• Journal of International Academy of Physical Therapy Research
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• v.8 no.2
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• pp.1158-1162
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• 2017

The purpose of the study was to investigate the strength of sokinetic muscle by the position of a volleyball players. Analysis and comparison of shoulder dynamic stability will be conducted according to rotational movement of the shoulder during spiking and serving amongst the various positions. Fifty professional Korean female volleyball players (age: 20~30), all different positions - attacker (left and right), center, setter, and libero were The concentric peak torque, strength ration of the internal and external rotation of the shoulder girdle for both dominant and non-dominant arms. Firstly, there were significant differences found for the strength ratio between the setter and the other positions in the dominant arm. On a second note, there was a significant decrease in shoulder dynamic stabilization for both the attacker and center in the dominant arm. However, there were no significant differences for the setter or the libero. This study suggests that the isokinetic muscle strengths of the volleyball players are different from each other.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.438-447
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• 2012

This study was to explore the social network structure of professional volleyball players and analyze network variables and resource exchange. This study selected 127 players of Korean professional volleyball in ten team of male and female using the purposive sampling method. The research method utilized general social survey of NGQ(Name Generator Question) and interview. To analyze data, NetMiner 3.0 and SNA(social network analysis) were used. The conclusion based on above study method and the result of material analysis are here below. First, social network of professional volleyball players is scale-free network following power law. Centrality and herb of club members' network show up richer-get-richer and poor-get-poor by collecting links of back of beyond. Second, social network structure of professional volleyball players influence resource exchange.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.45-55
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• 2007

We investigated the biomechanics and characteristics of shoulder rotator muscles for professional woman volleyball players. The purpose of this study was to analyze the isokinetic peak torque and range of motion for shoulder joint rotation. We measured the strength and ROM of the internal rotation(IR) and external rotation(ER) of shoulders joint for nine professional woman Volleyball players and nine University students with Biodex and Simi-motion. 1. We measured peak torques for the shoulder joint rotator at angular velocities of 60/s and 180/s. It was found that the peak torques were significantly different between the two groups and also between the hands used. 2. At angular velocity of 60/s, IR/ER ratio of the shoulder joint was significantly different depending on the groups and the hands in use. There was a significant difference for 'Dominant side' at angular velocity of 180/s, but no significant difference for 'Non-dominant side' and the controls group. 3. Regarding the ROM of rotation of the shoulder joint group, IR was significantly different between the groups and the hands in use. 4. IR/ER ratio of the shoulder joint for Dominant side was quite different between the groups.

• Journal of International Academy of Physical Therapy Research
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• v.12 no.1
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• pp.2279-2285
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• 2021

Background: The spinal nerves, which start at the lumbar level, are connected to the nerve innervation in the knees. Currently, there is a lack of research on the treatment of knee pain through lumbar mobilization. Objectives: To investigate the effects of lumbar joint mobilization (LJM) and transcutaneous electronic nerve stimulation (TENS) on proprioception and muscular strength in volleyball players with chronic knee pain. Design: Two group pre-posttest. Methods: A total of 26 professional volleyball players with chronic knee pain were allocated to the LJM (n=13) and TENS (n=13) groups. In the LJM group, grade III - IV amplitude was applied 3 times for 1 minute (80 times per minute) at the affected lumbar (L2-3) facet joint in the prone position. In the TENS group, the TENS treatment device was used to directly apply or 15 minutes to the area of chronic knee pain (100 Hz, 150 ㎲). Proprioception was measured by knee flexion and extension angles, and muscle strength was evaluated using an isokinetic test. Measurements were taken before and after interventions. Results: In the eye opened conditiond, proprioception significantly increased during both knee extension and flexion after LJM, while only knee extension was significantly increased in the TENS group. There was also a significant difference in knee extension between the two groups. In the eye close conditiond, proprioception was significantly improved only during knee extension in the LJM group, and the difference in knee extension between the groups was also significant (P<.05). The maximum torque of the affected knee joint was significantly improved at 60°/sec in both groups (P<.05); however, there was no difference between the two groups. There was no significant difference in the maximum flexion torque within or between the groups. Conclusion: This study suggests that LJM improved proprioception and muscular strength in volleyball players with chronic knee pain.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.549-555
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• 2009

The purpose of this study was to quantify the isokinetic peak torque and range of motion at the shoulder in 8 national male volleyball players who played during the 2008 professional leagues. In this study the strength and range of motion data in the internal rotation(IR) and external rotation(ER) of shoulder joint were measured with isokinetic measurement system(Biodex Inc) and motion analysis system (Simi motion system Inc.) from 3 volleyball players with atrophy of the infrasupinatus and 5 volleyball players without atrophy of the infraspinatus. Peak torques were determined using isokinetic measurement on the shoulder joint rotator at the point of angular velocities of $60^{\circ}$/s. Significant difference was found in the peak torque, IR / ER ratio and the range of motion through assessment of the dominant shoulder between two groups. we recommended functional exercises that improve both external rotators strength and stretching exercise for internal rotation in the dominant side during the prevention programs in volleyball players.

• Journal of International Academy of Physical Therapy Research
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• v.2 no.1
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• pp.229-236
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• 2011

The purpose of this study was to comparatively analyze the active stability of shoulder joints according to the frequency of overhead motions, such as serving and spiking, engaged in by female professional volleyball athletes who play different positions, and to provide the results as the basic data for developing exercise programs to prevent shoulder joint injuries. The subjects of this study were 50 Korean female professional volleyball players and positions were as follows: left and right attackers, centers, setters, and liberos. The external rotation and internal rotation muscle strength and muscle strength ratios of the dominant and non-dominant arms of all subjects were measured using Biodex. The results of this study are as follows: Frist, no significant differences were found in the internal and external rotation muscle strength of the dominant and non-dominant arms between positions. Second, for the shoulder joint muscle strength ratio of the dominant arm, by position, the setter showed significantly greater stability compared to the other positions. Third, for the shoulder joint muscle strength ratio of the non-dominant arm, by position, no significant difference in stability between positions was found. Fourth, it was found that the dominant arm had significantly greater instability of the shoulder joint than the non-dominant arm for attackers and centers, but no significant difference was found for setters and liberos. This study comparatively analyzed the muscle strength ratios of the external/internal rotations and dominant/non-dominant arms, which can determine the stability of the shoulder joints between female professional volleyball playing positions that engage in jumps and spikes using only the dominant hand and positions that do not.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.359-367
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• 2009

This study was conducted to provide useful information for the scientific training of spikes and instruction, by analyzing all kinematical variants including time, distance, velocity, angle factors in spike movements of volleyball matches. The subjects were 4 foreigner players, who participated in the V-League of 2008-2009. The conclusion from this study is as follows. Time for a jumping step was .33s, and Angelko had a bit longer takeoff time than other players. In Angelko and Anderson who were leading in attack power, the whole distance of a spike motion was relatively short, less than 4m. The moment when the center of gravity reached the lowest point was when the right foot bearing weight in the jumping step was passing the left foot, and the highest point of gravity was 2.30m, which appeared just before the impact. The horizontal speed of the center of the gravity was highest as 4.19m/s at the beginning of a jumping step, and lowest at the stance phase of the fore foot just before takeoff. The vertical speed of the center of the gravity was lowest after the right foot touched the ground, and highest after the takeoff of the fore foot. Impact was 3.22m, and the highest ball speed was 28.18m/s.

• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.619-630
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• 2015

The purpose of this study is to provide basic information to develop a game strategy plan of a team in a future by identifying the patterns of attack and pass of national men's professional volleyball teams and extracting core key words related with volleyball game performance to evaluate game performance using 'social network analysis' and 'text mining'. As for the analysis result of 'social network analysis' with the whole data, group '0' (6 players) and group '1' (11 players) were partitioned. A point of view the degree centrality and betweenness centrality in 'social network analysis' results, we can know that the group '1' more active game performance than the group '0'. The significant result for two group (win and loss) obtained by 'text mining' according to two groups ('0' and '1') obtained by 'social network analysis' showed significant difference (p-value: 0.001). As for clustering of each network, group '0' had the tendency to score points through set player D and E. In group '1', the player K had the tendency to fail if he attack through 'dig'; players C and D have a good performance through 'set' play.