• Journal of Korean Physical Therapy Science
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• v.26 no.2
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• pp.38-45
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• 2019

Purpose: This study purpose to comparison the effects of passive scapular alignment exercise and hold & relaxation technique on craniovertebral angle (C1~C7) with forward head posture due to using variety bag and using computer in healthy subjects. Design: Randomized Controlled Trial. Methods: 22 subjects were divide into two groups: PSAEx group and H/R group two groups. After exercise, the CVA were measured using C7 and tragus. Collected data were statistically analyzed by SPSS 20.2 Results: There were significant differences pre and post the exercise. Conclusion: PSAEx and H/R technique was effective to correct a abnormal CVA posture. The result of this study may helpful as basic data for orthopedic physical therapy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.4
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• pp.229-239
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• 2009

The purpose of this study is to evaluate the change in condylar position, width, and angle before and after orthognathic surgery using 3-dimensional computed tomograph. Pre and posterative 3-D CT was taken on 38 patients and through axial, frontal, sagittal measurements and by 3-dimensional reconstruction, the changes in condylar postion, mandibular width and angle were analyzed and others such as the difference in gender, operation and fixation method, setback length and in relation with temporomandibular disorders were done together too. The results were as follows: The inward rotation of condyle in axial condylar angle, the forward movement of right condyle in sagittal anterior-posterior distance, the superior movement of both condyles in sagittal superior-inferior distance, the decrease in gonial angle, the increase in mandibular width, the decrease in distance between the axial coronoid process distance and the increase in the frontal intercondylar distance were statistically significant. There were no statistically significant changes in gender difference, however in the difference in operation method, change in the gonial angle was observed and there was more change in bilateral sagittal split osteotomy group compared to two-jaw surgery group. In the difference in fixation method, the decrease in axial coronoid process distance and the change in sagittal anterior-posterior distance were statistically significant. In the difference in setback, the increase in setback didn't relate directly with the increased change in condyle position. In the relation with temporomandibular disorder, changes in left axial condylar angle and axial coronoid process distance were statistically significant. Changes in condylar position could be observed after the orthognathic surgery but it doesn't seem to have much of a clinical importance. The orthognathic surgery is effective in decreasing the mandibular angle, and it is not related with the temporomandibular disorder.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.97-108
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• 2006

C. H. OH, S. N. CHOI, T. G. NAM, The Kinematic Analysis of the Tennis Flat Serve Motion, Korean Jiurnal of Sports Biomechanics, Vol. 16, No. 2, pp. 97-108, 2006. By the comparison and the analysis of the different factors during the tennis flat serve motion such as the required time per section, the movement displacement of the racket, the velocity of the upper limbs joints, the physical center of gravity, and the angle and the angular velocity of the upper limbs joints between an ace player and a mediocre player, these following results were drawn. First, the experiment result of the total time required per section in a tennis flat serve motion showed that an ace player was faster than a mediocre player by 0.4 seconds. This result suggested that it was required to increase the speed of the racket head by a swift swing to perform an effective flat serve motion. Second, the experiment result of the movement displacement of the racket in the tennis flat serve motion showed that an ace player greatly moved toward the left side on an x-axis. But both an ace and a mediocre player were shown to be at the similar points on a y-axis at the moment of the impact of the racket. An ace player was also shown to be located at a higher position on a z-axis by 0.23m. Third, the velocity of the center of gravity of an ace player was faster in every phase than that of a mediocre player in a tennis flat serve motion. Fourth, the velocity of the upper limb joints of an ace player was faster in every phase than that of a mediocre player in a tennis flat serve motion. Fifth, the experiment result of the speed of the racket head in tennis flat serve motion showed that a mediocre player was faster than an ace player in the first phase, but the latter was faster than the former in the second, third, and the fourth phases. Sixth, at the moment of impact of a tennis flat serve, an ace player had greater flexion of the angle of the wrist joints by an 11.8 degree than a mediocre player. An ace player also had greater extension of the angle of the elbow joint and the shoulder joint respectively by a 5.2 degree and a 1.4 degree with a mediocre player. Seventh, an ace player had greater angular velocity of the upper limb joints and the hip joints than a mediocre player at the moment of the impact of tennis flat serve. Eighth, an ace player was shown to have a greater change of the forward and the backward inclination (or the anterior and posterior inclination) of the upper body

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.155-165
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• 2010

The purpose of this study was to analyze kinematic quantitative factors required of a forehand counter drive in table tennis through 3-D analysis. Four national table tennis players participated in this study. The mean of elapsed time for total drive motion was $1.009{\pm}0.23\;s$. At the phase of impact B1 was the fastest as 0.075 s. This may affect efficiency in the initial velocity and spin of the ball by making a powerful counter drive. The pattern of center of mass showed that it moved back and returned to where it was then moved forward. At the back swing, lower stance made wide base of support and a stronger and safer stance. It may help increasing the ball spin. Angle of the elbow was extended up to $110.75{\pm}1.25^{\circ}$ at the back swing and the angle decreased by $93.75{\pm}3.51^{\circ}$ at impact. Decreased rotation range of swinging arm increased linear velocity of racket-head and impulse on the ball. Eventually it led more spin to the ball and maximized the ball speed. Angle of knee joint decreased from ready position to back swing, then increased from the moment of the impact and decreased at the follow thorough. The velocity of racket-head was the fastest at impact of phase 2. Horizontal velocity was $7796.5{\pm}362\;mm/s$ and vertical velocity was $4589.4{\pm}298.4\;mm/s$ at the moment. It may help increase the speed and spin of the ball in a moment. The means of each ground reaction force result showed maximum at the back swing(E2) except A2. Vertical ground reaction force means suggest that all males and females showed maximum vertical power(E2), The maximum power of means was $499.7{\pm}38.8\;N$ for male players and $519.5{\pm}136.7\;N$ for female players.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.2
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• pp.30-37
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• 2000

The roll damping characteristics of the three models of a 3ton class fishing vessel, that is the bare hull, hull with bilge keels, and hull with bilge keels and a central wing are investigated by the free roll tests in head waves in a towing tank with the variations of the forward speed, initial angle and OG. The wave length variations are also included. The experimental results are compared with the numerical results of mathematical modellings by the energy method for these three models and the energy dissipation patterns are also compared. The roll damping speed increases, the effect of the waves on the roll damping of the models with the additional devices is negligible due to the much increased damping caused by the lift increase.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.851-856
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• 2003

A cross-flow fan consists of an impeller, a stabilizer and a rearguider. When it applied for an air conditioner, an evaporator should be added. It relatively makes high dynamic pressure at low speed because a working fluid passes through an impeller blade twice and blades have a forward curved shape. Therefore, the performance of a cross-flow fan is influenced 25% by the impeller, 60% by the rearguider and the stabilizer, 15% by the heat exchanger. At the low flow rate, there are a rapid pressure head reduction, a noise increase and an unsteady flow against a stabilizer and a rearguider. Moreover, the reciprocal relation between the impeller and the flow passage is the important factor for performance improvement of the cross-flow tan because each parameter is independent. The performance characteristics in the cross-flow fan are graphically depicted with various impeller outlet angles and rearguiders.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.97-104
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• 2022

Objective: Flexed posture commonly increases with age in older adults and is characterized by kyphosis and forward head posture. Changes in the posture with age affect both balance and mobility. This study was conducted to examine the effects of a cervical stabilization exercise for community-dwelling older adults to improve balance. Design: Two groups pretest-posttest design. Methods: Fifty older adults were randomly assigned into the cervical stabilization exercise group (n=24) and control group (n=25). The cervical stabilization exercise group (n=24) participated in group exercise for 60 minutes twice a week over 4 weeks. Timed up and go test (TUG), four square step test (FSST), functional reach test (FRT), postural sway, cervical range of motion (CROM), proprioception, craniovertebral angle (CVA) were evaluated before and after the intervention. Results: TUG, FSST, FRT, CROM, Proprioception, CVA showed significantly greater improvement, compared with a control group (p<0.05). Conclusions: Findings of this study demonstrate that cervical stabilization exercise can help improve not only neck functional capacities but also balance. Therefore, it may be used as an effective balance exercise program for community-dwelling older adults.

• PNF and Movement
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• v.21 no.1
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• pp.95-105
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• 2023

Purpose: The study aims to determine the effect of a breathing exercise on shoulder pain, range of motion (ROM), and forward head posture in patients with rotator cuff repair. Methods: In total, 25 patients with rotator cuff repair were included in this study. The experimental group (n = 13) underwent a breathing exercise, while the control group (n = 12) received traditional physical therapy. The visual analogue scales (VASs) for pain, flexion and abduction ROM, and the craniovertebral angle (CVA) of both groups were recorded at both pre- and post-intervention. Paired t-tests were used to determine significant changes in the post-intervention compared with the pre-intervention period, and independent t-tests were used to analyze differences in dependent variables between the two groups. Results: After the two-week intervention, the experimental group experienced a significantly decreased VAS (p < 0.05) and significantly increased ROM and CVA (p < 0.05), while the control group experienced a significantly decreased VAS (p < 0.05). Further, the experimental group that underwent the breathing exercise showed greater improvements in flexion and abduction ROM and in the CVA than the control group (p < 0.05). Conclusion: The results suggested that a breathing exercise can reduce shoulder pain and enhance ROM and posture in patients with rotator cuff repair.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.499-508
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• 2009

The purpose of this study was to compare and analyze flick shooting motion in penalty corner between high school players and national players in field hockey. Five high school players and six national players participated in this study. The 3D kinematic data were collected for each subject performing the penalty corner stroke. The results of the study were as follows: 1) The national players had higher stick head and ball velocity than the high school players. 2) The forward length between ball and support foot during ball catching with stick head was longer in the national players than the high school players. 3) At the Z axis of the E5 event, the center of gravity of the national players was lower than that of the high school players. 4) At the Z axis of the E5 event, left hip angle of the national players was lower than that of the high school players. 5) The national players had longer drag length of ball than the high school players. 6) The national players had higher hand and lower arm angular momentum than the high school players.

• Clinics in Shoulder and Elbow
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• v.22 no.1
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• pp.29-36
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• 2019

Background: The execution of fibular allograft augmentation in unstable proximal humerus fractures (PHFs) was technically demanding. In this study, the authors evaluated the clinical and radiographic outcomes after tricortical iliac allograft (TIA) augmentation in PHFs. Methods: We retrospectively assessed 38 PHF patients treated with locking-plate fixation and TIA augmentation. Insertion of a TIA was indicated when an unstable PHF showed a large cavitary defect and poor medial column support after open reduction, regardless of the presence of medial cortical comminution in preoperative images. Radiographic imaging parameters (humeral head height, HHH; humeral neck-shaft angle, HNSA; head mediolateral offset, HMLO; and status of the union), Constant score, and range of motion were evaluated. Patients were grouped according to whether the medial column support after open reduction was poor or not (groups A and B, respectively); clinical outcomes were compared for all parameters. Results: All fractures healed radiologically (average duration to complete union, 5.8 months). At final evaluation, the average Constant score was 73 points and the mean active forward flexion was $148^{\circ}$. Based on the Paavolainen assessment method, 33 patients had good results and 5 patients showed fair results. The mean loss of reduction was 1.32 mm in HHH and 5.02% in HMLO. None of the parameters evaluated showed a statistically significant difference between the two groups (poor and not poor medial column support). Conclusions: In unstable PHFs, TIA augmentation can provide good clinical and radiological results when there are poor medial column support and a large cavitary defect after open reduction.