Vlatko Vučetić

RELIABILITY AND FACTORIAL VALIDITY OF AGILITY TESTS FOR SOCCER PLAYERS

Sporis, G, Jukic, I, Milanovic, L, and Vucetic, V. Reliability and factorial validity of agility tests for soccer players. J Strength Cond Res 24(3): 679-686, 2010-The purpose of this study was to evaluate the reliability and factorial validity of agility tests used in soccer. One hundred fifty (n = 150), elite, male, junior soccer players, members of the First Junior League Team, volunteered to participate in the study. The slalom test (ST) sprint 4 × 5 m (S4 × 5) and sprint 9-3-6-3-6-9 m with 180° turns (S180°) tests had a greater reliability coefficient (α = 0.992, 0.979, and 0.976), whereas the within-subject variation ranged between 2.9 and 5.6%. The mentioned 6 agility tests resulted in the extraction of 2 significant components. The S4×5 test had the lowest correlation coefficient with the first component (r = 0.38), whereas the correlation coefficients of the other 5 agility tests were higher than 0.63. The T-test (TT) showed statistically significant differences between the defenders and midfielders (p < 0.05) and between the defenders and attackers (p < 0.05). Statistical significant differences were determined between the attackers and defenders in the sprint 9-3-6-3-9 m with backward and forward running (SBF) and p < 0.05. It can be concluded that of the 6 agility tests used in this study, the SBF, TT, and S180° are the most reliable and valid tests for estimating the agility of soccer players. According to the results of the study, the TT proved to be the most appropriate for estimating the agility of defenders, the SBF, and S180° for estimating the agility of midfielders, whereas the S4 × 5 test can be used for estimating the agility of attackers.

Scaling behaviour of VO2 in athletes and untrained individuals

Objective: The present study analysed the allometric relationship (MR = a · Mb) between human metabolic rate (MR), ranging from resting to maximal metabolic conditions, and body mass (M ), both in athletes of different specialization and untrained individuals. Subjects and methods: Two hundred and seventy male athletes and 43 untrained men performed a continuous incremental test to volitional exhaustion on a motorized treadmill. Metabolic rate (i.e. ) was measured during resting (), sub-maximal (walking at 5 km h−1 ; running at 7.5 km h−1 ; ventilatory anaerobic threshold ) and maximal exercise conditions (maximum oxygen uptake ). Results: A significant difference ( p < 0.001) in the MR–body mass relationships between athletes and controls was found. For the control group, the mass exponent b exhibited a non-significant ( p = 0.37) increase with increasing metabolic demand (b = 0.69, 0.76, 0.76, 0.84, and 0.89, for , , , , and , respectively). In contrast, the corresponding mass exponent for the athletic group significantly ( p < 0.01) decreased when moving from resting to maximal metabolic conditions (b = 0.98, 0.88, 0.80, 0.69, and 0.67). Conclusion: These results indicate that the recently proposed allometric cascade model may be valid in describing the scaling behaviour of MR in untrained individuals, but not in athletes of different specialization.

Reliability and factorial validity of flexibility tests for team sports.

Sporis, G, Vucetic, V, Jovanovic, M, Jukic, I, and Omrcen, D. Reliability and factorial validity of flexibility tests for Team Sports. J Strength Cond Res 25(4): 1168-1176, 2011-The main goal of this method paper was to evaluate the reliability and factorial validity of flexibility tests used in soccer, and to do crossvalidation study on 2 other team sports using handball and basketball players. The second aim was to compare the validity of the different tests and evaluate the flexibility of soccer players; the third was to determine the positional differences between attackers, defenders, and midfielders in all flexibility tests. One hundred and fifty (n = 150) elite male junior soccer players, members of the First Croatian Junior League Teams, and 60 (n = 60) handball and 60 (n = 60) basketball players also members of the First Croatian Junior League Teams volunteered to participate in the study, tested for the purpose of crossvalidation. The SAR and V-SAR had the greatest AVR and ICC. The within-subjects variation ranged from between 0.3 and 3.8%. The lowest value of CV was found between the LSPL and LSPR. Low to moderate statistically significant correlation coefficients were found among all the measured flexibility tests. It was observed that the greatest correlations existed between the SAR and V-SAR (r = 0.65) and between the LLSR and LLSL (r = 0.56). Statistically significant correlations were also observed between the BLPL and BLPR (r = 0.62). The principal components factor analysis of 9 flexibility tests resulted in the extraction of 3 significant components. The results of this study have the following implications for the assessment of flexibility in soccer: (a) all flexibility tests used in this study have the acceptable between and within-subjects reliability and they can be used to estimate the flexibility of soccer players; (b) the LSPL and LSPR tests are the most reliable and valid flexibility tests for the estimation of flexibility of professional soccer players.

The latent structure of standard game efficiency indicators in basketball.

This study defines the latent structure of standard indicators of situational efficiency in the game of basketball. Data was collected from 134 basketball matches played in the regional Goodyear League 2002/03 season. The sample of variables included 13 standard situational efficiency indicators recorded during a basketball match. The (Factorial) principle components method was employed and the number of significant factors was determined using the Guttman-Kaiser Criterion. The initial co-ordinate system was transformed through a non-orthogonal rotation according to the Oblimin criterion. Six inter-independent latent dimensions explaining 67.5 % of total variance were determined: basic offensive efficiency, the three-point play, errors in posting the defense and realisation from the free throw line, defensive agressivness on the player in possession of the ball and offensive agressivness of the player in possession of the ball, basic defensive efficiency and defensive/offensive back line efficiency. The obtained latent structure provided good interpretation of the continuance and functional dependence of 13 standardised indicators of player performance. However, these indicators are considered inadequate for explaining the complexity of the game. Additional player performance indicators should be included in future scientific analysis.

STRONG RELATIONSHIP BETWEEN HEART RATE DEFLECTION POINT AND VENTILATORY THRESHOLD IN TRAINED ROWERS

Mikulic, P, Vucetic, V, and Sentija, D. Strong relationship between heart rate deflection point and ventilatory threshold in trained rowers. J Strength Cond Res 25(2): 360-366, 2011-The purpose of this study was to assess the relationship between heart rate deflection point (HRDP) and ventilatory threshold (VT) to the physiological and performance variables in a relatively large group of trained men rowers. We proposed the hypothesis that physiological and performance variables corresponding to HRDP are not significantly different from corresponding variables at VT, which would justify the use of HRDP as a simple, affordable, and noninvasive method of anaerobic threshold assessment in trained rowers. Eighty-nine trained men rowers (mean ± SD: age 21.2 ± 4.1 years; stature 1.89 ± 0.06 m; body mass 89.2 ± 8.4 kg; &OV0312;o2max [maximum oxygen uptake] 5.39 ± 0.62 L/min−1) completed an incremental rowing ergometer exercise test to exhaustion. Three independent, experienced observers determined both HRDP and VT. HRDP was determined by visual and computer-aided regression analyses and was evident in all rowers. The main findings include (a) there is a strong relationship among all observed physiological and performance variables corresponding to HRHRDP and HRVT (r = 0.79-0.96; p < 0.001) and (b) power output, oxygen uptake, ventilation, tidal volume and breathing rate corresponding to HRHRDP and HRVT were not significantly different (p ≥ 0.011), whereas HRHRDP was slightly but significantly higher than HRVT (174.5 vs. 172.8 beats·min−1; p = 0.003). The standard error of the estimate in predicting the HRVT based on HRHRDP was 5.1 beats·min−1. The subsequent data suggest that, in general, trained rowers may be able to periodically assess their aerobic endurance and evaluate the effects of training programs using the HRDP method.

How reliable are the equations for predicting maximal heart rate values in military personnel

OBJECTIVES The purpose of this study was to evaluate the validity and reliability of equations for predicting maximal values of heart rate (HR) in military personnel. METHODS Five hundred and nine members of the Croatian Armed Forces (age 29.1 +/- 5.5 years; height 180.1 +/- 6.6 cm; body mass 83.4 +/- 11.3 kg; maximal oxygen uptake [VO2(max)] 49.7 +/- 6.9 mL O2/kg/min) were tested. The graded exercise test with gas exchange measurements was used to determine VO2(max) and maximum HR (HR(max)). The analysis of variance was used to determine the differences between the equations to calculate HR(max). RESULTS The analysis of variance yielded statistically significant differences between seven HR equations (p < 0.05). The values from Stevens Creeks (HR(max) = 205 - [age/2]) and Fox and Haskells (HR(max) = 220 - age) equations had the highest correlation with the HRmax obtained by the graded exercise test. CONCLUSION The authors recommend using the HR(max) values from the Stevens Creek and the Fox and Haskell equations for the purpose of training, testing, and daily exercise routine in military personnel.

Peak blood lactate parameters in athletes of different running events during low-intensity recovery after ramp-type protocol.

Abstract Vucetic, V, Mozek, M, and Rakovac, M. Peak blood lactate parameters in athletes of different running events during low-intensity recovery after ramp-type protocol. J Strength Cond Res 29(4): 1057–1063, 2015—The aims of this study were to explore the differences in the peak blood lactate concentration (Lapeak) and time to reach Lapeak during low-intensity recovery after an all-out treadmill ramp test in runners of 4 diverse running disciplines and different training regimes and to identify the most opportune sampling time to determine Lapeak in these athlete groups. The participants were 48 Croatian national-level male track runners (10 sprinters [S], fifteen 400-m runners [S4], 10 middle-distance [MD] runners and 13 long-distance [LD] runners). The runners performed an incremental treadmill protocol until volitional exhaustion, with the inclination of 1.5%, and speed increments of 1 km·h−1 every 60 seconds. During recovery, they walked at 5 km·h−1 for 5 minutes. Fingertip capillary blood samples were collected at the end of the first, third, and fifth minute of recovery. Peak blood lactate concentration in LD was significantly lower than in runners of other disciplines (10.9 ± 2.4 mmol·L−1 for LD; 13.7 ± 2.9 for MD; 14.0 ± 1.4 for S4; 15.1 ± 2.7 for S) (p < 0.01). No significant difference was observed among other groups. There was no significant difference in tLapeak among the 4 participant groups. In conclusion, LD had a significantly lower Lapeak in comparison to other runners; runners of all disciplines reached Lapeak within the first 2 minutes of recovery.

Preparation program of the youngest Top 100 tennis player: the training concepts and principles

Preparation Program of the Youngest Top 100 Tennis Player: The Training Concepts and Principles Conditioning preparation plays a key role in tennis. Typical microcyles and training session examples, together with main concepts and principles, are shown and explained in this paper. A very comprehensive array of anthropological and blood– producing system measures is also presented. Immediately after the preparation period, the young female tennis player achieved the greatest success in her career by playing in the finals of WTA tournament in Tashkent, Uzbekistan achieving the best placement in her career by becoming one of the worlds top 100 female tennis players, and being the youngest one among them.

Relationship between kicking and sprinting performance

Kicking is one of the most vital skills in soccer and strength and power share importance in the explosive movement of top level play. The full instep – kick is one of the kicks typically used to generate fastball speed. Twenty-seven Croatian national football team members (U-15) (mean (SD) age 15.8 (2.9) years, height 173.5 (5.5) cm, weight 62.1 (5.4) kg took part in the study, and performed sprint tests and kicking performance test (measured by radar gun, Stalker-Pro, Texas). The purpose of this study was to investigate the relationship between kicking performance and sprinting performance, using field performance tests. Kicking performance correlated with sprinting performance in all four sprinting variables (r = 0.49 to 0.54; p<0.05) and body mass (r =0,53, p<0,05). SRA revealed a simple solution with sprint distance of over 30m and body mass as significant predictors variables, which explained 52,6 % of kicking performance. Using a radar gun to measure the velocity of a soccer kick is a reliable test of kicking performance. Some motor abilities, also important to the basis of sprinting and kicking performance, are related. Players who perform well on sprinting test are also likely to be successful in kicking performance tests. A sprint of over 30m is one of the most important indicators of kicking performance efficiency.