.01{\pm}0.23m/s$ following by $0.52{\pm}0.15m/s$ for side, and $0.62{\pm}0.15m/s$ for rear. The average for total change of speed is $0.79{\pm}0.32m/s$ for front, $0.78{\pm}0.17m/s$ for side, and $0.49{\pm}0.08m/s$ for rear. 4. The joint angle gets smaller in a order by rear, front, and side for the size of hip joint angle and knee angle for different defensive type. 5. As a result of one-way ANOVA on linear velocity for hip joint in frontal defence(phase1) was significance ($\alpha$=.05), but phase 2 was not significance. Synthetically, analyzing on differences among three different defence types which were front, rear, and side of the body lock technique in the ground wrestling, front defensive type was the most effective. In future, there should be more studies regarding on defence at not a laboratory study but a field study to help out wrestler to pertinent techniques to improve the game of wrestling.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.3
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• pp.690-696
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• 2013

This study, which is conducted on two groups of skilled people and unskilled people, is purposed to analyze joint angle of lower extremity during short track speed skating in order to find out efficient body position and propose ideal training method. Short Track Speed Skating has a wide range of research areas, but their findings indicate a promising area for further research. Targeting 8 people who are skilled in short track speed skating and 8 people who are not skilled in it, this study analyzes three dimensional images using super-high speed camera to compare differences between these two groups of people. In this study, 6 sections of body positions including right foot push-off, right foot recovery, right foot basic position, left foot push-off, left foot recovery, and left foot basic position were analyzed using 8 super-high speed cameras of VICON. These body positions were analyzed in order to find out joint angles of the hip joint, the knee joint, and the ankle joint. In the section 4 of the inner and outer parts of the left hip angles showed significant difference, and most of the sections of knee joint angles also showed significant difference. In the section 1 and 2 of the plantar flexion, dorsiflexion of ankle joints showed significant difference(p<.001) It was found out that there were differences between groups of skilled people and unskilled people in terms of lower extremity's joint angles such as angles of the hip joint, the knee joint, and the ankle joint.

• Physical Therapy Korea
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• v.25 no.4
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• pp.19-26
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• 2018

Background: Alignment of the lower limb is an important factor, influencing balance and gait in kinematics and kinetics, in patients with and without a flat arched foot. Flat arched foot are associated with the range of motion (ROM) of the hip and alignments of the knee joints, is strongly influenced. Objects: The purpose of this research was to investigate the relationship between hip joint ROM and quadriceps angle (Q-angle), by dividing them into two groups according to the presence or absence of flat feet, using a navicular drop test (NDT) and resting calcaneal stance position (RCSP). Methods: Forty elderly patients were allocated to the experimental group (flat foot group, n1=20) or the control group (non-flat group, n2=20). Universal and digital goniometer, tractograph and tape measure were used to determine the related changes in the hip ROM, Q-angle, NDT and RCSP. Results: Data were analyzed using the Pearson correlation coefficients. Active internal ROM of the hip joint (right, r=.803, p<.001), (left, r=.951, p<.001) were highly correlated with NDT, and also, was moderately correlated with Q-angle (right, r=.562, p=.019), (left, r=.757, p<.001). Passive internal ROM of the hip joint (right, r=.742, p=.001), (left, r=.922, p<.001) were highly correlated with NDT, and also, was moderately correlated with RCSP (right, r=-.530, p=.029) and with Q-angle (right, r=.710, p=.001), (left, r=.698, p=.002) in the flat foot group. However, no strong correlation among the hip ROM, NDT, RCSP and Q-angle were found in the non-flat foot group. Conclusion: This research may provide evidence of the correlations between hip internal ROM and flat foot.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.1
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• pp.15-21
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• 2014

Purpose : The aim of this study was to find out differences between muscle activity of quadriceps according to hip angle. Method : 40 healthy adults produced maximum isometric muscle contraction of quadriceps femoris and each part of the quadriceps femoris were measured with a surface EMG in hip joint angle of $90^{\circ}$, $135^{\circ}$, $180^{\circ}$. Result : There was no significant difference between muscle activity of vastus medialis and lateralis according to hip angle. But there was significant difference in muscle activity of rectus femoris and the muscle activity was maximum at 135 degrees of hip angle. Conclusion : In conclusion, maximum muscle activation of rectus femoris is affected by hip angle, and the findings from this study may be helpful for physical therapists in selecting hip position when instructing patients to do Q-setting exercise. So, we suggest that patients perform Q-setting exercise at 135 degrees of hip angle for the best result.