Calculating Load and Intensity Using Muscle Oxygen Saturation Data.

The study aimed to calculate training intensity and load using muscle oxygen saturation (SmO2) during two differentiated physical tasks. 29 university athletes participated in a 40-m Maximal Shuttle Run Test (MST, 10 × 40-m with 30 s recovery between sprints) and a 3000-m time trial run. Distance and time were used to calculate external load (EL). Internal load indicators were calculated based on percentage of maximum heart rate (%HRMAX) and SmO2 variables: muscle oxygen extraction (∇%SmO2) and the cardio-muscle oxygen index (CMOI) was also provided by relating ∇%SmO2 ÷ %HRMAX, and the training load were calculated as the product of speed (m/min × IL) and the efficiency index [Effindex (m/min ÷ IL)]. A student t test was applied based on Bayesian factor analysis. As expected, EL differed in the 40-m MST (331 ± 22.8) vs. 3000-m trials (222 ± 56.8) [BF10 = 6.25e+6; p = <0.001]. Likewise, IL showed higher values in 40-m MST (39.20 ± 15.44) vs. 3000-m (30.51 ± 8.67) in CMOI: [BF10 = 1.70; p = 0.039]. Training load was greater in 40-m MST (85.77 ± 27.40) vs. 3000-m (15.55 ± 6.77) [(m/min × ∇%SmO2): BF10 = 12.5; p = 0.003] and 40-m MST (129.27 ± 49.44) vs. 3000-m (70.63 ± 32.98) [(m/min × CMOI): BF10 = 169.6; p = <0.001]. Also, the Effindex was higher in 40-m MST (10.19 ± 4.17) vs. 3000-m (6.06 ± 2.21) [(m/min × ∇%SmO2): BF10 = 137.03; p = <0.001] and 40-m MST (9.69 ± 4.11) vs. 3000-m (7.55 ± 1.87) [(m/min × CMOI): BF10 = 1.86; p = 0.035]. This study demonstrates calculations of training intensity and load based on SmO2 as an internal load indicator along with speed as an external load indicator during two differentiated exercises.

Effect of COVID-19 on Key Performance Indicators of Spanish Professional Soccer League.

The unprecedented COVID-19 health crisis severely disrupted global sports in 2020, prompting lengthy suspensions followed by resumed competitions under abnormal behind-closed-doors conditions without fans. These disruptions necessitated tactical adaptations by coaches and teams, attempting to still achieve successful outcomes. This study investigates the pandemic's impacts on performance metrics and indicators within Spanish professional soccer. Utilizing systematic notational analysis, 760 match cases from the 2019-2020 La Liga season were examined, comprising 27 matchdays from the pre-COVID context and 11 after resumption. Multivariate tests identified significant pre/post differences and interactions for various technical indicators including shots, cards, corners, and offside calls. The pandemic was associated with a reduction from 12 to just 5 identifiable playing styles, suggestive of increased conservatism featuring more passive play, limited attacking depth, and horizontal ball movement. Such tactical changes appear provoked by condensed fixture scheduling post-lockdown, the lack of supportive crowds, and compromised player fitness/recovery. By quantifying these COVID-precipitated changes, the analysis provides tangible evidence for coaches to make informed adjustments in training and preparation for functioning effectively in disrupted environments. The findings emphasize that versatility and flexibility will be vital to optimize performance during times of unprecedented uncertainty.

Intensity Thresholds for External Workload Demands in Basketball: Is Individualization Based on Playing Positions Necessary?

Currently, basketball teams use inertial devices for monitoring external and internal workload demands during training and competitions. However, the intensity thresholds preset by device manufacturers are generic and not adapted for specific sports (e.g., basketball) and players' positions (e.g., guards, forwards, and centers). Using universal intensity thresholds may lead to failure in accurately capturing the true external load faced by players in different positions. Therefore, the present study aimed to identify external load demands based on playing positions and establish different intensity thresholds based on match demands in order to have specific reference values for teams belonging to the highest competitive level of Spanish basketball. Professional male players (n = 68) from the Spanish ACB league were monitored during preseason official games. Three specific positions were used to group the players: guards, forwards, and centers. Speed, accelerations, decelerations, impacts/min, and player load/min were collected via inertial devices. Two-step clustering and k-means clustering categorized load metrics into intensity zones for guards, forwards, and centers. Guards covered more distance at high speeds (12.72-17.50 km/h) than forwards and centers (p < 0.001). Centers experienced the most impacts/min (p < 0.001). Guards exhibited greater accelerations/decelerations, albeit mostly low magnitude (p < 0.001). K-means clustering allowed the setting of five zones revealing additional thresholds. All positions showed differences in threshold values (p < 0.001). The findings provide insights into potential disparities in the external load during competition and help establish position-specific intensity thresholds for optimal monitoring in basketball. These data are highly applicable to the design of training tasks at the highest competitive level.

Crucial workload variables in female-male elite Brazilian Beach Handball: An exploratory factor analysis.

This study aimed to identify the most important variables of male and female beach handball workload demands and compare them by sex. A total of 92 elite Brazilian beach handball players (54 male: age 22.1 ± 2.6 years, height 1.8 ± 0.5 m, weight 77.6 ± 13.4 kg; and 38 female: age 24.4 ± 5.5 years, height 1.7 ± 0.5 m, weight 67.5 ± 6.5 kg) were analyzed in 24 official matches during a four-day congested tournament. From 250 variables measured by the inertial measurement unit, fourteen were extracted for analysis using Principal Component Analysis as selection criteria. Five Principal Components (PC) were extracted that explained 81.2-82.8% of total variance (overview of workload demands during beach handball). Specifically, 36.2-39.3% was explained by PC1 (DistanceExpl, Distance, Distance4-7 km/h, and Acc), 15-18% by PC2 (AccMax, Acc3-4 m/s, Dec4-3 m/s), 10.7-12.9% by PC3 (JumpsAvg Take-Off, JumpsAvg Landing and PLRT), 8-9.4% by PC4 (Distance> 18.1 km/h, SpeedMax), and 6.7-7.7% by PC5 (HRAvg and Step Balance). Sex-related differences were found in the PC distribution of variables, as well as in selected variables (HRAvg, Dec4-3 m/s, Acc3-4 m/s, JumpsAvg Take-Off, JumpsAvg Landing, AccMax, Distance, Distance4-7 km/h, Acc, SpeedMax) with higher values in male players (p < .05). In conclusion, the sex-related PC distribution and workload demands in beach handball should consider for training design and injury prevention programs.

What Is the Most Sensitive Test to Identify Fatigue through the Analysis of Neuromuscular Status in Male Elite Futsal Players?

The present study aimed to determine which of the neuromuscular status (NMS) monitoring tests (1: Counter-movement jump, CMJ; 2: back squat with additional load) is the most sensitive and effective for evaluating the state of fatigue in futsal players during the preseason. Seventeen professional futsal players were recruited for this study (age: 23.07 ± 6.76 years; height: 1.75 ± 0.06 m; body mass: 75.47 ± 7.47 kg; playing experience in elite: 5.38 ± 2.03 years). All of them were evaluated during the preseason phase in two tests (CMJ and back squat with additional load) before and after each training session (pre- vs. post-test). A jump platform was used to extract jump height during CMJ, while a linear position transducer was used to extract mean velocity (MV) and mean propulsive velocity (MPV) during the back squat exercise. Significant differences were obtained for intra-subject analysis for MV and MPV in loaded back squat exercise (p < 0.001), finding lower values during the post-test. In conclusion, the monitoring of NMS through the back squat provides greater sensitivity and objectivity in comparison with CMJ, due to a more direct neuromuscular extrapolation to the physical demands of futsal.

Accuracy and reliability of inertial devices for load assessment during flywheel workout / Precisión y confiabilidad de los dispositivos inerciales para la evaluación de la carga durante entrenamiento con polea cónica

Abstract There is currently an increase in inertial flywheel application in strength training; thus, it must be monitored by an accurate and reliable device. The present study tested: (1) the accuracy of an inertial measurement device (IMU) to correctly measure angular velocity and (2) its inter-unit reliability for the measurement of external load. The analysis was performed using Pearson Correlation and Intraclass Correlation Coefficient (ICC). The IMU accuracy was tested using Bland-Altman and the reliability with the coefficient of variation (CV). Ten elite-level football players performed ten series of 5 repetitions in a one-hand standing row exercise (5 series with each arm). A nearly perfect accuracy (ICC=.999) and a very good between-device reliability (Bias=-.010; CV=.017%) was found. IMU is a reliable and valid device to assess angular velocity in inertial flywheel workout objectively.

Resumen Actualmente, hay un aumento en la utilización de la polea cónica en el entrenamiento de fuerza; por lo tanto, es necesario monitorearlo con un dispositivo preciso y confiable. El presente estudio probó: (1) la precisión de un dispositivo de medición inercial (IMU), para medir correctamente la velocidad angular y (2) su confiabilidad entre unidades para la medición de carga externa. El análisis se realizó utilizando la correlación de Pearson y el Coeficiente de Correlación Intra-clase (CCI). La precisión de la IMU se probó usando Bland-Altman y la confiabilidad con el Coeficiente de Variación (CV). Diez jugadores de fútbol de nivel élite realizaron 10 series de 5 repeticiones en un ejercicio de fila de pie con una mano (5 series con cada brazo). Se encontró una precisión casi perfecta (ICC = .999) y una muy buena confiabilidad entre dispositivos (Sesgo = -. 010; CV = .017%). IMU´s es un dispositivo confiable y válido para evaluar objetivamente la velocidad angular en el entrenamiento inercial de la polea cónica.

Resumo Atualmente, há um aumento na utilização da polia cônica no treinamento de força; portanto, é necessário monitorá-lo com um dispositivo preciso e confiável. O presente estudo testou: (1) a precisão de um dispositivo de medição inercial (IMU), para medir corretamente a velocidade angular e (2) sua confiabilidade interunidades para medição de carga externa. A análise foi realizada por meio da correlação de Pearson e do Coeficiente de Correlação Intraclasse (ICC). A precisão do IMU foi testada usando Bland-Altman e a confiabilidade com o Coeficiente de Variação (CV). Dez jogadores de futebol de elite realizaram 10 séries de 5 repetições em um exercício de linha em pé com uma mão (5 séries com cada braço). Foi encontrado uma precisão quase perfeita (ICC = 0,999) e confiabilidade entre dispositivos muito boa (Bias = - 0,010; CV = 0,017%). IMU's é um dispositivo confiável e válido para avaliar objetivamente a velocidade angular no treinamento inercial da polia cônica.

Effect of training day, match, and length of the microcycle on workload periodization in professional soccer players: a full-season study.

The aims of this study were to: (a) describe and compare the volume and intensity from the workload of professional soccer players between training and MD, and (b) analyse the effect that the length of the microcycle had on the workload. A cohort study was designed for a full season in La Liga 123. Wearable tracking systems collected the distance covered in meters (m), total number of high-intensity accelerations (ACCHIGH) and decelerations (DECHIGH), total number of high-speed running actions (HSRA), high-speed running distance (HSRD), high metabolic load distance (HMLD), and player load (PL) from training days (MD+1, MD-4, MD-3, MD-2, and MD-1) and MD. Significant differences were found between training and MD workload, MD workload being the most demanding for all intensity and volume variables (F = 36.35-753.94; p < 0.01; wp 2 = 0.21-0.85). The greatest training intensity and volume were found on MD-4 and MD-3 (p < 0.05). In addition, a novel finding was that the length of the microcycle had a significant effect on the workload both in volume and intensity (F = 4.84-14.19; p < 0.01; wp 2 = 0.03-0.09), except for relative ACCHIGH, DECHIGH, and HMLD. Although MD-4 and MD-3 were the most suitable days for loading the players, the results showed that MD elicited a unique stimulus in terms of volume and intensity. Consequently, coaches need to include specific training drills to adapt the players for the competitive demands. Finally, special focus should be placed on MD from short and regular microcycles (5-day, 6-day, or 7-day microcycles) since declines in physical performance were observed in comparison with long microcycles (8-day or 9-day microcycles).

Individualization of Intensity Thresholds on External Workload Demands in Women's Basketball by K-Means Clustering: Differences Based on the Competitive Level.

In previous studies found in the literature speed (SP), acceleration (ACC), deceleration (DEC), and impact (IMP) zones have been created according to arbitrary thresholds without considering the specific workload profile of the players (e.g., sex, competitive level, sport discipline). The use of statistical methods based on raw data could be considered as an alternative to be able to individualize these thresholds. The study purposes were to: (a) individualize SP, ACC, DEC, and IMP zones in two female professional basketball teams; (b) characterize the external workload profile of 5 vs. 5 during training sessions; and (c) compare the external workload according to the competitive level (first vs. second division). Two basketball teams were recorded during a 15-day preseason microcycle using inertial devices with ultra-wideband indoor tracking technology and microsensors. The zones of external workload variables (speed, acceleration, deceleration, impacts) were categorized through k-means clusters. Competitive level differences were analyzed with Mann-Whitney's U test and with Cohen's d effect size. Five zones were categorized in speed (<2.31, 2.31-5.33, 5.34-9.32, 9.33-13.12, 13.13-17.08 km/h), acceleration (<0.50, 0.50-1.60, 1.61-2.87, 2.88-4.25, 4.26-6.71 m/s2), deceleration (<0.37, 0.37-1.13, 1.14-2.07, 2.08-3.23, 3.24-4.77 m/s2), and impacts (<1, 1-2.99, 3-4.99, 5-6.99, 7-10 g). The women's basketball players covered 60-51 m/min, performed 27-25 ACC-DEC/min, and experienced 134-120 IMP/min. Differences were found between the first and second division teams, with higher values in SP, ACC, DEC, and IMP in the first division team (p < 0.03; d = 0.21-0.56). In conclusion, k-means clustering can be considered as an optimal tool to categorize intensity zones in team sports. The individualization of external workload demands according to the competitive level is fundamental for designing training plans that optimize sports performance and reduce injury risk in sport.

Comparative external workload analysis based on the new functional classification in cerebral palsy football 7-a-side. A full-season study.

The evolution of functional classification (FT) is important for promoting competitive balance. Technological advances allow the objective monitoring of competitive demands that is required to manage and individualize workloads. Therefore, this study aimed to characterize external workload in all matches from the 2018/2019 season of the CPF7 Spanish National League and to compare demands based on the new FT (FT1, FT2 yFT3) in time-motion (locomotion and speed changes) and accelerometer-based workload (impacts). Statistical analysis was composed of one-way ANOVA with Bonferroni post-hoc and omega partial squared effect size. Differences were found among all FT in total distance, running, high-intensity, sprinting, very high accelerations and decelerations (FT3> FT2> FT1; p < .01; ωp2= 0.29-to-0.43); and with respect to the highest functional limitation (FT3 = FT2> FT1) in maximum sprinting, moderate-high accelerations and decelerations, total impacts and at very-low intensity (ωp2= 0.13-to-0.29). In conclusion, FT3 players presented a physical advantage with respect to FT2-FT1 players in competition, especially in high-intensity actions that are crucial in team-sports performance. The present results facilitate designing specific training workloads according to FT, players' disability and competition demands, being the first approach to characterize match demands with inertial devices based on the new FT.

Effect of training day, match, and length of the microcycle on the worst-case scenarios in professional soccer players.

This study aimed to describe in-season worst-case scenarios (WCS) of professional soccer players and compare the WCS between training and match days (MD), considering the length of microcycle. A cohort study was designed for four competitive mesocycles in LaLiga123. The WCS of distance covered (DIS), high-speed running distance (HSRD), and sprinting distance (SPD) for four different WCS durations (1', 3', 5', 10') were analysed. Statistical differences between the WCS from training and MD were found at all intensities and periods. The magnitude of differences was moderate in DIS-1' (F= 15.49; p< 0.01; ωp2= 0.09) and DIS-3' (F= 20.99; p< 0.01; ωp2= 0.12), and high in the rest of variables (F= 26.53-89.41; p< 0.01; ωp2= 0.15-0.38). Specifically, the WCS from MD reported the highest values at all intensities and periods. Regarding training days, the greatest WCS of DIS, HSRD, and SPD were found on MD-4, MD-3, and MD+1. Considering the length of microcycle, significant differences (p< 0.05) in training-days' WCS, but not in MD (p> 0.05). In conclusion, specific WCS training programmes (e.g., including 1 min to 10-min training drills in MD-4) may be useful to prepare the demands required on MD.

Characterization and sex-related differences in the multi-location external workload profile of semiprofessional basketball players. A cross-sectional study.

Commonly, the monitoring of external workload has been performed using a single device on player's scapulae. The human body is a complex multi-articular system and quantification in a single location is insufficient, being necessary the assessment in multiple body locations simultaneously. Therefore, this study aimed to characterize the multi-location external workload in men's and women's players and to analyze the sex-related differences during the most common movements in basketball. Twenty-six semi-professional basketball players (n = 13 men, n = 13 women) were evaluated in five tests: linear and curvilinear movements, changing of speed, jumping and in-game movements. PlayerLoadRT was evaluated at six anatomical locations simultaneously (scapulae, lumbar region, knees, and ankles) with WIMU PROTM inertial devices attached to the athlete using a full-body skinsuit. Statistical analysis was composed of a t-test of independent measures and Cohens d effect size. The main results indicated: (1) the type of movement modified the external workload supported by the musculoskeletal structures; (2) sex-related differences were found in the vertical absorption of external workload (p < 0.05); (3) no sex-related differences were shown in the horizontal profile (p > 0.16). The multi-location monitoring will allow the identification of musculoskeletal structures with high vertical absorption of external load depending on sex (men > women: scapulae-lumbar and knee-ankle; women > men: lumbar-knee) and type of movement (scapulae-lumbar: decelerations; lumbar-knee: jumping; knee-ankle: in-game), just like horizontal differences in lower limb (outer > inner leg: curvilinear). Equally movements distribution throughout training sessions, strengthening and recovery programmes of high-workload muscle groups according to player's characteristics could contributed to performance enhancement and reduce injury risk.HIGHLIGHTS Men's and women's basketball players presented different vertical musculoskeletal absorption of external workload. Men presented higher absorption in scapulae - lumbar and knee - ankle segments while women did so in the lumbar - knee segment.The type of movements had a direct effect in the multi-location external workload profile.A combined effect of sex and type of movement was found in the vertical musculoskeletal absorption of the external workload profile.No sex-related differences were found in the horizontal profile regarding the type of movement.

Exploring Physical Fitness Profile of Male and Female Semiprofessional Basketball Players through Principal Component Analysis-A Case Study.

Basketball is a sport in continuous evolution, being one of these key aspects of the players' physical fitness that has an impact on the game. Therefore, this study aimed to characterize and identify the physical fitness level and profiles of basketball players according to sex. Total of 26 semi-professional basketball players were assessed (13 male, 13 female) through inertial devices in different previously validated fitness tests. T-test for independent samples and principal component analysis were used to analyze sex-related differences and to identify physical fitness profiles. The results showed differences according to sex in all physical fitness indexes (p < 0.01; d > 1.04) with higher values in males, except in accelerometer load during small-sided games (p = 0.17; d < 0.20). Four principal components were identified in male and female basketball players, being two common ([PC1] aerobic capacity and in-game physical conditioning, [PC4 male, PC3 female] unipodal jump performance) and two different profiles (male: [PC2] bipodal jump capacity and acceleration, [PC3] curvilinear displacement; female: [PC2] bipodal jump capacity and curvilinear displacement, [PC4] deceleration). In conclusion, training design must be different and individualized according to different variables, including physical fitness profiles between them. For practical applications, these results will allow knowing the advantages and weaknesses of each athlete to adapt training tasks and game systems based on the skills and capabilities of the players in basketball.

Multi-Location External Workload Profile in Women's Basketball Players. A Case Study at the Semiprofessional-Level.

The external workload measured in one anatomical location does not determine the total load supported by the human body. Therefore, the purpose of the present study was to characterize the multi-location external workload through PlayerLoadRT of 13 semi-professional women's basketball players, as well as to analyze differences among anatomical locations (inter-scapulae line, lumbar region, 2× knee, 2× ankle) and laterality (left vs. right) during five tests that represent the most common movements in basketball-(a) linear locomotion, 30-15 IFT; (b) acceleration and deceleration, 16.25-m RSA (c) curvilinear locomotion, 6.75-m arc (d) jump, Abalakov test (e) small-sided game, 10' 3 vs. 3 10 × 15-m. Statistical analysis was composed of a repeated-measures t-test and eta partial squared effect size. Regarding laterality, differences were found only in curvilinear locomotion, with a higher workload in the outer leg (p < 0.01; ηp2 = 0.33-0.63). In the vertical profile, differences among anatomical locations were found in all tests (p < 0.01; ηp2 = 0.56-0.98). The nearer location to ground contact showed higher values except between the scapulae and lumbar region during jumps (p = 0.83; ηp2 = 0.00). In conclusion, the multi-location assessment of external workload through a previously validated test battery will make it possible to understand the individual effect of external workload in each anatomical location that depends on the type of locomotion. These results should be considered when designing specific strategies for training and injury prevention.

Assessment of the Multi-Location External Workload Profile in the Most Common Movements in Basketball.

The present study analyzed the multi-location external workload profile in basketball players using a previously validated test battery and compared the demands among anatomical locations. A basketball team comprising 13 semi-professional male players was evaluated in five tests (abilities/skills/tests): (a) aerobic, linear movement, 30-15 IFT; (b) lactic anaerobic, acceleration and deceleration, 16.25 m RSA (c) alactic anaerobic, curvilinear movement, 6.75 m arc (d) elastic, jump, Abalakov test (e) physical-conditioning, small-sided game, 10' 3 vs.3 10 × 15 m. PlayerLoadRT was evaluated at six anatomical locations simultaneously (interscapular line, lumbar region, knees and ankles) by six WIMU PROTM inertial devices attached to the player using an ad hoc integral suit. Statistical analysis was composed of an ANOVA of repeated measures and partial eta squared effect sizes. Significant differences among anatomical locations were found in all tests with higher values in the location nearer to ground contact (p < 0.01). However, differences between lower limb locations were only found in curvilinear movements, with a higher workload in the outside leg (p < 0.01). Additionally, high between-subject variability was found in team players, especially at lower limb locations. In conclusion, multi-location evaluation in sports movements will make it possible to establish an individual external workload profile and design specific strategies for training and injury prevention programs.

Accuracy of Xiaomi Mi Band 2.0, 3.0 and 4.0 to measure step count and distance for physical activity and healthcare in adults over 65 years.

BACKGROUND: The measurement of step count and distance covered are of interest in healthcare and rehabilitation medicine, so fitness trackers and smartwatches have incorporated these metrics. In 2014, the introduction of new brands of these devices peaked, although the highest number of new devices was introduced in 2015. Even though Mi Band Xiaomi was among the top 5 regarding sales, it is not at the top of the fitness bands considered in research articles. RESEARCH QUESTION: this study aimed to assess the validity of Xiaomi Mi Band 2.0, 3.0 and 4.0 for recording steps and distance covered. METHOD: The data were recorded from 26 elderly adults (71.2 ± 3.2 years old; 169.3 ± 5.8 height; 72.1 ± 9.2 weight), who covered the maximum distance possible at walking speed in a delimited outdoor space following different trajectories to compare data with the criterion measure, using three wristband devices (Xiaomi Mi Band versions 2.0, 3.0. and 4.0.). RESULTS: In step count, the average bias was small (<2.6 steps) and no statistical differences were found between instruments (p > 0.76; t=0.30). However, Xiaomi Mi Band 4.0 obtained questionable validity (ICC = 0.76) for distance estimation. SIGNIFICANCE: The accuracy of Mi Band Xiaomi 2.0., 3.0. and 4.0. may be considered as good to count the number of steps for physical activity monitoring, whereas distance estimation is considered questionable.

Training Design, Performance Analysis, and Talent Identification-A Systematic Review about the Most Relevant Variables through the Principal Component Analysis in Soccer, Basketball, and Rugby.

Since the accelerating development of technology applied to team sports and its subsequent high amount of information available, the need for data mining leads to the use of data reduction techniques such as Principal Component Analysis (PCA). This systematic review aims to identify determinant variables in soccer, basketball and rugby using exploratory factor analysis for, training design, performance analysis and talent identification. Three electronic databases (PubMed, Web of Science, SPORTDiscus) were systematically searched and 34 studies were finally included in the qualitative synthesis. Through PCA, data sets were reduced by 75.07%, and 3.9 ± 2.53 factors were retained that explained 80 ± 0.14% of the total variance. All team sports should be analyzed or trained based on the high level of aerobic capacity combined with adequate levels of power and strength to perform repeated high-intensity actions in a very short time, which differ between team sports. Accelerations and decelerations are mainly significant in soccer, jumps and landings are crucial in basketball, and impacts are primarily identified in rugby. Besides, from these team sports, primary information about different technical/tactical variables was extracted such as (a) soccer: occupied space, ball controls, passes, and shots; (b) basketball: throws, rebounds, and turnovers; or (c) rugby: possession game pace and team formation. Regarding talent identification, both anthropometrics and some physical capacity measures are relevant in soccer and basketball. Although overall, since these variables have been identified in different investigations, further studies should perform PCA on data sets that involve variables from different dimensions (technical, tactical, conditional).

Impact of high-heeled and sport shoes on multi-joint external load profile during walking.

BACKGROUND: Previous studies have analysed the effect of wearing high-heeled shoes (HHS) on gait analysis, balance and its relation to health. However, further research is needed to study its effect on the difference of chain reactions in the transfer of body impacts from the lower to the upper limbs. OBJECTIVES: The aims of the present research were: (a) to compare the effects of wearing HHS on impacts across body joints during walking with sport shoes (SS) as a reference, and (b) to examine such effects at different speeds. METHODS: Seven well-trained women completed this study. Incremental treadmill walking test were performed with two different footwear: SS and HHS. Inertial devices were used to quantify the chain reactions at selected anatomical lower limbs and trunk locations. Statistical analysis included the Wilcoxon test with ranges and Cohen's d effect size with percentage of differences. RESULTS: The highest values were found at the heel in both footwear and in both legs (SS: right =0.76 ± 0.27, left = 0.79 ± 0.27; HHS: right = 1.07 ± 0.38, left = 1.11 ± 0.41), while the lowest values were registered at lower and upper back. Furthermore, significant differences were found with the HHS load being higher at all locations (p< 0.05; %=𝑑𝑖𝑓𝑓 12.20-36.36%), influenced by the walking speed. In addition, a strong influence of footwear in the change of the laterality profile was found (p< 0.05). CONCLUSIONS: These findings suggest that the use of HHS increase the load on the lower limb and the trunk. Until reaching 5 km/h during walking, no significant differences were found between wearing HHS or SS in accelerometer load, producing exponential differences from this speed. The great between-subject variability implies that within-subject analysis is recommended, as it is more related to real clinical practice.

Impact of contextual variables on the representative external load profile of Spanish professional soccer match-play: A full season study.

The aims of this study were to: (1) identify the representative external load profile of match-play in Spanish professional soccer players by principal components analysis (PCA), and (2) analyse the effect of match location (home vs away), match outcome (win vs draw vs loss) and length of the microcycle (5 vs 6 vs 7 vs 8 vs 9 days) on the external load profile. Data were collected during one season consisting of 42 matches in LaLiga 123 and 11 external load variables were selected after the PCA. TD, total distance covered; DIS0-6: distance from 0 to 6 km/h; DIS21-24: distance from 21 to 24 km/h; HSRD: high-speed running distance above 21 km/h; HSRA: total of high-speed running actions above 21 km/h; VMAX: maximum speed in km/h; Sprints: total of actions above 24 km/h; ACC: total of accelerations; ACCG-avg: average accelerometer G-force; ACCMAX: maximum acceleration (m/s2); DECMAX: maximum deceleration (m/s2). Match location had an impact on HSRD (p < 0.01; ES = 0.05), DIS0-6 (p < 0.01; ES = 0.05), and ACCMAX (p < 0.01; ES = 0.05). Match outcome had a relation to TD (p < 0.01; ES = 0.05), DIS0-6 (p < 0.01; ES = 0.05) and HSRD (p < 0.01; ES = 0.05). Length of the microcycle had an impact on TD (p < 0.01; ES = 0.05), DIS0-6 (p < 0.01; ES = 0.11), ACC (p < 0.01; ES = 0.04) and VMAX (p < 0.01; ES = 0.04). This study provides coaches a selection of variables for match-play analysis, which could represent two-thirds of external load profile. Then, professionals should consider that these contextual variables could have an impact on the external load profile.

Worst case scenario match analysis and contextual variables in professional soccer players: a longitudinal study.

This study aimed to describe the worst-case scenarios (WCS) of professional soccer players by playing position in different durations and analyse WCS considering different contextual variables (match half, match location and match outcome). A longitudinal study was conducted in a professional soccer team. Data were collected from different WCS durations in the total distance (TD), high-speed running distance (HSRD), and sprinting distance (SPD). A mixed analysis of variance was performed to compare different WCS durations between playing positions and contextual variables, making pairwise comparisons by Bonferroni post hoc test. Positional differences were found for TD (p < 0.01, ω p 2 = 0.02), HSRD (p < 0.01, ω p 2 = 0.01) and SPD (p < 0.01, ω p 2 = 0.02). There was a significant interaction when comparing WCS by match half in TD (F = 6.1, p < 0.01, ω p 2 = 0.07) but no significant differences in HSRD (p = 0.403, ω p 2 = 0) or SPD (p = 0.376, ω p 2 = 0). A significant interaction was identified when comparing WCS by match location in TD (F = 51.5, p < 0.01, ω p 2 = 0.14), HSRD (F = 19.15, p < 0.01, ω p 2 = 0.05) and SPD (F = 8.95, p < 0.01, ω p 2 = 0.01) as well as WCS by match outcome in TD (F = 36.4, p < 0.01, ω p 2 = 0.08), HSRD (F = 13.6, p < 0.01, ω p 2 = 0.04) and SPD (F = 7.4, p < 0.01, ω p 2 = 0.02). Positional differences exist in TD, HSRD, and SPD in match-play WCS, and contextual variables such as match half, match location and match outcome have a significant impact on the WCS of professional soccer players.