Maturity Status and Relative Age of Elite Taekwondo Youth Competitors-Case Study on Croatian National Team.

This study examines the maturity status and relative age effect in elite youth taekwondo Croatian National Team athletes. Measurements of biological age, maturity offset, and body composition were taken from a sample of 17 junior athletes. Differences in maturity status were observed among athletes of the same chronological age, with variations in sitting height and age at peak height velocity. Male athletes generally exhibited higher values in body height, percentage of body fat, muscle mass, and total body water. No significant relative age effect was found. These findings highlight the importance of considering individual biological age and maturity status for talent development and training program adjustments. Further research involving athletes from different countries is recommended to validate these results and enhance the understanding of youth taekwondo athlete development.

Tensiomyography: from muscle assessment to talent identification tool.

Introduction: Tensiomyography (TMG) is a non-invasive and cost-effective tool that is gaining popularity in fields such as sports science, physical therapy, and medicine. In this narrative review, we examine the different applications of TMG and its strengths and limitations, including its use as a tool for sport talent identification and development. Methods: In the course of crafting this narrative review, an exhaustive literature search was carried out. Our exploration spanned several renowned scientific databases, such as PubMed, Scopus, Web of Science, and ResearchGate. The materials we sourced for our review included a broad spectrum of both experimental and non-experimental articles, all focusing on TMG. The experimental articles featured varied research designs including randomized controlled trials, quasi-experiments, as well as pre-post studies. As for the non-experimental articles, they encompassed a mix of case-control, cross-sectional, and cohort studies. Importantly, all articles included in our review were written in English and had been published in peer-reviewed journals. The assortment of studies considered provided a holistic view of the existing body of knowledge on TMG, and formed the basis of our comprehensive narrative review. Results: A total of 34 studies were included in the review, organized into three sections: 1) assessing muscle contractile properties of young athletes, 2) using TMG in the talent identification and development process and 3) Future research and perspectives. According to data presented here, the most consistent TMG parameters for determining muscle contractile properties are radial muscle belly displacement, contraction time, and delay time. Biopsy findings from the vastus lateralis (VL) confirmed TMG as a valid tool for estimating the ratio of myosin heavy chain (%MHC-I). Conclusion: TMGs ability to estimate the ratio of %MHC-I has the potential to aid in the selection of athletes with the muscle characteristics best suited for a particular sport, eliminating the need for more invasive procedures. However, more research is warranted to fully understand TMG's potential and its reliability when used with young athletes. Importantly, the use of TMG technology in this process can positively impact health status, reducing the frequency and severity of injuries and the duration of recovery, and subsequently can reduce drop out rates among youth athletes. Future studies should look at twin youth athletes, as a model capable of discriminating between the influence of hereditary factors vs. environmental factors, in therms of muscle contractility and TMG's potential for instance.

Energy cost differences between marathon runners and soccer players: Constant versus shuttle running.

Purpose: In the last decades, the energy cost assessment provided new insight on shuttle or constant running as training modalities. No study, though, quantified the benefit of constant/shuttle running in soccer-players and runners. Therefore, the aim of this study was to clarify if marathon runners and soccer players present specific energy cost values related to their training experience performing constant and shuttle running. Methods: To this aim, eight runners (age 34 ± 7.30y; training experience 5.70 ± 0.84y) and eight soccer-players (age 18.38 ± 0.52y; training experience 5.75 ± 1.84y) were assessed randomly for 6' on shuttle-running or constant-running with 3 days of recovery in-between. For each condition, the blood lactate (BL) and the energy cost of constant (Cr) and shuttle running (CSh) was determined. To assess differences for metabolic demand in terms of Cr, CSh and BL over the two running conditions on the two groups a MANOVA was used. Results: V·O2max were 67.9 ± 4.5 and 56.8 ± 4.3 ml·min-1 kg-1 (p = 0.0002) for marathon runners and soccer players, respectively. On constant running, the runners had a lower Cr compared to soccer players (3.86 ± 0.16 J kg-1m-1 vs. 4.19 ± 0.26 J kg-1 m-1; F = 9.759, respectively; p = 0.007). On shuttle running, runners had a higher CSh compared to soccer players (8.66 ± 0.60 J kg-1 m-1 vs. 7.86 ± 0.51 J kg-1 m-1; F = 8.282, respectively; with p = 0.012). BL on constant running was lower in runners compared to soccer players (1.06 ± 0.07 mmol L-1 vs. 1.56 ± 0.42 mmol L-1, respectively; with p = 0.005). Conversely, BL on shuttle running was higher in runners compared to soccer players 7.99 ± 1.49 mmol L-1 vs. 6.04 ± 1.69 mmol L-1, respectively; with p = 0.028). Conclusion: The energy cost optimization on constant or shuttle running is strictly related to the sport practiced.

Anthropometric variability of European taekwondo champions / Variabilidad antropométrica de los campeones europeos de taekwondo

SUMMARY: World Taekwondo (WT) as an Olympic sport gained much more attention than before, and there is a growing need for precise and specific profiles of successful taekwondo competitors. Aim of this investigation was to determine body composition, somatotype, and selected anthropometric parameters/indexes of elite taekwondo champions and medal winners on the most demanding taekwondo tournaments in the World. The sample for this research consisted of n=16 (n=4 male; n=12 female) elite taekwondo champions, n=8 juniors and n=8 seniors, who were European (n=13), and World (n=3) champions of European descent. Data was collected longitudinally for seven years since 2015. Obtained results revealed specific (absolute) phenotype of taekwondo champions, following: PI (11.50 female; 11.85 male), HWR (43.96 female; 44.47 male) and BMI (19.96 female; 22.04 male). Further analysis shows that champions have greater values of body height, and have slightly greater ectomorphy and mesomorphy values in regard to other elite competitors. Presented research is the first publication of referent values for the general anthropometric dataset, and such results represent the anthropometric variability of European WT champions.

World Taekwondo (TW) como deporte olímpico ha logrado una mayor importancia, y existe una creciente necesidad de contar con perfiles precisos y específicos de competidores exitosos de TW. El objetivo de esta investigación fue determinar la composición corporal, el somatotipo y parámetros/índices antropométricos seleccionados de campeones de TW de élite y los ganadores de medallas en los torneos de TW más exigentes del mundo. La muestra para esta investigación consistió en n=16 (n=4 hombres; n=12 mujeres) campeones de TW de élite, n=8 juniors y n=8 seniors, que eran europeos (n=13) y mundiales (n=3), campeones de ascendencia europea. Los datos se recopilaron longitudinalmente durante siete años desde 2015. Los resultados obtenidos revelaron un fenotipo específico (absoluto) de los campeones de TW, a continuación: PI (11,50 mujeres; 11,85 hombres), HWR (43,96 mujeres; 44,47 hombres) e IMC (19,96 mujeres; 22,04 hombres). Un análisis más detallado muestra que los campeones tienen mayores valores de altura corporal y tienen valores de ectomorfia y mesomorfia ligeramente mayores con respecto a otros competidores de élite. La investigación presentada es la primera publicación de valores de referencia para el conjunto de datos antropométricos generales, y dichos resultados representan la variabilidad antropométrica de los campeones europeos de TW.

Marathon shoes vs. track spikes: a crossover pilot study on metabolic demand at different speeds in experienced runners.

The aim of this study was to assess the metabolic cost (Cr) with marathon shoes (Adidas Adizero 3 [AA]) vs. track spikes (Nike Zoom Matumbo 3 [NZM]) on track. For this, five experienced runners were randomly assessed (NZM/AA) on a running track at 73% and 85% of best performance speed on 1500-m race. At first, speed (4.39 ± 0.53 m·s-1), Crs with AA and NZM resulted 3.63 ± 0.29 and 3.64 ± 0.43 J·kg-1·m-1 (+0.3% with NZM, effect size [ES] small and p = 0.951), respectively. Besides, at second speed (5.20 ± 0.18 m·s-1), Crs were 4.09 ± 0.28 and 4.07 ± 0.22 J·kg-1·m-1 (-0.5% with NZM, ES small and p = 0.919) with AA and NZM, respectively. It resulted in an increased Cr (+12.2%) between s1 and s2 with both shoe conditions (ES large and p = 0.009 and 0.011 with AA and NZM, respectively). There is a pattern yet to be confirmed for track spikes to become more beneficial at higher speeds (when duty factor becomes lower and therefore grip on track is crucial).

Whole-Body Vibration Effects on Flexibility in Artistic Gymnastics-A Systematic Review.

It is well documented that whole body-vibration training has effects on muscle strength and flexibility, blood circulation, decreases pain perception and strengthens bone and tendon. Although whole body-vibration has benefits in athletes' flexibility, we are not sure what its actual effects are in artistic gymnastics (since they already have stunning flexibility). Hence, the aim of this study was to analyse the studies on whole-body vibration in artistic gymnastics and to present the effects on flexibility. The search and analysis were carried out in accordance with PRISMA guidelines. The databases search (PubMed, Scopus, Google Scholar, Cochrane Library, ProQuest, EBSCOhost and Science Direct) yielded 18,057 potential studies. By the given inclusion criteria (studies from 2005 to 2022; full-text published in English; the study included male and female gymnasts as samples, and that participants were tested for evaluation of flexibility by whole-body vibration method), a total of 9 full-text studies were included, with a total of 210 participants, both male and female. As far as the measured flexibility tests conducted, front split, sit and reach and bridge were evaluated, while obtained results were 9.1-39.1%, 2.79-6.7%, 6.43-7.45%, respectively. All studies have conducted same vibration frequency (30 Hz) with same amplitude of displacements (2 mm), except for the one study who did not show the information of implemented amplitude. After analysing the obtained results, it can be concluded that the usage of whole-body vibration platform shows flexibility improvements in artistic gymnasts, both male and female. In addition, a combination of whole-body vibration and traditional static stretching may enhance the flexibility in artistic gymnasts. However, these results should be taken with caution. Since this review did not reveal the optimal vibrational protocol, it is necessary to invest time during the implementation of various vibrational experimental protocols, so future research is required.

Elite Croatian junior taekwondo competitors: morphological characteristics and body composition reference values / Competidores croatas de taekwondo junior de élite: características morfológicas y valores de referencia de composición corporal

SUMMARY: The main purpose of this study was to determine the body composition and anthropometric reference values of male and female junior Croatian taekwondo competitors according to official weight category. Additional aim of the study was to identify possible differences in variables between the weight categories. The sample comprised 247 junior participants of the national taekwondo championships divided into male (N=121) and female (N=126). The variable sample was defined by a set of 8 measurements: Body height (cm), Body mass (kg), Body mass index, Body fat (%), Body fat (kg), Muscle mass (kg), Lean body mass (kg) and Total body water (%). Results confirm previous studies proving that younger taekwondo practitioners have higher levels of body fat than their more experienced peers (seniors). Significant differences were only found between lean and heavy categories. Male junior taekwondo athletes show total body water percentages from 57.4 to 74.8 %, with significantly lower percentages in higher weight categories, while female athletes in heigher categories demonstrate a worrying level of hydration status, therefore endangering their performance and overall health. As the first paper that investigates the reference values of junior taekwondo athletes but based on official weight categories it is especially important as each weight category warrant different body composition requirements, as seen from significant differences across different variables. Future studies should include motor abilities inspection throughout the weight categories and possible use of calculation of metabolic age.

RESUMEN: El objetivo principal de este estudio fue determinar la composición corporal y los valores de referencia antropométricos de los competidores croatas masculinos y femeninos de taekwondo junior según la categoría oficial de peso. Además, se analizó identificar las posibles diferencias en las variables entre las categorías de peso. La muestra estuvo compuesta por 247 participantes junior de los campeonatos nacionales de taekwondo divididos en hombres (N = 121) y mujeres (N = 126). La muestra variable se definió mediante un conjunto de 8 medidas: altura corporal (cm), masa corporal (kg), índice de masa corporal, grasa corporal (%), grasa corporal (kg), masa muscular (kg), masa corporal magra (kg) y agua corporal total (%). Los resultados confirmaron estudios previos que demuestran que los practicantes de taekwondo más jóvenes tienen niveles más altos de grasa corporal que sus pares más experimentados (personas mayores). Solo se encontraron diferencias significativas entre las categorías magra y pesada. Los atletas masculinos de taekwondo junior muestran porcentajes de agua corporal total del 57,4 al 74,8 %, con porcentajes significativamente más bajos en las categorías de peso más alto, mientras que las atletas femeninas en las categorías más altas, demuestran un nivel preocupante de estado de hidratación, poniendo en peligro su rendimiento y salud en general. Como el primer artículo que investiga los valores de referencia de los atletas de taekwondo junior, pero basado en categorías de peso oficiales, es especialmente importante ya que cada categoría de peso garantiza diferentes requisitos de composición corporal, como se puede observar en las diferencias significativas entre las diversas variables. Los estudios futuros deberían incluir un análisis de las habilidades motoras en todas las categorías de peso y el posible uso del cálculo de la edad metabólica.

Validity and Reliability of a Light-Based Electronic Target for Testing Response Time in Fencers.

ABSTRACT: De Giorgio, A, Iuliano, E, Turner, A, Millevolte, C, Cular, D, Ardigò, LP, and Padulo, J. Validity and reliability of a light-based electronic target for testing response time in fencers. J Strength Cond Res 35(9): 2636-2644, 2021-Response time (RT) is a fencing fundamental sensorimotor skill. Therefore, the aim of the current study was to examine the efficacy of a light-based electronic target in fencers, designed to measure and train this entity. Ninety-five fencers (M = 53; F = 42) were tested in regard to their RT, using a light-based electronic target, for 3 different attack types: simple attack, the lunge, and an attack after a 1.5-m thrust. All subjects were divided into elite vs. novice fencers. Elite fencers had national and international rankings, and were again divided with regard to used weapon: épéeists (n = 32; M = 19; F = 13) and foilists (n = 30; M = 13; F = 17). Measurement was evaluated for validity/reliability, sensitivity/specificity, and correlation. Reliability was high for all attack types (intraclass correlation coefficient 0.94-0.96). Lower RTs were found in males for 2 attack types with good sensitivity (81-93%)/specificity (50-91%) for all attack types. Elite fencers responded faster than novice fencers for all attack types (p < 0.001), whereas elite males were faster than females for 2 attack types (p < 0.01). Lower RTs in females correlated with level for one attack type (r = 0.797, p < 0.05). In conclusion, the light-based electronic target system was found to be highly reliable and therefore could be used by fencing athletes as a further measure of performance.

Height-based model for the categorization of athletes in combat sports.

Reducing bodyweight within a short-time participating in kicking combat sports can adversely affect health. This study's aim creating an improved model to categorize athletes in kicking combat sports. The investigation focused on 795 athletes (11-24 years), participating in the Croatian National Taekwondo Championship. The sample included athletes from both sexes (371 males), cadets (n = 325), juniors (n = 247) and seniors (n = 223). Data were collected during the preparatory period and prior to the athletes competing, using a bioelectrical impedance analysis device. According to current categorization rules, athletes are categorized by arbitrarily determined ranges in bodyweight, whereas, in this current study, the authors have devised an improved model, based on body height and the analysis of data collected. The difference in coefficients between the official model and the proposed, improved categorization method in terms of body height (2.70 and 0.71, respectively), showed that the improved model homogenized athletes almost four times more than the official model, reducing the maximal difference in body height from 29 to 9 cm within specific categories. Proposed, improved model had same number of categories as the official structure and directly homogenized differences in height within a category up to a 3-cm maximum for the middle categories and a 9-cm maximum on the periphery of the bands. We expect this improved combat sports categorization model will indirectly reduce differences between other longitudinal body dimensions within categories (thus making match results less predictable) as well as reduce bodyweight manipulation potentially endangering athletes' health.

Reliability, Sensitivity, and Minimal Detectable Change of a New Specific Climbing Test for Assessing Asymmetry in Reach Technique.

ABSTRACT: Cular, D, Dhahbi, W, Kolak, I, Iacono, AD, Beslija, T, Laffaye, G, and Padulo, J. Reliability, sensitivity, and minimal detectable change of a new specific climbing test for assessing asymmetry in reach technique. J Strength Cond Res 35(2): 527-534, 2021-The aims of this study were to establish intertrial and intersession reliability, sensitivity, and minimal detectable change of a new climbing test specifically for assessing asymmetry in reach technique (TEST). Twenty-four young climbers (16 males and 8 females) participated in this study. The protocol consisted of performing, in counterbalanced random order, 3 tests; TEST, maximum handgrip force, and squat on the bench, in 2 sessions (with 3 trials for each session). TEST performance was expressed as: TEST performance for left hand (TESTL), TEST performance for right hand (TESTR), and absolute symmetry index (ASI). For intertrial and intersession reliability assessment, TESTL and TESTR showed excellent reliability (intraclass correlation coefficients ranged: 0.96-1.00; SEM% ranged: 0.07-1.23; and coefficient of variation-CV%: 1.28-2.53). In addition, SEMs were smaller than the smallest worthwhile change (SWC) values (SWC% = 1.07 and 0.99 for TESTL and TESTR, respectively), and the minimal detectable change (MDC95) for both sides was small (<4.36 cm). An exception was ASI, which showed low absolute reliability and marginal sensitivity (SEM% = 15.13 > SWC% = 8.40 and CV% = 41.98). Pairwise test comparisons revealed no difference between sides. Considering the high reliability and the satisfactory sensitivity, TEST can be used to define individual asymmetry in the performance of the reach technique to the left or the right body side in climbers. However, interpreting data using the ASI index requires caution because it had poor absolute reliability and marginal sensitivity.

External Responsiveness of the SuperOpTM Device to Assess Recovery After Exercise: A Pilot Study.

Post-exercise recovery is a complex process involving a return of performance and a physiological or perceptual feeling close to pre-exercise status. The hypothesis of this study is that the device investigated here is effective in evaluating the recovery state of professional cyclists in order to plan effective training. Ten professional male cyclists belonging to the same team were enrolled in this study. Participants performed a 7-day exercise program [D1, D4, and D7: low-intensity training; D2 and D5: passive recovery; D3: maximum oxygen consumption (VO2Max) test (for maximum mechanical power assessment only); and D6: constant load test]. During the week of monitoring, each morning before getting up, the device assessed each participant's so-called Organic Readiness {OR [arbitrary unit (a.u.)]}, based on blood pressure (BP), heart rate (HR), features of past exercise session, and following self-perceived condition. Based on its readings and algorithm, the device graphically displayed four different colors/values, indicating general exercise recommendations: green/3 = "you can train hard," yellow/2 = "you can train averagely," orange/1 = "you can train lightly," or red/0 = "you should recover passively." During the week of research, morning OR values and Bonferroni post-hoc comparisons showed significant differences between days and, namely, values (1) D2 (after low intensity training) was higher than D4 (after VO2Max test; P = 0.033 and d = 1.296) and (2) D3 and D6 (after passive recovery) were higher than D4 (after VO2Max test; P = 0.006 and d = 2.519) and D5 (after low intensity training; P = 0.033 and d = 1.341). The receiver operating characteristic analysis area under curve (AUC) recorded a result of 0.727 and could differentiate between D3 and D4 with a sensitivity and a specificity of 80%. Preliminarily, the device investigated is a sufficiently effective and sensitive/specific device to assess the recovery state of athletes in order to plan effective training.

Validity and Reliability of Isometric-Bench for Knee Isometric Assessment.

There is a strong need for a new, probably cheaper, smaller, and more portable isometric dynamometer. With this aim, we investigated the concurrent validity and reliability of a low-cost portable dynamometer to measure the isometric strength of the lower limb. Seventeen young participants (age 16.47 ± 0.51 years) were randomly assessed on three different days for knee flexion and extension isometric forces with two different devices: a commonly used isokinetic dynamometer (ISOC) and a portable isometric dynamometer prototype (ISOM). No significant differences were observed between the ISOC and the ISOM (all comparisons p > 0.05). Test-retest comparison showed the ISOM to have high reliability (ICC 0.879-0.990). This study showed that measurements with the ISOM could be performed without systematic bias and with high reliability. The ISOM is a device that is able to assess knee isometric strength with excellent concurrent validity and reliability.

The Psychophysiological Effects of Different Tempo Music on Endurance Versus High-Intensity Performances.

The use of music during training represents a special paradigm for trainers to stimulate people undertaking different types of exercise. However, the relationship between the tempo of music and perception of effort during different metabolic demands is still unclear. Therefore, the aim of this research was to determine whether high intensity exercise is more sensitive to the beneficial effects of music than endurance exercise. This study assessed 19 active women (age 26.4 ± 2.6 years) during endurance (walking for 10' at 6.5 km/h on a treadmill) and high intensity (80% on 1-RM) exercise under four different randomly assigned conditions: no music (NM), with music at 90-110 bpm (LOW), with music at 130-150 bpm (MED), and with music at 170-190 bpm (HIGH). During each trial, heart rate (HR) and the rating of perceived exertion (RPE) were assessed. Repeated analysis of variance measures was used to detect any differences between the four conditions during high intensity and low intensity exercise. RPE showed more substantial changes during the endurance exercises (11%), than during high intensity exercise (6.5%), between HIGH and NM conditions. The metabolic demand during the walking exercise increased between NM and HIGH bpm conditions. This study indicates the benefits of music under stress conditions as well as during endurance and high intensity training. The results demonstrate that the beneficial effects of music are more likely to be seen in endurance exercise. Consequently, music may be considered an important tool to stimulate people engaging in low intensity physical exercise.

The 30-15 Intermittent Fitness Test: A Reliable, Valid, and Useful Tool to Assess Aerobic Capacity in Female Basketball Players.

Purpose: The purpose of this study was to determine the reliability, validity, and usefulness of 30-15 Intermittent Fitness Test (30-15IFT) in female basketball players. Methods: Nineteen female basketball players (17.82 ± 1.94 yr, 175.4 ± 7.3 cm, 67.9 ± 7.7 kg) competing in the National Croatian League performed one trial of a continuous treadmill running test and two trials of the 30-15IFT. The 30-15IFT involves 30-s runs across a 40-m course interspersed with 15 s of walking, with running speed increasing every 45 s. The continuous treadmill running test was used as the criterion for validation. Results: High to very high reliability across test-retest trials were observed for maximal oxygen uptake (VO2max) (CV = 4.9%, ICC = 0.85), the 30-15IFT end-running velocity (VIFT) (CV = 6.0%, ICC = 0.85), and maximal heart rate (HRmax) (CV = 4.8%, ICC = 0.96). Criterion validity was supported for the 30-15IFT with strong to very strong relationships with VO2max (r =0.69), VIFT (r =0.74), and HRmax (r =0.73) attained during the continuous treadmill running test. The typical error (TE) of the 30-15IFT was greater than the smallest worthwhile change for VO2max (1.16 > 0.42 ml/kg/min), VIFT (0.56 > 0.20 km/h), and HRmax (2.15 > 1.89 bpm) adjudging usefulness of the test as marginal. The TE of 0.56 km/h (90% CI = 0.44-0.77 km/h) demonstrates changes in the performance of one to two stages (0.5-1.0 km/h) are meaningful. Conclusions: The 30-15IFT possesses acceptable reliability and validity to assess maximal aerobic fitness capacity in female basketball players. While the usefulness of the 30-15IFT was marginal, meaningful changes in performance consisted of only one to two stages. The present findings support the 30-15IFT as a practical testing option for basketball practitioners to assess fitness capacities in female players.

Validity and Reliability of a New Specific Parkour Test: Physiological and Performance Responses.

Main aim of this study was examining validity and reliability of using a new specific Parkour repeated sprint ability test (SPRSA) for assessing repeated sprint ability while facing obstacles and establishing between-day reliability and sensitivity of SPRSA related to its physiological and performance responses. Thirteen high-level traceurs (three females) performed in random order and twice eight tests for assessing a total of 23 variables: SPRSA (a typical maximal-speed shuttle run interspersed with four Parkour competition-common fundamentals) and seven established fitness tests, core stability, hand-grip, vertical-jump, long-jump, pull-up, 300-m shuttle run (as a field test for anaerobic capacity), and Leger test. Except for muscular elasticity index of vertical jump test (intra-class Correlation Coefficient model 3,1 [ICC3,1] = 0.54 [fair]), fitness tests' ICC3,1s resulted excellent (ICC3,1: 0.93-1.00). SPRSA total time and time of its fastest sprint (SPRSA peak time) were significantly correlated with the majority of core stability (r: -0.79 to 0.59; P < 0.01-0.05), jumping (r: -0.78 to 0.67; P < 0.01-0.05), pull-up tests (r: -0.86; P < 0.01), 300-m shuttle run test total time (r: 0.77-0.82; P < 0.01), and Leger test-estimated VO2 max (r: -0.78; P < 0.01). Principal component analysis (PCA) of the 23 variables led to extraction of four significant components (each due to different variables' combinations), which explained 90.2% of 23 variables' total variance. SPRSA (i.e., total and peak time) showed high reliability (ICC3,1: 0.991-0.998 and standard-error-of-measurement %: 0.07-0.32). Finally, SPRSA showed high sensitivity (smallest-worthwhile-change %: 0.29-0.68). Considering its excellent logical and strong ecological validity, SPRSA may serve as a valid specific field test for Parkour sport. In addition, thanks to its high reliability and sensitivity, this test is suitable for monitoring, evaluating, and programming training processes for Parkour practitioners in repeated sprint ability involving crossing obstacles.

Validity and reliability of a standalone low-end 50-Hz GNSS receiver during running.

The aim of the investigation was to verify the validity and reliability of a low-end 50-Hz Global Navigation Satellite System receiver (GNSSr) for different soccer-specific run distances and average speed assessments. Six soccer players were assessed on two different days while performing eight different running paths with changes of direction for a final total of 44 runs. During the runs, each participant was equipped with the GNSSr, while the time for each single run was recorded using a photocell gate. Reference vs. receiver assessment correspondences for distance and average speed were evaluated by calculating the standard error of the estimate (SEE), coefficient of variation (CV), and mean bias. Residual vs. predicted value comparison was performed by means of Bland-Altman plots. Finally, calculating the intra-class correlations coefficient (ICC) assessed the test-retest reliability of the measurement. Receiver distance assessment showed an SEE of 0.52 m (0.73%), and mean bias of 0.06 m. Receiver average speed assessment showed an SEE of 0.02 m·s-1 (0.74%) and mean bias of 0.001 m·s-1. The Bland-Altman plot showed a small difference between the two assessments with the 95% limits of agreement=±1.08 m/0.046 m·s-1. Receiver distance/speed assessment was found to be reliable, with ICC=0.999. In spite of its low cost, the new low-end GNSSr provides valid and reliable assessments of distance and average speed for young adults performing several standardized running actions of differing lengths within delimited setup spaces.

The Effect of Heart Rate on Jump-Shot Accuracy of Adolescent Basketball Players.

Basketball is a team sport, where fundamental skills - fundamentals - are key determinants for success. Jump-shot (JS) is a basketball fundamental used frequently during game. It is interesting to spread light on the relationship between effort intensity and JS ability. Study aim was to investigate different heart rates (HRs) effect on JS accuracy (JS%) in 22 male youth (15.7 ± 0.9 years) players. Experimental sessions consisted of 10 JSs from five spots 5 m from basket at three different HRs: rest (0HR) and after warm-up (50% [50HR] and 80% maximal HR [80HR]). Analysis of variance showed differences in JS% over sessions (42.27 ± 14.78% at 0HR, 38.18 ± 10.53% at 50HR, and 30.00 ± 16.62% at 80HR; P = 0.018). Least significant difference test did not show any significant difference between 50HR and 0HR JS% (P = 0.343), while 80HR elicited significantly lower values with respect to both 0HR (P = 0.006) and 50HR (P = 0.049). Study provided practical indications on maintaining high JS%: preliminary warm-up (even if injury-protecting) does not improve JS%, because between 50HR and 0HR difference was not significant; and 80HR significantly decreases JS%. Therefore, to maximize JS scoring players have to rest as much as possible during game-play pauses, and coaches should manage timeouts and substitutions accordingly, especially during final minutes of close games.

Validity and Reliability of the 30-s Continuous Jump for Anaerobic Power and Capacity Assessment in Combat Sport.

Cycling test such Wingate anaerobic test (WAnT) is used to measure anaerobic power (AP), but not anaerobic capacity (AC, i.e., the metabolic energy demand). However, in sports that do not involve cycling movements (Karate), the continuous jump for 30 s (vertical jumps for 30 s) has been extensively used to measure anaerobic performance in all young athletes. Limited information's are available concerning its validity and reliability especially in children. As such, the current study aimed to test validity and reliability of a continuous jumps test (the CJ30s), using WAnT as a reference. Thirteen female Karate kids (age: 11.07 ± 1.32 years; mass: 41.76 ± 15.32 kg; height: 152 ± 11.52 cm; training experience: 4.38 ± 2.14 years) were tested on three separate sessions. The first and second sessions were used to assess the reliability using Intra-class correlation coefficient (ICC) of CJ30s, whereas on the third session WAnT was administered. Following CJ30s and WAnT, we assessed AP (1/CJ30s, as jump height [JH], fatigue index [FI], and blood lactate [BL]; 2/WAnT, as mechanical power [P], FI, and BL) and AC as the excess post-exercise oxygen consumption (EPOC). Large/highly significant correlations were found between CJ30s and WAnT EPOCs (r = 0.730, P = 0.003), and BLs (r = 0.713, P = 0.009). Moderate/significant correlations were found between CJ30s and WAnT FIs (r = 0.640, P = 0.014), CJ30s first four jumps mean JH and WAnT peak P (r = 0.572, P = 0.032), and CJ30s mean JH and WAnT mean P (r = 0.589, P = 0.021). CJ30s showed excellent and moderate reliability (ICC) for AP (maximal JH 0.884, mean JH 0.742, FI 0.657, BL 0.653) and AC (EPOC 0.788), respectively. Correlations observed especially in terms of AC between CJ30s and WAnT provide evidence that former may adequately assess anaerobic performance for the young combat athlete. CJ30 is a reliable test and allow an easy assessment of AP and AC in karate children.

Reliability of Urinary Dehydration Markers in Elite Youth Boxers.

PURPOSE: To determine the reliability and diagnostic accuracy of noninvasive urinary dehydration markers in field-based settings on a day-to-day basis in elite adolescent amateur boxers. METHODS: Sixty-nine urine samples were collected daily from 23 athletes (17.3 ± 1.9 y) during their weight-stable phase and analyzed by field and laboratory measures of hydration status. Urine osmolality (UOSM), urine specific gravity (USG), total protein content (TPC), and body-mass stability were evaluated to determine fluid balance and hydration status. Overall macronutrient and water intake were determined using dietary records. According to their anthropometric characteristics, athletes were assigned into 2 groups: lightweight (LWB) and heavyweight (HWB) boxers. RESULTS: Data presented on UOSM demonstrated a uniform increment by 11.2% ± 12.8% (LWB) and 19.9% ± 22.7% (HWB) (P < .001) over the course of the study, even during the weight-stable phase (body mass, ICC = .99) and ad libitum fluid intake (42 ± 4 mL · kg-1 · d-1). The intraclass correlation coefficients (ICCs) ranged from .52 to .55 for USG and .38 to .52 for UOSM, further indicating inconsistency of the urinary dehydration markers. Poor correlations were found between USG and TPC metabolites (r = .27, P = .211). CONCLUSIONS: Urinary dehydration markers (both USG and UOSM) exhibit high variability and seem to be unreliable diagnostic tools to track actual body-weight loss in real-life settings. The ad libitum fluid intake was apparently inadequate to match acute fluid loss during and after intense preparation. The applicability of a single-time-point hydration-status assessment concept may preclude accurate assessment of actual body-weight deficits in youth boxers.

Game Profile-Based Training in Soccer: A New Field Approach.

Dello Iacono, A, Martone, D, Cular, D, Milic, M, and Padulo, J. Game profile-based training in soccer: a new field approach. J Strength Cond Res 31(12): 3333-3342, 2017-The aim of the study was to profile and compare the time-motion, physiological, and neuromuscular responses of both National Youth League (NYL) and UEFA Youth League (UYL) matches with those of an experimental game profile-based training (GPBT) protocol. Time-motion traits and physiological, perceptual, and neuromuscular responses were investigated in 24 male soccer players across 14 matches and 6 GPBT training sessions, for a total of 420 samples. The GPBT had a greater influence on time-motion traits and perceptual responses than the NYL and UYL matches (all p < 0.001). No significant GPBT vs. match differences were found for mean heart rate or blood lactate (F = 1.228, p = 0.304, and F = 0.978, p = 0.385, respectively). Finally, the GPBT protocol led to greater impairment of the neuromuscular explosive performances when compared with those of the postmatch scores (squat jump: F = 19.991, p < 0.001; countermovement jump: F = 61.703, p < 0.001). Results identified the GPBT protocol as characterized by relatively greater high-intensity workloads than official NYL and UYL matches, requiring increased demanding efforts. In light of these outcomes, the GPBT protocol can be considered an advantageous training method for elite soccer players, capable of stimulating the physical effort and physiological capabilities required during a match. This approach is favorable when designing a training intervention according to the principle of sport specificity, as it is based on the specific metabolic demands.