DETERMINING THE FUNCTIONS UPON WHICH FORCE GENERATION VELOCITY AND ITS DIMENSIONS ARE CHANGED IN LEG EXTENSORS

INTRODUCTION: The outcome of a judo combat depends on force generation velocity and the levels of its dimensions that vary throughout the combat according to the requirements arising from a specific situation. In order to program force generation velocity change and dimensions that it depends on in an individual, specially designed models are used to determine the principles according to which the followed values behave, in the interval between the beginning of generation and the achievement of maximum force. This was done in the present paper. METHODS: Functions upon which force generation velocity and its dimensions change in time in leg extensors were defined in a subject, top judoist and winner of gold and silver medals in Balkan, European and world competitions, aged 25, with body height BH = 1.91 m and body mass BM = 97.8 kg, using a special hardware-software designed at Police Academy in Belgrade. Force (N) was sampled under isometric conditions, at the angle of 115 degrees of flexion in knee joint, using Belt method (Everts,E.W. et all.,1938; Linfort,A. et all., 1971) at every millisecond. In our research we took data about force (Ft) and time (t) at every 1% of maximum force (Fmax). These data were used to calculate force generation velocity (FGV) expressed in Ns, for every % from 1 to 100. Its dimensions, such as muscle involvement velocity (C) expressed in absolute measures, and force generation velocity change (FGVS1) expressed in N/s, were also calculated for every % from 1 to 100. Force generation velocity change (FGVS2) expressed in N/s was calculated at an interval of 1%. Fitting, by least squares method, was used to determine the function forms affecting the followed values. RESULTS: In the experiment, the subject achieved Fmax of 6719.6 N at the time of 2.461 s. Fitting obtained the following functions that enabled determining the behaviour of force generation velocity and its components in the whole scope of force generation: FGV=1543.1Ln(t)+5604.5; C(t0.2)=-0.0978t3 +1.0727t2 - 2.5403t+3.423; FGVS1(t0.2)=1131.6t4-6607.5t3+13370t2-11042t+3344.3; FGVS2(t0.2) = 254.52t4 -1555.2t3+3484t2-3655.4t+2045.4. CONCLUSIONS: The obtained functions define the principles according to which force generation velocity and its dimensions behaved in the whole scope of generation in the individual subject. The functions are used to simulate the changes in the observed variables according to combat requirements, to design the training methods and to control the effects of the training

AN ANALYSIS OF THE RELIABILITY AND FACTORAL VALIDITY OF SELECTED MUSCLE FORCE MECHANICAL CHARACTERISTICS DURING ISOMETRIC

We applied the “Dead Lift” test in isometric conditions to establish the reliability and factoral validity of pre-selected muscle force mechanical characteristics on a sample of 23 young males. The muscle force mechanical characteristics (hip extensors, trunk extensors and shoulder elevators as a multi-joint system) were represented by maximum voluntary force (Fmax), time needed to reach Fmax (tFmax), rate of force development (RFD), force impulse (ImpF) and maximum value of muscle involvement velocity (Cmax). The results yielded highly acceptable rates for the indicators of sensitivity (cV%), reliability and validity at the significant level of p < 0.001. The standardization of the multi-joint test in isometric testing conditions requires three trials for Cmax and Fmax, where the result is the better value taken at the second or third trial, and three to five trials for RFD, ImpF and tFmax, with the best values taken as the result

200m breaststroke post-competition blood lactate removal characteristics: A case study of an international female swimmer—an example of individual modeling in relation to pool length

The goal of this study was to define the individual model characteristics of lactic acid removal after 200m breaststroke competitive load in a female swimmer in relation to different pool lengths (25m vs. 50m). The second goal was methodological and referred to the presentation of newly applied metrological procedures for the Individual Lactate Recovery Profile modeling. Six races from the competitive season 2021/22 were selected, in which the athlete achieved the most valuable results in relation to the FINA score. To establish the metabolic response of the organism to the competition effort, the method of determining the level of lactate concentration in capillary blood (La in mmol/L) was used. Differences between the mean values of variables were established using ANOVA. The polynomial curve equation function was used to create a blood lactate concentration in a function of recovery time model (La-trecovery). The ANOVA showed that there was no statistically significant difference between the monitored variables and the pool length function (p=.097). The maximum achieved blood lactate concentration in the acute race recovery phase was 13.17 ± 2.81 and 12.08 ± 1.80 mmol/L and the given concentration initially occurred in the time of 240.0 ± 85.6 s and 169.3 ± 79.9 s in the 25 and 50m pool, respectively. In relation to the time of complete passive recovery required to establish acidosis at the level of 2 mmol/L (25 and 50m pool) occurred in 1191.7 ± 481.3 s and 1326.7 ± 405.1 s, while the full index of intensity of blood lactate clearance was 135.7 ± 60.7 s/mmol/L and 124.0 ± 60.7 s/mmol/L for 25m and 50m pool, respectively, although no statistically significant difference was found between the parameters of recovery in relation to pool length. The offered mathematical models enabled a practical individual approach to controlling the specific adaptation to training for achieving a higher competitive level performance

Modeli morfološkog statusa studentkinja kriminalističko-policijske akademije definisani metodom multikanalne bioelektrične impedance

Multi-year impact of obesity and physical inactivity can lead to negative psycho­social and health consequences, especially for girls-women whose structure has a higher percentage of body fat mass compared with men. The aim of this study was to define the characteristic groups-clusters in terms of morphological space of ACPS female students. The measurements were performed at the Faculty of Sport and Physical Education, University of Belgrade, by multichannel bioelectrical impedance method - In Body 720. The sample of examinees were 144 ACPS female students: Age - 19.7 ± 1.1 years; BH-169.28 ± 5.27 cm, BW - 61.28 ± 6.86 kg, BMI - 21.37 ± 1.99 kg"m-2. The basic classification variables were: body weight (BW, kg), intra cellular water (ICW, L), extra cellular water (ECW, L), proteins (kg), minerals (kg), mass of mineral content of bone (osseous, kg), total body fat mass (BFM, kg), skeletal muscle mass (SMM, kg), visceral fat area (VFA, cm2) and body cell mass (BCM kg). The derived variables were: body mass index (BMI, kg m-2), percentage of body fat (PBF, %) and the percentage of skeletal muscle mass (PSMM, %). The results were statistically analyzed using descriptive statistics, cluster analysis and canonical discriminant analysis. Cluster analysis yielded 3.47% in the first, 30.56% in the second, 28.47% in the third, 29.17% in the fourth and 8.33% of female students in the fifth cluster. In separate discriminant functions, the first factor consists of four variables: VFA = 0.830, BFM = 0.631, BMI = 0.467 and PBF = 0.357, while the second factor consists of the nine variables remaining. The ratio of the basic structural elements of body are obtained by the following morphological types: Endomorphic type (obese and small body hight individuals), Ecto-Mesomorphic type (thin and average body hight individuals), Mesomorphic type (normal body weight and average body hight individuals), Meso-Ectomorphic type (normal body weight and tall individuals) and Endo-Mesomorphic type (obese and tall individuals).Višegodišnji uticaj gojaznosti i fizičke neaktivnosti može dovesti do negativnih psihosocijalnih i zdravstvenih posledica, a posebno kod devojaka i žena čija struktura tela ima veći procenat masne komponente u poređenju sa muškarcima. Cilj istraživanja bio je definisanje karakterističnih grupa (klastera) sa aspekta morfološkog prostora studentkinja KPA. Merenja su obavljena na Fakultetu sporta i fizičkog vaspitanja Univerziteta u Beogradu metodom multi- kanalne bioelektrične impedance - In Body 720. Uzoraka ispitanika su bile 144 studentkinje KPA: uzrast - 19,7 ± 1,1 godina; TV - 169,28 ± 5,27 cm; TM - 61,28 ± 6,86 kg; BMI - 21,37 ± 1,99 kg-m-2. Osnovne varijable klasifikacije su bile: telesna masa (TM, kg), intra celularna tečnost (ICW, L), ekstra celularna tečnost (ECW, L), proteini (kg), minerali (kg), masa minerala iz sadržaja kostiju (Osseous, kg), ukupna masa telesnih masti (BFM, kg), masa skeletnih mišića (SMM, kg), visceralna mast (VFA, cm2) i masa živih ćelija u organizmu (BCM, kg). Izvedene varijable su bile: indeks mase tela (BMI, kg-m-2), procenat masti u telu (PBF, %) i procenat mišića u telu (PSMM, %). Rezultati su statistički obrađeni primenom deskriptivne statistike, klaster analize i kanoničke diskriminativne analize. Klaster analizom je izdvojeno 3,47% u prvom, 30,56% u drugom, 28,47% u trećem, 29,17% u četvrtom i 8,33% studentkinja u petom klasteru. U izdvojenim diskriminantnim funkcijama, prvi faktor čine četiri varijable: VFA = 0,830, BFM = 0,631, BMI = 0,467 i PBF = 0,357, dok drugi faktor čine ostalih devet varijabli. Na osnovu odnosa osnovnih elemenata strukture tela dobijeni su sledeći morfološki tipovi: endomorfni tip (gojazne i niske osobe); ektomezomorfni tip (mršave i prosečno visoke osobe), mezomorfni tip (normalno uhranjene i prosečno visoke osobe), mezoektomorfni tip (normalno uhranjene i visoke osobe) i endomezomorfni tip (gojazne i visoke osobe)

A disciriminative model of basic anthropomorphological indicators for female handball players in the first phase of selecting position within the team

The purpose of this paper is to establish how young female handball players are selected in the Republic of Serbia on the basis of basic anthropomorphological indicators and what the relation between the anthropomorphological characteristics and the position within the team is. The sample of 57 selected handball players aged up to 14 was divided into 4 sub-samples, with respects to their positions within the team. Their basic anthropomorphological characteristics were measured – body mass (BM), body height (BH) and the respective body mass index (BMI) was calculated for each of them. The obtained results suggest that there were statistically significant differences with respect to the observed variables (BM, BH and BMI) for all the observed positions: F = 6.335; 8.424; 3.676, p = .001; .000; .018, respectively. Three canonical discriminative functions were singled out, the first two being of statistical significance, with the first one explaining 66.0% of the total variance and the second accounting for 31.1%, which means that together they explained 97.3% of the variance. The aforemetnioned implied that there were differences in the height among the selected handball players with respect to their positions on the team, which also applied to their weight, and lastly to the body mass index. The results of our observation showed that the players in the wing position were the shortest and had the lowest body mass, whereas the pivot position players were the tallest, had the highest body mass and the highest BMI, the lowest BMI being characteristic of backcourt players. With respect to the age group (up to 14 years of age) and from the aspect of the function of basic anthropomorphological characteristics (BM, BH, and BMI) it can be generally concluded that the selection of players with respect to the position was performed with the reliablity rate of 52.6% and that it was the most reliable for the position of backcourt players (69.2%), then wings (66.7%), whereas for the pivot position it was only 25.0% and as low as 0% for the position of the goalkeeper

Sprint Running, Agility and Anaerobic Endurance: Standards for the Students at the University of Criminal Investigation and Police Studies

Resolving critical incidents can be extremely physically demanding for police officers. Consequently, throughout the selection process, training, and working career, police officers’ physical abilities are often assessed with a battery of tests. Research has been conducted with a total sample of 523 students (232 female and 291 male) at the University of Criminal Investigation and Police Studies (UCIPS), with the aim of defining the norms for Linear sprint performance at 20 m (LSP20m), Illinois agility test (IAT) and Shuttle run 300-yard (ShR300y). The homogeneity of the results has been established by the low skewness and kurtosis coefficient, as well as by the values obtained from the Kolmogorov-Smirnov test, meaning the data are not significantly statistically different from the normal distribution. Based on the percentile distribution, qualitative and quantitative normative values have been defined for LSP20m, IAT and ShR300y. The achievement levels have been ranked as follows: < P10 (insufficient), P10 to P25 (poor), P25 to P50 (fair), P50 to P75 (good), P75 to P90 (very good) and > P90 (excellent). LSP20m, IAT and ShR300y tests can be used for assessing acceleration, running speed and change-of-direction speed in the anaerobic work regime. Furthermore, they correspond to the first stage of critical incidents resolution – getting to the problem (hence can be viewed as job-related fitness tests). Since population norms have been established, their implementation in the battery of tests for the assessment of UCIPS students’ physical abilities in the sense of running tests can be quantitatively applied at the situational system of testing of Specialized Physical Educatio