• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.49-59
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• 2006

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle 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. 1. In three dimensional linear velocity of blade the Y axis showed maximum linear velocity almost impact, the X axis(horizontal direction) and the Z axis(vertical direction) maximum linear velocity of blade did not show at impact but after impact this will resulted influence upon hitting puck. 2. The resultant linear velocity of each segment of right arm showed maximum resultant linear velocity at impact. It could be suggest that the right arm swing patterns is kind of push-like movement. therefore the upper arm is the most important role in the right arm swing. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed flexion all around the wrist shot. The angular displacement of trunk in internal-external rotation showed internal rotation angle at the backswing top and and increased the angle after the impact. while there is no significant adduction-abduction. 4. The three dimensional anatomical angular displacement of trunk showed most important role in wrist shot. and is follwed by shoulder joints, in addition the movement of elbow/wrist joints showed least to the shot. this study result showed upperlimb of left is more important role than upperlimb of right.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.25-31
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• 2016

PURPOSE: The purpose of this study was to compare the trunk muscle activity according to the direction of upper extremity lifting using elastic band. METHODS: Thirty three healthy individuals participated in this study. Each subject performed upper extremity lifting using elastic band on two different directions (straight and diagonal). And then we compared the muscle activity of respective trunk muscles of both directions. In order to examine the muscle activity of trunk muscle, we used the electromyogram to measure peak and mean torque in shoulder 90 degree flexion with sitting position. Electromyographic activities were recorded from the external oblique, internal oblique, rectus abdominis, and erector spine muscles during upper extremity lifting. RESULTS: As a result, first, there was significant difference between two directions. The muscle activity of ipsilateral external oblique and contralateral internal oblique is significantly increased in both straight and diagonal directions (p<0.05). Second, the muscle activities of external oblique and internal oblique of both side showed significant difference in diagonal direction (p<0.05). Third, the muscle activity of erector spine of both side showed significant difference in straight direction (p<0.05). CONCLUSION: Through this study, it is important that implement diagonal direction exercise at sitting positions to help increasing muscle activity of ipsilateral external oblique and contralateral internal oblique on patients when activating the trunk muscle or stabilizing the trunk.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.13-24
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• 2005

The purpose of this study was to compare kinematic data between experts and novices, and identify difference kinematic parameters changing direction to kick in penalty kick of soccer play. Novice subjects were 5 high school students Who has never been experienced a soccer player, and expert subjects were 5 competitive high school soccer players. The 3-d angle was calculated by Euler's Angle by inertial axis and local axis with three-dimensional cinematography. Kinematic parameters in this study consisted of angles of knee joints, hip joints, lower trunk and upper trunk when the support foot was contacted on ground and kicking foot impacted the ball. The difference of angle of knee joints in the flexion/extension was insignificantly showed below $4{\sim}9^{\circ}$ in groups and directions of ball at the time of support and impact. But the difference of angle of hip joint was significant in groups and directions of ball at the time of support and impact. Specially the right hip joint of experts were more flexed about $12^{\circ}$($43.99{\pm}6.17^{\circ}$ at left side, $31.87{\pm}4.49^{\circ}$ at right side), less abducted about $10^{\circ}$ ($-31.27{\pm}4.49^{\circ}$ at left side, $-41.97{\pm}6.67^{\circ}$ at right side) at impact when they kicked a ball to the left side of goalpost. The difference of amplitude angle in the trunk was significantly shown at upper trunk not lower trunk. The upper trunk was external rotated about $30^{\circ}$ (novice' angle was $-16.3{\pm}17.08^{\circ}$, expert's angle was $-43.73{\pm}12.79^{\circ}$) at impact. Therefore the significant difference of kinematic characteristics could be found at the right hip joint and the upper trunk at penalty kick depending on the direction of kicking.

• Journal of the Korean Society of Safety
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• v.26 no.3
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• pp.69-74
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• 2011

Despite most of tasks in manufacturing, construction and agriculture, etc., were currently mechanized and automated, manual materials handling still existed in atypical working condition. In case of manual materials handling, repetitive work, inappropriate working posture, excessive force, contact stress might cause overload, which could lead to work-related musculoskeletal disorders and low back pains. On this basis, the goal of this study is to reveal the effects of various lifting postures of trunk angles and lower extremity postures on maximum holding time(MHT). Twenty two subjects were recruited from a university population. The experiment was designed by a combination of three trunk angle ($0^{\circ}$, $20^{\circ}$, $60^{\circ}$) and three lower extremity postures(straight, bent, kneeling). Before experimental trials, subjects performed MVC(maximum voluntary contraction) exertions in three trunk angles ($0^{\circ}$, $20^{\circ}$, $60^{\circ}$) to calculate 30%MVC at designated postures. In each trial, they were required to hold the handheld load(30%MVC) for a designated posture as long as they could. The results of MVC by trunk angles were measured in $0^{\circ}$ > $20^{\circ}$ > $60^{\circ}$ orders, but those of MHT measured in $20^{\circ}$ > $0^{\circ}$ > $60^{\circ}$ orders. These results showed that straight posture is the ideal working posture in work exerted a strong force for a short time, but the ability to work might be improved in the trunk angle $20^{\circ}$ in work required 30%MVC for a long time. Also, results of MVC and MHT by lower extremity postures measured in straight > bent > kneeling orders.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.205-211
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• 2021

Objective: This study aimed to identify the effects of assuming different knee angles and hip abduction during bridge exercise and hip thrust exercise on lower body muscle activity. Design: Cross-sectional study Methods: Thirty-three healthy adults (18 men and 15 women) were instructed to perform the bridge and hip thrust exercises while randomly assuming 120°, 90° and 60° of knee flexion and 0° and 30° of hip abduction. EMG data (%maximum voluntary isometric contraction) were recorded three times from the erector spinae (ES), gluteus maximus (GM) and biceps femoris (BF) muscles of participant's dominant side and the mean values were analyzed. Results: The results showed that, during the hip thrust compared to the bridge exercise, there was significantly greater gluteus maximus muscle activity in all hip conditions while the biceps femoris activity was significantly less, and the erector spinae muscle activity was significantly greater with 30° of hip abduction (p<0.05). With all exercises, the erector spinae and the biceps femoris exhibited significantly greater muscle activity with 60° of knee flexion compared to 90° and 120° of knee flexion (p<0.05), and significantly greater muscle activity with 90° compared to 120° of knee flexion (p<0.05). In the case of the gluteus maximus, greater muscle activity was exhibited with 120° compared to 60° of knee flexion with all hip abduction conditions (p<0.05). Conclusions: It was effective for muscle activation of main agonists such as the gluteus maximus and erector spinae during thrust exercise, and the change in knee flexion angle was effective for muscle activation of the gluteus maximus. Therefore, it is considered that this study can be used as a selective indicator of the target movement angle during hip strengthening exercise for specific muscles.

• Physical Therapy Rehabilitation Science
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• v.8 no.4
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• pp.175-186
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• 2019

Objective: Non-specific chronic low back pain (NS-CLBP) has been related to abnormal trunk muscle activations, but literature reported considerable variability in muscle amplitudes of NS-CLBP patients during prolonged sitting periods. Therefore, the purpose of this study was to examine the differences among homogenous NS-CLBP subgroups in muscle activity, using muscle co-contraction indices as a more objective approach, and their roles on pain development during a 1-hour period of prolonged sitting. Design: Cross-sectional study. Methods: Twenty NS-CLBP subjects with motor control impairment (MCI) [10 classified as having flexion pattern disorder, and 10 with active extension pattern disorder], and 10 healthy controls participated in the study. Subjects followed a 1-hour sitting protocol on a standard office chair. Four trunk muscle activities including amplitudes and co-contraction indices were recorded using electromyography over the 1-hour period. Perceived back pain intensity was recorded using a numeric pain rating scale every 10 minutes throughout the sitting period. Results: All study groups presented with no significantly distinctive trunk muscle activities at the beginning of sitting, nor did they change over time when pain increased to a significant level. Both MCI subgroups reported a similarly significant increase in pain behavior through mid-sitting (p<0.001). However, after mid-sitting, they significantly differed from each other in pain (p<0.01) but did not differ in the levels of muscle activation. Conclusions: This study was the first to highlight the similarities in trunk muscle activities among homogenous NS-CLBP patients related to MCI and compared them to healthy controls while sitting for an extended period of time, and the significant increase in pain over the 1-hour sitting might not be attributed to trunk muscle activation.

• PNF and Movement
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• v.19 no.2
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• pp.183-193
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• 2021

Purpose: The purpose of this research was to investigate the effects of performing Pilates exercises for eight weeks on the isokinetic trunk strength and balance of female middle school students with lumbago. Methods: Twenty-four female students who met the test requirements were recruited and randomly divided into a control group (CG, n = 16) and a Pilates exercise group (Pilates group; PG, n = 8). The PG performed a Pilates program, which consisted of lumbar muscle strengthening exercises, for 60 minutes three times a week for eight weeks. Data analysis was conducted by two-way repeated ANOVA, and a Bonferroni test was carried out when significant differences appeared. The alpha level was set at 0.05. Results: Following the experimental treatment, the PG showed an increased trunk flexion peak torque of 17% and 13% at angular velocities of 180°/sec and 300°/sec, respectively. The intergroup comparison showed no significant difference at pre-measurement, while the PG increased about 31% (180°/sec) and 15% (300°/sec) higher than the control group at post-measurement. Following the experimental treatment, the PG showed an increased trunk extensor peak torque of approximately 29% and 21% at angular velocities of 180°/sec and 300°/sec, respectively. The intergroup comparison showed no significant difference at pre-measurement, while the PG increased approximately 27% (180°/sec) and 15% (300°/sec) higher than the control group at post-measurement. Both the CG and the PG showed a 20% and 50% decrease in pain index after the experimental treatment, respectively. After the experimental treatment, the PG had about 50% lower pain than the CG. The average error rate of static balance in the PG reduced by 19% from 3.28±0.45 to 2.65±0.36, confirming a significant improvement. Conclusion: Regular Pilates exercise for eight weeks improved the isokinetic trunk muscle strength of female middle school students with lumbago and relieved their pain. Pilates was also shown to be effective in improving balance.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.33-41
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• 2019

Purpose : The muscle strength of iliopsoas (IL) was measured commonly in sitting position with hip and knee flexed 90°. However, there is no study to determine the muscle strength of IL in various test positions. Therefore, the purpose of this study was to compare the muscle strength of IL and muscle activity of rectus femoris (RF) according to test position and knee flexion angle. Methods : Twenty healthy subjects were participated for this study. The muscle strength of IL and muscle activity of RF were measured by hand-held dynamometer and surface electromyography during maximum voluntary isometric contraction (MVIC) of IL, respectively. The muscle strength of IL and muscle activity of RF was measured in 4 conditions as follows; 1) knee flexion angles 90 ° in supine, 2) 130 ° in supine position, 3) 90 ° in sitting, 4) 130 ° in sitting. Each condition were performed randomly by three repetitions. Results : The muscle strength of the IL was the main effect on the test position and knee flexion angle (p<.05), and the muscle activity of RF was the main effect only on the knee flexion angle (p<.05). There was also no interaction between the factors (p>.05). In supine position, the muscle strength of IL in knee flexion 130 ° was significantly less than that in knee flexion 90 ° (p<.0125). In knee flexion 90 °, the muscle strength of IL in supine position was significantly greater than that in sitting position (p<.0125). The muscle activity of RF in knee flexion 130 ° was significantly less than that in knee flexion 90 ° in supine and sitting positions (p<.0125). Conclusion : When the muscle strength of IL was measured in clinic and sports fields, the supine position with knee flexion 130 ° was recommended to prevent the muscle activation of RF and to maintain the trunk stability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.190-199
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• 2017

The purpose of this study is to propose the standard of health-related fitness evaluation according to the working styles of male manufacturing workers. The subjects were 15,329 male manufacturing workers aged from 40 to 59 years old who had taken a health-related fitness test by K Institution. Health-related fitness components are cardiorespiratory endurance, muscular strength, muscular endurance, flexibility and body composition. We measured Vo2max, grip strength, sit-up, trunk flexion forward, and body fat percentage to ascertain each component. Data were analyzed with Two-way ANOVA, T-test, One-way ANOVA(Scheffe) and Percentile using SPSS version 18.0 program. The analysis results are as follows. First, the health-related fitness of manufacturing workers varied significantly according to their working styles(maximum oxygen uptake : F=88.67(p<.001), grip strength : F=20.09(p<.001), sit-up : F=42.06(p<.001), trunk flexion forward : F=69.44(p<.001), body fat percentage : F=136.75(p<.001)).Therefore, the evaluation standard was set based on the percentile of health fitness items. Second, the average Vo2max, grip strength, and trunk flexion forward of blue-collar workers were higher than those of white-collar workers at all ages. On the other hand, the average sit-up and body fat percentage of white-collar workers were higher than those of blue-collar workers at all ages. Third, these evaluation criteria differed greatly when compared with the results of the National Physical Fitness Survey. Therefore, we have confirmed that the evaluation criteria should be applied differently according to the working style of a worker when evaluating his health-related fitness.

• Journal of Yeungnam Medical Science
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• v.37 no.2
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• pp.84-89
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• 2020

Spinal pain is a common patient complaint in clinical practice. Conservative treatment methods include oral medication, physical therapy, injections, and spinal orthoses. The clinical application of orthoses is debated because of potential complications associated with long-term use, such as muscle weakness and joint contracture. We reviewed the orthoses most frequently used to manage spinal pain. We review the use of soft cervical and Philadelphia collars, lumbosacral corsets, and thoracolumbosacral orthosis to manage spinal pain. Spinal orthoses can help reduce pain by protecting the muscles and joints of the injured spinal region, preventing or correcting malformations, and limiting trunk flexion, extension, lateral flexion, and rotation. The short-term use of spinal orthoses is known to improve pain and disability during the treatment period without significant adverse effects. Spinal orthoses are expected to alleviate pain and improve patients' lifestyle.