CHANGES IN SPEED, AGILITY AND BODY COMPOSITION OF TOP-RANKED FEMALE HANDBALL PLAYERS DURING THE PLAYING SEASON

Handball is a dynamic Olympic sport dominated by acyclic movements (sudden changes in direction, jumps, landings, contacts between the players, etc.) with speed and agility playing an important role in their successful realization. Our aim was to establish which changes occurred in the body composition, speed and agility of top-ranked female handball players during the playing season. The parameters for estimating body composition were: body mass, body mass index (BMI), the percentage of muscle and fat. The ability to achieve speed (in 5, 10 and 30m sprints) and agility (new envelope test without a ball, straight slalom run without a ball and Straight slalom run with a ball, zig-zag with and zig-zag without a ball) was estimated with the portable timing system. The differences between the initial and the final measurements were established with the Student’s t-test. The results obtained show that there were statistically significant changes and weaker results in almost all the tested variables. The only improvements were detected in the maximum speed in 30m sprint and the agility without a ball (new envelope test and slalom run without a ball). It is recommended that the training plan should be carefully devised (the activities of the high intensity load should be applied throughout the season) as well as the plan for proper sports nutrition (body mass should be reduced with simultaneous increase in the muscular mass component)

VARIATIONS OF MUSCULAR STRENGTH AND POWER IN MALE HANDBALL PLAYERS DURING AN ENTIRE SEASON

Competition performance in handball depends on various individual skills and interaction with teammates. Technical and tactical efficiency are probably the most influential factors, while physical characteristics represent the prerequisite to attaining high level of competition performance. The purpose of the study was to determine the variations of muscular strength and power in male handball players during an entire season. The study was carried out on a sample of14 male handball players, members of the handball club, the participant of the Serbian male handball league during the 2014/2015 season. Measurements were taken four times during the period between the 6th and the 18th round of the handball league. The investigation protocol consisted of anthropometric measurements, determinations of the one-repetition maximum and assessments of muscular power. The obtained data indicate that no significant variations of muscular strength and power in male handball players occur during a competitive season. Besides, this study showed that players who compete in the Serbian male handball league have similar anthropometric characteristics, but significantly lower values of muscular strength and power when compared to top level European male handball players, and that it is necessary to pay much more attention to resistance training during the preparation period. Low values of the first measurement, which was the closest to the preparation period, are the probable reason for the non-existence of major variations during the competitive season

MEHANIČKE I FUNKCIONALNE KARAKTERISTIKE SNAGE STISKA ŠAKE MLADIH RUKOMETAŠICA

The aim of this research was to define differences in functional and mechanical characteristics of isometric hand grip (HG) strength between young female handball players and the CG comprised of physically active girls with no experience in sport. 70 individuals participated in the research, 36 of whom were the best young female handball players (of cadet and junior categories) while 34 girls comprised the CG. The results obtained show that the young female handball players who took part in the tests achieved Fmax at the levels from 306.4±40.8 to 335.5±47.0 N and RFDmax at the levels ranging from 1918.1±366.8 to 2174.4±382.1 N/s for the non-dominant and dominant hand. When these results are compared to the ones achieved by the CG it is clear that the young female handball players had a statistically significant higher level of the maximum HG force of both arms as well as the higher level of maximum explosiveness. There was no statistically significant difference between the groups regarding all the indexes of dimorphism (ID) as well as the values of the time needed for achieving the maximum intensity of muscle excitation (tRFDmax). Therefore, it can be concluded that the handball players who underwent the testing procedures showed positive adaptation from the aspect of the mechanical characteristics of hand grip strength, which can most likely be ascribed to the phenomenon of biological adaptation to the training stimuli characteristic for handball. However, the same influence was not detected from the aspect of functional characteristics, more precisely, dimorphism.Cilj ovog istraživanja bio je da se utvrde razlike u funkcionalnim i mehaničkim karakteristikama izometrijske snage stiska šake (SŠ) između mladih rukometašica i kontrolne grupe (KG) koju čine fizički aktivne devojke bez iskustva u sportu. U istraživanju je učestvovalo 70 ispitanika, od kojih je 36 najboljih mladih rukometašica (kadetske i juniorske kategorije), a 34 KG devojke. Dobijeni rezultati pokazuju da su mlade rukometašice koje su učestvovale u testovima postigle Fmax na nivoima od 306.4±40,8 do 335.5±47.0 N i RFDmax na nivoima od 1918.1±366.8 do 2174.4±382.1 N/s za nedominantnu i dominantnu šaku. Kada se ovi rezultati uporede sa rezultatima KG, jasno je da su mlade rukometašice imale statistički značajno viši nivo maksimalne snage SŠ obe šake, kao i viši nivo maksimalne eksplozivnosti. Nije bilo statistički značajne razlike između grupa u pogledu svih indeksa dimorfizma (ID), kao i u pogledu vremena potrebnog za postizanje maksimalnog intenziteta mišićne ekscitacije (tRFDmax). Na osnovu toga se može zaključiti da su rukometašice koje su prošle proces testiranja pokazale pozitivnu adaptaciju sa aspekta mehaničkih karakteristika snage stiska šake, što se najverovatnije može pripisati fenomenu biološke adaptacije na trenažne stimuluse karakteristične za rukomet.  Nije međutim zapažen isti uticaj sa aspekta funkcionalnih karakteristika, tačnije dimorfizma

TELESNA STRUKTURA RUKOMETAŠA REPUBLIKE SRBIJE SA RAZLITIČIH NIVOA TAKMIČENJA MERENA METODOM BIOELEKTRIČNE IMPENDANCE

The goal of this study was to define body composition characteristics and differences between Serbian male handballers measured by the multiple bioimpedance method. The sample of subjects consisted of 94 male senior handballers from three different competition levels, distributed  as follows: the Serbian male national team = 19; the Serbian Super National League = 43; and the Serbian First National League = 32. Twenty-two (22) variables were measured in this research, structured as follows: eight (8) basic and fourteen (14) derived or index variables, with six (6) of the latter being dependent on body voluminosity, seven (7) dependent on body longitudinality, and one (1) was an index variable. For all the results, descriptive statistical characteristics were calculated and multivariate and univariate analysis of variance (MANOVA and ANOVA) were used to establish both general and partial potential inter-group differences, by applying Wilks’s Lambda criterion. The results of the MANOVA showed, in general, statistically significant differences in the examined body composition variables between samples of handballers at Wilks's Lambda Value 0.370, F = 2.048, p = 0.001. Established differences explained 39.2% of the general variability (Partial Eta2 =0.392) with the observed statistical power of the data of 100% (Observed Power = 1.000). The statistically significant variables that predominantly defined body composition differences, were: BH, BM, Proteins, Skeletal Muscle Mass, Minerals, Total Body Water, Free Fat Mass and Muscle Mass Index (p = 0.000). The findings of this study show a statistically varied body composition of handballers of different competitive success; in other words, the most successful players, or players in the ranks of the Serbian national team, morphologically differ from players in lower competitive ranks. Also, the findings show that the multiple bioimpedance method is valid in defining the mentioned body composition differences for handball players of different competitive success, and therefore it can be used, both in general and in particular, in practice and in the science of handball. In respect to the partitioning of the initial variables, the findings have shown that this partitioning for defining the differences between the observed samples is somewhat more handball, body composition, males, bioimpedance. sensitive than the one in respect to the bodily height, i.e., longitudinality.Cilj ovog istraživanja bio je da se definišu odlike telesne kompozicije i razlike između srpskih rukometaša, merene metodom bioelektrične impendance. Uzorak ispitanika činilo je 94 rukometaša seniorske grupe koji se takmiče na različitim nivoima takmičenja, a koji su bili podeljeni na sledeći način: srpska muška rukometna reprezentacija = 19; srpska super nacionalna liga = 43; i srpska prva nacionalna liga = 32. Ukupno, 22 varijable merene su u ovom istraživanju, podeljene na sledeći način: (8) osnovnih i (14) indeks varijabli, od kojih (6) zavise od voluminoznosti tela, (7) od longitudinalnosti tela, a (1) je indeks varijabla. Deskriptivni statistički parametri su izračunati, kao i MANOVA i ANOVA koje su odredile i opšte i delimične međugrupne razlike, primenom Wilks’s Lambda kriterijuma. Rezultati MANOVA pokazali su da postoje statistički značajne razlike između analiziranih varijabli telesne kompozicije između uzorka rukometaša, za vrednost Wilks's Lambda Value 0.370, F = 2.048, p = 0.001. Utvrđene razlike objašnjavaju 39.2% opšte varijabilnosti (Partial Eta2 =0.392) pri Observed Power = 1.000. Statistički značajne varijable koje u najvećoj meri definišu telesnu kompoziciju su: BH, BM, Proteini, Skeletni mišići, Minerali, Ukupna količina vode u telu, Telesna masa bez masnih naslaga i Indeks mišićne mase (p = 0.000). Rezultati ovog istraživanja ukazuju na statistički raznovrsnu telesnu kompoziciju rukometaša koji postižu različite nivoe uspeha; drugim rečima, najuspešniji igrači, ili igrači srpskog nacionalnog tima se u morfološkom smislu razlikuju od rukometaša nižih rangova takmičenja.  Takođe, rezultati ukazuju na to da metoda bioelektrične impendance je validan metod za određivanje razlika u telesnoj kompozicij na primeru rukometaša, pa se samim tim može primenjivati u daljim istraživanjima u oblasti rukometa. Što se tiče podele inicijalnih varijabli, rezultati su pokazali da se ova podela radi definisanja razlika između posmatranih uzorka može smatrati delikatnijom od one koja zavisi od visine tela, odnosno longitudinalnosti

RAZLIKE KARAKTERISTIKA VIZUELNOG REAGOVANJA KOD KADETSKIH I JUNIORSKIH IGRAČICA RUKOMETA NACIONALNOG NIVOA

This paper aims to define differences in Simple Visual Reaction Time (SVRT) and Reaction Time Variation (RTV), related to age and player position in Serbian female cadet and junior national handball team members. The method used in this research was laboratory testing. All data sampling was performed using specially designed testing software that recorded visual reaction time with 1 ms precision. SVRT was expressed in ms, and RTV was expressed as a coefficient of variation percentage value. The overall sample consisted of 34 players - 19 cadets and 15 juniors. Mean SVRT of 194.28±16.55 and 184.73±16.68 ms was determined in the subsamples of cadet and junior players, respectively. It was found that cadets have a mean RTV of 4.74±2.41% while juniors have a mean RTV of 7.90±3.70%. Results of the Factorial ANOVA have shown that there are no general, statistically significant, differences in SVRT in relation to age, player position, and interaction of these factors (p>0.05). Statistically significant difference in RTV on a general level was found in relation to age (F=9.752, p=0.005), while differences in relation to player position or combination of these factors were not statistically significant (p>0.05). Post hoc tests have shown partial differences in relation to player position. The method of mathematical modelling was used to define the statistical model of performance in relation to the given variables. The final form of the model explained 100% of the measured variance (AdjR2 = 1.000), which implies its absolute predictive potential considering the characteristics of the sample.Cilj ovog rada je definisanje razlika u vremenu reagovanja na jednostavan vizuelni stimulus (SVRT) i varijaciji vremena reagovanja (RTV), odnosno neurovizuelnog odgovora i akutne koncentracije, vezanih za uzrast i poziciju igračica kod članova kadetske i juniorske selekcije ženskog rukometnog tima R. Srbije. U ovom istraživanju je korišćen metod laboratorijskog testiranja. Uzorkovanje podataka je izvršeno korišćenjem specijalno dizajniranog softvera koji registruje vreme vizuelne reakcije na nivou preciznosti od 1ms. SVRT je izražen u ms, dok je RTV izražen kao procentualna vrednost koeficijenta varijacije rezultata. Ukupni uzorak se sastojao od 34 igračice – 19 kadetkinja i 15 juniorki. Prosečna vrednost SVRT od 194.28±16.55 i 184.73±16.68 ms je utvrđena na uzorcima kadetkinja I juniorki, respektivno. Utvrđeno je da kadetkinje imaju prosečan RTV od 4.74±2.41% dok juniorke imaju proseečan RTV na nivou 7.90±3.70%. Rezultati Faktorske ANOVE su pokazali da ne postoje generalne statistički značajne rezlike SVRT u odnosu na uzrast, poziciju igračica, ili interakciju ovih faktora (p>0.05). Statistički značajne razlike RTV na generalnom nivou nađene su samo u odnosu na uzrast (F=9.752, p=0.005), dok razlike u odnosu na poziciju igračica i interakciju ovih faktoranisu nisu bile statistički značajne (p>0.05). Post hok testovi su pokazali postojanje parcijalnih razlika u odnosu na poziciju igračica. Metoda matematičkog modelovanja je korišćena za definisanje statističkog modela uspešnosti u funkciji zadatih varijabli. Finalna forma modela je objasnila 100% izmerene varijanse (AdjR2 = 1.000), što ukazuje na apsolutni prediktivni potencijal uzimajući u obzir karakteristike uzorka

Self-preferred initial position could be a viable alternative to the standard squat jump testing procedure

The purpose of this study was to compare both the magnitude and reliability of different variables (knee angle, squat depth, jump height [Hmax], maximum force [Fmax], and maximum power [Pmax]) between the standardized squat jump (SJ) and the SJ performed from the self-preferred position. Eleven team handball players (age: 19.5 +/- 1.1 years; height: 1.88 +/- 0.06 m; and body mass: 82.1 +/- 8.7 kg) and 13 physically active students (age: 20.5 +/- 0.9 years; height: 1.81 +/- 0.06 m; and body mass: 76.6 +/- 6.6 kg) were evaluated on 2 sessions during the standardized SJ (knee angle fixed at 90 degrees) and the self-preferred SJ (self-selected knee angle to maximize Hmax). Two blocks of both 3 standardized SJ and 3 self-preferred SJ were performed on the first session, whereas only 1 block was performed in the second session. The squat depth was smaller for the self-preferred SJ, whereas the knee angle, Fmax, and Pmax were higher for the self-preferred SJ (p lt 0.025). The magnitude of Hmax did not significantly differ between both jump types. Most importantly, the reliability of the mechanical outputs (Hmax, Fmax, and Pmax) was generally higher for the self-preferred SJ (9 of 12 comparisons), whereas only in 2 of 12 comparisons the reliability was meaningfully higher for the standardized SJ. No differences were observed between presumably more (handball players) and less skilled individuals (physically active subjects). These results suggest that the self-preferred SJ should be recommended over the standardized SJ (90 degrees knee angle) because it is not only quicker and more ecologically valid, but could also provide the performance variables with higher reliability