Loss of muscle strength characterizes the period before total hip arthroplasty (THA). Little is known about whether muscle strength imbalances caused by muscle strength decline could be considered another clinical predictor for THA. This study aimed to determine whether muscle imbalances may be used as a clinical predictor for THA surgery. Thirty-six participants were enrolled in the study. Eighteen patients had THA (THA group), while 18 were healthy elders (CON group). Ipsilateral (H/Q) and bilateral (% Def) muscle imbalances of the knee were assessed. THA patients showed impairment of the extensors on the affected extremity compared to those unaffected. A comparison between the groups proved there were weakened flexors in the THA group on both extremities. A comparison of the imbalances revealed a significant bilateral imbalance of the extensors and ipsilateral imbalance of both extremities in the THA group. We computed two logistic regressions using bilateral and ipsilateral imbalance as the predictors of THA surgery. We found that bilateral extensor imbalance may be used as a predictor for THA (Nagelkerke R2 = 0.22). A decrease of the bilateral extensors imbalance by 8% decreases the probability of THA by 8%. The most interesting finding is that the evaluation of the bilateral extensor imbalance may be used as another clinical predictor for THA.

Purpose: Change of direction speed (CODS) and reactive agility (RAG) are important qual-ities in futsal, but studies rarely examined the predictors of these conditioning capacities in players of advanced level. This study aimed to evaluate predictive validity of certain an-thropometric and conditioning capacities in evaluation of futsal specific CODS and RAG in top-level players. Methods: The sample comprised 54 male players from Croatia and Bosnia and Herzegovina, members of teams competing at the highest national rank, including national champions for the 2017–2018 competitive season in both countries. The variables comprised set of pre-dictors (body mass, body height, triceps skinfold, reactive strength index [RSI], sprint 10 m [S10M], and broad jump [BJ]; and four criteria: futsal specific CODS and RAG, performed with and without dribbling (CODS_D, CODS_WD, RAG_D, RAG_WD). To identify the asso-ciation between variables Pearson’s correlation and multiple regressions were calculated. Results: Observed predictors explained statistically significant (p < 0.05) percentage of vari-ance for all four criteria (Rsq: 0.28, 0.30, 0.23 and 0.25, for CODS_WD, CODS_D, RAG_WD, RAG_D, respectively). Body mass was significant predictor for all criteria (Beta: 0.35–0.51), with poorer performances in heavier players. In both performances which involved dribbling, significant predictors was RSI (Beta: −0.27 and −0.31 for CODS_D and RAG_D, respective-ly), with superior performances in players with better RSI. The S10M and BJ were not identi-fied as being significantly correlated to studied RAG and CODS performances. Conclusion: Study confirmed specific influence of studied predictors of futsal specific CODS and RAG with consistent negative influence of body mass on studied performances. Almost certainly this can be explained by specifics of RAG and CODS execution. Specifically, tests are performed over relatively small distances, with several changes of direction, which clear-ly mimic the futsal specific performances. Although sprint performance is often observed as important determinant of CODS and RAG, herein we did not confirm its predictive validity in explanation of futsal specific CODS and RAG. Future studies should evaluate other poten-tially important predictors of these capacities in futsal.

Character of modern tennis game in the last decade has become significantly more dynamic, fast and powerful, which brings high strain to joint and muscular system. The aim of this research was to establish strength level of external and internal shoulder rotators, and to compare the competitive tennis players group of boys (TEN, n=10, aged 12-14 years) and boys who did not perform any sport activity at competitive level (CS, n=10, aged 12-14 years) as well as to assess lateral differences in both groups. Using isokinetic dynamometry method (Humac Norm CSMI Stoughton, MA, USA), we tested strength level of external and internal shoulder rotators (180°/s, 300°/s). The TEN and CS group are comparable from the aspects of age, body height and body weight. Comparison of isokinetic strength values in TEN and CS groups proved significantly higher strength level of external and internal rotators in both (dominant and non-dominant) extremities for the TEN group. The lateral difference assessment proved the insignificant difference in external and significant difference in internal rotators in the TEN group, and the insignificant difference in both the external and internal rotators in the CS group. A lower strength level was found in the internal rotators in comparison with the external rotators in both groups (for both the dominant and non-dominant extremity), whereas in the TEN group lower differences between the external and internal rotators of the dominant extremity were proved. Although researches on adult highly skilled tennis players refer to a higher strength level of the upper extremity internal rotators, this fact has not been pronounced in the TEN group. An ideal external/internal rotators̕ ratio in adult players is considered within the interval of 66-75%. Significantly higher values obtained in the TEN group might be attributed to lower age and also lower performance level. It can be said that the level of isokinetic strength in the TEN the group is significantly higher than in the CS group, due to the influence of long-term game and training load.

Purpose: Classical ballet, Slovakian folklore dance, and sport dance training differ in their way how to master the art of dance; however, postural control is essential for the correct exe-cution of complex movements used in all types of dance. The aim of this study was to analyse the differences in static postural control between classical ballet dancers, Slovakian folklore dancers and sport dancers and to analyse the effect of body mass, body height and toe grip strength on postural control. Methods: 68 dancers, between 17 to 28 years of age, participated in this study: 21 dancers from Slovakian folklore dance group VSLPT Poľana Brno (12 females, 9 males), 22 dancers from Brno Dance conservatory (16 females, 6 males) and 25 sport dancers competing at Brno Dance Open 2019 (12 females, 13 males). All participants were asked to stand upright, barefooted, arms along the body, both feet on the Emed-at platform (Novel GmbH, Germany) for 10 seconds with their eyes open to obtain the length of COP line (cm), average velocity of COP (cm/s), the elliptic area (mm2) and numerical eccentricity of the ellipse. The toe grip strength was measured for each foot when sitting using toe grip dynamometer (Takei Scien-tific Instruments, Niigata, Japan). To analyse the effect of dance style, to grip strength, body mass, body height, and gender on postural control variables, Kruskal Wallis test, and Spear-man Rank Order Correlation were used. Results: Abetter postural stability measured by the length and average velocity of COP was observed in sport dancers, compared to classical ballet and Slovakian folklore dancers. Sport dancers are used to a greater load on the forefoot and to a special foot roll-of pattern when dancing, which may lead together with a constantly changing environment during competi-tions to their enhanced postural stability. Despite the differences in dance training and dance footwear of female and male dancers (high-heel shoes in sport and Slovakian folklore female dancers, pointe shoes in female ballet dancers), no statistically significant difference in pos-tural variables between genders was observed. Similarly, in analysed dancers, no effect of age, body mass, and body weight on postural control were observed. The toe grip strength was not observed to affect the postural variables in this study. The greatest toe grip strength was observed in female ballet dancers, despite their younger age. Ballet dance training in-cludes repetitive exercises focused on foot and toes such as battement tendu or demi-pointe and en pointe positions probably resulting in the greater strength of the toes. Conclusion: In this study, better postural stability measured by the length and average ve-locity of COP was observed in sport dancers, compared to classical ballet and Slovakian folklore dancers. In analysed dancers, no effect of body mass, body weight, gender, and toe grip strength on postural control variables was observed. Future studies focused on postural stability changes in non-dancers after a sport dance, classical ballet and Slovakian folklore dance training program would provide additional knowledge about the process how each type of dance enhance the balance and other coordinative skills.

In Special Olympics, athletes' foot deformities, abnormal postural patterns and overweight and obesity were observed to be more common than in the general population. Therefore, the purpose of this study was to analyze the relationship between body composition and foot posture index. Additionally, the effect of gender and other factors on the body composition and foot posture index in athletes with intellectual disability (ID) were analyzed. Methods: 131 athletes with ID participated in this study: 36 table tennis players, 66 cross country skiers and 29 downhill skiers. Their body composition was assessed using the bioimpedance analysis InBody 230 (Biospace, Korea). The foot screening included the assessment of foot posture index, which evaluates the degree of pronated, supinated and neutral position of the foot, gait speed and the last part of the procedure consisted of a short questionnaire, providing the information about the type of housing, age, and the usage of orthotics. Results: A low correlation between body composition and some of the foot posture index criteria was observed. The mean foot posture index score in athletes with ID was observed to be slightly pronated, as also described in the general population, with no statistically significant difference between female and male athletes. The gender differences were observed only in body composition. Conclusions: The high body weight and body fat percentage observed in this study highlight the need for healthy lifestyle education in athletes with ID.