FILIPCIC, A.; CUK, I. & FILIPCIC, T.Lateral asymmetry in upper and lower limb bioelectrical impedance analysis in youth tennis players. Int. J. Morphol., 34(3):890-895, 2016. SUMMARY:Tennis is a sport that requires asymmetric movements of dominat limbs and may lead to an asymmetric distribution of muscle mass. The main aim of the presented study was to determine the volume and degree of lateral asymmetry of the upper and lower limbs in youth tennis players using a bioelectrical impedance analysis. T-test was applied to find differences between the dominant and non-dominant arm and the right and left leg and thigh in four age categories. There were no significant differences between the right and left leg lean mass in the 12 and under, 14 and under and 16 and under age groups, but there were significant differences between the dominant and non-dominant arm lean mass and arm circumferences in all four age groups. All young tennis players had greater lean mass and arm circumferences of the dominant limb. Tennis players in the 18 and under group had higher average values of right leg lean mass and the differences are statistically significant. There were significant differences between right and left thigh circumferences in all age groups. Findings show that it is possible with such a simple, non-invasive and quick procedure as bioelectrical impedance to determine asymmetry in tennis players.

Hemodialysis (HD) patients have lower functional abilities compared to healthy people, and this is associated with lower physical activity in everyday life. This may affect their quality of life, but research on this topic is limited. Therefore, the present study aimed to determine the relationship between habitual physical activity and quality of life in HD patients and healthy controls. Ninety-three HD patients and 140 controls participated in the study. Quality of life was assessed using a 36-item medical outcomes study short-form health survey (SF-36). Human Activity Profile (HAP) was used to assess habitual physical activity. The adjusted activity score (AAS) from HAP, age, gender, fat tissue index (FTI), lean tissue index (LTI), and Davies comorbidity score were analyzed as possible predictors of the Physical Component Summary (PCS) of the SF-36. Three sequential linear models were used to model PCS. In Model 1, PCS was regressed by gender and age; in Model 2 the LTI, FTI, and Davies comorbidity scores were added. Model 3 also included AAS. After controlling for age and gender (ModelHD 1: p = 0.056), LTI, FTI, and Davies comorbidity score effects (ModelHD 2: p = 0.181), the AAS accounted for 32% of the variation in PCS of HD patients (ModelHD 3: p < 0.001). Consequently, the PCS of HD patients would increase by 0.431 points if the AAS increased by one point. However, in healthy controls, AAS had a lower impact than in the HD sample (B = 0.359 vs. 0.431), while the corresponding effects of age and gender (ModelH 1: p < 0.001), LTI, FTI, and Davies comorbidity score (ModelH 2: p < 0.001) were adjusted for. The proportion of variation in PCS attributed to AAS was 14.9% (ModelH 3: p < 0.001). The current study results showed that physical activity in everyday life as measured by the HAP questionnaire is associated to a higher degree with the quality of life of HD patients than in healthy subjects. Routine physical activity programs are therefore highly justified, and the nephrology community should play a leading role in this effort.

Performance analysis during match play is vital for the long-term development of tennis players. The primary goal of this study was to establish the differences between junior and entry professional tennis player's selected performance indicators in five-game situations. Data were collected using the Sagit/Tennis tracking system during six junior and four professional tennis matches. Eight boys performed 3,112 strokes, while eight male professional players hit 1,631 strokes. The results showed slight differences in the distance covered by the two observed groups in the specific game situations. Professional players performed faster shots in all game situations, except when playing at the net. They played at a significantly faster tempo than the juniors. This difference was also affected by the higher shots speed and shorter distance between the two players during the rallies. When playing from the baseline, the entry professional players performed shots at a smaller angle than the juniors; and when serving, receiving and playing at the net, they hit shots at a greater angle than the juniors. Our findings may assist coaches and players in improving the effectiveness of their tactical and technical training to enhance their competitive performance.

The higher quality of life of people with spinal cord injury is closely related with their reintegration into the social environment. Social reintegration is a demanding and complex process, requiring individuals to become active again and acquire age-, gender-, and culture-appropriate roles and social status. It also involves independence and productive behavior as part of multiple interpersonal relationships with family, friends, and others. In order to establish whether individuals with spinal cord injury who are physically active subjectively rate their quality of life to be higher compared to those who are not, sixty-two respondents from Slovenia with spinal cord injury were interviewed. Thirty-one of them were physically active, and 31 were not. The level of injury of the responders was from Th6–Th12. The participants gave the highest assessments to their interpersonal relationships, and the lowest to their satisfaction with material prosperity. Data comparison showed that subjective estimates in all areas of quality of life are higher in respondents who were involved in physical activity after their injury. The results may encourage persons with spinal cord injury to participate more often in sports programs, and also encourage others to do so.

The purpose of the study was to determine the timing of a split-step in three categories of tennis players in four groups of strokes. Subjects were divided into three groups: male and female junior, and male professional tennis players. During two tournaments, all matches were recorded with two fixed video cameras. For every stroke, the timing of the split-step between the opponent’s impact point when hitting the ball and the player’s split-step was measured. A two-way analysis of variance (ANOVA) was used to determine the differences between groups of strokes, players and the interaction Player x Stroke Group. A Tukey post-hoc test was employed to determine specific differences. The results revealed differences between players in detecting the opponent’s movement, stroke and ball flight, which were reflected in different split-step timings. Each tennis player has his/her own timing mechanism which they adapt to various game situations. Response times differ significantly depending on the game situation. On average, they are the lowest in the serve, and then gradually rise from the return of the serve to baseline game, reaching the highest values in specific game situations. Players react faster in the first serve than in the second one and in the return of the serve, the response times are lower after the return of the second serve