Usporedba Conconijevog i ventilacijskog anaerobnog praga određenog kratkim i standardnim protokolom testa na pokretnoj traci

The purpose of this study was to compare two methods for determination of anaerobic threshold from two different treadmill protocols. Forty-eight Croatian runners of national rank (ten sprinters, fifteen 400-m runners, ten middle distance runners and thirteen long distance runners), mean age 21.7}5.1 years, participated in the study. They performed two graded maximal exercise tests on a treadmill, a standard ramp treadmill test (TSR, speed increments of 1 km•h-1 every 60 seconds) and a fast ramp treadmill test (TFR, speed increments of 1 km•h-1 every 30 seconds) to determine and compare the parameters at peak values and at heart rate at the deflection point (HR DP) and ventilation threshold (VT ). There were no significant differences between protocols (p>0.05) for peak values of oxygen uptake (VO2max, 4.48±0.43 and 4.44±0.45 L•min-1), weight related VO2max (62.5±6.2 and 62.0±6.0 mL•kg-1•min-1), pulmonary ventilation (VE max, 163.1}18.7 and 161.3}19.9 L•min-1) and heart rate (HR max, 192.3}8.5 and 194.4}8.7 bpm) (TFR and TSR, respectively). Moreover, no significant differences between TFR and TSR where found for VT and HR DP when expressed as VO2 and HR . However, there was a significant effect of ramp slope on running speed at VO2max and at the anaerobic threshold (AnT) , independent of the method used (VT : 16.0}2.2 vs 14.9}2.2 km•h-1;HR DP: 16.5}1.9 vs 14.9±2.0 km•h-1 for TFR and TSR respectively). Linear regression analysis revealed high between-test and between-method correlations for VO2, HR and running speed parameters (r=0.78-0.89, p<0.01). The present study has indicated that the VT and HR DP for running (VO2, ventilation, and heart rate at VT /HR DP) are independent of test protocol, while there is a significant effect of ramp slope on VT and HR DP when expressed as running speed. Moreover, this study demonstrates that the point of deflection from linearity of heart rate may be an accurate predictor of the anaerobic threshold in trained runners, independently of the protocol used.Cilj istraživanja bio je usporediti dvije metode za utvrđivanje anaerobnog praga u dva različita protokola opterećenja. U istraživanju je sudjelovalo 48 trkača hrvatskog nacionalnog ranga (10 sprintera na 100 m, 15 sprintera na 400 m, 10 srednjeprugaša i 13 dugoprugaša) srednje dobi 21,7}5,1 god. Ispitanici su testirani dvama različitim protokolima maksimalnog opterećenja na pokretnoj traci: standardnim progresivnim protokolom opterećenja (TSR, brzina trake povećava se svake minute za 1 km/h) i brzo-rastućim progresivnim testom opterećenja (TFR, brzina trake povećava se za 1 km/h svakih 30 sekunda), u cilju mjerenja i usporedbe vršnih vrijednosti i vrijednosti pri ventilacijskom anaerobnom pragu (VT ) i točki defleksije frekvencije srca (HR DP). Vršne vrijednosti izmjerene u dva protokola (TFR :TSR) nisu se značajno razlikovale za primitak kisika (VO2max, 4,48:4,44 L/min), relativni VO2max (62,5:62,0 mL/kg/min), minutni volumen disanja (VE max, 163,1:161,3 L/min) i frekvenciju srca (192,3:194,4 otkucaja/min). Značajne razlike između TFR i TSR nisu utvrđene niti za VT i HR DP izražene primitkom kisika i frekvencijom srca. Međutim, utvrđen je značajan utjecaj protokola testa (akceleracije brzine trake) na brzine trčanja pri maksimumu i pri anaerobnom pragu, neovisno o primijenjenoj metodi (VT : 16,0±2,2 prema 14,9±2,2 km•h-1; HRDP: 16,5±1,9 prema 14,9±2,0 km•h-1 za TFR i TSR). Linearnom regresijskom analizom utvrđene su visoke pozitivne korelacije između protokola i između metoda određivanja praga za parametre primitka kisika, frekvencije srca i brzine trčanja (r=0,78-0,89, p<0,01). Rezultati rada pokazuju da su VT i HR DP za trčanje (VO2, VE i HR pri VT /HR DP) neovisni o protokolu testa, dok je značajan utjecaj protokola (brzine porasta brzine trake) na VT i HRDP izražene brzinom trčanja. Nadalje, ovo istraživanje pokazuje da se točka defleksije frekvencije srca (Conconijev test) može pouzdano koristiti za predviđanje anaerobnog praga u treniranih trkača neovisno o primijenjenom protokolu testa

HAEMATOLOGICAL AND IRON STATUS FOLLOWING A SOCCER MATCH

: The aim of the present investigation was to verify the responses of haematological and iron concentrations in Croatian U-21 soccer players following an official soccer match. A group of 19 trained, healthy male soccer players from the U-21 category of the Croatian soccer association took part in this study. An analysis of red blood cell concentration (RBC), haemoglobin (Hb), haematocrit (Htc), mean corpuscular volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin corpuscular (MCHC), and Thrombocytes was performed to indicate the haematological status. In addition, iron, total iron binding capacity (TIBC), the unsaturated iron-binding capacity (UIBC) and ferritin analyses were obtained immediately after the soccer match. A significant decrease in Hct (%) was observed immediately after the game. However, there were no significant changes in the haemoglobin levels. Iron concentration increased significantly (p< 0.01) after the soccer match. Ferritin levels were also higher at the end of the match compared to baseline measures. It can be reported that a soccer match may induce an iron increase immediately after the game which was contradictory to recent studies. In summary, this study provided a valuable opportunity to study biochemical parameters that could lead to a possible illness, injuries and severity in match-play

Usporedba Conconijevog i ventilacijskog anaerobnog praga određenog kratkim i standardnim protokolom testa na pokretnoj traci

The purpose of this study was to compare two methods for determination of anaerobic threshold from two different treadmill protocols. Forty-eight Croatian runners of national rank (ten sprinters, fifteen 400-m runners, ten middle distance runners and thirteen long distance runners), mean age 21.7}5.1 years, participated in the study. They performed two graded maximal exercise tests on a treadmill, a standard ramp treadmill test (TSR, speed increments of 1 km•h-1 every 60 seconds) and a fast ramp treadmill test (TFR, speed increments of 1 km•h-1 every 30 seconds) to determine and compare the parameters at peak values and at heart rate at the deflection point (HR DP) and ventilation threshold (VT ). There were no significant differences between protocols (p>0.05) for peak values of oxygen uptake (VO2max, 4.48±0.43 and 4.44±0.45 L•min-1), weight related VO2max (62.5±6.2 and 62.0±6.0 mL•kg-1•min-1), pulmonary ventilation (VE max, 163.1}18.7 and 161.3}19.9 L•min-1) and heart rate (HR max, 192.3}8.5 and 194.4}8.7 bpm) (TFR and TSR, respectively). Moreover, no significant differences between TFR and TSR where found for VT and HR DP when expressed as VO2 and HR . However, there was a significant effect of ramp slope on running speed at VO2max and at the anaerobic threshold (AnT) , independent of the method used (VT : 16.0}2.2 vs 14.9}2.2 km•h-1;HR DP: 16.5}1.9 vs 14.9±2.0 km•h-1 for TFR and TSR respectively). Linear regression analysis revealed high between-test and between-method correlations for VO2, HR and running speed parameters (r=0.78-0.89, p<0.01). The present study has indicated that the VT and HR DP for running (VO2, ventilation, and heart rate at VT /HR DP) are independent of test protocol, while there is a significant effect of ramp slope on VT and HR DP when expressed as running speed. Moreover, this study demonstrates that the point of deflection from linearity of heart rate may be an accurate predictor of the anaerobic threshold in trained runners, independently of the protocol used.Cilj istraživanja bio je usporediti dvije metode za utvrđivanje anaerobnog praga u dva različita protokola opterećenja. U istraživanju je sudjelovalo 48 trkača hrvatskog nacionalnog ranga (10 sprintera na 100 m, 15 sprintera na 400 m, 10 srednjeprugaša i 13 dugoprugaša) srednje dobi 21,7}5,1 god. Ispitanici su testirani dvama različitim protokolima maksimalnog opterećenja na pokretnoj traci: standardnim progresivnim protokolom opterećenja (TSR, brzina trake povećava se svake minute za 1 km/h) i brzo-rastućim progresivnim testom opterećenja (TFR, brzina trake povećava se za 1 km/h svakih 30 sekunda), u cilju mjerenja i usporedbe vršnih vrijednosti i vrijednosti pri ventilacijskom anaerobnom pragu (VT ) i točki defleksije frekvencije srca (HR DP). Vršne vrijednosti izmjerene u dva protokola (TFR :TSR) nisu se značajno razlikovale za primitak kisika (VO2max, 4,48:4,44 L/min), relativni VO2max (62,5:62,0 mL/kg/min), minutni volumen disanja (VE max, 163,1:161,3 L/min) i frekvenciju srca (192,3:194,4 otkucaja/min). Značajne razlike između TFR i TSR nisu utvrđene niti za VT i HR DP izražene primitkom kisika i frekvencijom srca. Međutim, utvrđen je značajan utjecaj protokola testa (akceleracije brzine trake) na brzine trčanja pri maksimumu i pri anaerobnom pragu, neovisno o primijenjenoj metodi (VT : 16,0±2,2 prema 14,9±2,2 km•h-1; HRDP: 16,5±1,9 prema 14,9±2,0 km•h-1 za TFR i TSR). Linearnom regresijskom analizom utvrđene su visoke pozitivne korelacije između protokola i između metoda određivanja praga za parametre primitka kisika, frekvencije srca i brzine trčanja (r=0,78-0,89, p<0,01). Rezultati rada pokazuju da su VT i HR DP za trčanje (VO2, VE i HR pri VT /HR DP) neovisni o protokolu testa, dok je značajan utjecaj protokola (brzine porasta brzine trake) na VT i HRDP izražene brzinom trčanja. Nadalje, ovo istraživanje pokazuje da se točka defleksije frekvencije srca (Conconijev test) može pouzdano koristiti za predviđanje anaerobnog praga u treniranih trkača neovisno o primijenjenom protokolu testa

EXPLOSIVE POWER IN GYMNASTS: IS THERE ANY SCIENTIFIC BASIS FOR GENDER DIFFERENCES?

Abstract. The purpose of this study was to examine potential differences in vertical jump performance between male and female highly trained gymnasts, and to determine the relationship between parameters of the vertical jump performance and skill difficulty on the floor exercise. Forty-six highly trained gymnasts, comprising 15 female (Mean±SD; age: 21.08±1.83 y, height: 159.37±4.87 cm, mass: 50.88±5.41 kg) and 33 male (Mean±SD; age: 21.5±1.79 years, height: 170.67±4.66 cm, mass: 67.08±6.26 kg) consented to participate in study. Results showed statistically significant differences between male and female gymnasts (P 0.05) were shown between instantaneous powers. Correlation coefficients for CMJ variables were calculated for both groups. Statistically significant positive correlations were found only between D score values and jump height in male gymnasts (0.53) and relative jump power (0.39). Among female gymnasts, statistically significant, but negative correlations between E scores and jump height (-0.64) and with relative power (- 0.65), and between F scores and jump height (-0.52) were found.Key words: artistic gymnastics, vertical jump, floor exercise

Uticaj situaciono-kondicionog treninga na eksplozivnu snagu i preciznost kod odbojkaša

The aim of this research is to determine the effects of game-based training on explosive strength and accuracy in adolescent volleyball players. The authors hypothesized that this program might significantly improve explosive strength and accuracy in adolescent volleyball players. Fifty six adolescent volleyball players participated in this study (16,26±1,01). Players were randomly allocated into a game-based conditioning group (n = 30) or a control group (n = 26). Each player participated in a 8-week training program that included 3 organized court training sessions per week. Training effects were analyzed using a multivariate analysis of variance (MANOVA) and one-way univariate analysis of variance (ANOVA). Game-based conditioning training induced a significant improvement (p < 0.05) in squat jump (SJ), countermovement jump (CMJ), sitting (MEDS) and standing medicine ball throw (MEDST), whereas traditional volleyball activities did not significantly improved any of the tested variables. In SJ and CMJ results revealed a statistically significant difference between groups pre- to post-training (p < 0.05). After 8 weeks of training, there were increases in two medicine ball tests (MEDS and MEDST) for training group (p<0.05). There were no significant changes for lying medicine ball throw in both groups (p> 0.05). Experimental group did not significantly improved accuracy in contrast to control group which had significant improvement in several variables. Game-based training appears to be an effective way of improving explosive strength in adolescent volleyball players. The results of this study indicate that game-based training method was more effective for explosive strength performance than traditional instructional programme

Uticaj situaciono-kondicionog treninga na eksplozivnu snagu i preciznost kod odbojkaša

The aim of this research is to determine the effects of game-based training on explosive strength and accuracy in adolescent volleyball players. The authors hypothesized that this program might significantly improve explosive strength and accuracy in adolescent volleyball players. Fifty six adolescent volleyball players participated in this study (16,26±1,01). Players were randomly allocated into a game-based conditioning group (n = 30) or a control group (n = 26). Each player participated in a 8-week training program that included 3 organized court training sessions per week. Training effects were analyzed using a multivariate analysis of variance (MANOVA) and one-way univariate analysis of variance (ANOVA). Game-based conditioning training induced a significant improvement (p < 0.05) in squat jump (SJ), countermovement jump (CMJ), sitting (MEDS) and standing medicine ball throw (MEDST), whereas traditional volleyball activities did not significantly improved any of the tested variables. In SJ and CMJ results revealed a statistically significant difference between groups pre- to post-training (p < 0.05). After 8 weeks of training, there were increases in two medicine ball tests (MEDS and MEDST) for training group (p<0.05). There were no significant changes for lying medicine ball throw in both groups (p> 0.05). Experimental group did not significantly improved accuracy in contrast to control group which had significant improvement in several variables. Game-based training appears to be an effective way of improving explosive strength in adolescent volleyball players. The results of this study indicate that game-based training method was more effective for explosive strength performance than traditional instructional programme

Effects of neuromuscular training on motor competence and physical performance in young female volleyball players

Although neuromuscular training (NMT) emphasizes injury prevention training, there is little information about its effects on performance in young athletes. This study aimed to investigate the effects of eight-weeks NMT on motor competence and physical performance in 10- to 12-year-old female volleyball players. Sixty-six participants (mean ± SD11.05 ± 0.72 years) were randomized into either the NMT group (NTGn = 32) or control group (CONn = 34). Sprint on 10-m, modified T-test, plank, vertical jump, and medicine ball throw tests were used to assess the physical performance. The Körperkoordinationstest für Kinder (KTK) was used to assess the subjects’ motor competence. The NMT was performed twice a week during the first 30 min of each regularly scheduled 90-minute volleyball training. Participants in the CON group attended only their regular volleyball training. A significant group x time interaction was found for Motor Quotient KTK (MQKTK) (p 0.05). The NMT promoted significant gains in motor competence and physical performance in youth female volleyball players

Predictions of experimentally observed stochastic ground vibrations induced by blasting

In the present paper, we investigate the blast induced ground motion recorded at the limestone quarry “Suva Vrela” near Kosjerić, which is located in the western part of Serbia. We examine the recorded signals by means of surrogate data methods and a determinism test, in order to determine whether the recorded ground velocity is stochastic or deterministic in nature. Longitudinal, transversal and the vertical ground motion component are analyzed at three monitoring points that are located at different distances from the blasting source. The analysis reveals that the recordings belong to a class of stationary linear stochastic processes with Gaussian inputs, which could be distorted by a monotonic, instantaneous, time-independent nonlinear function. Low determinism factors obtained with the determinism test further confirm the stochastic nature of the recordings. Guided by the outcome of time series analysis, we propose an improved prediction model for the peak particle velocity based on a neural network. We show that, while conventional predictors fail to provide acceptable prediction accuracy, the neural network model with four main blast parameters as input, namely total charge, maximum charge per delay, distance from the blasting source to the measuring point, and hole depth, delivers significantly more accurate predictions that may be applicable on site. We also perform a sensitivity analysis, which reveals that the distance from the blasting source has the strongest influence on the final value of the peak particle velocity. This is in full agreement with previous observations and theory, thus additionally validating our methodology and main conclusions