Agility Testing in Youth Football (Soccer)Players; Evaluating Reliability, Validity, and Correlates of Newly Developed Testing Protocols.

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.

Importance of Agility Performance in Professional Futsal Players; Reliability and Applicability of Newly Developed Testing Protocols.

The purpose of this study was to determine the inter- and intra-testing reliability of newly developed tests of the change of direction speed (CODS) and reactive agility (RAG) in competitive futsal players. Additionally, the developed tests were evaluated for their validity with regard to the differentiation of two performance-levels. Thirty-two professional male futsal players (age = 26.22 ± 5.22 years; body height = 182.13 ± 5.99 cm, body mass = 77.43 ± 8.00 kg) participated in the study. The sample was divided into two groups based on their level of futsal performance: A top-level-group (n = 12) and a team-level-group (n = 20). The variables included body height, mass, body mass index, a sprint over a 10-m distance (S10M), and eight newly developed futsal specific CODS and RAG tests. The CODS and RAG tests were performed by dribbling the balls (CODS_D and RAG_D) and without dribbling (CODS_T and RAG_T), and the performances on the dominant and non-dominant sides were observed separately. All CODS, and RAG tests performed on dominant side and RAG_T tests performed on the non-dominant side had good inter-testing (CV = 5-8%; ICC = 0.76-0.89) and intra-testing (CV = 4-9%; ICC = 0.77-0.91) reliability. However, RAG_D performed on the non-dominant side was not reliable (ICC = 0.60, CV = 10%). The top-level-players outperformed the team-level-players in the CODS and RAG tests that involved dribbling (t-test: 4.28 and 2.40, p < 0.05; effect sizes (ES): 0.81 and 1.5, respectively), while the team-level players achieved better results in the CODS_T (t-test: 2.08, p < 0.05; ES: 0.60). The proposed CODS and RAG tests that involved dribbling over a 3.2-m distance, especially on the dominant side, appeared to be reliable, as well as valid for distinguishing the performance level in futsal players.

Vitamin D Status and Analysis of Specific Correlates in Preschool Children: A Cross-Sectional Study in Southern Croatia.

Vitamin D deficiency is a globally important problem, particularly in children, but there is a lack of information regarding this deficiency in preschool children from southeastern Europe. This study aimed to establish the levels of 25-hydroxyvitamin D (25(OH)D) and associations of gender, time spent outdoors, physical activity (PA), and body mass index (as predictors) with the 25(OH)D level (outcome) in healthy preschool children. The participants were preschoolers (all 5⁻6 years of age) from southern Croatia. All the participants were tested during their mandatory medical examination 6⁻7 months prior to school enrollment. The PA was obtained using the preschool-age physical activity questionnaire (Pre-PAQ), which categorizes PA into five levels (from sedentary to vigorous PA). The prevalence of 25(OH)D deficiency was high: 58% of the children had 25(OH)D levels of <50 nmol/L (deficiency), and an additional 29% had an insufficient level of 25(OH)D (50⁻75 nmol/L). Boys had higher levels of 25(OH)D than girls. A multinomial regression using 25(OH)D categories as the outcome and a sufficient level (>75 nmol/L) as the reference value identified gender as the only significant predictor of 25(OH)D status, with boys being at lower risk for 25(OH)D deficiency than girls. These results showed a high prevalence of 25(OH)D deficiency in preschoolers from the southern part of Croatia, which is additionally alarming based on the geographical position of the studied region (42° N) and its high number of sunshine hours (>2600 h per year). Future studies examining other potential correlates of 25(OH)D in the region are warranted.

Maturity Status as a Determinant of the Relationships Between Conditioning Qualities and Preplanned Agility in Young Handball Athletes.

Hammami, R, Sekulic, D, Selmi, MA, Fadhloun, M, Spasic, M, Uljevic, O, and Chaouachi, A. Maturity status as a determinant of the relationships between conditioning qualities and preplanned agility in young handball athletes. J Strength Cond Res 32(8): 2302-2313, 2018-Studies performed thus far have not accounted for the potential influence of maturity on determinants of preplanned agility. This study aimed to examine how determinants of preplanned agility are affected by the period of peak height velocity (PHV) regarding the anthropometrics and conditioning qualities in young handball players. The sample comprised 56 handball players (male; 12-14 years of age), allocated into 2 groups according to their biological age of maturity: Pre-PHV (N = 34) and Post-PHV (N = 22). Players were evaluated on handball-specific tests of preplanned agility (CODAT and T-HALF). Predictors included anthropometrics, sprinting, horizontal and vertical jumps, and reactive strength index (RSI). The reliability of the tests was appropriate (intraclass correlation coefficient: 0.87-0.95; coefficient of variation: 4.4-5.8%). In the Pre-PHV group, 67% variance of the T-HALF accounted for horizontal countermovement jump (ß: -0.83, p < 0.01), 20-m sprint (ß: 0.91, p < 0.01), and body mass (ß: 0.19, p = 0.02). In the Post-PHV group, 80% of the T-HALF variance was explained, with a significant influence of 20-m sprint (ß: 0.52, p < 0.01), RSI (ß: -0.24, p = 0.04), and standing long jump (ß: -0.57, p = 0.03). In the Pre-PHV group, 45% of the CODAT variance accounted for the partial influence of body fat percentage (ß: 0.44, p = 0.04) and a 20-m sprint (ß: 0.74, p < 0.01). In the Post-PHV group, the predictors accounted for 79% of the CODAT variance, with a significant influence of the RSI (ß: -0.26, p = 0.04) and a 10-m sprint (ß: 0.87, p = 0.03). Our results reinforce the need for differential strength and conditioning programs aimed at improving the preplanned agility of young athletes who differ in maturity status.

Importance of Reactive Agility and Change of Direction Speed in Differentiating Performance Levels in Junior Soccer Players: Reliability and Validity of Newly Developed Soccer-Specific Tests.

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.

The Effects of 3-Month Skill-Based and Plyometric Conditioning on Fitness Parameters in Junior Female Volleyball Players.

PURPOSE: This study compared the effects of skill-based and plyometric conditioning (both performed in addition to regular volleyball training twice a week for 12 wk) on fitness parameters in female junior volleyball players. METHODS: The participants [n = 47; age: 16.6 (0.6) y; mass: 59.4 (8.1) kg; height: 175.1 (3.0) cm] were randomized into a plyometric (n = 13), a skill-based (n = 17), and a control (n = 17) groups. The variables included body height, body mass, calf girth, calf skinfold, corrected calf girth, countermovement jump, 20-m-sprint, medicine ball toss, and sit-and-reach test. RESULTS: Two-way analysis of variance (time × group) effects for time were significant (P < .05) for all variables except body mass. Significant group × time interactions were observed for calf skinfold [η2 = .14; medium effect size (ES)], 20-m sprint (η2 = .09; small ES), countermovement jump (η2 = .29; large ES), medicine ball (η2 = .58; large ES), with greater gains (reduction of skinfold) for plyometric group, and sit-and-reach (η2 = .35; large ES), with greater gains in plyometric and skill-based groups. The magnitude-based inference indicated positive changes in 1) medicine ball toss and countermovement jump for all groups; 2) sit-and-reach for the plyometric and skill-based groups; and 3) 20-m sprint, calf girth, calf skinfold, and corrected calf girth for plyometric group only. CONCLUSION: Selected variables can be improved by adding 2 plyometric training sessions throughout the period of 12 weeks. Additional skill-based conditioning did not contribute to improvement in the studied variables compared with regular volleyball training.

Analyzing the relationship between anthropometric and motor indices with basketball specific pre-planned and non-planned agility performances.

BACKGROUND: Although agility is an important quality in basketball, factors associated with basketball specific pre-planned-agility (change-of-direction-speed, CODS) and non-planned-agility (reactive agility, RA) are rarely investigated. The aim of this study was to evaluate relationship between anthropometric and motor indices with basketball-specific CODS and RA in male basketball players of high performance level. METHODS: We tested 88 high-level male basketball players (height: 194.62±8.09 cm; body mass: 89.13±10.81 kg; age: 21.12±3.47 years). The sample was randomly divided into validation (N.=44) and cross-validation (N.=44) subsamples. The study variables included: broad-jump, countermovement-jump, reactive-strength-index, visual-reaction-time, body height, body mass, and body fat percentage (predictors); as well as basketball-specific CODS and RA (criteria). Univariate associations were assessed by Pearson's correlation coefficients. Multivariate relationships between the predictors and the criteria were assessed with multiple regression analysis for the validation subsample, which was then cross-validated. RESULTS: The established multiple regression models were successfully cross-validated for CODS (R2=0.40 and 0.36; P=0.01) and RA (R2=0.38 and 0.41; P=0.01, for validation and cross-validation subsample, respectively). The broad-jump (i.e., horizontal displacement) is important predictor of CODS (Beta=-0.41; P=0.01); anthropometrics and body build are specifically associated with RA (Beta=0.51, -0.61 and 0.41 for body height, body mass and body fat percentage, respectively; all P<0.05), while reactive-strength-index is directly related both to CODS (Beta=-0.41, P=0.02), and RA (Beta=-0.40, P=0.03). CONCLUSIONS: While basketball players are differentially oriented toward specific game duties, specific capacities should be developed in order to meet specific sport requirements.

Plyometric Training Improves Sprinting, Jumping and Throwing Capacities of High Level Female Volleyball Players Better Than Skill-Based Conditioning.

There is an evident lack of studies on the effectiveness of plyometric- and skill-based-conditioning in volleyball. This study aimed to evaluate effects of 12-week plyometric- and volleyball-skill-based training on specific conditioning abilities in female volleyball players. The sample included 41 high-level female volleyball players (21.8 ± 2.1 years of age; 1.76 ± 0.06 cm; 60.8 ± 7.0 kg), who participated in plyometric- (n = 21), or skill-based-conditioning-program (n = 20). Both programs were performed twice per week. Participants were tested on body-height, body-mass (BM), countermovement jump (CMJ), standing broad jump (SBJ), medicine ball throw, (MBT) and 20-m sprint (S20M). All tests were assessed at the study baseline (pre-) and at the end of the 12-week programs (post-testing). Two-way ANOVA for repeated measurements showed significant (p<0.05) "Group x Time" effects for all variables but body-height. Plyometric group significantly reduced body-mass (trivial effect size [ES] differences; 1% average pre- to post-measurement changes), and improved their performance in S20M (moderate ES; 8%), MBT (very large ES; 25%), CMJ (large ES; 27%), and SBJ (moderate ES; 8%). Players involved in skill-based-conditioning significantly improved CMJ (large ES; 18%), SBJ (small ES; 3%), and MBT (large ES; 9%). The changes which occurred between pre- and post-testing were more inter-correlated in plyometric-group. Although both training-modalities induced positive changes in jumping- and throwing-capacities, plyometric-training is found to be more effective than skill-based conditioning in improvement of conditioning capacities of female senior volleyball players. Future studies should evaluate differential program effects in less experienced and younger players.

Evaluation of different jumping tests in defining position-specific and performance-level differences in high level basketball players.

The importance of jumping ability in basketball is well known, but there is an evident lack of studies that have examined different jumping testing protocols in basketball players at advanced levels. The aim of this study was to assess the applicability of different tests of jumping capacity in identifying differences between (i) playing position and (ii) competitive levels of professional players. Participants were 110 male professional basketball players (height: 194.92±8.09 cm; body mass: 89.33±10.91 kg; 21.58±3.92 years of age; Guards, 49; Forwards, 22; Centres, 39) who competed in the first (n = 58) and second division (n = 52). The variables included anthropometrics and jumping test performance. Jumping performances were evaluated by the standing broad jump (SBJ), countermovement jump (CMJ), reactive strength index (RSI), repeated reactive strength ability (RRSA) and four running vertical jumps: maximal jump with (i) take-off from the dominant leg and (ii) non-dominant leg, lay-up shot jump with take-off from the (iii) dominant leg and (iv) non-dominant leg. First-division players were taller (ES: 0.76, 95%CI: 0.35-1.16, moderate differences), heavier (0.69, 0.29-1.10), had higher maximal reach height (0.67, 0.26-1.07, moderate differences), and had lower body fat % (-0.87, -1.27-0.45, moderate differences) than second-division players. The playing positions differed significantly in three of four running jump achievements, RSI and RRSA, with Centres being least successful. The first-division players were superior to second-division players in SBJ (0.63, 0.23-1.03; 0.87, 0.26-1.43; 0.76, 0.11-1.63, all moderate differences, for total sample, Guards, and Forwards, respectively). Running vertical jumps and repeated jumping capacity can be used as valid measures of position-specific jumping ability in basketball. The differences between playing levels in vertical jumping achievement can be observed by assessing vertical jump scores together with differences in anthropometric indices between levels.

Reliability and Factorial Validity of Non-Specific and Tennis-Specific Pre-Planned Agility Tests; Preliminary Analysis.

Agility is an important quality in tennis, yet there is an evident lack of studies focussing on the applicability of tennis-specific agility performances and comparing them to equivalent non-specific agility performances. The aim of this study was to evaluate the reliability and factorial validity of three tests of pre-planned agility, performed in specific (with a tennis racquet) and non-specific (without a tennis racquet) conditions. The sample consisted of 33 tennis players (13 males and 20 females; age: 18.3 ± 1.1 years and 18.6 ± 1.3 years; body height: 185.4 ± 51 cm and 169.3 ± 4.2 cm, 74.0 ± 4.4 kg and 61.2 ± 3.1 kg, respectively). The variables comprised three agility tests: a 20-yard test, a T-test and the Illinois test, all performed in both specific and non-specific conditions. Between-subject and within-subject reliability were found to be high (Cronbach Alpha: 0.93 to 0.98; Coefficient of Variation: 3 to 8%), with better within-subject reliability and stability of the measurement for specific tests. Pearson's product moment correlations between the non-specific and specific agility performances were high (r ≥0.84), while factor analysis extracted only one significant latent dimension on the basis of the Guttman-Kaiser criterion. The results of the 20-yard test were better when the test was conducted in the specific conditions (t-test = 2.66; p < 0.05). For the Illinois test, superior results were recorded in the non-specific conditions (t-test = 2.96; p < 0.05), which can be explained by the test duration (about 20 s) and non-specific locomotion forms such as rotational movements. Considering the findings of the present study, when testing tennis-specific pre-planned agility, we suggest using tests of short duration (less than 10 s) and sport-specific types of locomotion.

Evidencing the association between swimming capacities and performance indicators in water polo: a multiple regression study.

BACKGROUND: Swimming capacities are hypothesized to be important determinants of water polo performance but there is an evident lack of studies examining different swimming capacities in relation to specific offensive and defensive performance variables in this sport. The aim of this study was to determine the relationship between five swimming capacities and six performance determinants in water polo. METHODS: The sample comprised 79 high-level youth water polo players (all males, 17-18 years of age). The variables included six performance-related variables (agility in offence and defense, efficacy in offence and defense, polyvalence in offence and defense), and five swimming-capacity tests (water polo sprint test [15 m], swimming sprint test [25 m], short-distance [100 m], aerobic endurance [400 m] and an anaerobic lactate endurance test [4× 50 m]). First, multiple regressions were calculated for one-half of the sample of subjects which were then validated with the remaining half of the sample. The 25-m swim was not included in the regression analyses due to the multicollinearity with other predictors. RESULTS: The originally calculated regression models were validated for defensive agility (R=0.67 and R=0.55 for the original regression calculation and validation subsample, respectively) offensive agility (R=0.59 and R=0.61), and offensive efficacy (R=0.64 and R=0.58). Anaerobic lactate endurance is a significant predictor of offensive and defensive agility, while 15 m sprint significantly contributes to offensive efficacy. Swimming capacities are not found to be related to the polyvalence of the players. CONCLUSIONS: The most superior offensive performance can be expected from those players with a high level of anaerobic lactate endurance and advanced sprinting capacity, while anaerobic lactate endurance is recognized as most important quality in defensive duties. Future studies should observe players' polyvalence in relation to (theoretical) knowledge of technical and tactical tasks. Results reinforce the need for the cross-validation of the prediction-models in sport and exercise sciences.

Evaluation of Basketball-Specific Agility: Applicability of Preplanned and Nonplanned Agility Performances for Differentiating Playing Positions and Playing Levels.

Sekulic, D, Pehar, M, Krolo, A, Spasic, M, Uljevic, O, Calleja-González, J, and Sattler, T. Evaluation of basketball-specific agility: applicability of preplanned and nonplanned agility performances for differentiating playing positions and playing levels. J Strength Cond Res 31(8): 2278-2288, 2017-The importance of agility in basketball is well known, but there is an evident lack of studies examining basketball-specific agility performances in high-level players. The aim of this study was to determine the reliability and discriminative validity of 1 standard agility test (test of preplanned agility [change-of-direction speed] over T course, T-TEST), and 4 newly developed basketball-specific agility tests, in defining playing positions and performance levels in basketball. The study comprised 110 high-level male basketball players (height: 194.92 ± 8.09 cm; body mass: 89.33 ± 10.91 kg; age: 21.58 ± 3.92 years). The variables included playing position (Guard, Forward, Center), performance level (first division vs. second division), anthropometrics (body height, body mass, and percentage of body fat), T-TEST, nonplanned basketball agility test performed on dominant (BBAGILdom) and nondominant sides (BBAGILnond), and a preplanned (change-of-direction speed) basketball agility test performed on dominant (BBCODSdom) and nondominant sides (BBCODSnond). The reliability of agility tests was high (intraclass correlation coefficient of 0.81-0.95). Forwards were most successful in the T-TEST (F test: 13.57; p = 0.01). Guards outperformed Centers in BBCODSdom, BBCODSndom, BBAGILdom, and BBAGILnond (F test: 5.06, p = 0.01; 6.57, 0.01; 6.26, 0.01; 3.37, 0.04, respectively). First division Guards achieved better results than second division Guards in BBCODSdom (t: 2.55; p = 0.02; moderate effect size differences), BBAGILdom, and BBAGILnond (t: 3.04 and 3.06, respectively; both p = 0.01 and moderate effect size differences). First division Centers outperformed second division Centers in BBAGILdom (t: 2.50; p = 0.02; moderate effect size differences). The developed basketball-specific agility tests are applicable when defining position-specific agility. Both preplanned and nonplanned agilities are important qualities in differentiating between Guards of 2 performance levels. The results confirmed the importance of testing basketball-specific nonplanned agility when evaluating the performance level of Centers.

Doping Attitudes and Covariates of Potential Doping Behaviour in High-Level Team-Sport Athletes; Gender Specific Analysis.

Team sports are rarely studied with regard to doping behaviour and doping-related factors regardless of their global popularity. This study aimed to investigate doping factors and covariates of potential doping behaviour in high-level team-sport athletes. The subjects were 457 high-performing, national- and international-level athletes (21.9 ± 3.4 years of age; 179 females) involved in volleyball (n = 77), soccer (n = 163), basketball (n = 114) and handball (n = 103). Previously validated self-administered questionnaires aimed at evidencing sport factors, doping-related factors, knowledge on sport nutrition and doping, and attitudes to performance enhancement were used. The results indicated a higher doping likelihood in male athletes, with a significant gender difference for basketball and handball. In males, a higher doping likelihood is found for athletes who had achieved better results at junior-age level, those who regularly consume dietary supplements, and who perceive their sport as being contaminated by doping. A higher sport achievement at senior-age level is protective against potential doping behaviour in males. In females, a higher likelihood of doping is evidenced in those athletes involved in binge drinking, while a lower tendency for doping is evidenced in female athletes who possess better knowledge on sport nutrition. Knowledge about doping is very low and thus education about doping is urgently needed. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in females. Future studies should consider other approaches and theories, such as theory of planned behaviour and/or social-cognitive theory, in studying the problem of doping behaviour in team-sports.

Analysis of the Association Between Motor and Anthropometric Variables with Change of Direction Speed and Reactive Agility Performance.

There is an evident lack of studies examining the factors associated with reactive agility performances. The aim of this study was to evaluate the association between anthropometrics, body composition, jumping capacity, reactive strength, and balance with a stop-and-go change of direction speed (CODS) and reactive agility. The total sample comprised 39 male (body height: 182.95 ± 5.19 cm; body mass: 80.66 ± 7.69 kg) and 34 female (body height: 171.45 ± 6.81 cm; body mass: 61.95 ± 6.70 kg) college-level athletes (21.9 ± 1.9 years of age). The variables included body height, body mass, the percentage of body fat (BF%), balance as measured by an overall-stability index, the countermovement jump (CMJ), a reactive-strength index (RSI), stop-and-go reactive agility, and stop-and-go CODS. To define the associations between motor and anthropometric variables with CODS and reactive agility, the participants were clustered into three achievement groups based on their CODS and reactive agility performances. The ANOVA showed a significant difference between the CODS-based achievement groups for the CMJ (F test = 3.45 and 3.60 for males and females, respectively; p < 0.05), the RSI (F test = 6.94 and 5.29 for males and females, respectively; p < 0.05), and balance (F test = 3.47; p < 0.05 for males). In females, the reactive agility achievement groups differed significantly in the RSI (F test = 6.46; p < 0.05), the CMJ (F test = 4.35; p < 0.05) and BF% (F test = 4.07; p < 0.05), which is further confirmed by discriminant canonical analysis (Can R = 0.74; p < 0.05). The results confirm the need for independent evaluation and training for both CODS and reactive agility performance in sports.

Examination of the community-specific prevalence of and factors associated with substance use and misuse among Rural and Urban adolescents: a cross-sectional analysis in Bosnia and Herzegovina.

OBJECTIVE: The community of residence (ie, urban vs rural) is one of the known factors of influence on substance use and misuse (SUM). The aim of this study was to explore the community-specific prevalence of SUM and the associations that exist between scholastic, familial, sports and sociodemographic factors with SUM in adolescents from Bosnia and Herzegovina. METHODS: In this cross-sectional study, which was completed between November and December 2014, the participants were 957 adolescents (aged 17 to 18 years) from Bosnia and Herzegovina (485; 50.6% females). The independent variables were sociodemographic, academic, sport and familial factors. The dependent variables consisted of questions on cigarette smoking and alcohol consumption. We have calculated differences between groups of participants (gender, community), while the logistic regressions were applied to define associations between the independent and dependent variables. RESULTS: In the urban community, cigarette smoking is more prevalent in girls (OR=2.05; 95% CI 1.27 to 3.35), while harmful drinking is more prevalent in boys (OR=2.07; 95% CI 1.59 to 2.73). When data are weighted by gender and community, harmful drinking is more prevalent in urban boys (OR=1.97; 95% CI 1.31 to 2.95), cigarette smoking is more frequent in rural boys (OR=1.61; 95% CI 1.04 to 2.39), and urban girls misuse substances to a greater extent than rural girls (OR=1.70; 95% CI 1.16 to 2.51,OR=2.85; 95% CI 1.88 to 4.31,OR=2.78; 95% CI 1.67 to 4.61 for cigarette smoking, harmful drinking and simultaneous smoking-drinking, respectively). Academic failure is strongly associated with a higher likelihood of SUM. The associations between parental factors and SUM are more evident in urban youth. Sports factors are specifically correlated with SUM for urban girls. CONCLUSIONS: Living in an urban environment should be considered as a higher risk factor for SUM in girls. Parental variables are more strongly associated with SUM among urban youth, most probably because of the higher parental involvement in children' personal lives in urban communities (ie, college plans, for example). Specific indicators should be monitored in the prevention of SUM.

Success in Adopting Technique of Alpine Skiing with Respect to Motor Abilities of the Children Aged 7-8 Years.

The aim of this research was to determine relations between estimated motor abilities and efficiency of alpine ski learning in children ski beginners. It included 54 children between 7 and 8 years of age (average 7.44 ± 0.52 years). Children were tested for balance, agility, strength, coordination and frequency of movement on ten motor ability tests. After motor abilities were assessed, participants learned alpine skiing during six-day alpine ski school and upon completion of ski school program, were tested on three elements of alpine ski technique (stopping in a snow-plough, uphill turn and turns around the posted marks) by three independent judges. According to achieved level of ski knowledge, they were allocated to three groups differing by the level of success; less successful (N = 18; 26-44 points), moderately successful (N = 11; 45-48 points) and successful (N = 25; 49-55 points). Significant differences in success of adopting basic ski technique were noticed with respect to the results achieved in the task polygon backwards (F = 6.162, p = 0.004), foot tapping (F = 6.337, p = 0.003) and crossed arm sit-ups (F = 3.099, p = 0.053). The participants who successfully adopted the basic ski technique also achieved good results in tests: polygon backwards, foot tapping, crossed arm sit-ups, side steps, balancing on left leg perpendicular on balance board, vertical jump and medium results in tests 20m dash and balancing on right leg perpendicular on balance board. Our results suggest that successful participants have better developed coordination, frequency of movement, strength and agility.

The development of a new stop'n'go reactive-agility test.

The main objective of this study was to evaluate the reliability and the validity of a newly constructed reactive-agility test that can be used to define the reactive-agility performance in sports that employ repeated scenarios of "stop'n'go" agility. Measuring is done by original hardware based on the ATMEL microcontroller AT89C51RE2. A total of 36 college-aged male athletes (age, 22.1 ± 2.4 years; body height, 182.45 ± 5.19 cm; body mass, 80.67 ± 7.69 kg) and 21 college-aged female athletes (age, 21.4 ± 2.5 years; body height, 171.45 ± 6.81 cm; body mass, 61.95 ± 6.70 kg) were evaluated for a stop'n'go reactive-agility test (SNG-RAT), stop'n'go change of direction speed (SNG-CODS), countermovement jump, and anthropometrics. The reliability analyses suggested a high consistency for the applied tests (SNG-CODS, intraclass correlation coefficient [ICC] = 0.87 and 0.92; SNG-RAT, ICC = 0.81 and 0.86, for men and women, respectively). The SNG-RAT and SNG-CODS shared <40% of the common variance. The longer version of the SNG-RAT, which included 5 unpredictable changes of direction, was found to be valid among men. At the same time, the shorter version of the SNG-RAT (3 unpredictable changes of direction) is suggested for women because it better discriminates more agile from less agile athletes. Because the SNG-RAT and SNG-CODS were performed on the same course, we believe that simultaneously performing both tests can be beneficial when defining "stop'n'go" agility. This implies that the calculated SNG-CODS to SNG-RAT ratio will allow strength and conditioning coaches to indirectly determine the perceptual and reaction capacities of their athletes.

Reliability, validity, and applicability of isolated and combined sport-specific tests of conditioning capacities in top-level junior water polo athletes.

Standard testing procedures are of limited applicability in water sports, such as water polo. The aim of this investigation was to construct and validate methods for determining water polo-specific conditioning capacities. We constructed 4 combined-capacity tests that were designed to mimic real-game water polo performances: sprint swimming performance, shooting performance, jumping performance, and precision performance. In all cases, combined-capacity tests included a period of standardized exhaustion followed by the performance of the targeted quality (swimming, shooting, jumping, and precision). In the first part of the study, single-capacity tests (sprint swim, in-water jump, drive shoot, and precision performance) were tested and later included in the combined-capacity tests. Study subjects consisted of 54 young male water polo players (15-18 years of age, 185.6 ± 6.7 cm, and 83.1 ± 9.9 kg). Most of the tests evaluated were found to be reliable with Cronbach alpha values ranging from 0.83 to 0.96 and coefficients of variation from 21 to 2% (for the single-capacity tests) and 0.75 to 0.93 test-retest correlation (intraclass correlation coefficients) with Bland-Altman tight limits of agreement (for combined-capacity tests). The combined-capacity tests discriminated qualitative groups of junior water polo players (national squad vs. team athletes) more effectively than single-capacity tests. This is most likely because combined-capacity tests more closely represent the complex fitness capacities required in real game situations. Strength and conditioning practitioners and coaches working with water polo athletes should consider incorporating these validated tests into their assessment protocols.

Sport nutrition and doping in tennis: an analysis of athletes' attitudes and knowledge.

Nutrition and doping issues are rarely studied in the sport of tennis. The aims of this investigation were to determine knowledge on doping (KD) and knowledge on sport nutrition (KSN), and corresponding socio-demographic-, sport-, and sport-nutrition- and doping-factors among an international sample of high-level tennis players of both sexes (43 females; 22 years old on average). In the first phase of the investigation, the KSN and KD questionnaires were studied for their reliability and validity. The consumption of NS is found to be very high, with almost of all the females and 80% of the males using NS at least occasionally. The athletes showed a low tendency regarding future doping usage, although most of them are convinced that doping does exist in tennis. Since athletes declared that their coaches are their main source of information about NS and doping, future studies should investigate what coaches actually know about such problems. KSN has been found to be protective against potential doping behavior in the future. Males are found to be more prone to doping than females. Therefore, in order to prevent doping behavior in tennis we strongly suggest intensive educational programs on sports nutrition and doping-related problems. Key PointsThe incidence of nutritional supplementation use among the tennis players is found to be very high, especially among the females.Although most of the subjects are of the opinion that the doping behavior is present in tennis circuit, we have found a low tendency regarding future doping usage, and high levels of athletes' trust in their coaches with regard to nutritional supplementation and doping.There are indices that the knowledge about nutrition is protective factor against potential doping behavior. It clearly reinforces the need to include a wide educational program on sports nutrition in tennis, but also in other sports.

Sport-specific and anthropometric factors of quality in junior male water polo players.

There is evident lack of studies which examined anthropological determinants of success in water polo. The aim of this investigation was to study the physical fitness differences between two qualitative levels of junior water polo players (males; 16-18 years of age; 6+ year of experience in water polo). The sample (N = 54) comprised of 13 members of the junior national-squad (5 centers and 8 perimeter players), and 41 team-athletes (11 centers and 30 perimeter players). The sample of variables included: four anthropometric measures (body height, body mass, BMI and body fat percentage), and five sport-specific fitness tests (20-meters-sprint-swimming, maximal dynamometric force in eggbeater kick, in-water vertical jump, drive-shoot-speed, and sport-swimming-endurance). Discriminant analysis and t-test revealed no significant differences between national-squad and team-players for center players. The national-squad perimeters were advanced over their team-level peers in most of the fitness capacities and body-height. The result highlights the necessity of the playing-position-specific approach in defining anthropological factors of success in team-sports.