Running speed in the form of sprinting is one of the most important abilities that can significantly define performance success in many sports. From the perspective of genetically inherited motor functions, running speed can be classified as a primary phylogenetic human movement, manifested in the form of a “threesegment model” consisting of speed, power, and coordination. By comprehensively analyzing the general and partial predictive contributions of dynamic-kinematic parameters of running, speed-power abilities, and morphological characteristics, on a sample of 80 boys aged 10-12 years, it can be concluded that regardless of the choice of criteria, achieved maximal speeds (KVMAX) or results in children’s athletic sprint over 50 meters (KT50m), the same or related predictor variables contributed to the explanation. The variable running time for 20m from a flying start (KTLS20m) has the greatest predictive contribution (β=0.83, p<0.001) to explaining both criteria, which may indicate the importance of conducting this test in the identification and selection for athletic sprint. Additionally, the selection of tests to assess speed-power abilities is extremely important for the identification and selection for athletic sprint. It can be concluded that tests of horizontal and vertical jumps are significant for identification, as well as tests for assessing neuro-muscular excitation. Tests for assessing continuous horizontal jump are also important, although there is an impression that, in boys aged 10-12 years, coordinatively simpler tests should be used. In the analysis of morphological characteristics, variables that significantly contributed to the explanation of criteria at a partial level were body height, back skinfold, and ankle diameter, indicating that in the identification of talented individuals, it should be considered that elite sprinters are characterized by light bones, optimal muscle mass, and low levels of subcutaneous fat tissue.

Athletic performance is affected by numerous factors such as genetic makeup, environmental factors, and psychological factors. The goal of the present study was to examine the effects of fine motor skills and BMI on athletic performance of college students. The sample for this study consisted of 31 students (mean age 19 years, SD- 1.1 year; 7 females, 24 males) recruited from the Faculty of Kinesiology at the University of Sarajevo. The students were given Purdue Pegboard test of motor skills and Test of Athletic performance consisting of 8 tests: sprint running, high/low start, relay running, hurdle racing, high jump, long jump, shot put, and javelin throw. We assessed the impact of their BMI and fine motor skills on the Athletic performance. The results revealed a statistically significant effect of fine motor skills and BMI on Athletic performance. More specifically, these two factors explained around 30% of the variance in Athletic performance. These findings could be beneficial for designing more effective training programs that not only focus on general physical fitness but also consider the role of fine motor skills and body composition in improving overall athletic performance.

Purpose: The main aim of this study was to examine and analyse the body composition of young soccer players across different age groups. Methods: A cross-sectional study was carried out among 126 young soccer players divided into age categories: U15 – 53 players (age=14.68±0.47); U17 – 51 players (age=16.47±0.50); U19 – 22 players (age=18.05±0.38). The subjects’ height was measured using an anthropometer, while their body composition was measured using the TANITA BC-420MA digital scale. Results: On average, soccer players in the U15 group had significantly lower body height, weight, body mass index and fat free mass than U17 and U19 players, but had a higher percentage of body fat (p < 0.05). In addition to the percent of body fat mass, which tends to significantly decrease with age, the results also demonstrate significant non-linear increases in body height, weight, and lean body composition concurrent with the players’ ages. Conclusion: These results indicate that younger soccer players have lower absolute values of morphological characteristics compared to senior players.

High relationships between muscle strength and various forms of jumps are usually based on the research samples of professional athletes or students of sports and physical education. However such studies are less known in the case of recreational women. This study aimed to determine the relationship between isokinetic parameters of knee joint muscle strength with the efficiency of performing vertical jumps. The sample represents a group of 16 healthy and physically active women (age=31.04±3.71; height 168.13±8.34; weight 59.80±9.80). Knee extensors and flexors were evaluated by using an isokinetic dynamometer, while the two-foot vertical jump performance was measured using the Opto Jump System. Pearson's correlation coefficient was used to determine correlation magnitude (p<.05). The obtained results indicated high correlations of the knee extension peak torque dominant leg (KEPT D), knee extension peak torque non-dominant leg (KEPT ND) and knee flexion peak torque non-dominant leg (KFPT ND) with counter movement jump free arms (CMJFA) (r=.525; r=.511; r=.594; p<.05). High correlations was also indicated between KFPT ND with counter movement jump (CMJ) (r=.514; p<.05). Given that these are recreational women, we can assume that the countermovement free arm jump type was the most natural form of expressing their explosive potential. It is certainly important that future studies further examine the relationships between muscle strength and performance of primary and specific motor tasks in recreational women.

Restricting movement for the population and the impact of preventative measures due to the COVID-19 pandemic have spurred research interests in analyzing the healthy lifestyle of the student population. The aim of the study was to examine gender differences between students in physical activity, and the perceptions of physical fitness and well-being during lock-down due to COVID-19. The sample consisted of male (n=268; 25.9%; age 22.56±2.12) and female students (n=768; 74.1%; age 22.12±1.73) at the University of Sarajevo (UNSA). The questionnaire included questions and scales constructed to measure: physical activity, physical fitness, and the acute effects on well-being. χ² independence test were used to determine gender differences (p<0.05). Prior to the declaration of the COVID-19, there was a significant difference in the level of regular physical activity between male and female students at UNSA (p<.01). The data indicated that at that time 65% of male students were regularly physically active, while 45% of female students had regular physical activity. During the lock-down measures at UNSA: 46% of male and 40% of female students reported being regularly physically active and no significant differences were found in relation to gender (p>.05); 65% of male and 58% of female students reported a decline in physical fitness and significant gender differences were found (p<.05). After exercising male students reported better concentration and mood, more energy and motivation, and less nervousness in the range of 62–79%, while female students reported better concentration and mood, more energy and motivation, and less nervousness in the range of 62-81%. No significant differences were found in the physical activity acute effects on students' well-being in relation to gender (p>.05). Although gender differences in physical activity disappeared during the early phase of COVID-19 and lockdown measures, a more pronounced decrease in physical fitness was present in female students. The reported physical activity had equally positive acute effects on students' well-being.

This research aimed to determine the isokinetic strength differences between two groups of athletes (karate and track-and-field athletics) and to analyse factors that possibly contribute to the differences. We examined possible differences in peak power output and power ratio between agonist and antagonist thigh muscles of the knee. The sample consisted of 20 respondents: karate athletes (n=10; age 19±2.4) and track-and-field athletes (n=10; age 18±2.6). For this study, a valid test (CV<5%) of the isokinetic strength output of the knee extensors and flexors, was used at the angular velocity of 60°/s. Isokinetic variables: Peak torque in extension for both legs (Nm); Peak torque in flexion for both legs (Nm); Total work for both legs (J); Strength deficit involved/uninvolved leg and agonist/antagonist ratio for involved and uninvolved leg. A t-test for independent samples was used to determine the differences. Statistical significance was set at the conventional 95%. In the sample of examined variables, the first tested group of athletes (karate) achieved higher power output values with the dominant leg, except in the case of the peak torque extensors. In the second tested group of athletes (track-and-field athletics), a higher power output values are registered with dominant leg, except in the case of the total work flexor with almost identical value of dominant and non-dominant leg. In the variables of the peak torque of the dominant leg (p=0.002) and the peak torque of the non-dominant leg (p=0.019), statistically significant differences were noted between two tested groups of athletes (p<0.01, p<0.05). The unilateral relationship of the dominant leg (p=.003) significantly differentiates two groups of athletes (p<0.01). The better performance of track-and-field athletes is probably the result of the specificity of the structure of their motor movement and greater muscular work in training and competition. In contrast, the lower results of peak torque and total work in karate athletes compared to track athletes do not necessarily mean situational inferiority. Evaluation and assessment of knee dynamic stabilizers’ isokinetic profile can lead to the optimal selection of training operators, during the construction of the overall training program for athletes. Results of different outputs of force and strength may indicate a differently shaped approach to training.

Uvod Poznato je da starenje za posljedicu ima opadanje tjelesnih sposobnosti čovjeka, što je uz globalni problem hipokinezije, jedan od vodećih savremenih problema društva (Čaušević, Ormanović, Doder, & Čović, 2017; Ćirić, Čaušević, & Bejdić, 2015). Individualni aerobni fi tness se smanjuje za 8-10% tokom svake decenije života, dok veoma aktivni ljudi mogu smanjiti ovaj nivo na 2-3%. Opadanje snage je osjetno u šezdesetim, a posebno u sedamdesetim godinama života (15% odnosno 30%), (Sharkey & Gaskill, 2008). Takođe u brojnim studijama, utvrđeno je da su promjene koje nastaju kao posljedica biološkog starenja, povezane sa smanjenim stepenom fi zičke aktivnosti osoba starije dobi, a koje za posljedicu imaju smanjenje mišićne mase i tjelesne funkcije. Poznato je da organizovano tjelesno vježbanje ima mnogo pozitivnih efekata na organizam čovjeka u cjelini, te da ima jasan i prioritetan fi zički i zdravstveni uticaj na osobe i njihove radne aktivnosti. Međutim, bez obzira na to šta osoba radi – bilo da se bavi prostim fi zičkim poslom (nošenjem, podizanjem, poljoprivrednim radom) ili vrši fi zičke vježbe, njen mišić ni, kardio-vaskularni, respiratorni i centralni nervni sistem aktivno funkcionišu. Shodno tome će fi zička aktivnost, bilo kao tjelesna vježba ili fi zički rad, uvijek uticati na naše tijelo i tako dovesti do poveć anog nivoa funkcionisanja (Bjelica & Krivikapić, 2019). S druge strane, neaktivnost uzrokuje 9% prerane smrtnosti, što brojem iznosi više nego 5,3 od 57 miliona smrtnih slučajeva širom svijeta tokom 2008. godine (Lee i sar. 2012). Istoimeni autori navode da ukoliko neaktivnost nije eliminisana ali jeste umanjena za 10% ili 25%, onda bi se smrtnost tokom svake godine mogla izbjeći za više od 533 000 odnosno za više od 1,3 miliona slučajeva. Ovakav navod potvrđuje i činjenica da Abstract

Uvod Informisanost o nivou treniranosti sportista, te uzrocima i posljedicama takvog stanja, bitna je za njihov uspjeh. Poznato je da fudbaleri u igri ostvare veći broj kratkih sprinteva, te da primjenjuju različite načine vođenja lopte, pravolinijski i sa promjenom smjera kretanja. Struktura agilnosti s loptom je mnogo složenija u odnosu na takvo kretanje bez lopte (Sporiš, Milanović, Trajković, & Joksimović, 2011). Brzina i eksplozivna snaga se smatraju preduslovom za uspjeh u omladinskom fudbalu (Reilly, Bangsbo, & Franks, 2000), naglašavajući pritom ubrzanja na kratkim udaljenostima. Visina i tjelesna težina su značajno povezane sa fi zičkom izvedbom u slučaju mladih fudbalera ( Mathisen & Petersen, 2015). Ipak se sa sigurnošću ne može izolovati neka osobinu ili sposobnost koja donosi odlučujuću prednost u utakmici. Fudbaleri su tjelesno lakši od osoba koje žive sedentarnim načinom života (Popović, Akpinar, Jaksic, Matic, & Bjelica, 2013), ali i niži u odnosu košarkaše, odbojkaše i rukometaše juniorske kategorije (Masanovic & Vukasevic, 2009; Masanovic, 2018). Međutim, u sportovima gdje se traži velika brzina kretanja, nagla promjena pravca u velikoj brzini kretanja, grubi sudari sa protivnikom (fudbal i hokej), tjelesna visina ne samo da nije dominantna, nego je u određenoj mjeri i nepovoljna (Bjelica & Fratrić, 2011). Međusobni odnos tjelesne visine i težine (body mass index), te udio masne komponente (% fat mass) u ukupnoj tjelesnoj masi, za trenere može biti važna informacija. Optimalne vrijednosti BMI-a mogu rezultirati u poboljšanju opšteg nivoa tjelesne i anaerobne snage (Nikolaidis, 2014). Fudbaleri imaju povoljan sadržaj mišića sa niskim nivoom tjelesnih masti (Popovic, Bjelica, Jaksic, & Hadzic, 2014). Ipak, višak tjelesnih masti stvara nepotreban teret i umanjuje učinkovitost u igri, te značajno narušava elemente tehnike mladih fudbalera (Nemčić, Fiorentini, & Sporiš, 2018). Vrijednosti tjelesnih masti za vrhunske fudbalere su u prosjeku 7-12%, te su niže nego u slučaju sedentarnih ljudi, ali su takođe više u odnosu na trkače u sportovima izdržljivosti (Shephard, 1999.). Pored optimalizacije voluminoznosti mišića, na količinu potkožnog masnog tkiva se može uticati dopunskim treningom (Conroy i Earle, 2000), i to djelovanjem u pravcu njene redukcije. S obzirom da se takmičenja omladinskih liga organizuju shodno hronološkoj, a ne biološkoj starosti, često se pojedinci Abstract

Uvod Dehidracija može ugroziti sportsku izvedbu i povećati rizik od teške tjelesne povrede. Negativni efekti dehidratacije na performanse se uočavaju već pri <2% (Barr, 1999). Naime, manjak tečnosti koji se javlja tokom jedne vježbe može potencijalno kompromitovati sljedeću sesiju vježbanja, ukoliko ne dođe do adekvatne zamjene tečnosti. Dakle, zamjena te čnosti poslije vježbanja često se može smatrati hidratacijom prije sljedećeg treninga (Shirreff s, Armstrong, & Cheuvront, 2004). Ipak, sportisti samoinicijativno ne piju dovoljnu količinu vode za sprječavanje dehidracije tokom fi zičke aktivnosti (Casa, Armstrong, Hillman, Montain, Reiff , Rich, Roberts, & Stone, 2000; Maughan i sar., 2010). Maughan & Shirreff s (2010), navode da neki sportisti piju previše tečnosti, dok neki mogu razviti i hiponatremiju zbog prevelikog unosa tečnosti. S druge strane, slobodnim mikropauzama koje se tokom treninga planiraju u cilju nadoknađivanja tečnosti gubi se na intenzitetu treninga, a ukoliko je cilj treninga sticanje motoričkog znanja onda dolazi do narušavanja organizacije i kontinuiteta rada (Gobson i sar., 2012). Pogotovo je to slučaj prilikom rada u parovima, kada jedan od partnera nadoknađuje tečnost, dok drugi stoji i čeka ga. Interesantno bi bilo ispitati da li nadoknađivanje tečnosti tokom treninga predstavlja samo naviku sportiste, ili zato zaista postoji objektivna potreba nastala kao rezultat gubitka tečnosti znojenjem i naprezanjem tokom treninga. Sam osječaj žeđi je individualnog karaktera, te bi stoga bilo potrebno provjeriti opravdanost slobodnog načina rehidriranja. Poznato je i da vrhunski judo takmičari hipohidracijom smanjuju težinu prije takmičenja, što takođe negativno utiče na organizam sportiste i dovodi do smanjenja funkcije te negativnih učinaka na zdravlje (Jung & Malliaropoulos, 2014). Gubitak tečnosti rezultira osjećajem letargije i gubitkom motivacije za nastavak vježbanja, pridonoseći razvoju umora (Watson, 2008). Kratkoročne promjene u hidrataciji mogu se procijeniti na temelju promjene mase tijela (Maughan & Shirreff s, 2010). Rezultati ove studije bi trebali potvrditi dehidraciju organizma u slučaju nekonzumiranja tečnosti tokom judo treninga, te ukazati na opravdanost organizovane rehidratacije u slučaju sportista 11-12 godina starosti. Abstract

The aim of this paper is to determine the differences in the level of morphological characteristics, speed abilities and aerobic endurance according to the team positions of top female football players. The study included 18 female football players (age 21.33±3.67, body mass index 20.94±1.95). Female football players are classified under the following team positions: defenders (n = 7 ; 23±16.4 years), midfielders (n = 6, 20.5±14.3 years) and attackers (n = 5 ; 20±31.3 years). The following tests were used: 0-5m sprint (s), 0-10m sprint (s), 0-20m sprint (s), 0-30m sprint (s) and Beep test. Body mass index (BMI) was calculated based on the ratio of body weight (kg) and body height (cm). Based on the Beep test, the maximum oxygen consumption (VO2max) was calculated and presented in its relative value (ml/kg/min). The attackers had a higher body height (170.1±7.46) and weight (59.60±8.84) than those playing in midfield and defense positions. Also, the attackers were faster in the sprint on the 5m (1.17±.06), 10m (1.91±.06), 20m (3.27±.10) and 30m (4.51±.17) than female players in midfield and defense positions. Midfield players had higher level of VO2max (50.03±2.69) than female players in defensive and offensive team positions. Test results of univariate analysis of variance (ANOVA) showed that there are significant differences in the level of morphological features, speed and aerobic endurance capabilities between the top female football players, regardless of their team position (p>0.05). It is obvious that good speed abilities on short sprint sections as well as high level of aerobic endurance at high intensity are required regardless of players team position in the women’s football. It is important to note that selection for team positions can not only be based on morphological characteristics, speed abilities and aerobic endurance of players. Also, tactical tasks as well as technical characteristics of players need to be considered for selection of team positions in the women’s football.

The aim of the research is to determine the relationship between morphological characteristics and dynamic parameters of running in the case of boys aged 10-12 years. The study was conducted on a sample of 75 respondents, who are separated from the fourth-grade elementary school population. Morphological characteristics are measured by a set of fifteen variables: longitudinal dimensionality (3 variables), transversal dimensionality (4 variables), volume and body mass (4 variables), fatt tissue (4 variables), and body mass index. Dynamic parameters of running were estimated by measuring the passing time at 5m segments of the whole distance. Variables of dynamic running parameters have achieved statistically significant correlation with variables of transversal dimensionality, volume and body mass and fat tissue (p<0.05). Also, statistically significant correlation (p<0.01) of mean intensity was obtained between body mass index and all variables of dynamic running parameters. Based on the results of dynamic running parameters it can be concluded that the analyzed sample of boys aged 10-12 years is characterized by the following pattern of running structure at 50 meters: the acceleration phase lasts from the start to the fifteen meters section; stable running phase lasts from 15 to 40 meters, indicating that the maintenance length of the maximum speed level is 25 meters; and the deceleration phase of running lasts from 40 to 50 meters.

The subject of this study is to determine predictive contributions of morphological characteristics and motor abilities on the 60m hurdles, with an aim to form a group of easily applicable field tests so as to identify boys who are talented in hurdle racing. The subject sample of this study was comprised of 60 boys aged 12-13. The variable sample consisted of a 60m hurdles criterion variable and a set of 13 predictor variables comprising of morphological characteristics, speed - strength abilities and the subjects' coordination qualities.  Applying the regression analysis, the predictive contribution of a complete variable set of morphological characteristics and motor abilities was determined as an above average statistical significance, influencing 60m hurdle outcome. The greatest individual statistically significant predictive contribution was achieved by the variables of speed-strength quality assessment: 20m flying start race result with a standing long jump; and only one variable from the field of morphological characteristics: the shin length. The results support the following conclusion: the two specific variables of speed-strength quality, and 20m flying start race results along with standing long jump, can be relevant predictors of successful outcome in hurdle races.