Change in body composition of female junior volleyball players

The purpose of our study is to monitor and analyze the composition of selected body masses of female v junior volleyball players. The data were obtained from 18 players, aged 14 to 19 years, of the Královo Pole volleyball club in Brno, Czech Republic (VV KP Brno), between 1 August 2014 and 20 December 2014. Body composition was measured by Inbody 230 – Biospace using the bioimpedance measurement method. We obtained the following data from measurement: BMI (Body Mass Index), PBF (Percentage Body Fat), body mass, muscle and fat mass of both upper and lower limbs and the trunk. Mann-Whitney U test is used to compare differences between the values obtained before the preseason preparation, after the preseason preparation and after three months of the season. All statistical computations were performed using R software (R Core Team 2013). Comparing the results after the preliminary part we diagnosed a significant difference (p<0.05) increase of percentage of total fat mass (p=0.0266). After the preliminary part of the season significant difference describing increase of body mass (p=0.0462) was found, together with increase of body fat in left upper (p=0.0313), right upper (p=0.0429) limb and with increase of trunk mass (p=0.0379). The study revealed interesting information about a change of the body mass and body fat percentage of volleyball players of VK KP Brno during the regular season. The findings from the preseason preparation confirmed the expected change, i.e. that the muscle mass increases while the body mass and body fat percentage decrease

Diagnostics Of Isometric And Isokinetic Strength In Junior Elite Tennis Players Within The Context Of Muscular Disbalances

This research aims to determine the strength level of muscle groups in wrist and forearm and to assess lateral differences in junior tennis player group (TEN, n = 10, aged 12–14) and a control group of boys who do not perform any sport activity (CS, n=10, aged12–14) by isometric (hand dynamometer GRIP-D TKK 5401, Takei, Japan) and isokinetic dynamometry (dynamometer Humac Norm CSMI, Stoughton, USA) methods. Diagnostics of concentric extension and flexion was carried out in concordance with Ellenbecker methodology (1991) in angular velocities of 90°/s and 300°/s, results are given in Newton metres (Nm). Data analysis proved substantive insignificant differences between TEN and CS group as long as age, body height and weight are concerned. Isometric dynamometry: using Cohen’s d there were proved substantially significant differences in the strength of dominant extremity in favour of TEN group (d = 0.76) and lateral difference in strength level of right and left upper extremity in TEN group TEN (d = 0.60). Isokinetic dynamometry: in angular velocity of 90°/s were proved substantially significant differences between TEN and CS group in the strength of extensors (d = 1.16) and flexors of right wrist (d = 1.33) as well as in extensors (d = 0.83) and flexors (d = 0.99) of left wrist in favour of TEN group. Similarly, there was proved substantially significant lateral difference in strength level of wrist flexors of right and left hand (d = 0.84). In angular velocity of 300°/s there were proved substantially significant differences between TEN and CS group in favour of TEN group, both in right wrist extensors (d = 0.94) and flexors (d = 1.39). Substantially significant differences in favour of TEN group have been proved also in non dominant upper extremity, both in left wrist extensors (d = 1.27) and flexors (d = 1.12). Neither in TEN nor CS group were proved substantially significant lateral differences in strength of wrist extensors and flexors – with the exception of lateral differences between extensors (d = 0.62) in CS group. Values obtained by assessment of extensors and flexors strength ratio in both TEN and CS groups in both angular velocities signal an increased risk of injury incidence in all cases. From conclusions described above, it is obvious that long-term game and training load significantly increases the level of maximal strength in junior elite tennis players in comparison with the group of their peers who do not perform any sport activity.This research aims to determine the strength level of muscle groups in the wrist and forearm and to assess the lateral differences in a junior tennis player group (TEN, n = 10, aged 12–14) and a control group of boys who do not perform any sport activity (CS, n=10, aged12–14). The method used was by isometric (hand dynamometer GRIP-D TKK 5401, Takei, Japan) and isokinetic dynamometry (dynamometer Humac Norm CSMI, Stoughton, USA). Diagnostics of concentric extension and flexion were carried out in concordance with Ellenbecker methodology (1991) in angular velocities of 90°/s and 300°/s, results are given in Newton metres (Nm). Data analysis proved substantive insignificant differences between TEN and CS group as long as age, body height and weight are concerned. Isometric dynamometry: using Cohen’s d there were proven substantially significant differences in the strength of dominant extremity in favour of the TEN group (d = 0.76) along with a lateral difference in strength level of the right and left upper extremity in TEN group TEN (d = 0.60). Isokinetic dynamometry: in angular velocity of 90°/s revealed substantially significant differences between the TEN and CS group in the strength of extensors (d = 1.16) and flexors of right wrist (d = 1.33) as well as in extensors (d = 0.83) and flexors (d = 0.99) of left wrist particularly in favour of TEN group. Similarly, substantially significant lateral difference in strength level of wrist flexors of right and left hand (d = 0.84) were shown. In angular velocity of 300°/s there was a substantially significant difference between TEN and CS group in favour of the TEN group, both in right wrist extensors (d = 0.94) and flexors (d = 1.39). Substantially significant differences shown in the TEN group have been proved but also in the non-dominant upper extremity, both in left wrist extensors (d = 1.27) and flexors (d = 1.12). Neither group revealed substantially significant lateral differences in strength of wrist extensors and flexors – with the exception of lateral differences between extensors (d = 0.62) in CS group. Values obtained by assessment of extensors and flexors strength ratio in both TEN and CS groups in both angular velocities signal an increased risk of injury incidence in all cases. From the conclusions described above, it is obvious that long-term game and training load significantly increases the level of maximal strength in junior elite tennis players in comparison with the peer group who do not perform any sport activity

The study of vertical ground reaction during walk of Czech women

The aim of this study was to find whether it is possible to explain different plantar loading during absorption and propulsive stages of stance in the observed persons by means of basic body indicators or time characteristics of gait. Fifty-one healthy women participated in the study; their age range was between 30 and 60 years of age. The women were divided into two groups according to whether they reached higher values of vertical ground reaction during absorption (group A, 8 women, 16 %) or propulsive (group B, 43 women, 84 %) stage of stance. Capacitive pressure insoles in the shoe were used (PedarX, Novel Munich). During laboratory survey each woman performed monitored natural walk. Three stances of each leg were assessed, always from between the third and eighth steps. Five parameters had been chosen for monitoring, three recording force characteristics of gait and two time parameters. Group A reached relative value of 121 % of BW during the first stage and 110 % of BW during the second one. Group B reached 105 % in the initial stage, and 117 % of BW in the other stage. A significant difference was found for F1 parameter between groups A and B, not for the second part of stage. Group A manifested shorter duration of both stages of stance (not significantly different from group B). The level of relationship between stance duration as well as its stages and force manifestations in both groups of women was very low (from r= 0.010 to 0.015). Only in group A, the weight of the women correlated with relative values of both F1 and F2 (r = - 0.795, r = - 0.625 resp.)

Physical activity of Czech schoolchildren in the autumn season

The aim of the study was to measure and subsequently evaluate the quantitative and qualitative factors of physical activity (PA) of primary school pupils in the Czech Republic in the autumn period using an objective method and to assess whether these factors differ significantly before and after clock shift from the summer time (Daylight Savings Time) to winter time. The data were acquired from 37 pupils (20 boys, 17 girls) aged 10–13, at primary schools in Brno (CZE) in the period from 22 October to 26 October 2014 and subsequently from 12 November to 16 November 2014. PA was measured using the Actigraph GT3X accelerometer (Actigraph corp., USA) in the week when the clocks were changed, on 26 October 2014 and two weeks later. Three business days and two weekend days were measured. The monitored characteristics included those related to energy output, movement time according to intensity and the number of steps. Changes in measured characteristics after the clock shift were tested statistically using Wilcoxon signed-rank test. Throughout the business days the pupils demonstrated more than med > 10000 steps a day and MVPA did not fall under med > 60 min/day. However, during the weekend these values did not exceed 6600 steps a day 39 min MVPA/day. When comparing the results of all the investigated PA factors before and after the clock shift, significant differences have been found only in boys during business days for moderate PA (p = 0.02) and MVPA (p = 0.04). The study has revealed substantial differences between PA of children during business days when compared to days off in the autumn period. However, the changes in the PA structure before and after the winter clock shift have only been diagnosed at the level of moderate PA and MVPA in boys, even though the daytime duration has been reduced significantly by more than one hour from 10 hours 23 minutes before to 9 hours and 16 minutes after the clock shift