Aneta Popieluch, Michał Staniszewski and Michał Wychowański
Introduction. The main aim of the study was to assess the strength of the shoulder rotator muscles of a group of second-league volleyball players. These muscles are assumed to have a crucial impact on attack effectiveness in volleyball. Strength was assessed based on peak torque values obtained for the rotator muscles measured using the maximal voluntary contraction (MVC) method. Torque was measured in both limbs and the differences between the two limbs were examined. The torque values obtained for the volleyball players were also compared against those measured in a group of students who had never trained any sports.
Material and methods. The study involved 20 students (mean age = 20 ± 1 years) who played in the second league when the study was conducted. Their results were compared with those of a control group consisting of 30 students (mean age = 20 ± 1 years) who had not trained any sports. Peak torque of the shoulder rotator muscles was measured during external and internal rotation of the shoulder in isometric conditions. The assessment was performed on a special measuring station with the forearm in a vertical and horizontal position. The following basic statistics were calculated for the torque values obtained in the measurement: the mean, standard deviation, minimum value, and maximum value. The data were then subjected to statistical testing.
Results. Compared to the students, the volleyball players had higher torque values of the internal and external rotators of the right and left shoulders, in both positions of the forearm. When the results obtained for the right and left limbs were compared for the group of volleyball players, it was found that the torque values for the right limb, which was the dominant limb, were significantly higher than those recorded for the left limb. The study also showed that the position of the forearm had an impact on torque values: when the forearm was in a horizontal position, higher mean values were obtained for the external rotators of the right (p < 0.05) and left (p < 0.01) limbs, and when it was in a vertical one, the internal rotators were stronger compared to the external rotators.
Conclusions. The shoulder rotator muscles of the volleyball players were found to be considerably stronger than those of the students, and the rotators of the dominant limb were significantly stronger than those of the non-dominant limb in the group of volleyball players. The position of the forearm had a considerable impact on the strength of the internal and external rotator muscles. The maximal voluntary contraction method used in the study can be helpful in measuring the strength of the shoulder rotator muscles in any phase of the training process.
Ronald L. Snarr, Ashleigh V. Hallmark, Jason C. Casey and Michael R. Esco
during three common pull-up exercise variations. Balanced training of the shoulder joint complex is crucial for increasing endurance and strength of the multitude of muscles responsible for glenohumeral movement ( Lehman et al., 2004 ; Lusk et al., 2010 ). Traditional weight lifting programs often demonstrate a strong focus on pressing exercises with less concern for pulling movements; thereby creating a common muscular imbalance within the shouldercomplex. Although a push:pull ratio for the upper body should be approximately 1.00 ( Beeler et al., 2013 ), research
Elżbieta Olszewska, Piotr Tabor and Renata Czarniecka
Study aim: The aim of this study was to evaluate the incidence of contractures of selected muscle groups with respect to the magnitude of the physiological curvatures of the spine in young men with above-average levels of physical activity.
Material and methods: The study included 96 students at the University of Physical Education in Warsaw aged between 20 and 22 years (21.2 ± 1.05). Ninety-five percent of the students participated in sports training activities. The study was conducted between January and February 2016. The selected traits of the body posture were evaluated with an inclinometer, which was used to measure the inclination angles of sections of the spine relative to the vertical. The ranges of motion in the shoulder complex and the pelvic complex were measured with a goniometer. Values of 175º (for the shoulder complex) and 174° (for the hip joint) were assumed to indicate a decreased range of motion.
Results: The analysis of the individual results concerning mobility disorders in the shoulder complex and the pelvic complex revealed significant abnormalities in the researched group of students. About 90% of the study participants showed contractures of selected muscle groups within the shoulder girdle, primarily in the right upper limb. Similar results were obtained for the incidence of contractures in the flexors of the hip joint. Flexion contractures in the hip joint were observed in around 84% of the participants, primarily in the left lower limb. The correlations between the inclination angles of the sections of the spine relative to the vertical and the ranges of motion in the shoulder complex and the pelvic complex, established using Pearson correlation coefficients, were ambiguous. The angles γ, β1 and α were inversely proportional to the range of raising motions of the upper limbs through flexion, where the correlation coefficients of all angles were statistically significant. Similar tendencies were observed for the correlations between the angles β2, β1 and α and the range of the extension movements at the hip joint, although the correlation coefficients were statistically significant only in the case of the angle β1.
Conclusions: Ranges of movement in the shoulder complex and pelvic complex have an influence on magnitude of physiological curvatures of the spine and the functioning of body posture.
Arletta Hawrylak, Dorota Wojna and Krystyna Chromik
Introduction. Doing asymmetric sports when one suffers from body asymmetry may cause body posture disorders. The aim of the study was to assess the spinal and shoulder complex mobility of professionally trained volleyball athletes compared to that of their peers who do not practise any sports.
Material and methods. The study involved 60 participants divided into two groups. Group 1 consisted of 30 girls aged 14 years. The average height in the group was 176.37 ± 6.29 cm, and the average body mass was 64.53 ± 7.12 kg. Group 2 consisted of 30 girls aged 15.6 ± 1.12 years who did not practise any sports. The average body height in this group was 159.37 ± 3.33 cm, and the average body mass was 51.83 ± 4.03 kg. The dominant limb was defined on the basis of lateralization. The spinal range of motion was measured by means of a Saunders digital inclinometer, and the shoulder complex range of motion was examined using the goniometric method. Means and standard deviations were calculated, and Student’s t-test was applied in order to determine the differences between the two groups.
Results. The differences in the values obtained in the two groups for the spinal range of motion in the sagittal plane were statistically significant only for the range of lumbar spine bending and extension. It was found that group 1 had a higher range of spine mobility in the frontal and transverse planes, and the differences were statistically significant in all the assessed ranges towards the dominant limb. An analysis of the shoulder girdle range of motion in the groups revealed that the differences were also statistically significant in all of the examined ranges.
Conclusion. Professional volleyball practice can cause an increase in spine flexibility in most of its ranges, and the shoulder girdle range of motion in female volleyball players can exceed population norms, especially for the upper dominant limb.
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, Woodhouse D, Briffa K, Hopper D. Throwing velocity and jump height in female water polo players: performance predictors. J Sci Med Sport 2010; 13(2): 236–240 10.1016/j.jsams.2009.02.008
McCluskey L Lynskey S Leung CK Woodhouse D Briffa K Hopper D Throwing velocity and jump height in female water polo players: performance predictors J Sci Med Sport 2010 13 2 236 – 240
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Nuno Batalha, Sónia Dias, Daniel A. Marinho and José A. Parraca
2004 91 22 29
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