• Korean Journal of Applied Biomechanics
• /
• v.31 no.1
• /
• pp.50-58
• /
• 2021

Objective: This study aimed to determine the effect of wrist and trunk weight loading using sandbags in stroke patients in order to provide the quantitative data for enhancement of gait movement. Method: Twelve stroke patients, who have been diagnosed with hemiplegia over a year ago, were participated in this study. All subjects were asked to perform normal walking [N], wrist sandbag walking [W], wrist & trunk sandbag walking [WT], and both wrist sandbag walking [B] and both wrist & trunk sandbag walking [BT], respectively. Eight infrared cameras were used to collect the raw data. Gait parameters, arm swing, shoulder-pelvic kinematics, and lower extremity joint angle were calculated to examine the differences during walking. Results: As a result, there were no significant differences in the gait parameters, shoulder-pelvis, and lower extremities joint angles, but significant differences were found in the range of motion and the anteversion in arm swing. Conclusion: Wrist and trunk weight loading using sandbags affected the movement of the upper extremities only while it did not affect the movement of the lower extremities. It implies that it can reduce the risk of falling caused by a sudden movement change in lower extremities. In addition, the wrist and trunk weight loading using sandbags can induce changes in movement of the upper extremities independently and contribute to functional rehabilitation through resistance training.

• PNF and Movement
• /
• v.12 no.4
• /
• pp.243-248
• /
• 2014

Purpose: The transverse abdominis and themultifidus muscle are located in the core. They surround one's trunk and help in body stabilization. Specifically, they control spine articulation to maintain posture and balance. Therefore, weakened deep muscle in the trunk may cause spinal malalignment. This study aims to compare the correlation between the thickness of the transverse abdominis and the multifidus muscle and the spine alignment among college students in their 20s. Methods: This study measured the thickness of the transverse abdominis and the multifidus muscle of 42 healthy college students in their 20s using ultrasonic waves. The thickness of the muscle was measured for the length of the cross-section except for fascia. The thickness of the left and right muscles was measured, and the mean value was calculated. As the thickness of the transverse abdominis can increase because of pressure during exhalation, it was measured at the last moment of exhalation. Spinal alignment was measured by the kyphosis angle, lordosis angle, pelvic tilt, trunk inclination, lateral deviation, trunk imbalance, and surface rotation using Formetric III, which is a three-dimensional imaging equipment. They were measured for three times, and the mean values were calculated. The general characteristics of the subjects were analyzed using descriptive statistics. The correlations between each factor were analyzed using Pearson's correlation analysis. Results: The transverse abdominis showed asignificant correlation with trunk inclination (p<.05). The multifidus muscle showed a significant positive correlation with pelvic tilt and a negative correlation with surface rotation (p<.05). Conclusion: The thickness of transverse abdominis and the multifidus muscle appears to influence spinal alignment. Specifically, the multifidus muscle, which plays an important role on the sagittal plane, influences surface rotation, thus making it an important muscle for scoliosis patients. Therefore, a strengthening training program for the transverse abdominis and the multifidus muscle is necessary according to specific purposes among adults with spinal malalignment.

• Korean Journal of Applied Biomechanics
• /
• v.33 no.2
• /
• pp.73-83
• /
• 2023

Objective: Adolescent idiopathic scoliosis patients make up 40% of all scoliosis patients, and it is likely to increase even more because of the increase in sitting times due to the pandemic. Method: The subject of this study was a 16-year-old female student. The Cobb's Angle at initial value was 42° at the thoracic and 33° at the lumbar. The subject's height was 161.6 cm, and the type of scoliosis was 3CL. The brace was built with fabric materials with the size information from the X-ray information and actual measurements. The brace was made for the adolescents to wear for a longer time by making them put pressure on the same pressure points of the existing braces. The subjects were required to wear the device for 16 hours every day for three months. Additional features to check the pressure and time were synchronized through an app for easier communication and management with the responsible investigator. Results: After wearing the 3D Fabric brace, Cobb's angle changed from 42° to 33° at the thoracic and 33° to 23° at the lumbar. The ATR changed from 9° to 8° at the thoracic and 11° to 6° at the lumbar. As a result, the changes in the ATR angle do relate to the decrease of Cobb's angle, which made the angle of scoliosis that is bent in a three-dimensional way improve, making the height of the subject increase from 161.6 cm to 163.5 cm. Conclusion: Through this study, developing a brace that is made in the form of the 3CL to align the strap direction and putting pressure on the proper pressure points makes Cobb's angle and the ATR smaller. This means that there is a positive effect on the changes in height. A brace made of light fabric material is a good brace to help treat adolescent idiopathic scoliosis. There was an opinion that it is more comfortable to wear than existing braces, but it seems necessary to conduct a quantitative study about the before and after of wearing the brace and a survey for Korean specific cases.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.4
• /
• pp.169-179
• /
• 2007

The purpose of this study was to investigate the relations between the segments of the body and to qualitatively analyze coordination pattern of joints and segments during Sweep Shot movement in Ice Hockey, by utilizing coordination variables was angle vs. angle plots. By the utilization the three dimensional anatomical angle cinematography, the angles of individual joint and segment according to sweep shot in ice hockey. The subjects of this study were five professional ice hockey players. The reflective makers were attached on anatomical boundary line of body. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and ice hockey stick were defined. The three dimensional anatomical angular displacement and coordination pattern of trunk and Upper limb(shoulder-elbow, elbow-wrist linked system) showed important role of sweep shot in ice hockey. As the result of this paper, for the successful movement of sweep shot in ice hockey, it is most important role of coordination pattern of trunk-shoulder, shoulder-elbow and elbow-wrist. specially turnk movememt as a proximal segment. Coordination pattern of Upper Limb(upperarm-forearm-hand) of Sweep Shot movement in Ice Hockey that utilizes coordination variables seems to be one of useful research direction to understand basic control mechanisms of Ice hockey sweep shooting linked system skill. this study result showed flexion-extension, adduction-abduction and internal-external rotation of trunk are important role of power and shooting direction coordination pattern of upper Limb of Sweep Shot movement in Ice Hockey.

• Korean Journal of Applied Biomechanics
• /
• v.20 no.4
• /
• pp.437-445
• /
• 2010

This study was aimed at comparing selected joint angles at the golf address stance by categorizing three different body types. 43 elite male golfers were selected and 9 of them turned out to be the ectoderm while 24 of them to be the mesoderm. The remaining 10 subjects were the endoderm. The measurement was carried out at the address stance with the number 7 iron and the driver. The result showed that the angle of trunk flexion did not different among body types. The trunk tilting angle became more inclined to the right side, which confirmed the guidelines from most of golf lesson books, for bigger people since they tended to put more weight on the right foot. The angle of both knees showed similar but the right knee was bent more than the left knee. The target direction and body alignment faced more to the left side than the target spot because of the influence of open stance and natural aiming position. It seems that pelvis and knees turned a little bit more to the right side than the target direction in order to maintain the parallel. Overall, significant differences among body types were found at the trunk tilting angle and pelvis-target alignment and golf address configuration can be differentiate by these factors.

• Physical Therapy Rehabilitation Science
• /
• v.5 no.1
• /
• pp.22-28
• /
• 2016

Objective: The Back Mapper is one type of Rasterstereography and it can be used in the clinic without radiation exposure. The purpose of our study was to prove the reliability and validity of the Back Mapper and to compare it with the Spinal Mouse, which is an assessment tool for spinal curvatures using a wheeled mouse, and the Cobb angle by X-ray. Design: Cross-sectional study. Methods: Twenty healthy adults participated in the test to investigate for the inter-rater reliability, intra-rater reliability, and concurrent validity. The tests were performed with assessment devices for scoliosis such as the Back Mapper, Spinal Mouse and Cobb's angle. Data was analyzed by an intraclass correlation coefficient (ICC) value and a standard error of measurement for reliability and correlation analysis for validity. Results: Intra-rater reliability of the Back Mapper was good (Cronbach's ${\alpha}$=0.821-0.984, ICC=0.696-0.969) except for assessing the lordotic angle. Inter-rater reliability was good (Cronbach's ${\alpha}$=0.870-0.958, ICC=0.770-0.919) in assessment for trunk imbalance, rotation of scapulae, thoracic angle, lumbar angle, and kyphotic angle. The kyphotic angle in the Spinal Mouse had a significant correlation icompared with the Back Mapper (r=0.510, p<0.05), and the Cobb's angle from an X-ray had a significant correlation with trunk inclination (r=0.532, p<0.05). Conclusions: These findings provide good intra-reliability of the Back Mapper in healthy subjects, but the Back Mapper requires more experienced practice to have good inter-reliability. Also, the variables of the Back Mapper does not seem as appropriate compared with the Cobb angle by X-ray.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.4
• /
• pp.73-82
• /
• 2007

The purpose of this study was to qualitatively analyze coordination pattern of joints and segments during Dwichagi in Taekwondo and present a point of difference as compared with the previous study on Dolryeochagi in Taekwondo. By the utilization of three-dimensional cinematography, the angles of individual joints and segments of six male Taekwondo experts during Dwichagi were calculated by using Euler's angle. The used coordination variables were angle vs. angle plots between adjacent joints and segments and angle vs. angular velocity plots of individual joints and segments, respectively. It was observed during Dwichagi that in-phase coordination and spring-like rotational control mechanism of the lower and upper trunk were transferred into straight spring-like control mechanism of lower leg passing through flexion-extension and the fixation of degree-of-freedom of lower trunk and hip joint alternatively. This comparative study that coordination variables were used seems to be more useful research direction to deeply understand basic control mechanisms of Taekwondo kicking techniques when compared with the previous studies that defined Dwichagi as a thrust movement pattern merely based on biomechanical variables of a kicking leg.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.7
• /
• pp.805-810
• /
• 2012

Determining of the exercise intensity is very important in terms of induction of low fatigue during exercise. Little information is available on the contraction level of the trunk muscles during whole body tilts with and without axial rotation. This study was to investigate the difference muscle activation level according to axial rotation. Twenty subjects were participated. The muscle activities of the five trunk muscles were bilaterally measured at eight axial rotation angles with 12 tilt angles along $15^{\circ}$ intervals. The results showed that tilt with $45^{\circ}$ axial rotation was more balanced in the same tilt angle and was maintained approximately level of 40% MVC at over $60^{\circ}$ tilt angle with respect to co-contraction of abdominal and back muscle. Lumbar stabilization exercise using whole body tilts would be more effective with axial rotation than without axial rotation in terms of muscle co-contraction.

• Korean Journal of Applied Biomechanics
• /
• v.31 no.1
• /
• pp.37-43
• /
• 2021

Objective: The purpose of this study was to investigate the effect of mobile phone text messaging on the collision avoidance strategy for an approaching and stationary pedestrian. Method: Eighteen healthy young adults participated in this study. Each participant was asked to perform a task to walking with/without mobile phone text messaging and a task to avoid collisions with another pedestrian who was approaching or stationary during walking. Results: When text messaging with avoidance collision, it showed an early onset time, a larger mediolateral COM trajectory, trunk rotation angle and trunk rotation velocity (p<.05). Also, compared to an approaching pedestrian, when avoiding collision with a stationary pedestrian, it showed a later onset time, a lager avoidance displacement, mediolateral COM trajectory, trunk rotation angle (p<.05). Conclusion: Results suggest that mobile phone text messaging while collision avoidance leads to delay the perception stage and alters the adaptation stage. Consequently, pedestrian executed in an exaggerated avoidance action to create a greater safety margin when attending to mobile phone test messages while avoiding another pedestrian.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.5
• /
• pp.637-644
• /
• 2011

Objective & Background: When applying various evaluation tools that analyze work posture risk through observation, accurate measurement of body flexion angle is very important. Method: This study investigated differences and appropriateness of 5 different existing reference points commonly used in the analysis of the work posture. Twenty five ergonomist and trained professionals were participated in this study. A Same flexion angle was utilized for the evaluation of risk assessment of musculoskeletal disorders using five different reference points to investigate the degree of difference between them. To investigate how different the observers' preferred flexion angle measuring methods were compared to the ISO 11226 Reference Posture, a virtual body model was constructed using the Poser 6.0 program. Six types of body flexion postures were constructed, and since neck flexion differs according to body angle, five types of neck flexion postures were constructed with the trunk bending $20^{\circ}$ forward, making up a total of 30 virtual flexion postures. Results: Results showed that the observers used personally preferred reference points instead of reference points recommend in the evaluation tools. Also the results revealed the their seems to be 6 types of flexion angle for the trunk and 11 types of measurement methods for the neck flexion angle in the form of personally preferred reference points. The results showed that a mean difference of $14^{\circ}$($4{\sim}23^{\circ}$) occurred in the trunk, and a mean difference of $20^{\circ}$($-8{\sim}51^{\circ}$) occurred in the neck. To increase accuracy when using the 5 evaluation tools in combination, the ISO 11226 standards, observers' preferred flexion posture standards, and common flexion posture standards of the evaluation tools were compared with the reference points of the 5 evaluation tools. Results showed considerable variance in angle difference for each evaluation tool. Conclusion: According to the results of this study, considering the angle difference between the flexion angle reference points of the evaluation tool and the reference points selected by the observers, it is concluded that instead of personally preferred reference points, the standardized reference points to enhance the accuracy and the objectivity. Application: The result of this study can be used as reference guide to develop the standardized reference point in the future.