Evaluation of the external and internal workload in female futsal players

External Load Evaluation in Elite Futsal: Influence of Match Results and Game Location with IMU Technology

The purpose of this study was to assess the external load demands in futsal, considering both home and away matches and their outcomes, in order to plan microcycles throughout the season based on the external load of each match. The external load of 10 players from a First Division team in the Spanish Futsal League was recorded throughout 15 official matches in the first half of the league championship. The players' external load was monitored using OLIVER devices. To analyse the influence of the match outcome and location on the external load, a univariate general linear model (GLM) analysis was conducted with Bonferroni post hoc. There are no differences between the variables neither comparing results nor location factors, except for accelerations of 2 to 3 m/s2 (m) per minute and the number of accelerations of 2 to 3 m/s2 per minute, reporting higher value winnings at home than away (p < 0.05). The location and results are not factors that influence on external load in futsal matches, except the number and distance performed in accelerations and distance covered at a low to medium speed. These findings are important for planning microcycles and providing the appropriate dosage to each player to achieve optimal performance in matches.

Space and players' number constrains the external and internal load demands in youth futsal

Introduction

The aim of this study was to analyze the effects of space and number of players manipulation on the external and internal load demands of youth futsal athletes.

Methods

Forty-two male U17 players (age = 15.62 ± 0.58 years) from three futsal teams participated in the study. In this cross-sectional study that lasted 8-week, the player's sample practiced six futsal tasks (T1-T6) and a futsal game played under the official rules (T7). From T1-T6, two task constraints were manipulated: (i) the number of players and, (ii) the space of play. The WIMU PRO™ Ultra-Wideband (UWB) tracking system was used to measure the external and internal load during the futsal tasks. External load was quantified using kinematic and mechanical variables extracted from positional data and, the internal load was quantified using Heart rate (HR) and rating of perceived exertion (RPE). Repeated measures ANOVA was used for comparison purposes.

Results

In general, the results showed high external (total distance, distance 18.1-21, above 21 Km/h, and high intensity acceleration and deceleration, p < 0.001) and internal load (heart rate average and rating of perceived exertion, p < 0.001) in the tasks with low number of players and high area. In relation to the match, the tasks with small relative area per player (GK + 2 vs. 2 + GK and GK + 3 vs. 3 + GK in 20 × 20 m) promoted low external load.

Conclusion

It was concluded that increasing the relative area by reducing the number of players involved in the tasks in the form of small-sided games (GK + 2 vs. 2 + GK and GK + 3 vs. 3 + GK), in relation to the futsal game (GK + 4 vs. 4 + GK), can be considered a pedagogical strategy to increase the external and internal load demands of young futsal players.

In-contest body acceleration profiles for the judo male and female weight divisions

Introduction

This study aimed to determine the body accelerations (BA) profile of the judo contest of the male and female weight divisions and to ascertain the involvement of the vertical, mediolateral and anteroposterior axes in it.

Methods

Forty-eight male and forty-eight female national and international level athletes (some of them medalists in World, European and national championships) participated in a 5-min simulated contest (official fight time plus breaks) against an opponent of the same sex and weight division, wearing an accelerometer. Heart rate, blood lactate and ratings of perceived exertion were recorded to certify that the athletes performed the fullest.

Results

The t2way test expressed differences in the athletes' BA (p = 0.001) and three profiles were identified: the light/middle weight male divisions, the light/middle weight female divisions and the heavy male and female ones. Athletes of all weight divisions performed their BA during the contest in all three directions (the one-sample Person's chi-square did not detect any significantly predominant one: p = 0.400, p = 0.631, p = 0.844, p = 0.749, p = 0.644 and p = 0.895, for male light, moderate and heavy, female light, moderate and heavyweight athletes, respectively). Monte Carlo method simulations suggested as the most likely scenarios those with BA involving all axes, with a slight preference of the anteroposterior and mediolateral ones.

Discussion

These results suggest that the demands on judo athletes in a contest differ between weight classes and sexes.

Research on women's futsal: a scoping review

The aim of this study was to conduct a comprehensive scoping literature review to provide an overview of the current state of research within women's futsal. We searched four electronic databases (SPORTDiscus, PubMed, Scopus, and Web of Science) up to December 2023. Inclusion criteria comprised original research published in peer-reviewed journals, available in English, Spanish, or Portuguese. The focus was on studies investigating women in futsal, encompassing both players and those in leadership positions, regardless of their age or skill level. The analysis included the authorship (location), population characteristics (number of participants, level of play, and age), themes explored, and primary findings. A total of 692 records were found, but only 175 met the selection criteria. The results highlighted a recent attention in the scientific literature, with the first publications emerging in 2005 and a notable increase since 2016. Strength and Conditioning topics constituted the most frequently explored area, comprising 32% of the studies. Notably, no studies focusing on coaching or management aspects were identified. In terms of the participant population, most studies concentrated on high-level (33%) and senior (84%) players. Few studies have investigated practitioners with disabilities or women in other positions such as coaches or managers. Most of the studies were conducted by Brazilian researchers (60%), indicating the need for investigations in different socio-cultural contexts. The recent academic attention and the upcoming inaugural edition of the FIFA Futsal Women's World CupTM in 2025 reinforce the need for further studies on women's futsal. This review contributes by identifying the scientific gaps that can be explored by future investigations.

Time Course of Performance Indexes, Oxidative Stress, Inflammation, and Muscle Damage Markers after a Female Futsal Match

BACKGROUND

Our aims were to investigate the time-course effects of a futsal match on performance, oxidative stress, and muscle damage markers, as well as inflammatory and antioxidant responses during a 6-day post-match period.

METHODS

Thirty-four female high-level futsal players were assessed on several oxidative stress, inflammation, subjective muscle soreness, subjective rate perceived exertion, and performance tests before a futsal match, immediately after, and 24 h to 144 h after.

RESULTS

Counter movement jump, 20 m, and 10 m sprints performance significantly decreased immediately after the match (p < 0.05) and returned to baseline 72 h post-match (p > 0.05). Delayed onset muscle soreness peaked 24 h post-match and rate perceived exertion peaked post-match (p < 0.05) and returned to baseline 96 h post-match (p > 0.05). Inflammatory biomarkers peaked at 24 h (p < 0.05) and remained significantly elevated for 72 h after the match (p < 0.05). Muscle damage biomarkers peaked at 24 h (p < 0.05) and remained significantly (p < 0.05) elevated for at least 72 h after the match. Oxidative stress markers peaked at 24 h-48 h (p < 0.05) and returned to baseline 120 h post-match (p > 0.05). In respect to antioxidant responses, these peaked at 24 h-48 h post-match (p < 0.05) and returned to baseline 120 h after the match (p > 0.05).

CONCLUSIONS

A single futsal match induces short/mid-term changes in performance, inflammation, oxidative stress, and muscle damage markers for about 72 h-96 h post-match.

Systematic review of the anthropometric profile of female futsal players 2010-2020

The objective was to summarize the scientific literature on the anthropometric characteristics of female futsal players. A systematic review documentary study was carried out. SCOPUS, PUBMED and SCIELO databases were used to search for information on primary studies related to the anthropometric profile of women's indoor soccer (elite and non-elite). The keywords used were: futsal, female, anthropometry. The range of years for the search was from 2010 to 2020. To analyze anthropometric differences, two groups were formed: group A: elite and group B: non-elite. 31 primary studies were identified, 22 (71%) in Scopus, 5 (16.1%) in PUBMED and 4 (12.9%) in SCIELO. Three publication languages were considered (English, Spanish and Portuguese) and 6 countries were identified (Brazil, Spain, Iran, Turkey, Venezuela and Italy). Players in the elite group evidenced higher weight, height, and BMI relative to their non-elite counterparts. Discrepancy in anthropometric characteristics between elite and non-elite players was verified. These results suggest that in order to participate in competitions at the highest level in women's futsal, they should have greater weight, height and BMI than their non-elite counterparts.

The Influence of Sprint Mechanical Properties on Change of Direction in Female Futsal Players

The aim of the present study was to analyze the association of the sprint force-velocity profile [Hzt FV profile] variables with change of direction [COD] performance in female futsal players. Twelve female futsal players (age: 19.83 ± 4.2 years; body height: 160.75 ± 8.37 cm; body mass: 57.64 ± 8.3 kg) volunteered to be evaluated in the following assessments: Hzt FV profile, 505 test, modified 505 test [M505test] and V-cut test. The Spearman's correlation coefficient [r_s] (p < 0.05) was used to determine the relationship of the mechanical variables of the sprint (maximum power output [P_max], maximum horizontal force production [F₀] and maximum velocity [V₀]) with COD performance. V₀ showed a very large significant association with the 505 test (r_s = -0.767; 90% CI: (-0.92 to -0.43); p < 0.01) and a large association with the V-cut test (r_s = -0.641; 90% CI: (-0.86 to -0.21); p < 0.05), whereas P_max was strongly associated with results of the 505 test (r_s = -0.821; 90% CI: (-0.94 to -0.55); p < 0.01) and largely associated with the V-cut test results (r_s = -0.596; 90% CI: (-0.84 to -0.14); p < 0.05). In conclusion, maximal power and velocity output during sprinting are determinant factors to successful COD in 180º and 45º cuts, thus, the Hzt FV profile should be assessed in female futsal players to better understand the influence of sprint mechanical properties on COD performance and prescribe individualized training programs.

Analysis of key external and internal load variables in professional female futsal players: a longitudinal study

The aims of this study were to identify the key external and internal load variables in professional futsal through principal components analysis (PCA), and analyse the physical performance required by the players in official matches. Data were collected from 14 female players during 10 matches using WIMU PRO^TM. The PCA selected a total of 22 variables as key indicators of players' load. Specifically, these variables were represented by five principal components. However, a novel finding was that different components were extracted when the analysis was carried out by full match (68.83% of total variance), first half (69.81% of total variance), or second half (65.96% of total variance). Also, this study found that the players decreased their physical performance during the second half. Based on these results, this study may help optimize performance and reduce the injury risk. Performance should not be only analysed considering the full match external/internal load but also specifying by match halves. This is explained by the fact that there were variables that made up the principal components in the first half, but not in the second half or full match. Finally, coaches should adopt training strategies which deal with the decrease in physical performance during the second half.

Comprehensive Lower Extremities Joints Range of Motion Profile in Futsal Players

The purposes of this study were to describe the lower extremities joints range of motion (ROM) profile using a comprehensive approach in futsal players and to examine potential player position (goalkeepers vs. outfield players), competitive level (first [top] division vs. second division), number of playing years, sex (males vs. females), and bilateral (dominant limb vs. non-dominant limb) differences. A total of 72 male and 67 female elite futsal players from 11 clubs were measured of passive hip (flexion with knee flexed [HF_KF] and extended [HF_KE], extension [HE], abduction [HA], external [HER], and internal [HIR] rotation), knee (flexion [KF]) and ankle (dorsiflexion with knee flexed [ADF_KF] and extended [ADF_KE]) ROMs. Bayesian inferences exploring differences between player position, competitive level, sex and limb were made. A Bayesian correlation analysis was conducted to explore the influence of playing years on joints ROMs. The results showed no significant player position or competitive level related differences in any average ROM score. However, statistically significant sex-related differences were documented whereby female players reported higher hip and knee joints ROM average values than their male counterparts. Especially relevant were the proportions of males (72%) and players from teams engaged in the second division (61%) displaying limited HF_KE ROMs. Likewise, around 35% of all players showed restricted ADF_KF ROMs. In addition, approximately 21, 18, 22, and 25% of the futsal players were identified as having bilateral asymmetries (≥8°) for HA, HIR, HER, and KF ROMs, respectively. Finally, Bayesian correlation analysis did not report any significant association between years of playing futsal and ROM measures (all r values < 0.34). The implications that these restricted HF_KE and ADF_KF ROMs and bilateral asymmetries in hip (abduction, internal and external rotation) and knee (flexion) ROMs caused by the practice of futsal may have on physical performance and injury risk warrant future research.

Monitoring and Behavior of Biomotor Skills in Futsal Athletes During a Season

Futsal is a sport that presents alternation of high and low intensity moments, which lacks investigations regarding the effects of the organization of the training load on biomotor skills. In this sense, this study aims to verify the monitoring of the training load throughout the season and the behavior of biomotor skills in futsal athletes. Twelve futsal athletes (24.5 ± 4.9 years, 1.79 ± 0.6 m, 72.4 ± 9.4 kg, and 9.4 ± 4.3% fat) from the adult category who competed in the first division of the Paulista championship participated in the study. Throughout the season the internal training load (ITL) was calculated, through the relationship between volume (minutes) and the rate of perceived exertion (RPE), monotony, and training strain. The training periods were divided into: preparatory, competitive and competitive II, for a total of four moments of evaluation: M1: at the beginning of the preparatory period; M2: 5th week, at the end of the preparatory period; M3: 13th week, in the middle of the competitive period; and M4: at the start of the competitive period II. The tests used were: (i) Power of lower limbs: counter movement jump (CMJ); (ii) Displacement speed, over the 10-meter distance (V10m); and (iii) Aerobic power, by the Carminatti test (T-CAR). The variables analyzed were compared at the different moments of evaluation, normally distributed variables (Volume, S-RPE, strain, and monotony) were analyzed using the ANOVA ONE-WAY variance test followed by the Tukey. Variables that did not show normality (lower limb power, speed, and aerobic power) were compared using the Friedman test followed by Dunn's multiple comparisons test and was presented by median and interquartile interval. The significance value adopted was p < 0.05. A significant improvement (p < 0.05) was observed in the power of lower limbs from M1 (37.5 ± 5.5 cm) to M3 (40.8 ± 5.7 cm), from M2 (38.9 ± 5.5 cm) to M3 (40.8 ± 5.7 cm), and from M1 (37.5 ± 5.5 cm) to M4 (40.2 ± 5.4 cm). Aerobic power showed a significant increase (p < 0.05) from M1 (12.1 ± 0.7 km/h) to M3 (12.7 ± 7 km/h) and from M1 (12.1 ± 0.7 km/h) to M4 (12.73 ± 1.04 km/h). The internal training load showed a difference between competitive I and II in relation to the preparatory period (p < 0.05). In conclusion, the proposed training organization was sufficient to improve the power of the lower limbs and the aerobic power.

Mechanism of the Effect of High-Intensity Training on Urinary Metabolism in Female Water Polo Players Based on UHPLC-MS Non-Targeted Metabolomics Technique

OBJECTIVE

To study the changes in urine metabolism in female water polo players before and after high-intensity training by using ultra-high performance liquid chromatography-mass spectrometry, and to explore the biometabolic characteristics of urine after training and competition.

METHODS

Twelve young female water polo players (except goalkeepers) from Shanxi Province were selected. A 4-week formal training was started after 1 week of acclimatization according to experimental requirements. Urine samples (5 mL) were collected before formal training, early morning after 4 weeks of training, and immediately after 4 weeks of training matches, and labeled as T1, T2, and T3, respectively. The samples were tested by LC-MS after pre-treatment. XCMS, SIMCA-P 14.1, and SPSS16.0 were used to process the data and identify differential metabolites.

RESULTS

On comparing the immediate post-competition period with the pre-training period (T3 vs. T1), 24 differential metabolites involved in 16 metabolic pathways were identified, among which niacin and niacinamide metabolism and purine metabolism were potential post-competition urinary metabolic pathways in the untrained state of the athletes. On comparing the immediate post-competition period with the post-training period (T3 vs. T2), 10 metabolites involved in three metabolic pathways were identified, among which niacin and niacinamide metabolism was a potential target urinary metabolic pathway for the athletes after training. Niacinamide, 1-methylnicotinamide, 2-pyridone, L-Gln, AMP, and Hx were involved in two metabolic pathways before and after the training.

CONCLUSION

Differential changes in urine after water polo games are due to changes in the metabolic pathways of niacin and niacinamide.

Global Positioning System Analysis of Physical Demands in Elite Women's Beach Handball Players in an Official Spanish Championship

This cross-sectional study aims to analyze the physical demands of elite beach handball players during an official competition. Nine elite female (mean age: 24.6 ± 4.0 years; body weight: 62.4 ± 4.6 kg; body height: 1.68 ± 0.059 m; training experience: 5 years; training: 6 h/week) beach handball players of the Spanish National Team were recruited for this study. A Global Positioning System was incorporated on each player’s back to analyze their movement patterns. Speed and distance were recorded at a sampling frequency of 15 Hz, whereas acceleration was recorded at 100 Hz by means of a built-in triaxial accelerometer. The main finding of the study is that 53% of the distance travelled is done at speeds between 1.5 and 5 km/h and 30% of the distance is between 9 and 13 km/h (83% of the total distance covered), which shows the intermittent efforts that beach handball involves at high intensity, as reflected in the analysis of the internal load with 62.82 ± 14.73% of the game time above 80% of the maximum heart rate. These data help to orientate training objectives to the physical demands required by the competition in order to optimize the players’ performance.

Identification of Maximal Running Intensities During Elite Hurling Match-Play

Young, D, Malone, S, Beato, M, Mourot, L, and Coratella, G. Iidentification of maximal running intensities during elite hurling match-play. J Strength Cond Res 34(9): 2608-2617, 2020-The current study aimed to describe the duration-specific running intensities of elite hurling players during competition with respect to position using a rolling average method. Global positioning systems (10-Hz Viper; STATSport, Viper, Newry, Northern Ireland) were used to collect data from 36 elite hurling players across 2 seasons. Players were categorized according to playing positions (full-backs, half-backs, midfielders, half-forwards, and full-forwards). A total of 230 full match samples were obtained from 22 competitive games for analysis. The velocity-time curve was analyzed using a rolling average method, in which the maximum relative total distance (TD; m·min), high-speed running distance (HSR; m·min), and sprint distance (SD; m·min) intensities were calculated across 10 different rolling time durations (1-10 minutes) within each game. There were large to very large (effect sizes [ES] = 0.66-4.33) differences between 1 minute rolling averages and all other durations for TD, HSR, and SD. However, pairwise comparisons between 6 and 10 minutes for TD, HSR, and SD were smaller and more variable (ES = 0.07, trivial to ES = 0.85, moderate). Half-backs, midfielders, and half-forwards achieved a higher maximal relative TD and HSR in all duration-specific fields when compared with full-backs and full-forwards. No positional difference was observed in 1- and 2-minute durations for SD. Because the rolling average duration increased the maximum TD, HSR and SD running intensities decreased across all positions. These data provide knowledge of the peak running intensities of elite hurling competition and can be used to design training activities to sufficiently prepare players for these "worst-case scenarios."

Match-Play Temporal and Position-Specific Physical and Physiological Demands of Senior Hurlers

Young, D, Beato, M, Mourot, L, and Coratella, G. Match-play temporal and position-specific physical and physiological demands of senior hurlers. J Strength Cond Res 34(6): 1759-1768, 2020-The aims of the current study were to examine the temporal differences in match-running performances and heart rate (HR) in elite senior hurling players between halves of play and field positions. Global positioning systems (10 Hz) and HR monitors were used to collect data from 48 players over 18 games. Running performances (total distance [TD], relative distance, high-speed running [HSR], sprint efforts [SE], mean length of sprints, and sprint distance [SD]) and HR values (HRmean and HRpeak) were assessed. Decrements in TD (p = 0.009, effect size [ES] = -0.15), relative distance (p = 0.009, ES = -0.18), HSR (p = 0.001, ES = -0.28), SE (p = 0.001, ES = -0.23), SD (p = 0.001, ES = -0.24), HRmean (p < 0.001, ES = -0.38), and HRpeak (p < 0.001, ES = -0.21) were found between halves. Half backs showed between-half decrements in all metrics (p < 0.05) except SD (p = 0.130, ES = -0.26). Midfielders (p < 0.001, ES = -0.68) and half forwards (p < 0.001, ES = -0.79) experienced second-half decrements in HSR. No decrements (p > 0.05) in running performances were found between halves for full backs. HRmean was lower in full backs (p = 0.007, ES = -0.46) and half backs (p = 0.001, ES = -0.76) in the second half. Coaches should consider the specific HSR between-half temporal decrements in half backs, midfielders, and half forwards, and customize training program design to minimize these decrements.

Environmental Conditions, Preseason Fitness Levels, and Game Workload: Analysis of a Female NCAA DI National Championship Soccer Season

Benjamin, CL, Hosokawa, Y, Curtis, RM, Schaefer, DA, Bergin, RT, Abegg, MR, and Casa, DJ. Environmental conditions, preseason fitness levels, and game workload: Analysis of a female NCAA DI National Championship Soccer Season. J Strength Cond Res 34(4): 988-994, 2020-The purpose of this study was to determine the independent and combined moderating effect of aerobic fitness and environmental conditions on physical workloads during collegiate female soccer matches. Nineteen National Collegiate Athletic Association female soccer athletes were included in this study (mean ± SD: age, 20.6 ± 1.4 years; height, 169 ± 6.1 cm; body mass 64.7 ± 5.3 kg). Maximal oxygen consumption (V[Combining Dot Above]O2max) was estimated from the yo-yo intermittent recovery test before preseason training and wet-bulb globe temperature (WBGT) was recorded onsite for home matches and at the nearest weather station for away matches. Relative distance (TD), relative high-speed running distance (%HSD), and relative high metabolic load (%HML) performance were collected during each match using a global positioning system unit (Viper Pod; STATSports, Chicago, IL). Statistically significant differences were observed in TD between LOW WBGT and MOD WBGT (mean difference [MD] = 7.08 m·min; effect size [ES] = 0.54; p < 0.001), in %HSD between LOW WBGT and MOD WBGT (MD = 1.97%; ES = 0.64; p = 0.01) and between LOW WBGT and HIGH WBGT (MD = 2.71%; ES = 1.01; p < 0.001), and in %HML between LOW WBGT and MOD WBGT (MD = 1.24%; ES = 0.56; p < 0.001) and between LOW WBGT and HIGH WBGT (MD = 1.55%; ES = 0.78; p = 0.01). There was a significant interaction between WBGT and V[Combining Dot Above]O2max for %HSD (p = 0.03). These findings demonstrate that physical performance metrics were affected by increased WBGT. In addition, aerobic fitness seemed to moderate the effect of increasing WBGT on %HSD, meaning maximizing aerobic capacity is important for optimizing running performance in the heat. Coaches and sports medicine staff could alter training time and session length based on environmental conditions as well as potentially use aggressive cooling strategies to mitigate the imposed heat stress and decrements in physical performance.

Acute Photobiomodulation Does Not Influence Specific High-Intensity and Intermittent Performance in Female Futsal Players

The acute improvement of performance after photobiomodulation therapy (PBMT) has been reported in different types of exercise. However, the effect on high-intensity and intermittent exercises that are relevant for team sports is unknown. Thus, we evaluated the effect of prior acute application of PBMT on high-intensity and intermittent exercise performance, muscle oxygenation, and physiological/perceptual indicators in amateur female futsal players. Thirteen players (24.1 ± 3.7 years) performed a testing battery (countermovement jump (CMJ), Illinois agility and YoYo intermittent recovery test level 1 (YYIR1)) preceded by 15 min of PBMT (1 min 30 s each muscular point; five muscular points in each lower limbs) or 15 min of placebo (SHAM), in a counterbalanced randomized cross-over design (one-week in-between PBMT/SHAM). All test performance did not differ (p > 0.05) between PBMT and SHAM, as well as blood lactate, rating of perceived exertion, heart rate, and muscle oxygenation (via near infrared spectroscopy) responses. The acute application of PBMT prior to a physical testing battery does not influence high-intensity and intermittent exercises performance, neither physiological nor perceptual responses in amateur female futsal players.

Local Positioning System Analysis of Physical Demands during Official Matches in the Spanish Futsal League

The aim of this study was to analyze the influence of the match half and the playing position on physical requirements in the Spanish Professional Futsal League players during official games. The external load from distance, speed, acceleration and deceleration variables were obtained from fourteen elite futsal players during 10 official matches of the 2019–2020 season using a Local Positioning System with ultra-wideband technology installed on the futsal pitch. The results revealed similar results from physical requirements between first and second half (p > 0.05). Wingers demonstrated greater high-speed running distance (+4.04 m·min⁻¹; CI95%: 0.35 to 7.72; ES: 0.87) than pivots (p > 0.05). There were a high number of accelerations (7.42–9.41 n·min⁻¹) and decelerations (7.37–9.12 n·min⁻¹) per minute in all player positions. The principal finding of the current manuscript did not evidence differences in the physical performance of players between the first and second half. The physical requirements varied among pivots and wingers regarding high-intensity actions. These outcomes add new contributions to the understanding of futsal physical demands.

Game Running Performance and Fitness in Women’s Futsal

The study aimed to verify possible associations between game-play running performance and outcomes derived from fitness (running) tests in female futsal players. Sixteen women professional elite futsal players from a 1st division league team (19.2±2 years-old, 4.3±2.1 years of experience) participated. Firstly, a graded incremental treadmill test was adopted to determine maximal oxygen uptake (VO2max). Following 72 h of laboratory protocol, players were asked to perform a repeated-sprint test on a court (8×40 m with two 180° change-of-directions). Twenty-four hours after, players participated in a one-off friendly game (two 20-min half-times). A computerized automatic image recognition software (DVIDEOW; 30 Hz) allowed to determine game running performance variables. Fatigue index and best time in the court test and VO2max and its attached speed derived from laboratory-based test showed significant moderate-to-moderately high correlations (r=− 0.59–0.76; p<0.05) with some game running performance outputs, notably related to high-intensity running. In conclusion, the present study provided initial evidence on associations between two fitness tests and one-off game running performance in female futsal. Information derived from the work potentially help conditioning professionals working with female futsal athletes gain awareness about some properties of common testing tools.

Activity Profile and Physical Performance of Match Play in Elite Futsal Players

Understanding the physical demands of futsal requires a precise quantification of the players’ activities during match play. This study aimed to (1) describe external load, identifying the differences between the first and second halves in official futsal matches; (2) identify the most important external workload metrics to profile the players; and (3) identify the collinearity between variables in the analysis of physical performance of futsal players. Match external load data were collected from male players (n = 28) in six games of the Final Eight of the Portuguese Futsal Cup 2018. The players increased the distance covered per minute at 12–18 km/h in the second half (p < 0.01). Dynamic stress load also increased in the second half (p = 0.01). The variables that best predicted the physical profile of each player were decelerations (predictor importance, PI = 1), walking (PI = 1), sprinting (PI = 1), jogging (PI = 0.997), total distance covered per minute (PI = 0.992), and metabolic power (PI = 0.989). Decelerations showed the highest association with the clusters levels (p < 0.001; PI = 1); this suggests decelerations as a potential candidate for best analyzing the physical load of futsal players. Overall, the data from this exploratory study suggest that distance covered per minute (m/min), number of sprints (>18 km/h), decelerations (greater than-2 m/s), and metabolic power (W/kg) are the variables that most discriminate the load intensity of elite futsal players.

Perceptions of the technical staff of professional teams regarding injury prevention in Spanish national futsal leagues: a cross-sectional study

Futsal is a sport with increasing popularity and level of performance, both in male and female categories. Also, there are several injuries along a season, so it is needed to know how to reduce this burden. The purpose of this study was to describe the perceptions of technical staff on injury risk factors, risk testing and preventive measures, and the strategies used by them within professional male and female futsal teams. A cross-sectional study was designed during the 2017–2018 season. A total of 32 futsal teams involved in male and female Spanish national futsal leagues completed, through an online survey platform, a questionnaire about injury risk factors, risk testing and preventive measures. Findings showed that: (a) most teams reported enough human resources, but insufficient material and time resources, (b) the main risk factors detected were previous injuries, strength deficits and dehydration, (c) functional movement patterns, flexibility tests and self-report questionnaires were the most applied tests for detecting injury risks in their players and (d) most of the main preventive measures used by technical staff matched with the best valued by them. Technical staff defined properly the main risk factors in futsal performance, as well as they applied preventive strategies with scientific support. The information provided in this research could be of interest for sport scientists and technical staff when designing more accurate and efficient injury prevention programs in futsal.

The Effect of a Single Session of Plyometric Training Per Week on Fitness Parameters in Professional Female Soccer Players: A Randomized Controlled Trial

Nonnato, A, Hulton, AT, Brownlee, TE, and Beato, M. The effect of a single session of plyometric training per week on fitness parameters in professional female soccer players. A randomized controlled trial. J Strength Cond Res XX(X): 000-000, 2020-As the interest and popularity of female soccer has increased over the last few decades, there still lacks research conducted with the elite population, specifically ecological training interventions during the competitive season. Therefore, the aim of this study was to compare the effectiveness of 12 weeks (undertaken once a week) of plyometric (PLY) training on physical performance in professional female soccer players during the season. Using a randomized controlled trial design, 16 players were included in the current study (mean ± SD; age 23 ± 4 years, weight 60.3 ± 4.9 kg, height 167 ± 3.7 cm) and randomized in PLY (n = 8) and Control groups (CON, n = 8), respectively. Squat jump (SJ), counter movement jump (CMJ), long jump (LJ), single-leg triple jump distance test (triple jump test), changes of direction 505 test (505-COD), and sprint 10 and 30 m were performed before and after 12 weeks of PLY training. Significant within-group differences were found in triple jump test dominant (p = 0.031, effect size [ES] = moderate) and nondominant limb (p = 0.021, ES = moderate) and sprint 10 m (p = 0.05, ES = large), whereas the CON did not report any positive variation. However, neither group reported significant variation in SJ, CMJ, LJ, 505-COD, and sprint 30 m (underlining the difficulties in obtain meaningful variation in season). These findings have strong practical applications because this study showed for the first time that a single session a week of plyometric training can significantly increase sport-specific fitness parameters in professional female soccer players during the season.

Match performance in a reference futsal team during an international tournament - implications for talent development in soccer

Anecdotal evidence suggests that futsal can aid talent development for 11 a-side soccer through the potential for transfer of the game’s skills and constraints. However, additional scientific research is necessary to enhance understanding of the technical and physical demands of futsal and the potential returns for soccer player development. Accordingly, this study examined selected characteristics of physical (internal and external loads) and technical performance in international futsal match-play in order to study the potential of these for skill transfer and aiding soccer player development. Performance was investigated in futsal players (n = 16, 25.74±4.71 years) belonging to a national team during an international tournament. Pre-tournament fitness testing determined maximum heart rate (MHR) via the Yo-Yo IR1 test (194.6±11.1 beats min^-1) to aid interpretation of internal load via heart rate measures during match-play. External load (accelerations and deceleration events) was measured using an inertial movement unit. Finally, post-tournament analysis of selected technical events was performed. Results reported a mean heart rate value during ‘court time’ of 164.7±22.3 beats min^-1, which as a percentage of participants’ MHR was 87.7%±4.4%, and a mean peak MHR of 98.3±2.5%. Results showed 2.16±0.25 accelerating (>1.5 m·s^-2) and 2.78±0.13 decelerating (>1.5 m·s^-2) events per player per minute. Team statistics included 647 passing, ~51 dribbling and 78 set play events per team per game. Match analyses showed that 77.3% of ball receptions were completed with the sole of the foot. Assessment of two-footedness showed 80.1±16.7% of individual possessions used the dominant foot to receive and 84.1±10.7% to pass the ball thereby displaying strong foot dominance. These results have quantified characteristics of elite futsal match-play that are no doubt intrinsically related to the environmental and task constraints of the sport. In addition to enhancing understanding of futsal, there are potential learning returns and implications for skills transfer and the development of soccer players.

Metabolic power in hurling with respect to position and halves of match-play

The current investigation compared the metabolic power and energetic characteristics in team sports with respect to positional lines and halves of match-play. Global positioning system (GPS) technology data were collected from 22 elite competitive hurling matches over a 3-season period. A total of 250 complete match-files were recorded with players split into positional groups of full-back; half-back; midfield; half-forward; full-forward. Raw GPS data were exported into a customized spreadsheet that provided estimations of metabolic power and speed variables across match-play events (average metabolic power [P_met], high metabolic load distance [HMLD], total distance, relative distance, high-speed distance, maximal speed, accelerations, and deceleration). P_met, HMLD, total, relative and high-speed distance were 8.9 ± 1.6 W·kg^-1, 1457 ± 349 m, 7506 ± 1364 m, 107 ± 20 m·min^-1 and 1169 ± 260 m respectively. Half-backs, midfielders and half-forwards outperformed full-backs (Effect Size [ES] = 1.03, 1.22 and 2.07 respectively), and full-forwards in P_met (Effect Size [ES] = 1.70, 2.07 and 1.28 respectively), and HMLD (full-backs: ES = -1.23, -1.37 and -0.84 respectively, and full-forwards: ES = -1.77, -2.00 and -1.38 respectively). Half-backs (ES = -0.60), midfielders (ES = -0.81), and half-forwards (ES = -0.74) experienced a second-half temporal decrement in HMLD. The current investigation demonstrates that metabolic power may increase our understanding of the match-play demands placed on elite hurling players. Coaches may utilize these findings to construct training drills that replicate match-play demands.

Injury incidence, characteristics and burden among female sub-elite futsal players: a prospective study with three-year follow-up

The main purpose of the current study was to analyze the injury incidence, characteristics and burden among sub-elite female futsal players. Individual exposure to match play and training, injury incidence and characteristics (player position, injury mechanism, type of injuries, severity of injuries, recurrent vs. new injuries, season variation of injury pattern) in a female futsal team were prospectively recorded for three consecutive seasons (2015-2018). Incidences were calculated per 1,000 h of exposure. A total of 30 injuries were reported during the three seasons within a total exposure of 4,446.1 h. The overall, match and training incidence of injuries were 6.7, 6.4 and 6.8 injuries/1,000 h of exposure, respectively. Most injuries had a non-contact mechanism (93%), with the lower extremity being the most frequently injured anatomical region (5.62 injuries/1,000 h of exposure). The most common type of injury was muscle/tendon (4.9 injuries/1,000 h of exposure) followed by joint (non-bone) and ligament (1.3 injuries/1,000 h of exposure). The injuries with the highest injury burden were those that occurred at the knee (31.9 days loss/1,000 h exposure), followed by quadriceps (15.3 day loss/1,000 h) and hamstring (14.4 day loss/1,000 h) strains. The first few weeks of competition after pre-season and soon after the Christmas break were the time points when most injuries occurred. These data indicate that sub-elite female futsal players are exposed to a substantial risk of sustaining an injury. To reduce overall injury burden, efforts should be directed toward the design, implementation and assessment of preventative measures that target the most common diagnoses, namely, muscle/tendon and ligament injuries.

Change in Lactate, Ammonia, and Hypoxanthine Concentrations in a 1-Year Training Cycle in Highly Trained Athletes: Applying Biomarkers as Tools to Assess Training Status

Włodarczyk, M, Kusy, K, Słomińska, E, Krasiński, Z, and Zieliński, J. Change in lactate, ammonia, and hypoxanthine concentrations in a 1-year training cycle in highly trained athletes: applying biomarkers as tools to assess training status. J Strength Cond Res 34(2): 355-364, 2020-The aim was to determine changes in biomarker (LA, NH3, purine metabolites) blood concentration during graded exercise and recovery throughout an annual training cycle in highly trained athletes of different training profiles. The study included 12 sprinters (SP, 21-30 years), 11 triathletes (TR, 20-31 years), 12 futsal players (FU, 19-31 years), and 13 amateur runners (AM, 20-33 years). Purine metabolite (hypoxanthine, xanthine, uric acid), ammonia (NH3), and lactate (LA) concentrations were determined at rest, during an incremental treadmill exercise test (every 3 minutes), and during recovery (5, 10, 15, 20, and 30 minutes postexercise) in 4 phases of an annual training cycle. Purine metabolite concentration was determined from plasma, whereas LA and NH3 from whole blood. For LA during exercise and recovery, certain significant differences between training phases within groups were observed for FU, TR, and SP but not for AM. For NH3, the greatest differences between examination points were observed for SP and TR near maximal exercise and in the first few stages of recovery. For hypoxanthine (Hx), the largest amount of differences between examination points was observed for FU, TR, and FU throughout the entire exercise spectrum. Biomarker concentration dynamics change during an incremental exercise test and postexercise in an annual training cycle. Biomarker responses differ depending on training type and magnitude of training loads used in various phases of an annual training cycle. When assessing training status using an incremental exercise test throughout an annual training cycle, NH3 and Hx concentration changes are more sensitive compared with LA.

Changes in Blood Concentration of Adenosine Triphosphate Metabolism Biomarkers During Incremental Exercise in Highly Trained Athletes of Different Sport Specializations

Włodarczyk, M, Kusy, K, Słomińska, E, Krasiński, Z, and Zieliński, J. Changes in blood concentration of adenosine triphosphate metabolism biomarkers during incremental exercise in highly trained athletes of different sport specializations. J Strength Cond Res 33(5): 1192-1200, 2019-We hypothesized that (a) high-level specialized sport training causes different adaptations that induce specific biomarker release dynamics during exercise and recovery and (b) skeletal muscle mass affects biomarker release. Eleven sprinters (21-30 years), 16 endurance runners (18-31 years), 12 futsal players (18-29 years), and 12 amateur runners as controls (22-33 years) were examined. Hypoxanthine (Hx), xanthine (X), uric acid (UA), ammonia (NH3), and lactate (LA) concentrations were determined at rest, during an incremental treadmill exercise test (every 3 minutes), and during recovery (5, 10, 15, 20, and 30 minutes after exercise). Hx, X, and UA concentration was determined from plasma, while LA and NH3 from whole blood, and muscle mass was assessed using dual X-ray absorptiometry method. At rest, during incremental exercise, and up to 30 minutes into the postexercise recovery period, sprinters had lowest Hx, X, and UA concentrations, and endurance athletes had lowest NH3 concentrations. For LA during exercise, the lowest concentrations were noted in endurance athletes, except when reaching maximum intensity, where the differences between groups were not significant. There were no significant correlations observed between skeletal muscle mass and biomarker concentration at maximal intensity and recovery in any group. In conclusion, the magnitude of exercise-induced biomarker concentration is only related to training adaptations through specific training profile but not to muscle mass. In addition, the results suggest that combined measuring of LA, NH3, and Hx concentration in blood is useful in indirectly reflecting key changes in exercise- and training-induced energy status. Further research should focus on studying how specific training sessions affect individual biomarker response in highly trained athletes.

Monitoring Fatigue During Intermittent Exercise With Accelerometer-Derived Metrics

The aim of this study was to assess the sensitivity of accelerometer-derived metrics for monitoring fatigue during an intermittent exercise protocol. Fifteen university students were enrolled in the study (age 20 ± 1 years). A submaximal intermitted recovery test (Sub-IRT) with a duration of 6 min and 30 s (drill 1) was performed. In order to increase the participants’ fatigue, after that, a repeated sprint protocol (1×6 maximal 20 m sprints) was performed. Following that, participants repeated the Sub-IRT (drill 2) to evaluate the external and internal training load (TL) variations related to fatigue. Apex 10 Hz global navigation satellite system (GNSS) units were used to collect the variables total distance (TD), high metabolic distance (HMD), relative velocity (RV), average metabolic power (MP), heart rate maximal (HRmax) and mean (HRmean), muscular (RPEmus) and respiratory rating of perceived exertion (RPEres), dynamic stress load (DSL), and fatigue index (FI). A Bayesian statistical approach was used. A likelihood difference (between drill 1 and drill 2) was found for the following parameters: TD (BF₁₀ = 0.33, moderate per H₀), HMD (BF₁₀ = 1.3, anecdotal), RV (BF₁₀ = 0.29, moderate per H₀), MP (BF₁₀ = 1.3, anecdotal), accelerations (BF₁₀ = 1.6, anecdotal ), FI (BF₁₀ = 4.7, moderate), HRmax (BF₁₀ = 2.2, anecdotal), HRmean (BF₁₀ = 4.3, moderate), RPEmus (BF₁₀ = 11.6, strong), RPEres (BF₁₀ = 3.1, moderate), DSL (BF₁₀ = 5.7, moderate), and DSL•m⁻¹ (BF₁₀ = 4.3, moderate). In conclusion, this study reports that DSL, DSL•m⁻¹, and FI can be valid metrics to monitor fatigue related to movement strategy during a standardized submaximal intermittent exercise protocol.

The match-play sprint performance of elite senior hurlers during competitive games

The typical sprint profile in elite hurling has yet to be established. The purpose of this study was to investigate the sprinting demands of elite hurling competition and characterize the sprinting patterns of different playing positions. GPS (10-Hz, STATSports Viper) were used to collect data from 51 hurlers during 18 games. The total sprint (≥22 km·h-1) distance (TSD), the number of sprints (NOS) classified as length (<20 m, ≥20 m) and relative speed thresholds (<80%, 80-90%, >90%), the between-sprint duration and the number of repeated-sprint bouts (≥2 sprints in ≤60 s) were analyzed. The NOS was 22.2 ± 6.8 accumulating 415 ± 140 m TSD. The NOS <20 m, ≥20 m was 14.0 ± 4.7 and 8.1 ± 3.6 respectively. The NOS <80%, 80-90% and >90% was 10.6 ± 4.3, 8.2 ± 3.6, 3.4 ± 2.4 respectively. The between-sprint duration and the repeated-sprint bouts were 208 ± 86 s and 4.5 ± 2.6 respectively. TSD (ES = -0.20), NOS (ES = -0.34), NOS <20 m (ES = -0.33), ≥20 m (ES = -0.24), 80-90% (ES = -0.35) >90% (ES = -0.13) and repeated-sprint bouts (ES = -0.28) decreased between-halves. Full-backs performed a lower NOS <80% than half-backs (ES = -0.66) and a shorter mean duration of sprints than half-backs (ES = -0.75), midfielders (ES = -1.00) and full-forwards (ES = -0.59). These findings provide a sprint profile of elite hurling match-play that coaches should consider to replicate the sprint demands of competition in training.

The Relationship of Age and BMI with Physical Fitness in Futsal Players

The aim of this study was to examine the relationship of age and body mass status with field and laboratory measures of physical fitness in futsal players. Futsal players (n = 65, age 12.9 ± 2.8 years), who were classified into U11 (n = 28, 9-11 years), U13 (n = 21, 11-13 years), and adults (n = 16, >18 years), performed a physical fitness battery consisting of both laboratory and field tests. A similar prevalence of overweight (25%) was observed in all age groups (χ² = 1.94, p = 0.380, φ = 0.17). Age groups differed for all parameters, except body fat percentage, with adult players showing higher values than the younger groups (p < 0.05). U13 was heavier, taller, and had larger fat-free mass than U11 (p < 0.05). Adult players had superior values than their younger counterparts for all physical fitness parameters (p < 0.05). Body mass index (BMI) correlated inversely with aerobic capacity (U13), jumping ability, relative isometric muscle strength, and relative mean power in the Wingate anaerobic test (WAnT) (U11) (p < 0.05). Also, it correlated directly with absolute isometric muscle strength (U11) and peak power, mean power (all groups), and fatigue index (U11, U13) in WAnT (p < 0.05). Considering the results of this study, it was concluded that the prevalence of overweight in futsal players should be an important concern for practitioners working in this team sport. Optimizing BMI should be considered as a training and nutrition goal in order to improve sport performance.

Effects of Low-Moderate Load High-Velocity Resistance Training on Physical Performance of Under-20 Futsal Players

Resistance training (RT) is an effective methodology to improve physical performance of athletes. However, up to now, no studies have addressed the RT benefits in under-20 futsal players. The purpose of this study was to evaluate the effects of six weeks of RT with high-velocity movements, low-to-moderate loads, and low volume on physical performance of under-20 futsal players. A total of 21 players were divided into two groups: A control group (CG, n = 10) and a RT group (RTG, n = 11). The RTG performed two weekly training sessions constituted by leg-press, jumps, and sprints, along with three futsal training sessions, while the CG only performed the futsal training. Before and after the intervention, the sprint time in 0⁻10 m (T10), 10⁻20 m (T10⁻20), and 0⁻20 m (T20), the countermovement jump (CMJ) height, the T-Test time, the kicking ball speed (KBS), and the maximum dynamic strength in the leg-press, were assessed. In post-test, significant improvements in CMJ, T-Test, KBS, and leg-press were found for the RTG, whilst a significant decrease in T10⁻20 was evidenced in the CG. The present results suggested that RT based on high velocity movements, low-to-moderate loads, and low volume produce positive effects on physical performance of under-20 futsal players.

Match-Play Demands of Elite U17 Hurlers During Competitive Matches

Young, D, Mourot, L, Beato, M, and Coratella, G. Match-play demands of elite U17 hurlers during competitive matches. J Strength Cond Res 34(7): 1982-1989, 2020-The current study aimed to quantify the match-play workload in elite male under 17 hurlers, measuring the differences between the first and second halves and between positions. Global positioning system (10-Hz) and heart rate monitors were used to collect data from 76 players during 18 matches. Players' total distance (TD), relative distance (RD), high-speed running (HSR), the number and length of sprints, and the total sprint distance (TSD) was 6,483 ± 1,145 m, 108 ± 19 m·min, 583 ± 215 m, 18 ± 6, 15 ± 3 m, and 272 ± 77 m, respectively. Peak and mean heart rate were 194 ± 8 b·min and 167 ± 4 b·min, respectively. Decrements in TD (p < 0.001, effect size [ES] = 0.72), RD (p < 0.001, ES = 0.72), HSR (p < 0.001, ES = 0.55), the number of sprints (p < 0.001, ES = 0.57), mean length of sprint (p < 0.011, ES = 0.25), TSD (p < 0.001, ES = 0.69), mean heart rate (p < 0.001, ES = 0.35), and peak heart rate (p < 0.001, ES = 0.52) were found between halves. Largely-to-very largely greater TD, RD, and HSR were covered by midfielders, half-backs, and half-forwards compared with full-backs and full-forwards. No between-position difference was found in peak and mean heart rate. The current results are the first to highlight the differences in external and internal position-specific workload in elite male under 17 hurlers. Coaches need to consider the position-specific demands and between-half drop-off to prepare young hurlers appropriately to repeat the match-play performances of competition.

Validity and Reliability of Global Positioning System Units (STATSports Viper) for Measuring Distance and Peak Speed in Sports

Beato, M, Devereux, G, and Stiff, A. Validity and reliability of global positioning system units (STATSports Viper) for measuring distance and peak speed in sports. J Strength Cond Res 32(10): 2831-2837, 2018-Previous evidence has proven that large variability exists in the accuracy of different brands of global positioning systems (GPS). Therefore, any GPS model should be validated independently, and the results of a specific brand cannot be extended to others. The aim of this study is to assess the validity and reliability of GPS units (STATSports Viper) for measuring distance and peak speed in sports. Twenty participants were enrolled (age 21 ± 2 years [range 18 to 24 years], body mass 73 ± 5 kg, and height 1.78 ± 0.04 m). Global positioning system validity was evaluated by comparing the instantaneous values of speed (peak speed) determined by GPS (10 Hz, Viper Units; STATSports, Newry, Ireland) with those determined by a radar gun during a 20-m sprint. Data were analyzed using the Stalker (34.7 GHz, USA) ATS Version 5.0.3.0 software as gold standard. Distance recorded by GPS was also compared with a known circuit distance (400-m running, 128.5-m sports-specific circuit, and 20-m linear running). The distance bias in the 400-m trial, 128.5-m circuit, and 20-m trial was 1.99 ± 1.81%, 2.7 ± 1.2%, and 1.26 ± 1.04%, respectively. Peak speed measured by the GPS was 26.3 ± 2.4 km·h, and criterion was 26.1 ± 2.6 km·h, with a bias of 1.80 ± 1.93%. The major finding of this study was that GPS did not underestimate the criterion distance during a 400-m trial, 128.5-m circuit, and 20-m trial, as well as peak speed. Small errors (<5%, good) were found for peak speed and distances. This study supported the validity and reliability of this GPS model.

The Match Heart Rate and Running Profile of Elite Under-21 Hurlers During Competitive Match-Play

Young, D, Mourot, L, Beato, M, and Coratella, G. The match heart rate and running profile of elite under-21 hurlers during competitive match-play. J Strength Cond Res 32(10): 2925-2933, 2018-The aims of the current study were to examine the physical and physiological demands of elite under-21 male hurling match-play across halves of play and between positions. Global positioning systems (10 Hz) and heart rate (HR) monitors were used to collect data from 95 players during 10 games. Total distance (TD), relative speed, high-speed running (HSR), sprint distance, total sprints, and mean length of sprint was 6,688 ± 942 m, 112 ± 16 m·min, 661 ± 203 m, 274 ± 111 m, 18 ± 8 m, and 16 ± 5 m, respectively. Players' mean HR (HRmean) and peak HR (HRpeak) was 165 ± 9 b·min and 190 ± 7 b·min, respectively. Decrements in TD (p < 0.05, effect size [ES] = 0.81), HSR (p < 0.05, ES = 0.69), and HRmean (p < 0.05, ES = 0.80) were found between halves. Full backs covered significantly less TD than half backs (p < 0.05, ES = -1.24), midfielders (p < 0.05, ES = -1.39), and half forwards (p < 0.05, ES = -1.85). Half forwards covered a greater TD than full forwards (p < 0.05, ES = 0.94), greater HSR than full backs (p < 0.05, ES = 1.13), and greater sprint distance than half backs (p < 0.05, ES = 1.41). Between-half decreases were evident in TD, HSR, and HRmean, with no significant positional differences observed in TD, HSR, number of sprints, length of sprint, HRpeak, and HRmean between half backs, midfielders, and half forwards. The current findings provide data that coaches should consider to customize training program design for under-21 hurlers.

The Validity and Between-Unit Variability of GNSS Units (STATSports Apex 10 and 18 Hz) for Measuring Distance and Peak Speed in Team Sports

The aims of this study were (i) to investigate the criterion validity (vs. gold standard measurements) of the 10 and 18 Hz STATSports Apex units for measuring distances and peak speed (Vpeak) outcomes and (ii) to investigate the between-unit variability. Twenty university students were enrolled in the study (age 21 ± 2 years, weight 72 ± 6 kg, and height 1.76 ± 0.05 m). The criterion validity was tested by comparing the distances recorded by the units with ground truth reference (400-m trial, 128.5-m circuit, and 20-m trial). Vpeak values were compared with those determined by a gold standard criterion device (Stalker ATS Radar Gun) during a linear 20-m sprint. The distance biases for the Apex 10 Hz in the 400-m trial, 128.5-m circuit, and 20-m trial were 1.05 ± 0.87%, 2.3 ± 1.1%, and 1.11 ± 0.99%, respectively, while for the Apex 18 Hz the biases were 1.17 ± 0.73%, 2.11 ± 1.06%, and 1.15 ± 1.23%, respectively. Vpeak measured by the Apex 10 and 18 Hz were 26.5 ± 2.3 km h^-1 and 26.5 ± 2.6 km h^-1, respectively, with the criterion method reporting 26.3 ± 2.4 km h^-1, with a bias of 2.36 ± 1.67% and 2.02 ± 1.24%, respectively. This study is the first to validate and compare the STATSports Apex 10 and 18 Hz. Between-analysis (t-test) for total distance and Vpeak reported non-significant differences. Apex units reported a small error of around 1–2% compared to the criterion distances during 400-m, 128.5-m circuit, 20-m trials, and Vpeak. In conclusion, both units could be used with confidence to measure these variables during training and match play.