The paper addresses relations between the characteristics of body composition in international sprint swimmers and sprint performance. The research included 82 swimmers of international level (N = 46 male and N = 36 female athletes) from 8 countries. We measured body composition using multifrequency bioelectrical impedance methods with “InBody 720” device. In the case of male swimmers, it was established that the most important statistically significant correlation with sprint performance is seen in variables, which define the quantitative relationship between their fat and muscle with the contractile potential of the body (Protein-Fat Index, r = 0.392, p = 0.007; Index of Body Composition, r = 0.392, p = 0.007; Percent of Skeletal Muscle Mass, r = 0.392, p = 0.016). In the case of female athletes, statistically significant relations with sprint performance were established for variables that define the absolute and relative amount of a contractile component in the body, but also with the variables that define the structure of body fat characteristics (Percent of Skeletal Muscle Mass, r = 0.732, p = 0.000; Free Fat Mass, r = 0.702, p = 0.000; Fat Mass Index, r = −0.642, p = 0.000; Percent of Body Fat, r = −0.621, p = 0.000). Using Multiple Regression Analysis, we managed to predict swimming performance of sprint swimmers with the help of body composition variables, where the models defined explained 35.1 and 75.1% of the mutual variability of performance, for male and female swimmers, respectively. This data clearly demonstrate the importance of body composition control in sprint swimmers as a valuable method for monitoring the efficiency of body adaptation to training process in order to optimize competitive performance.

This study assessed differences in agility performance between athletes of team and individual sports by assessing change-of-direction speed (CODS) as pre-planned agility and reactive agility (RA) as non-planed in different spatial configurations. The study involved 36 individual (sprint, hurdles, jumping, tennis, and judo) and 34 team (soccer, basketball, and handball) athletes. CODS and RA were measured with a light-based reactive training system in a frontal (FR), universal (UN), semicircular (SC), and lateral (LA) design. Lower limb power and sprint performance were also measured in a 10 m single leg jump test and 15 m sprint. Individual athletes showed significantly better performance in three of the eight agility tests: LA-RA, UN-RA, and SC-CODS (p < 0.008, p < 0.036, and p < 0.027, respectively) and were found to present stronger correlations (p < 0.01) between jump test performance and the CODS condition. Team athletes showed stronger associations between sprint performance and the CODS condition. In the RA condition both jump and sprint performance showed stronger correlations in the group of individual athletes. Agility performance as measured by CODS and RA should improve with enhanced of motor proficiency. Finally, the tests applied in this experiment seem to be multidimensional, but require spatio-temporal adjustment for their implementation, so that they meet the requirements of the particular sport.

To investigate the level of bilateral symmetry or asymmetry between right and left foot center of pressure (COP) trajectory in the mediolateral and anteroposterior directions, this study involved 102 participants (54 females and 48 males). Ground reaction forces were measured using two Kistler force plates during two 45-s quiet standing trials. Comparisons of COP trajectory were performed by correlation and scatter plot analysis. Strong and very strong positive correlations (from 0.6 to 1.0) were observed between right and left foot anteroposterior COP displacement trajectory in 91 participants; 11 individuals presented weak or negative correlations. In the mediolateral direction, moderate and strong negative correlations (from −0.5 to −1.0) were observed in 69 participants, weak negative or weak positive correlations in 30 individuals, and three showed strong positive correlations (0.6 to 1.0). Additional investigation is warranted to compare COP trajectories between asymptotic individuals as assessed herein (to determine normative data) and those with foot or leg symptoms to better understand the causes of COP asymmetry and aid clinicians with the diagnosis of posture-related pathologies.

The purpose of our research was to establish the variability of correlation between the length of the jumps and selected multi-item kinematic variables (n=9) in the early flight phase technique of ski jumping. This study was conducted on a sample of elite Slovenian ski jumpers (N=29) who participated in the experiment on a jumping hill in Hinterzarten, Germany (HS95m) on the 20^th of August, 2008. The highest and most significant correlations (p=0.01) with the length of the ski jump were found in the multi-item variable height of flying, which was also expressed with the highest level of stability of the explained total variance (TV) on the first factor (TV=69.13%). The most important characteristic of the aerodynamic aspect of early flight was the variable angle between the body chord and the horizontal axis with significantly high correlations (p<0.05). The stability of that aerodynamic factor was very high (TV=65.04%). The results were essentially similar for the multi-item variable angle between left leg and the horizontal axis (TV=61.88%). The rest of the multi-item kinematic variables did not have significant correlations with the multi-item variable length of jump. Only two more variables, the angle between the upper body and the horizontal plane (TV=53.69%), and the angle between left ski and left leg (TV=50.13%), had an explained common variance on the first factor greater than 50% of total variance. The results indicated that some kinematic parameters of ski jumping early flight technique were more important for success considering the length of the jump.

The aim of this study was to assess the effect of drop height and selected somatic parameters on the landing kinetics of rebound jumps in force and power production, performed by male and female student athletes. Twenty female and forty male students with a sports background participated in the experiment (mean and standard deviation (± SD): age 20.28 ± 1.31 years, height 166.78 ± 5.29 cm, mass 62.23 ± 7.21 kg and 21.18 ± 1.29, 182.18 ± 6.43, 78.65 ± 7.09). Each participant performed three maximal jumps on two independent and synchronized force platforms (Bilateral Tensiometric Platform S2P) at each of the two assigned drop-jump heights (20-, and 40-, cm for female and 30-, and 60-, cm for the male special platform). Significant between-sex differences were observed in all variables of selected somatics, with men outperforming women. Statistically significant differences were noted in four parameters, between men and women, in both DJs from 20/40 and 30/60 cm. The height of the jump was 6 cm and 4 cm higher for men. A slightly higher statistical significance (p = 0.011) was demonstrated by the relative strength (% BW) generated by the left limb in both men and women. Only women showed a significant relationship between body mass, body height, and five parameters, dropping off of a 20 cm box. In men, only the left leg—relative maximal F (p =−0.45)—showed a relationship with body mass. There were no relationships between the above-mentioned dependencies in both groups, in jumps from a higher height: 40 cm and 60 cm. From a practical application, the DJ with lower 20/30 cm or higher 40/60 cm (women/men) respectively emphasizes either the force or power output via an increase in the velocity component of the rebound action or increased height of the DJ jump.

The Factor Structure of Chosen Kinematic Characteristics of Take-Off in Ski Jumping: With a sample of 29 of the best Slovenian ski jumpers, a research project was carried out with the purpose of determining the structure relation of chosen dynamic and kinematic variables during the take-off of ski jumpers. The experiment was performed in August 2008 on the jumping hill in Hinterzarten, Germany (K=95m). The subjects jumped seven times without breaks between rounds. The analysis was done on variables that determine the technique of take-off in ski jumping (in-run velocity - km/h, vertical take-off velocity - m/s, precision of take-off - cm). The criteria variable was the length of the jump (m). The variability of the long distance of the jumps was significantly strong. The reliability of all used multi-item variables was high and satisfactory in most variables (in-run velocity - 0.98, vertical take-off velocity - 0.98, precision of take-off - 0.85, length of the jump - 0.95). The factor analysis produced an independent latent structure (explanation of variance = 93.3%) of five specific factors (1. in-run velocity connected to distance jumped (39.8 % of VAR.), 2. vertical take-off velocity strongly connected to distance jumped (26.0 % of VAR.), 3. precision of take-off partly connected to distance jumped (14.9 % of VAR.), 4. precision of take-off in the 7th round (6.7 % of VAR.), 5. precision at take-off in the 4th round (5.7 % of VAR.). The present factor structure confirms the hypothetical model of three independent motor tasks to be optimally realized in the take-off of the ski jumper. Criteria variables influencing the length of jumps were mainly associated with the first two factors, which confirm the basic hypothesis that the length of the jump reflects the overall output quality of the first two factors. The accurancy factor of take-off affects the length of the jumps indirectly and latently through these two fundamental factors.