• Structural Engineering and Mechanics
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• v.85 no.6
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• pp.809-823
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• 2023

In this work, dynamic stability analysis of the ball after contacting with the earth in the volleyball game is presented. Via spherical shell coordinate, the governing equations and general boundary conditions of the ball after contacting with the earth in the volleyball game is studied. Via Comsol multi-physics simulation, some results are presented and a verification between the outcomes is studied. Harmonic differential quadrature method (HDQM) is utilized to solve the dynamic equations with the aid of boundary nodes of the current spherical shell structure. Finally, the results demonstrated that thickness, mass of the ball and internal pressure of the ball alters the frequency response of the structure. One important results of this study is influence of the internal pressure. Higher internal pressure causes lower frequency and hence reduces the stability of the ball.

• Archives of Plastic Surgery
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• v.49 no.3
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• pp.440-443
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• 2022

Spinal accessory nerve (SAN) palsy is typically a result of posterior triangle surgery and can present with partial or complete paralysis of the trapezius muscle and severe shoulder dysfunction. We share an atypical case of a patient who presented with SAN palsy following an injury sustained playing competitive volleyball. A 19-year-old right hand dominant competitive volleyball player presented with right shoulder weakness, dyskinesia, and pain. She injured the right shoulder during a volleyball game 2 years prior when diving routinely for a ball. On physical examination she had weakness of shoulder shrug and a pronounced shift of the scapula when abducting or forward flexing her shoulder greater than 90 degrees. Manual stabilization of the scapula eliminated this shift, so we performed scapulopexy to stabilize the inferior angle of the scapula. At 6 months postoperative, she had full active range of motion of the shoulder. SAN palsy can occur following what would seem to be a routine volleyball maneuver. This could be due to a combination of muscle hypertrophy from intensive volleyball training and stretch sustained while diving for a ball. Despite delayed presentation and complete atrophy of the trapezius, a satisfactory outcome was achieved with scapulopexy.

• Structural Engineering and Mechanics
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• v.83 no.5
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• pp.681-692
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• 2022

The vibrational response of the two bones in a Volleyball player's arm under ball impact is conducted. The two bones in hand, Ulna and Radius, are modeled as two cylindrical shells. The formulations associated with the shells' vibration are obtained using the energy method. Then, the results are extracted with the aid of the two-dimensional form of DQM in conjunction with Runge-Kutta. The results are validated by means of a published paper. Lastly, the role of parameters in determining vibrational frequency as well as deflection is explored through parametric studies. It was shown that the impactor speed and the time of the impact could be essential factors in determining the vibration behavior of the bones. This work can be used in the further investigation of the behavior of bones and physiological structures.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.191-199
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• 2007

This study was conducted to examine the biomechanical characteristics of open spike in the volleyball to improve the technique of the volleyball spike. The subjects were six male college and high school athletes. The motions of volleyball spike were filmed by using two Sony VX 2000 Video Cameras. The mechanical factors were angle and angular velocity of body segments in the upper and the lower limbs. The conclusions were as follows; 1. The angle of the shoulder joint of the skilled showed larger than that of the unskilled in impacting of the volley ball spike. 2. The angle of the elbow joint of the skilled showed larger than that of the unskilled in impacting of the volley ball spike. 3. The angle of the wrist joint of the skilled showed smaller than that of the unskilled in impacting of the volley ball spike. 4. The angle of the hip joint of skilled showed larger than that of unskilled in impacting of the volley ball spike. 5. The angle of the knee joint of the skilled and the unskilled showed same in take off and impacting of the volley ball spike, and that of the skilled showed smaller than that of the unskilled in take-off touchdown and touchdown after impact of the volley ball spike. 6. The angle of the ankle joint of skilled showed larger than unskilled in take-off of the volley ball spike. 7. The angular velocity of the shoulder joint, elbow joint, wrist joint of the skilled showed faster than that of the unskilled in impacting of the volley ball spike. Taken together the result of them, I have come to conclusion that knee joint angle in touchdown of the take off should be decreased and knee joint angle in take off should be increased, and then stability of the take off should be made and, and that extension of the elbow joint should be made and wrist joint angle decreased and shoulder and hip joint angle increased, and then C.O.G of the arm and hand should be positioned ahead C.O.G of the body in impacting for effective impact of the spike, and that the transfer of the angular velocity of body segments for effective impact of the spike make from the proximal segment to the distal segment at spike in volleyball.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.1-18
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• 2005

The purpose of this study was to evaluate performance characteristics. in the success of team attack during volleyball competition. For this, real game was analyzed using S-VHS video camera for three dimensional cinematography. The contents of this research were receive to set time, set to spike time, setter moving distance, ball position during set and attacker's relative ball position during jump and spike, and open area at spike. Among the various kinematical factors considered in this study, the ball height relative spiker and open area were found to be related to offensive performance. This finding implies that although their direct impact were not significant the other factors could have indirect impact on offensive performance by increasing open area. Thus, receiver, setter, assistant attacker, and main attacker should practice for successful performance in each stage. Lastly, it is necessary to develop kinematic variables to evaluate performance characteristics of players. Further study may consider the best defense position against the attack of the opponent player.

• Journal of Convergence for Information Technology
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• v.9 no.7
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• pp.153-158
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• 2019

The purpose of this study was to compare the isokinetic muscular strength of the knee joint between female volleyball and table tennis players. A total of 27 elite volleyball players and 27 table tennis players participated in the study. This study measured both knee extensor and flexor strengths of volleyball and table tennis players using the isokinetic dynamic test. Peak torque was measured by performing maximal voluntary flexion and extension three times at $60^{\circ}/s$. Volleyball players had higher knee extensor and flexor strengths than table tennis players. No significant difference in both knee strengths was noted in table tennis players. However, volleyball players showed significant differences in both knee strengths. Height and weight showed a positive correlation with knee strength. This study found that volleyball players had greater knee strength than that of table tennis players. We also found that volleyball players have asymmetrical knee strength. Comparison with other sport players is warranted to better understand isokinetic muscular strength of the knee joint.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.143-151
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• 2021

The purpose of our study is to confirm the trend of the muscle activity of the trunk and lower limb muscles by the attack method and phase during volleyball exercise. To achieve this purpose, spike serve and spike were conducted for 9 male middle school students, and at that time, it was divided into four phase, such as run jump, take off, impact, and follow, and the rectus abdominis, erector spine, and left rectus femoris, left biceps femoris, left anterior tibialis, left gastrocnemius midialis, right rectus femoris, right biceps femoris, right anterior tibialis, right gastrocnemius midialis, were examined. Spike serve and spike were each performed three times, and randomly cross-allocated to extract accurate data. We was no difference in all muscles according to the attack method, and the muscle activity of the rectus abdominis was highest in the impact phase and the muscle activity of the vertebral spine muscle was highest in the close-up phase. In addition, all of the measured left and right lower limb muscles showed the highest muscle activity between the assisted devices. As a result, We found out that regardless of the method of spike serve and spike, the lower limbs in the run-up phase for a high jump, the vertebrae in the take off phase, the preparation phase for hitting the ball strongly, and in the impact phase at the moment of hitting the ball. It can be seen that it exerts the greatest power in the rectus abdominis.

• Journal of the Korean Data and Information Science Society
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• v.27 no.5
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• pp.1413-1421
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• 2016

In this paper graphical exploratory data analyses are proposed for ball games in sports. The plot of sequence of scoring points of each team can be used to see how the playing game has been processed until the end of each set or quarter. With the plot of sequential score differences through all the games we can see a dominance of each team and the times of score changes, i.e., turnovers. The ternary plots show the contours of scoring compositions for each player and enable us to compare the scoring patterns of each team if any. Using the score sequence plot we also can see the score pattern distribution of players. For demonstration we use the results of the gold medal match between Russia and Brazil for men's volleyball and between USA and Spain for men's basketball at the London 2012 Summer Olympics.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.125-134
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• 2006

The purpose of this study was to analyze the Biomechanical elements by looking at the differences on the motions of the right and left spikes of right-handed offense volleyball players, using 3D image analysis and force platform. For that purpose, spike motions of six male university volleyball players were recorded three times each using two 16mm high speed cameras and the speed of recording was set at 60 frames/sec. The coordinated raw data was leveled as 6Hz using low pass filtering method and the calculation of 3D coordinates was done by using a DLT (Direct Linear Transformation) method. Also KWON 3D program was used to analyze the variables. Through the experiments and research, the following results were found: That is, in case of the right spike, the required time from the toss to the impact, which affected the success rate of offense showed as longer and on the take-off, the exact timing to touch the ball was longer because the pace between right and left feet was wider, and also after the jump, the distance between the feet indicated shorter, than the left. In addition, the degree of somersault and horizontal adduction of shoulder joint was smaller and the degree of medial rotation of shoulder joint showed bigger than the left, so it indicated that it was not centered on the body, but by the arm with an axis of shoulder using a swing motion. After the impact, the speed of the ball indicated slower compared to the left spike.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.57-64
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• 2015

Purpose : The purpose of this study was to analyze setter toss motion kinematically according to toss types. Method : Dependent variables were elapsed time, vertical displacement of the body center, the projected speed of the ball, and differences of the joint angle to the target for four setters positioning. Result : There was no significant difference in the time but the ball contact time was shorter when the toss distance of P3 was longer. There was significant difference in the vertical displacement of COM (p<.05). The vertical displacement of COM showed that the vertical movement gradually decreased when the quick distance was longer. The vertical displacement of COM was difference (p<.05), also there was difference of the ball speed (p<.001) at the Release point(E4). There was significant difference in the knee joint angle at a certain moment among the Release(E4) and Landing point(E5)(p<.05). The hip joint was significant difference among the Apex(E2), Ball Touch(E3), Release(E4), and the Landing point(E5) on the surface(E2, E3, E4 p<.05; E5 p<.005). The shoulder angle was significant difference among the Ball Touch(E3), Release(E4) and the Landing point(E5) on the surface(E3, E4 p<.05; E5 p<.001). The elbow was significant difference in the Apex(E2) (p<.05). The wrist was significant difference in the Release(E4) (p<.05). Conclusion : If we find the clue to expect the direction of the setter's ball, we have to fine the clues in the Apex(E2) that hip join and elbow, Ball Touch(E3) that hip joint and shoulder joint, Release(E4) that wrist, elbow, hip joint, and knee joint.