• Physical Therapy Korea
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• v.25 no.4
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• pp.46-52
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• 2018

Background: The hamstring muscles in the lower extremity are highly important for knee joint stability and can be classified into medial and lateral hamstrings according to the anatomical position, which have some different functions. To measure the strength of the individual hamstring muscles, manual muscle testing is clinically performed by dividing rotation postures into internal and external postures. However, this has no sufficient scientific background. Objects: This study aimed to test the difference that the tibial rotation would cause in the muscle activity of the medial and lateral hamstrings. Methods: The muscle activities of the biceps femoris, semitendinosus, and semimembranosus were measured in a total of three different postures (neutral position and internal and external rotations) with 3 replications. During the maximal isometric contraction, resistance was constantly provided by the string attached to the strap, not by manual resistance of the examiner. Before and after electromyography measurements, the participants underwent hamstring flexibility measurement using the active knee extension test in the supine position on the treatment table. Results: The semitendinosus had a 12.56% reduction in muscle activity in external rotation as compared with that in neutral position. The biceps femoris and semimembranosus showed reduced muscle activities in both external and internal rotations as compared with those in neutral position. Only the women showed significant decreases in the comparison between pre and post-active knee extension. Conclusion: Only the semitendinosus muscle was consistent with the anatomical speculation. However, the reduction in the muscle activity of the semitendinosus as compared with that in neutral position was only 12.56%, the clinical value of which may be difficult to justify.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.2
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• pp.177-185
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• 2022

Purpose : The purpose of this study was to compare the effect of additional isometric contraction of trunk, shoulder, and hip muscles during abdominal crunch exercise on abdominal muscle thickness and to identify the most effective intervention for core muscle activation. Methods : This study was conducted on 22 healthy male adults. Subjects performed three types of crunch exercises (abdominal crunches accompanied by internal and external isometric rotation of the hip, horizontal shoulder adduction and abduction, and rotation of the trunk). The thickness of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) were evaluated using ultrasonography. The collected data used one-way repeated ANOVA statistics. Wilcoxon signed-rank test of nonparametric statistics was used for post-test analysis. Results : The IO thickness was significantly lower than general abdominal crunch when shoulder adduction was added (p<.05). The crunch with shoulder abduction, hip external rotation, and ipsilateral trunk rotation was significantly higher than the abdominal crunch (p<.05). The EO thickness was significantly greater in the crunch with hip external rotation than in the abdominal crunch (p<.05). Conclusion : The level of contraction in abdominal muscles appears to vary when isometric contractions of the trunk, shoulder, and hip muscles are added to the abdominal crunch exercise. Therefore, the use of isometric contractions of other joints to selectively induce contraction of the abdominal muscles may be considered.

• Korean Journal of Applied Biomechanics
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• v.20 no.3
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• pp.293-301
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• 2010

The purpose of this study was to investigate the kinematic difference between skilled and less skilled group for the forward walk at dance sports rumba. Six female players(skilled group: 3, less skilled group: 3) were participated as the subjects. To obtain the three-dimensional location coordinates in the joints and segments, it shot with 100Hz/s using 8 video cameras. Step length, shoulder rotation angle, orientation angle and angular velocity of pelvis were analyzed for each trail. The skilled group showed a bigger movement than the less skilled group at the shoulder rotation angle and ROM. The skilled group showed a bigger movement than the less skilled group at the up/down obliquity and internal/external rotation movement for pelvis. And the skilled group showed a bigger movement than the less skilled group at Maximum angle (down obliquity) of P2 and Maximum angle (up obliquity) of P3 to pelvis ROM. The skilled group showed a faster angular velocity than the less skilled group at P2 (+ direction, posterior) of anterior & posterior tilt, P2 & P3 (- direction, up) of up & down obliquity, and P2 (+ direction, external) of internal & external rotation.

• PNF and Movement
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• v.12 no.1
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• pp.33-37
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• 2014

Purpose: In this research, the properties of the shoulder joint were measured through eccentric resistive exercise with the patients who have rotator cuff tear of shoulder joints as the targets. Methods: 23 patients who have pain due to the rupture of rotator cuff on shoulder joints were selected and divided into Exercise group (12) and Control group (11). Two groups executed exercise for 30 minutes 3 days a week. Exercise group had executed eccentric resistive exercise, and the Control group executed Complex exercise. Results: In external rotation $180^{\circ}/s$, $240^{\circ}/s$, the Exercise group showed to be an average of 8% higher than the Control group. For Internal rotation $90^{\circ}/s$, $180^{\circ}/s$, $240^{\circ}/s$ the Exercise group showed to be an average of 30% higher that the Control group. Conclusion: To lessen the rupture of rotator cuff on shoulder joints, muscles strengthening is very important across various methods of eccentric exercise programs which are external/internal rotators of the shoulder joint needed for throwing. This is effective in preventing injury and improving rotation.

• Journal of Korean Physical Therapy Science
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• v.30 no.3
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• pp.41-48
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• 2023

Background: This study examined the effects of the bridge exercise with trunk rotation on the thickness of body trunk muscles, including external oblique, internal oblique, and transverse abdominis in healthy male adults. Design: Randomized controlled trial Methods: Twenty-four men were evenly divided into a trunk rotation bridge exercise group and a basic bridge exercise group by drawing lots. The two groups performed the respective exercise for thirty minutes, three times a week for six weeks. repeated measure analysis of variance (ANOVA) was used after distinguishing between three different time points before the experiment, three weeks after the experiment, and six weeks after the experiment. The significance level was set at 0.05. In case an interaction between time and group existed, the paired t-test was used to examine the within-group difference. The independent-sample t-test was used to check the between-group difference. The significance level was set at 0.05. Results: All the men showed a significant change over time in their external oblique, internal oblique, and transverse abdominis muscles. An interaction between time and group was also found (p<0.05). Conclusion: The bridge exercise with trunk rotation causes a meaningful difference in the thickness of external oblique, internal oblique, and transverse abdominis muscles. Therefore, this study proposes the use of this exercise for lower-back stabilization in future research and clinical settings.

• PNF and Movement
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• v.7 no.1
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• pp.25-32
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• 2009

Objective : The purpose of this study was conducted to find the change of shoulder flexion by degree of freedom between the Proprioceptive Neuromuscular Facilitation(PNF) pattern, the flexion- abduction- external rotation, and not PNF pattern, the flexion- exteral rotation(except abduction)movement. Method : PNF pattern applied on the unilateral upper extremity in all subjects were the flexion- abduction- external rotation, and not PNF pattern, and twenty-six normal subjects(13 male, 13 female) were tested by Cybex Norm Testing & Rehabilitation System. Results : PNF pattern showed significant increase of flexion than not PNF pattern, the flexion-exteral rotation(except abduction)movement, and also the female group was significantly increased than male group. Conclusion : The results suggested that the application of PNF pattern to the unilateral upper extremity had affected on the shoulder flexion by degree of freedom.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.4
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• pp.41-48
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• 2017

Purpose : The purpose of this study was to verify the relationships among the knee adduction moment, hip rotation range, strength of hip rotators, and Foot Posture Index of healthy young adults. Method : Thirty-two healthy adults(24 male, 8 females) participated in this study. Subjects performed 5 walking trials to evaluate the knee adduction moments using a three-dimensional motion analysis system. Hip rotation ranges and hip rotator strengths were measured using a standard goniometer and a handheld dynamometer, respectively. The mean of three trials of clinical tests was used for data analysis. Results : The first peak knee adduction moment was significantly correlated with the hip rotation ranges and hip rotator strengths (P<.05). The second peak knee adduction moment was showed significant correlations with hip external rotation and rotation ratio. There were no correlations between Foot Posture Index and all knee adduction moments (P>.05). Conclusion : This study suggests that imbalances of the range of motion and strength of the internal and external rotation of the hip joint can affect knee adduction moments. The impact may exacerbate musculoskeletal disorders such as osteoarthritis of the knee. Therefore, further studies should be conducted to evaluate the effects of clinical interventions to correct these imbalances on the reduction of the knee adduction moments in patients with knee osteoarthritis.

• PNF and Movement
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• v.14 no.3
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• pp.195-202
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• 2016

Purpose: This study investigates the influence of applying proprioceptive neuromuscular facilitation (PNF) leg patterns on the activation of three types of mesogluteal fibers at the opposite side. Methods: The target subjects of this study were 19 healthy men who voluntarily agreed to participate in the program. For all subjects, the following four PNF leg patterns were applied while they were in a standing position, and then, the activation of the gluteus medius at the opposite side was measured: (1) flexion abduction internal rotation pattern, (2) flexion adduction external rotation pattern, (3) extension abduction internal rotation pattern, and (4) extension adduction external rotation pattern. In each position, a pattern was executed three times in 5 s, and the average of each measurement was used for the statistics. Results: Among the PNF leg patterns, the activation of the mesogluteal fibers at the opposite side was most significant under the application of the extension abduction internal rotation pattern. The activation of the back muscular fiber was significantly high under the application of the flexion abduction internal rotation pattern. Conclusion: Selective application of PNF leg patterns can improve the functional activity of each mesogluteal fiber.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.45-55
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• 2007

We investigated the biomechanics and characteristics of shoulder rotator muscles for professional woman volleyball players. The purpose of this study was to analyze the isokinetic peak torque and range of motion for shoulder joint rotation. We measured the strength and ROM of the internal rotation(IR) and external rotation(ER) of shoulders joint for nine professional woman Volleyball players and nine University students with Biodex and Simi-motion. 1. We measured peak torques for the shoulder joint rotator at angular velocities of 60/s and 180/s. It was found that the peak torques were significantly different between the two groups and also between the hands used. 2. At angular velocity of 60/s, IR/ER ratio of the shoulder joint was significantly different depending on the groups and the hands in use. There was a significant difference for 'Dominant side' at angular velocity of 180/s, but no significant difference for 'Non-dominant side' and the controls group. 3. Regarding the ROM of rotation of the shoulder joint group, IR was significantly different between the groups and the hands in use. 4. IR/ER ratio of the shoulder joint for Dominant side was quite different between the groups.

• Physical Therapy Korea
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• v.30 no.3
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• pp.237-244
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• 2023

Background: The external rotation (ER) exercise in performed at a 90° abduction of the shoulder joint is an effective to strengthen the infraspinatus. However, failure of the humeral head to control axial rotation during exercise can be increased the posterior deltoid over activity. Biofeedback training is an effective method of promoting motor learning and control it could look forward to activate the infraspinatus selectively by controlling the humeral head during exercise. Objects: The aim of this study was investigated that whether biofeedback for axial rotation was effective to activate selectively the infraspinatus during ER exercise. Methods: The 15 healthy males participated, and all subjects performed both ER exercise in a sitting position with shoulder abducted 90° under conditions with and without axial rotation biofeedback. Exercise was performed in a range of 90° ER, divided into three phases: concentric, isometric, and eccentric. The infraspinatus and posterior deltoid muscle activity were observed using surface electromyography. Results: Both infraspinatus activity (p < 0.01) and infraspinatus to posterior deltoid activity ratio (p = 0.01) were significantly higher with biofeedback however, posterior deltoid activity was significantly lower with biofeedback (p = 0.01). The infraspinatus muscle activity and muscle activity ratio were the highest in the isometric contraction type, and there were significant differences for all contraction types (p < 0.05). Whereas, the posterior deltoid activity was the lowest in the isometric contraction type, and showed a significant difference between isometric and other two contraction types (p < 0.05), but no significant different between concentric and eccentric contraction. Conclusion: Our results indicate that the axial rotation biofeedback during sitting ER exercise might be effective method to activating selective infraspinatus muscle and recommended to enhance the dynamic stability of the shoulder joint.