Reactive agility (RAG) and change of direction speed (CODS) are important determinants of success in football (soccer), but there is an evident lack of information on reliable and valid football-specific testing procedures which will be applicable in defining sport-specific RAG and CODS in youth players. This study evaluated reliability and construct validity of newly developed tests of football-specific RAG (FS_RAG) and CODS (FS_CODS), which involved the ball kicking football technique. Additionally, factors associated with FS_RAG and FS_CODS were evaluated. The participants were youth football players (n = 59; age: 13.40 ± 1.25 years) divided according to their age into U13 (11–12 years of age; n = 29), and U15 (13–14 years of age; n = 30) categories. Additionally, performance levels (starters [first-team] vs. non-starters [substitutes]) were observed in each age category. The dependent variables were newly developed FS_RAG and FS_CODS tests. The independent variables were sprinting capacities over 10 and 20 meters (S10M, S20M), countermovement jump (CMJ), the reactive strength index (RSI), and a generic CODS test of 20 yards (20Y). The newly developed FS_CODS and FS_RAG were observed as dependent variables. Results showed appropriate intra-testing and inter-testing reliability of the FS_RAG and FS_CODS, with somewhat better reliability of the FS_CODS (ICC=0.82 and 0.79, respectively). Additionally, better reliability was evidenced in U15 than in U13 (ICC: 0.82–0.85, and 0.78-0.80 for U15 and U13, respectively). Independent samples t-test indicated significant differences between U13 and U15 in S10 (t-test: 3.57, p < 0.001), S20M (t-test: 3.13, p < 0.001), 20Y (t-test: 4.89, p < 0.001), FS_RAG (t-test: 3.96, p < 0.001), and FS_CODS (t-test: 6.42, p < 0.001), with better performance in U15. Starters outperformed non-starters in most capacities among U13, but only in FS_RAG among U15 (t-test: 1.56, p < 0.05). Multiple regression calculations indicated nonsignificant association between independent and dependent variables in U13 (FS_CODS: 19%, FS_RAG: 21% of the explained variance, both p > 0.05), but independent variables explained significant proportion of both dependent variables in U15 (FS_CODS: 35%, FS_RAG: 33% explained variance, both p < 0.05). The study confirmed the applicability of newly developed tests in distinguishing studied age categories of players. Results indicate that superiority in all studied fitness capacities is translated into performance level in U13. Meanwhile, FS_RAG seems to be important determinant of quality in U15.

The importance of response time (RT) in sports is well known, but there is an evident lack of reliable and valid sport-specific measurement tools applicable in the evaluation of RT in trained athletes. This study aimed to identify the validity, reliability, and usefulness of four newly developed RT testing protocols among athletes from agility-saturated (AG) and non-agility-saturated (NAG) sports. Thirty-seven AG and ten NAG athletes (age: 20.9 ± 2.9; eleven females) volunteered to undergo: three randomized simple response time (SRT-1, SRT-2, and SRT-3) protocols that included a single limb movement, and one complex response time (CRT) protocol that included multi joint movements and whole body transition over a short distance (1.5 and 1.8m). Each RT test involved 3 trials with 5 randomized attempts per trial. Two sensors were placed at the left- and right-hand side for SRT-1 and SRT-2. Three sensors were positioned (left, middle, right) in SRT-3 and CRT. The intra-class-correlation coefficient (ICC) was calculated as a measure of reliability. Independent sample t-test, effect size (d), and area-under-the-curve (AUC) were calculated to define discriminative validity of the tests. The results showed the newly developed tests were more reliable and useful in the AG than NAG athletes (i.e., ICC between 0.68 and 0.97 versus 0.31-0.90, respectively). The RT of AG athletes was faster than that of NAG athletes in the CRT test from the left (p <0.01, d = 2.40, AUC: 0.98), centre (p < 0.01, d = 1.57, AUC: 0.89), and right sensor (p < 0.01, d = 1.93, AUC: 0.89) locations. In contrast, there were no differences between the groups in the SRT tests. The weak correlation (i.e., r= 0.00-0.33) between the SRT and CRT tests suggests that response time of the single limb and multijoint limb movements should not be considered as a single motor capacity. In conclusion, this study showed that AG athletes had faster response time than their NAG peers during complex motor tasks. Such enhanced ability to rapidly and accurately reprogram complex motor tasks can be considered one of the essential qualities required for advanced performance in agility-based sports.

Background: This study aimed to investigate the accuracy and reliability of a free mobile heart rate variability (HRV) application in measuring HRV. Methods: Twelve females and 12 males underwent five-minute simultaneous HRV recording from electrocardiogram (ECG) and chest strap connected to a free mobile HRV application (HRVapp) in a supine position. HRV data from ECG and HRVapp were used to examine accuracy and reliability via relative error and intraclass correlation coefficient respectively. Results: The natural log of the square root of the mean of the sum of the squares of differences between adjacent normal to normal intervals (lnRMSSD) exhibited accuracy and high reliability in HRVapp. Conclusion: lnRMSSD in HRVapp can serve as an alternative, low-cost technology for measurement of autonomic activity.

The purpose of this study was to perform a systematic review and meta-analysis on the effect of contrast training(CT) on vertical jump performance. Thirteen out of 83 studies were included for syst ...

Introduction: Response time (RT) has been defi ned as the time needed for a person to perceive and respondto some external stimulus (Schmidt et al., 2018). Defi ned in such a way, we can say that R ...

The importance of response time (RT) in sports is well known, but there is an evident lack of reliable and valid sport-specific measurement tools applicable in the evaluation of RT in trained athle ...

This study aimed to examine: (i) the level of physical activity (PA), obesity indices and cardiorespiratory fitness (CRF) among boys and girls in primary school, and (ii) to determine the association of obesity indices and PA with CRF for the total number of participants, and then separately for boys and girls. 753 sixth to ninth grade girls and boys aged 10–14 years took part in this cross-sectional study. The PA was assessed by the “Physical Activity Questionnaire – Children” and CRF was assessed by the Maximal multistage a 20 m shuttle run test. Body mass index (BMI), waist circumferences (WC), and waist to height ratio (WHtR) were considered as obesity indices. Multiple linear regression analyses were performed to explore correlates of CRF. The results obtained showed the prevalence of general overweight and obesity was 25.5% in our sample which was lower than that in the regional estimate (e.g., ∼28%) for Eastern Europe. Among all participants, CRF was associated with male sex, older age, a lower WC percentile, higher WHtR, and higher level of PA. The model accounted for 24% of the variance. CRF was associated with older age and higher level of PA among girls and boys. Lower WC percentile was a significant determinant of CRF among boys. In conclusion, general overweight/obesity was not independently associated with CRF. Those with better CRF were more likely to be male and older, had a higher level of PA and lower central adiposity. These findings emphasize the importance of supporting school age children to take a part in programmed physical activity regardless of their body composition.

Sport participation is considered as a factor of potential influence on illicit drug misuse (IDM) in adolescence, but there is an evident lack of studies which prospectively investigated this problem. This study aimed to prospectively investigate the sports-related factors related to IDM and the initiation of IDM among older adolescents. The participants were 436 adolescents (202 females; 16 years old at study baseline). They were tested at baseline and follow-up (two years later). The predictors included variables associated with different facets of sports participation and success in sports. The criteria were (i) baseline IDM, (ii) follow-up IDM, and (iii) initiation of IDM between baseline and follow-up. Crude and adjusted (controlled for parental conflict, age, socioeconomic status, and gender) logistic regressions were applied to establish correlations between predictors and criteria. There were higher odds for baseline IDM in adolescents who quit individual sports (OR: 4.2, 95% CI: 1.3-13.9), who had better competitive sports achievements (OR: 1.8, 95% CI: 1.0-3.3), and those involved in sports for a longer time (OR: 1.6, 95% CI: 1.0-2.5). The IDM at follow-up was more prevalent in adolescents who were involved in sports for a longer time (OR: 1.7, 95% CI: 1.1-2.6). Initiation of drug use was predicted by longer experience in sports (OR: 1.8, 95% CI: 1.1-3.1). Sports-related factors were more negatively than positively related to illicit drug use. Most probably, the transition from junior to senior level in sports put specific stress on those adolescents who were highly committed to sports until that time, but who then had to question their own sports abilities and future potential in sports. Sport-authorities should be informed on established results and specific public-health efforts aimed at preventing IDM in athletic adolescents are urgently needed.

Agility is a significant determinant of success in soccer; however, studies have rarely presented and evaluated soccer-specific tests of reactive agility (S_RAG) and non-reactive agility (change of direction speed – S_CODS) or their applicability in this sport. The aim of this study was to define the reliability and validity of newly developed tests of the S_RAG and S_CODS to discriminate between the performance levels of junior soccer players. The study consisted of 20 players who were involved at the highest national competitive rank (all males; age: 17.0 ± 0.9 years), divided into three playing positions (defenders, midfielders, and forwards) and two performance levels (U17 and U19). Variables included body mass (BM), body height, body fat percentage, 20-m sprint, squat jump, countermovement jump, reactive-strength-index, unilateral jump, 1RM-back-squat, S_CODS, and three protocols of S_RAG. The reliabilities of the S_RAG and S_CODS were appropriate to high (ICC: 0.70 to 0.92), with the strongest reliability evidenced for the S_CODS. The S_CODS and S_RAG shared 25–40% of the common variance. Playing positions significantly differed in BM (large effect-size differences [ES]; midfielders were lightest) and 1RM-back-squat (large ES; lowest results in midfielders). The performance levels significantly differed in age and experience in soccer; U19 achieved better results in the S_CODS (t-test: 3.61, p < 0.05, large ES) and two S_RAG protocols (t-test: 2.14 and 2.41, p < 0.05, moderate ES). Newly developed tests of soccer-specific agility are applicable to differentiate U17 and U19 players. Coaches who work with young soccer athletes should be informed that the development of soccer-specific CODS and RAG in this age is mostly dependent on training of the specific motor proficiency.

Background: This study aimed to prospectively investigate the scholastic factors related to illicit drug misuse (IDM) and the initiation of IDM among older adolescents from Bosnia and Herzegovina. Methods: This 2-year prospective study included 436 participants (202 females), who were an average of 16 years old at the beginning of the study (baseline). The participants were tested at baseline and follow-up (20 months later). The predictors included variables of scholastic-achievement (grade point average, school absences, unexcused absences and behavioral grade). The criteria were: (i) IDM at baseline; (ii) IDM at follow-up; and (iii) initiation of IDM over the study course. Results: Logistic regression indicated increased odds of IDM in adolescents who were more frequent absent from school (baseline: Odds Ratio (OR): 3.73, 95% Confidence Interval (CI): 2.12–6.57; follow-up: OR: 2.91, 95% CI: 1.90–4.65). The lower grade point average and more unexcused absences were evidenced for adolescents who consumed drugs on follow-up (OR: 1.67, 95% CI: 1.11–2.51; OR: 1.74, 95% CI: 1.30–2.32 for grade point average and unexcused absences, respectively). Initiation of IDM was predicted by frequent absences from school (OR: 2.2, 95% CI: 1.3–3.8), and lower behavioral grades (OR: 1.9, 95% CI: 1.2–3.3). Conclusions: The findings confirmed strong correlations between scholastic failure and IDM. Absences from school and lower behavioral grades at baseline were predictive of the initiation of IDM in older adolescents.

INTRODUCTION: Definition of Agility is based on a model that separates agility in two components, change of direction speed and perceptual and decision making processes. Based on that, two independ ...

Abstract Pojskic, H, Sisic, N, Separovic, V, and Sekulic, D. Association between conditioning capacities and shooting performance in professional basketball players: an analysis of stationary and dynamic shooting skills. J Strength Cond Res 32(7): 1981–1992, 2018—Little is known about the influence of conditioning capacities on shooting performance in basketball. The aim of this study was to examine the relationship between different conditioning capacities and shooting performance in professional basketball players. In this investigation, we examined 38 males (all perimeter players; height: 185.5 ± 6.73 cm; mass: 78.66 ± 10.35 kg). Conditioning capacities were evaluated by tests of muscular strength, aerobic endurance, jumping and throwing capacities, sprinting speed, preplanned agility, anaerobic endurance, and fatigue resistance. Shooting performance was evaluated using game statistics, as well as 6 tests of shooting performance performed in controlled settings: (a) 3 tests of static (i.e., nonfatigued) shooting performance (standardized execution of 1- [S1], 2- [S2] and 3-point shots [S3] in stationary conditions), and (b) 3 tests of dynamic (i.e., fatigued) shooting performance (standardized execution of 1- [D1], 2- (D2), and 3-point shots [D3] in dynamic conditions). All 3 dynamic shooting tests and the S1 test were significantly (p ⩽ 0.05) correlated with corresponding game statistics. Multiple regression indicated that conditioning capacities were significantly related to D1 (R2 = 0.36; p = 0.03), D2 (R2 = 0.44; p = 0.03), S3 (R2 = 0.41; p = 0.02), and D3 (R2 = 0.39; p = 0.03) tests. Players with a higher fatigue resistance achieved better results on the D1 test (&bgr; = −0.37, p = 0.03). Preplanned agility (&bgr; = −0.33, p = 0.04), countermovement jump (&bgr; = 0.42, p = 0.03), and fatigue resistance (&bgr; = −0.37, p = 0.02) were significant predictors of D2 performance. The countermovement jump (&bgr; = 0.39, p = 0.04), medicine ball toss (&bgr; = 0.34, p = 0.04), and anaerobic endurance (&bgr; = 0.46, p = 0.04) predicted the results of D3 performance. Jumping, throwing, and anaerobic endurance capacities were good determinants of the skill of dynamic shooting over a long distance. These findings emphasize the importance of explosive power and anaerobic capacity as determinants of shooting performance in high-level basketball players.

Objective Sport and scholastic factors are known to be associated with cigarette smoking in adolescence, but little is known about the causality of this association. The aim of this study was to prospectively explore the relationships of different sport and scholastic factors with smoking prevalence initiation in older adolescents from Bosnia and Herzegovina. Methods In this 2-year prospective cohort study, there were 872 adolescent participants (16 years at baseline; 46% females). The study consisted of baseline tests at the beginning of the third year (September 2013) and follow-up at the end of the fourth year of high school (late May to early June 2015). The independent variables were scholastic and sport-related factors. The dependent variables were (1) smoking at baseline, (2) smoking at follow-up and (3) smoking initiation over the course of the study. Logistic regressions controlling for age, gender and socioeconomic status were applied to define the relationships between independent and dependent variables. Results School absence at the baseline study was a significant predictor of smoking initiation during the course of the study (OR 1.4, 95% CI 1.1 to 1.8). Those who reported quitting sports at baseline showed an increased risk of smoking at the end of the study (OR 1.4, 95% CI 1.1 to 2.0) and of smoking initiation (OR 1.8, 95% CI 1.3 to 2.0). Adolescents who reported lower competitive achievements in sport were at a higher risk of (1) smoking at baseline (OR 1.5, 95% CI 1.1 to 2.1), (2) smoking at follow-up (OR 1.5, 95% CI 1.1 to 2.1) and (3) smoking initiation (OR 1.6, 95% CI 1.1 to 2.6). Conclusions In developing accurate antismoking public health policies for older adolescents, the most vulnerable groups should be targeted. The results showed that most participants initiated smoking before 16 years of age. Therefore, further investigations should evaluate the predictors of smoking in younger ages.

Purpose: Non-planned agility (reactive agility - RAG), and pre-planned agility (change of direction speed- CODS) are important determinants of success in basketball. However, the association betwee ...

Abstract The aim of the present study was to compare the aerobic and anaerobic power and capacity of elite male basketball players who played multiple positions. Fifty-five healthy players were divided into the following three different subsamples according to their positional role: guards (n = 22), forwards (n = 19) and centers (n = 14). The following three tests were applied to estimate their aerobic and anaerobic power and capacities: the countermovement jump (CMJ), a multistage shuttle run test and the Running-based Anaerobic Sprint Test (RAST). The obtained data were used to calculate the players’ aerobic and anaerobic power and capacities. To determine the possible differences between the subjects considering their different positions on the court, one-way analysis of variance (ANOVA) with the Bonferroni post-hoc test for multiple comparisons was used. The results showed that there was a significant difference between the different groups of players in eleven out of sixteen measured variables. Guards and forwards exhibited greater aerobic and relative values of anaerobic power, allowing shorter recovery times and the ability to repeat high intensity, basketball-specific activities. Centers presented greater values of absolute anaerobic power and capacities, permitting greater force production during discrete tasks. Coaches can use these data to create more individualized strength and conditioning programs for different positional roles.