• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.149-163
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• 2006

The purpose of this study was to compare the lower extremity's joint and segment coupling patterns between forward and backward running in subjects who were twelve healthy males. Three-dimensional kinematic data were collected with Qualisys system while subjects ran to forward and backward. The thigh internal/external rotation and tibia internal/external rotation, thigh flexion/extension and tibia flexion/extension, tibia internal/external rotation and foot inversion/eversion, knee internal/external rotation and ankle inversion/eversion, knee flexion/extension and ankle inversion/eversion, knee flexion/extension and ankle flexion/extension, and knee flexion/extension and tibia internal/external rotation coupling patterns were determined using a vector coding technique. The comparison for each coupling between forward and backward running were conducted using a dependent, two-tailed t-test at a significant level of .05 for the mean of each of five stride regions, midstance(1l-30%), toe-off(31-50%), swing acceleration(51-70%), swing deceleration(71-90), and heel-strike(91-10%), respectively. 1. The knee flexion/extension and ankle flexion/extension coupling pattern of both foreward and backward running over the stride was converged on a complete coordination. However, the ankle flexion/extension to knee flexion/extension was relatively greater at heel-strike in backward running compared with forward running. At the swing deceleration, backward running was dominantly led by the ankle flexion/extension, but forward running done by the knee flexion/extension. 2. The knee flexion/extension and ankle inversion/eversion coupling pattern for both running was also converged on a complete coordination. At the mid-stance. the ankle movement in the frontal plane was large during forward running, but the knee movement in the sagital plane was large during backward running and vice versa at the swing deceleration. 3. The knee flexion/extension and tibia internal/external rotation coupling while forward and backward run was also centered on the angle of 45 degrees, which indicate a complete coordination. However, tibia internal/external rotation dominated the knee flexion/extension at heel strike phase in forward running and vice versa in backward running. It was diametrically opposed to the swing deceleration for each running. 4. Both running was governed by the ankle movement in the frontal plane across the stride cycle within the knee internal/external rotation and tibia internal/external rotation. The knee internal/external rotation of backward running was greater than that of forward running at the swing deceleration. 5. The tibia internal/external rotation in coupling between the tibia internal/external rotation and foot inversion/eversion was relatively great compared with the foot inversion/eversion over a stride for both running. At heel strike, the tibia internal/external rotation of backward running was shown greater than that of forward(p<.05). 6. The thigh internal/external rotation took the lead for both running in the thigh internal/external rotation and tibia internal/external rotation coupling. In comparison of phase, the thigh internal/external rotation movement at the swing acceleration phase in backward running worked greater in comparison with forward running(p<.05). However, it was greater at the swing deceleration in forward running(p<.05). 7. With the exception of the swing deceleration phase in forward running, the tibia flexion/extension surpassed the thigh flexion/extension across the stride cycle in both running. Analysis of the specific stride phases revealed the forward running had greater tibia flexion/extension movement at the heel strike than backward running(p<.05). In addition, the thigh flexion/extension and tibia flexion/extension coupling displayed almost coordination at the heel strike phase in backward running. On the other hand the thigh flexion/extension of forward running at the swing deceleration phase was greater than the tibia flexion/extension, but it was opposite from backward running. In summary, coupling which were the knee flexion/extension and ankle flexion/extension, the knee flexion/extension and ankle inversion/eversion, the knee internal/external rotation and ankle inversion/eversion, the tibia internal/external rotation and foot inversion/eversion, the thigh internal/external rotation and tibia internal/external rotation, and the thigh flexion/extension and tibia flexion/extension patterns were most similar across the strike cycle in both running, but it showed that coupling patterns in the specific stride phases were different from average point of view between two running types.

• Physical Therapy Korea
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• v.29 no.2
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• pp.106-116
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• 2022

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. However, during exercise, excessive activation of the posterior deltoid compared to the infraspinatus causes the humeral head to move anteriorly in an abnormal position. Many researchers have emphasized selective activation of the infraspinatus during shoulder external rotation exercise. Objects: This study aims to delineate the optimal exercise method for selective activation of infraspinatus by investigating the muscle activities of the infraspinatus and posterior deltoid according to the four shoulder exercise methods and two forearm positions. Methods: Thirty healthy individuals participated in this study. The participants were instructed to perform shoulder external rotation exercises following four exercise methods: sitting external rotation (SIER); standing external rotation at 90° abduction (STER); prone external rotation at 90° abduction (PRER); side-lying external rotation (SLER), and two forearm positions (neutral, supinated). The electromyography (EMG) signal amplitude was measured during each exercise. Surface EMG signals were recorded from the posterior deltoid, infraspinatus, and biceps brachii. Results: EMG results of the infraspinatus and posterior deltoid in PRER, were significantly higher than that of the other exercises (p < 0.01). The EMG ratio (infraspinatus/posterior deltoid) in SIER was significantly higher than that of the other exercises. EMG activation of the posterior deltoid in SIER, PRER, and SLER was significantly higher in neutral than in supinated (p < 0.01). Furthermore, the EMG of the infraspinatus in SIER was significantly higher in neutral than in supinated (p < 0.01). The EMG ratio (infraspinatus/ posterior deltoid) in SIER was significantly higher in neutral than in supinated (p < 0.05.) Contrarily EMG ratios in PRER and SLER were significantly higher in supinated than in neutral (p < 0.05). Conclusion: The results show that clinicians should consider these exercise methods and forearm positions when planning shoulder external rotation exercises for optimal shoulder rehabilitation.

• Physical Therapy Korea
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• v.26 no.3
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• pp.91-98
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• 2019

Background: The bridge exercise targets the gluteus maximus (Gmax) and gluteus medius (Gmed). However, there is also a risk of dominant hamstring (HAM) and erector spinae (ES) muscles. Objects: To analyze the muscle activity the of Gmax, Gmed, HAM and ES during the bridge exercise with and without hip external rotation in different degrees of knee flexion. Methods: Twenty-three subjects were participated. The electormyography (EMG) activity of the Gmax, Gmed, HAM and ES muscles was recorded during the exercise. The subjects performed the bridge exercise under four different conditions: (a) with $90^{\circ}$ knee flexion, without hip external rotation (b) with $90^{\circ}$ knee flexion, with hip external rotation (c) with $135^{\circ}$ knee flexion, without hip external rotation (d) with $135^{\circ}$ knee flexion, with hip external rotation. Results: There was no significant interaction effect between the degree of knee flexion and hip external rotation. There was a significant main effect for degree of knee flexion in Gmax, HAM muscles activity. Gmax muscle activity was significantly greater in the $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p<.001). While HAM muscle activity was significantly less in $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p<.001). ES muscle activity was significantly less in the $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p=.002). The activity of both the Gmax and Gmed muscles was significantly greater with hip external rotation (p<.001 and p=.005, respectively). Conclusion: For patients performing the bridge exercise, positioning the knee in $135^{\circ}$ of flexion with hip external rotation is effective for improving Gmax and Gmed muscle activity while decreasing HAM, and ES muscle activity.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.2
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• pp.23-29
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• 2023

Background: There is still controversy as to whether hip external rotation and dorsiflexion selectively activate the vastus medialis obliquus (VMO) during straight leg raise exercise. Due to the anatomical characteristics, hip adduction must be preceded to activate the VMO. In this study, the activities of the rectus femoris (RF), vastus lateralis (VL), VMO were measured by adding the hip adduction movement to the straight leg raise exercise with hip 45° external rotation and straight leg raise exercise with hip 45° external rotation and dorsiflexion. Through this, we want to find out whether the VMO is selectively activated. Methods: Thirteen healthy participants performed straight leg raise exercise with hip 45° external rotation, straight leg raise exercise with hip 45° external rotation and dorsiflexion, straight leg raise exercise with hip 45° external rotation and adduction, straight leg raise exercise with hip 45° external rotation and adduction and dorsiflexion was randomly performed. Through this, EMG data of the RF, VL, VMO were collected. Results: During the straight leg raise exercise, hip adduction increased the activity of the VMO and VL, no significant difference was found(p>.05). However, in the VMO/VL ratio, straight leg raise exercise with hip 45° external rotation and adduction and dorsiflexion activated the VMO and the VL at a ratio of about 1:1, It showed a significantly higher rate than straight leg raise exercise with hip 45° external rotation(p<.05). Conclusion: During the straight leg raise exercise, hip adduction is considered to be an important movement that can selectively induce the activity of the VMO. Therefore, follow-up studies on this should be conducted.

• PNF and Movement
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• v.19 no.1
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• pp.1-8
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• 2021

Purpose: The purpose of this study was to determine how the position of tibial rotation affects peak force and hamstring muscle activation during isometric knee flexion in healthy women. Methods: Seventeen healthy women performed maximum isometric knee flexion at 30˚ with three tibial rotation positions (tibial internal rotation, neutral position, and tibial external rotation). Surface electromyographic (EMG) activity was recorded from the medial hamstring (MH) and lateral hamstring (LH) muscles. The strength of the knee flexor was measured with a load-cell-type strength-measurement sensor. Data were analyzed using one-way repeated analysis of variance. Results: The results showed that MH and LH activities and peak force were significantly different among the three tibial rotation conditions (p < 0.01). The post-hoc comparison revealed that the MH EMG activity in tibial neutral and internal rotation positions were significantly greater than tibial external rotation (p < 0.01). The LH activity in tibial external rotation was significantly greater than the tibial neutral position and internal rotation (p < 0.01). The peak force of the knee flexor was also greater in the external tibial rotation position compared with the tibial neutral and internal rotation positions (p < 0.01). Conclusion: Our findings suggest that hamstring muscle activation could be changed by tibial rotation.

• Physical Therapy Rehabilitation Science
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• v.8 no.3
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• pp.152-157
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• 2019

Objective: We aimed to investigate differences of range of motion in measuring shoulder internal rotation (IR) and external rotation (ER) resulting from posture change in manual scapular stabilization in prone, hook-lying, sitting, and standing positions in healthy young adults. Design: Cross-sectional study. Methods: This study included healthy young adults who agreed to participate after a thorough explanation about the study purpose and methods. A clinometer was used to measure shoulder rotation. Measurements of shoulder rotation according to postural change were performed in prone, hook-lying, sitting, and standing positions. The repeated measures analysis of variance was used to compare between-group differences in postural change. Results: The lower the posture, the greater the average value of IR angle. In contrast, the higher the posture, the greater the average value of the external rotation angle. In active and passive IR with posture change, there was difference in average value but with no statistical significance. In active and passive ER, there was a statistically significant difference between prone and sitting, prone and standing, hook-lying and sitting, hook-lying and standing, and sitting and standing position (p<0.05). Conclusions: Our findings suggest that postural change should be considered in order to increase the strength or range of motion of the internal and external rotation of the patient's shoulder joint.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.1
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• pp.99-105
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• 2018

PURPOSE: The aim of this study was to evaluate the concurrent validity and clinical usefulness of the universal plastic goniometer to measure the range of motion of the internal and external rotation of the hip joint using the three dimensional motion analysis which can analyze the joints and segment movements in the most objective and quantitative method. METHODS: Clinical and kinematic data were collected from thirty individuals using a universal plastic goniometer and a ten camera motion analysis system. Passive hip rotation range was obtained three trials for left and right hip joints using two measure methods simultaneously. RESULTS: There were significant differences between all matching measures of the two measures of internal and external rotation of the hip joint (p<.05). The relationship between the two tests for all measurements of the internal and external rotation of the hip was statistically significant with correlation coefficient form r=.87 to .96. (p<.01). CONCLUSION: Clinical measurement of the internal and external rotation of the hip using a universal plastic goniometer is effective to assess the hip condition. However, application of universal plastic goniometer requires careful attention in more accurate evaluation and research verification of the internal and external rotation of hip joint.

• Physical Therapy Korea
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• v.21 no.3
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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.

• Journal of Korean Physical Therapy Science
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• v.8 no.1
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• pp.893-906
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• 2001

The purposes of this study were to compare pelvic tilt. range of motion(ROM) of hip rotation, and leg length difference before and after manipulation and to investigate correlation between changes of each variables after manipulation of sacroiliac pint in 31 low back pain patients(11 males, 20 females) with sacroiliac pint dysfunction. The sacroiliac pint of patients was manipulated on the side of anterior pelvic tilt, using the technique described by Stoddard(1962) and Greenmann (1996). I used this technique because it usually eliminated sacroiliac Pint dysfunction in one treatment session. SPSS for window computer system was used to analyze the data. Also t-test was performed for comparison of the variables before and after manipulation, and Pearson product-moment correlation analysis and regression analysis were performed for changes of each variables after manipulation. The result were as follows: 1. The pelvic tilt after manipulation was significantly decreased(mean=$2.79^{\circ}$) compared with the pelvic tilt before manipulation(p=.001). 2. The PROM of hip internal rotation ipsilateral to anterior pelvic tilt after manipulation significantly decreased (mean = $1.88^{\circ}$) compared with hip internal rotation before manipulation (p=.008). The PROM of hip internal rotation ipsilateral to posterior pelvic tilt after manipulation significantly increased(mean = $1.29^{\circ}$) compared with hip internal rotation before manipulation (p=.029). 3. The PROM of hip external rotation ipsilateral to anterior pelvic tilt after manipulation significantly increased(mean=$2.42^{\circ}$) compared with the hip external rotation before manipulation(p=$2.42^{\circ}$) compared with the hip external rotation ipsilateral to posterior pelvic tilt after manipulation significantly decreased(mean = $1.84^{\circ}$) compared with the hip external rotation before manipulation (p=.008). 4. Leg length difference after manipulation significantly decreased(mean=2.15 mm) compared with leg length difference before manipulation (p=.008). Regression analysis revealed that a fair correlation was found between change in leg length difference and change in anterior pelvic tilt after manipulation(p=.009). 5. Pearson product-moment correlation coefficient was used to assess differences of the variables after manipulation. A fair correlation was found between change in leg length difference and change in anterior pelvic tilt after manipulation(r=.462, p<.01). A fair correlation was found between change in anterior pelvic tilt and change in hip internal rotation ipsilateral to anterior pelvic tilt(r=.397, p<.05) and between change in anterior pelvic tilt and change in hip external rotation ipsilateral to anterior pelvic tilt(r=.516, p<.01). A fair correlation was found between change in posterior pelvic tilt and changes in hip internal rotation ipsilateral to posterior pelvic tilt (r=.441, p<.05) and between change in posterior pelvic tilt and change in hip external rotation ipsilateral to posterior pelvic tilt(r=.361, p<.05). A fair correlation was found between change in hip internal rotation ipsilateral to anterior pelvic tilt and change in hip external rotation ipsilateral to posterior pelvic tilt(r=.388, p<.05) and between change in hip internal rotation ipsilateral to posterior pelvic tilt and change in hip internal rotation ipsilateral to anterior pelvic tilt(r=.426. p<.05).

• Physical Therapy Korea
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• v.20 no.2
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• pp.60-68
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• 2013

The purpose of this study was to assess the intra-rater test-retest reliability of tibial external rotation angle measurement using a smartphone-based photographic goniometer, DrGoniometer (DrG) compared to a three-dimensional motion analysis system (Vicon). The current study showed an interchangeable method using DrG to measure the tibial external rotation angle in standing knee flexion at $90^{\circ}$. Twelve healthy subjects participated in this study. A rest session was conducted 30 minutes later for within-day reliability and five days later for between-day intra-rater test-retest reliability. To assess the validity of the measurement using DrG, we used a three dimensional motion analysis system as a gold standard to measure the angle of tibial external rotation. Intra-class correlation coefficient (ICC) and the standard error of measurement (SEM) values were used to determine the within- and between- day intra-rater test-retest reliability of using DrG and a three dimensional motion analysis system. To assess validity, Pearson correlation coefficients were used for two measurement techniques. The measurement for tibial external rotation had high intra-rater test-retest reliability of within-day (ICC=.88) and between-day (ICC=.83) reliability using DrG and of within-day (ICC=.93) and between-day (ICC=.77) reliability using a three-dimentional motion analysis system. Tibial external rotation angle measurement using DrG was highly correlated with those of the three-dimensional motion analysis system (r=.86). These results represented that the tibial external rotation angle measurement using DrG showed acceptable reliability and validity compared with the use of three-dimensional motion analysis system.