• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.61-70
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• 2005

The purpose of study was to investigate the kinematic variables of Kenmotsu motion in Parallel bars. To this study, by 3 dimensional kinematical analysis of 4 male national gymnasts participants in the 28th Athens Olympic Game in 2004, kinematic data collected using video camera. Coordinate data were smoothed by using a fourth-order Butterworth low pass digital filter with cutoff frequency of 6Hz. The conclusions were as follows. 1. In P2, because the constrained swing movement made the movement of a rising back difficult7, the movements of Reg. were performed at low position after Air phase. 2. In E5 event, for the shake of a stable handstand and applied techniques like a Belle(E-value), a Belle Piked(super E-value), a vertical velocity in E2, a horizontal velocity in E3 and a vertical velocity in E4 were necessary for high velocities. 3. In E4 event, it was appeared that for a flexible body's movement of a vertical up-flight, the large angle of the shoulder joint and the flexion & extension of the hip joint were necessary in Air phase and a long flight time and vertical displacement made Reg. movements stable at the high position.

• Safety and Health at Work
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• v.13 no.3
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• pp.315-325
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• 2022

Background: Firefighters are required to carry self-contained breathing apparatus (SCBA), which increases the risk of musculoskeletal disorders. This study assessed the newly recruited firefighters' internal forces and potential musculoskeletal disorders when carrying SCBA. The effects of SCBA strap lengths were also evaluated. Methods: Kinematic parameters of twelve male subjects running in a control condition with no SCBA equipped and three varying-strapped SCBAs were measured using 3D inertial motion capture. Subsequently, motion data and predicted ground reaction force were inputted for subject-specific musculoskeletal modeling to estimate joint and muscle forces. Results: The knee was exposed to the highest internal force when carrying SCBA, followed by the rectus femoris and hip, while the shoulder had the lowest force compared to the no-SCBA condition. Our model also revealed that adjusting SCBA straps length was an efficient strategy to influence the force that occurred at the lumbar spine, hip, and knee regions. Grey relation analysis indicated that the deviation of the center of mass, step length, and knee flexion-extension angle could be used as the predictor of musculoskeletal disorders. Conclusion: The finding suggested that the training of the newly recruits focuses on the coordinated movement of muscle and joints in the lower limb. The strap lengths around 98-105 cm were also recommended. The findings are expected to provide injury interventions to enhance the occupational health and safety of the newly recruited firefighters.

• Clinics in Shoulder and Elbow
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• v.17 no.1
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• pp.18-24
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• 2014

Background: To evaluate the efficacy of the subclavian portal approach for the arthroscopic repair of isolated subscapularis tendon tear. Methods: We used the subclavian portal to carry out arthroscopic repair of the isolated subscapularis tendon tear. The surgery was carried out in 18 cases (average age of 53) from May 2006 to December 2009 with a mean follow-up period of 35 months. Of these cases, 13 patients had the tear in their dominant arms, 16 were male, and 12 were from traumatic ruptures with on average 7.6 months of symptom period to operation. Additional surgery, acromioplasty and subacromial debridement, were carried out on 4 cases each during the subscapularis repair. The integrity of cuff status was assessed by ultrasonographic examination at 6 months and at 1 year after operation. Results: The initial average range of motion in forward flexion, external rotation, and internal rotation were $160^{\circ}$, $50^{\circ}$ and L4, respectively. At the 1 year follow-up period, these improved to $160^{\circ}$, $52^{\circ}$ and T12, respectively. The initial average functional scores were assessed by KSS, ASES, UCLA, and Constant scoring systems, which were 67, 60, 26, and 65, respectively. These scores improved progressively with time. At 3 months after operation, the scores were 74, 67, 27, and 74; at 6 months, 83, 77, 31, and 75; at 1 year, 88, 86, 32, and 79; and at the final follow-up of 35 months, 84, 92, 34, and 84. Conclusions: In the repair of isolated subscapularis tendon tear, the subclavian portal approach provided a good angle for anchor insertion and sufficient space to manage the upper portion of the tendon tear. In turn, these provisions resulted in satisfactory clinical results.

• 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.

• Physical Therapy Korea
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• v.19 no.2
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• pp.12-19
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• 2012

The purpose of this study was to assess the influence of scapular alignment on the electromyographic (EMG) activity of the trapezius in people with a short pectoralis minor muscle. For the study, we recruited 15 volunteers who had positive results for short on a pectoralis minor muscle length test. We measured the EMG activity of the upper, middle and lower trapezius muscles. The participants lifted their dominant arm to ear level with the thumb up toward the ceiling in the prone position on a table with the shoulder at a flexion angle of 180 degrees and a horizontal abduction angle of 120 degrees. Scapula was manually aligned by an experienced physical therapist prior to arm lift for the scapular alignment condition. A paired t-test was used to compare the effects of scapular alignment on the EMG activity of the trapezius muscles. The EMG activity of the lower trapezius muscle was significantly increased during the test with the scapular alignment compared to that without scapular alignment (p<.05), while the upper trapezius and middle trapezius exhibited no significant difference between the two conditions (p>.05). The findings of this study suggest that a scapular alignment may alter the recruitment of the lower trapezius muscle during arm lifting in the prone position in people with a short pectoralis minor muscle.

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.209-218
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• 2013

This study was to perform the kinetic analysis of forward $1\frac{1}{2}$ somersault on the platform diving. Six men's diving players of the Korea national reserve athletes participated in this study. The variables were analyzed response time, velocity, center of mass (COM), angle, center of pressure (COP) and ground reaction force (GRF) of motion. For measure and analysis of this study, used to synchronized to 4 camcorder and 1 force plate, used to the Kwon3D XP (Ver. 4.0, Visol, Korea) and Kwon GRF (Ver. 2.0, Visol, Korea) for analyzed of variables. The results were as follows; Time factor were observed in maximum knee flexion depending on the extent of use at phase 1 of take-off to execute the somersault. This enabled the subject to secure the highest possible body position in space at the moment of jumping to execute the somersault and prepare for the entry into the water with more ease. Regarding the displacement of COM, all subjects showed rightward movement in the lateral displacement during technical execution. Changes in forward and downward movements were observed in the horizontal and vertical displacements, respectively. In terms of angular shift, the shoulder joint angle tended to decrease on average, and the elbow joints showed gradually increasing angles. This finding can be explained by the shift of the coordinate points of body segments around the rotational axis in order to execute the half-bending movement that can be implemented by pulling the lower limb segments toward the trunk using the upper limb segments. The hip joint angles gradually decreased; this accelerated the rotational movement by narrowing the distance to the trunk. Movement-specific shifts in the COP occurred in the front of and vertical directions. Regarding the changes in GRF, which is influenced by the strong compressive load exerted by the supporting feet, efficient aerial movements were executed through a vertical jump, with no energy lost to the lateral GRF.

• Physical Therapy Korea
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• v.27 no.1
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• pp.1-10
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• 2020

Background: Thoracic spine self-mobilization exercise is commonly used to manage patients with neck pain. However, no previous studies have investigated the effects of thoracic spine self-mobilization exercise alone in patients with chronic neck pain. Objects: The purpose of this study was to investigate the effects of thoracic self-mobilization using a tool on cervical range of motion (ROM), disability level, upper body posture, pain and fear-avoidance beliefs questionnaire (FABQ) in patients with chronic neck pain. Methods: The subjects were 49 patients (21 males, 28 females) with chronic neck pain. The subjects were randomly divided into an experimental group (EG, n = 23) and control group (CG, n = 26). For the EG, thoracic self-mobilization was applied. We placed a tool (made with 2 tennis balls) under 3 different vertebral levels (T1-4, T5-8, T9-12) of the thoracic spine and the subjects performed crunches, which included thoracic flexion and extension in supine position. Five times × 3 sets for each levels, twice a week, for 4 weeks. Cervical pain, disability, upper body posture, FABQ results, and ROM were evaluated at baseline, after 4 weeks of intervention, and at 8 weeks of follow-up. Assessments included the quadruple visual analogue scale (QVAS); Northwick Park neck pain questionnaire (NPQ); craniovertebral angles (CVA), forward shoulder angle (FSA) and kyphosis angle (KA) measurements for upper body posture; FABQ and cervical ROM testing. Results: The EG showed a statistically significant improvement after intervention in the QVAS (-51.16%); NPQ (-53.46%); flexion (20.95%), extension (25.32%), left rotation (14.04%), and right rotation (25.32%) in the ROM of the cervical joint; KA (-7.14%); CVA (9.82%); and FSA (-4.12%). Conclusion: These results suggest that, for patients with chronic neck pain, thoracic self-mobilization exercise using a tool (tennis balls) is effective to improve neck pain, disability level, the ROM, and upper body posture.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.109-130
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• 2002

The purpose of this paper was to make a comparative analysis for the difference of the various kinematic variation which is occurred in the each situation when pitchers throw a straight and a curve ball. Four pitchers, who are two national team players and two high level pitchers, were selected among the right over hand pitchers of D university in the Busan for this paper. The data were analyzed by using 3D equipment. The results of the analysis which was about the elapsed time of the pitching, the movement of the body center-point, the highest height of the left knee, stride length, knee joint angle, shoulder joint angle, elbow joint angle and wrist joint angle in the each section(ST, LKU, HBP, LCF, MCP, BRP) were as follows : 1. Pitching time in the each section and step in the pitching for straight and curve ball was similar. The total elapsed time of the straight and curve ball was 1.78${\pm}$0.07sec and 1.77${\pm}$0.11sec in the order. 2. The position change of the body center to the Z(above below) direction did not show significant difference in the each situation of the section and step between pitching for the straight and curve ball. 3. Height of the left knee did not show significant difference as 125.38${\pm}$11.85cm and 124.95${\pm}$11.63m in the each pitching motion for straight and curve ball. The rate(%H) between height and stride length showed 68.42${\pm}$5.53(%H), 68.40${\pm}$5.45(%H) in the each pitching motion. 4. Pitching for curve ball showed longer stride length than pitching for straight ball that as the stride length was 140.35${\pm}$4.96cm and 144.8${\pm}$1.69cm. The rate(%H) between height and stride length showed 76.9${\pm}$3.77(%H), 79.39${\pm}$2.23(%H) in the each pitching motion. 5. Left knee joint angle did not show significant difference in the ST, LKU and HBP section in the each pitching motion. However, it was shown that knee joint angle was flexed much more in the LFC, MCP and BRP section in the pitching for curve ball. 6. Right shoulder joint angle did not show significant difference in the ST, LKU and HSP section. However, when pitches threw a curve ball in the LKU section. In the LFC section, the right shoulder joint angle was extended much more in the pitching for curve ball, and the angle was extended much in the MCP and BRP section in the pitching for curve ball than straight ball. 7. Right elbow joint angle did not show significant difference in the ST, LKU and HRP section in the two pitching motion. The angle had more flexion in the LFC and MCP section in the pitching for curve ball than the pitching for straight ball. The angle in the each pitching motion for straight ball and curve ball were extended by a narrow margin in the BRP section. 8. Right wrist joint angle was extended much more in the LFC and MCP section in the pitching for curve ball. In the BRP section, the angle was extended much more in the pitching for straight ball than curve ball.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.43-53
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• 2005

This study is to define how the difference of athletic change influence on the last regrasp after somersault in Belle movement of parallel bars. For his study, the following conclusion was produced by analysis of athletic change by means of three dimensional visual image in three athlete of nation. 1. As the picture of S1, there are total used time(2.01 sec), S3(2.17 sec) and S2(2.19 sec). In case of a short needed time, it is difficult for them to perform the remaining movement of the vertical elevating flight easily and comfortably, it is judged as performing the small movement with restrict swing. 2 In the change of body center sped by each event, it is calculated as $-89.1^{\circ}$ the narrowest in S1, $-81.96^{\circ}$ the widest and then $86.34^{\circ}$ in S3. In E3 event, average compound speed is 4.07m/s, S2 showed the fastest speed of 4.14m/s whereas S1 the narrowest angle of 3.95m/s. 3. A shoulder joint and coxa are the period of mention in E3. In E4 which was pointed out the longest vertical distance, S2 that is indicated the highest vertical height as the period of detach in parallel bars. showed -3.91m. This is regarded as a preparatory movement for dynamic performance after using effectively elastic movement of shoulder joint and coxa while easily going up with turning back movement. In the 5th phrase, long airborne time and vertical change position is showed as the start while regrasping securely air flight movement from high position. 4. In E5, a long flight time and a long vertical displacement were shown as the regrasp after somersault efficiently in high position with stability from the point of the highest peak of the center of the body. Especially, S2 is marked as a little bit long position, while S1 is reversely indicated as performing somersault and unstable motion in a low position. 5. In E3, at the point of the largest extension of the shoulder joint and hip joint the shoulder joint is largely marked in $182^{\circ}$ and the hip point $182^{\circ}$ in S2. The shoulder joint is marked at the smallest angle in $177^{\circ}$ and the hip point $176^{\circ}$ in S1. And S1 is being judged by its performance of the less self - confident motion with lessening a breath of swing. S2 makes the most use of flexion and extension of the shoulder joint and the hip joint effectively. It was performed greatly with swinging and dropping the rotary movement and the rotary inertia naturally. 6. In E6, as the point of regrasp of the upper arm in parallel bars it is recognized by the that of components of vertical and horizontal velocity stably. During this study, the insufficient thing and the study on the parallel bars at a real game later are more activated than now. If it is really used as the basic materials by means of Belle Picked Study of Super E level after Bell movement, you may perceive the technique movement previously and perform without difficulty. Especially, such technique as crucifix is quite advantageous for oriental people thanks to small body shape condition. In conclusion we will nicely prepare for our suitable environment to gradually lessen trials and errors by analyzing and studying kinematically this movement.

• Fashion & Textile Research Journal
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• v.14 no.1
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• pp.109-121
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• 2012

This study aims at developing ergonomics patterns for the sleeve of structural firefighting protective clothing through 3D motion analysis in order to ensure efficiency and safety of firefighters who are exposed to harmful environment at work. A new research pattern was developed by applying the total results of 3D motion analysis, changes of body surface length measurements, and 2D data on 3D body shape analysis on the size 3 patterns of the existing coat sleeve. For the sleeves, we used the body surface length of the range of shoulder's flexion and the joint angle of the range of wrist's ulnar deviation. And for the production of structural firefighting protective clothing using the research pattern, we recruited a recognized producer of structural firefighting protective clothing designated by KFI. Unlike everyday clothes, structural firefighting protective clothing should be able to fully protect the wearers from the harmful environment that threatens their lives and should not cause any restrictions on their movement. Therefore, the focus of research and development of such protective clothing should be placed on consistent development of new technologies and production methods that will provide protection and comfort for the wearer rather than production cost reduction or operational efficiency. This study is meaningful as it applied 3D motion analysis instead of the existing methods to develop the patterns. In particular, since 3D motion analysis enables the measurement of the range of motion, there should be continuous research on the development of ergonomics patterns that consider workers' range of motion.