When Is a Sprint a Sprint? A Review of the Analysis of Team-Sport Athlete Activity Profile

Intensity Zones and Intensity Thresholds Used to Quantify External Load in Competitive Basketball: A Systematic Review

BACKGROUND

Despite widespread use of intensity zones to quantify external load variables in basketball research, the consistency in identifying zones and accompanying intensity thresholds using predominant monitoring approaches in training and games remains unclear.

OBJECTIVES

The purpose of this work was to examine the external load intensity zones and thresholds adopted across basketball studies using video-based time-motion analysis (TMA), microsensors, and local positioning systems (LPS).

METHODS

PubMed, MEDLINE, and SPORTDiscus databases were searched from inception until 31 January 2023 for studies using intensity zones to quantify external load during basketball training sessions or games. Studies were excluded if they examined players participating in recreational or wheelchair basketball, were reviews or meta-analyses, or utilized monitoring approaches other than video-based TMA, microsensors, or LPS.

RESULTS

Following screening, 86 studies were included. Video-based TMA studies consistently classified jogging, running, sprinting, and jumping as intensity zones, but demonstrated considerable variation in classifying low-intensity (standing and walking) and basketball-specific activities. Microsensor studies mostly utilized a single, and rather consistent, threshold to identify only high-intensity activities (> 3.5 m·s-2 for accelerations, decelerations, and changes-in-direction or > 40 cm for jumps), not separately quantifying lower intensity zones. Similarly, LPS studies predominantly quantified only high-intensity activities in a relatively consistent manner for speed (> 18.0 m·s-1) and acceleration/deceleration zones (> 2.0 m·s-2); however, the thresholds adopted for various intensity zones differed greatly to those used in TMA and microsensor research.

CONCLUSIONS

Notable inconsistencies were mostly evident for low-intensity activities, basketball-specific activities, and between the different monitoring approaches. Accordingly, we recommend further research to inform the development of consensus guidelines outlining suitable approaches when setting external load intensity zones and accompanying thresholds in research and practice.

Adapting the percentage intensity method to assess accelerations and decelerations in football: moving beyond absolute and arbitrary thresholds

 We adapted the percentage intensity approach to monitor accelerations and decelerations allowing players' individualisation. Forty-two players were monitored during four microcycles via global navigation satellite system devices. Raw velocity and time data were collected to calculate acceleration and deceleration magnitudes according to specific starting speed intervals, and the efforts intensities were established as very low (<25% of the maximal effort), low (25-50%), moderate (50-75%) and high (>75%). Linear regressions and Pearson correlation (r) analysed the relationship between maximal efforts and starting speeds; additionally, mean paired differences compared efforts magnitudes between subsequent starting speed intervals. Most very low intensity accelerations (86%) and decelerations (79%) started from <5 km.h-1. Correlation between maximal efforts and starting speeds were r = -0.97 (p < .001) for acceleration, and r = -0.94 (p < .01) for deceleration. Maximal acceleration decreased as starting speed increases (very large effect sizes), but deceleration is less starting speed dependent (unclear to large effect sizes). This adaptation allows practitioners to individualise accelerations and decelerations classification during real-life scenarios, leading to a more precise training prescription. The very low intensity interval could be excluded to consider only relevant efforts. Maximal acceleration should be collected for each starting speed interval because accelerations are starting speed dependents.

Determining female-specific high-intensity activity GPS thresholds in women's rugby union: Use of current use of male-derived absolute speed thresholds underestimates true levels

GPS speed thresholds in women's rugby union are usually based on data derived from the men's game. However, evidence suggests the maximum speeds achieved by female players are 2-8 km.h-1 slower and the volume of high-intensity running (HIR) in women's rugby may be underestimated. The aim of the study was to examine the effect of adjusting absolute thresholds on the volume of high-intensity locomotion. GPS units recorded movement data from 58 players across 18 English Premier15 s matches. Distance in HIR and sprint (Spr) zones were calculated using male-derived criteria: AbsMale (HIR >18 km.h-1; Spr ≥21 km.h-1). Two alternative thresholds were compared: AbsFVmax (HIR >16 km.h-1; Spr ≥19 km.h-1); AbsFemale (HIR >14 km.h-1; Spr ≥17 km.h-1). Data were analysed using one-way ANOVA and effect sizes to determine differences in distances between thresholds. AbsMale HIR and Spr distances were 63 ± 71 m and 30 ± 53 m. Significantly greater distances at higher-intensity speeds were observed with female-adjusted thresholds. AbsFVmax: HIR: 139 ± 116 m (p = 0.01, ES 0.80); Spr: 60 ± 90 m (p = 0.131, ES 0.41) and AbsFemale: HIR: 239 ± 157 m (p < 0.01, ES 1.45); Spr: 137 ± 152 m (p < 0.01, ES 0.94). 24 players (41%) achieved speeds greater than the 21 km·h-1 threshold with the male-derived thresholds. At AbsFVmax threshold this increased to 44 (76%) and 100% at the AbsFemale threshold. Existing male-derived thresholds appear to underestimate high-intensity locomotion of female players. With adjusted thresholds, specifically the AbsFemale, the proportional volume of high-intensity activity in the women's game (8.2% total distance) aligns more closely to that observed during men's match-play.

Relationship Between External Training Load and Session Rating of Perceived Exertion Training Impulse in Elite Sprinters

PURPOSE

To quantify the change in session rating of perceived exertion training impulse (RPE-TRIMP) that may occur in response to increased running distance at 3 running velocity ranges in elite sprinters.

METHODS

We monitored training load in elite sprinters (women: n = 7; men: n = 11) using wearable Global Positioning System technology and RPE-TRIMP for a total of 681 individual training sessions during a 22-week competition-preparation period. Internal training load was operationalized by RPE-TRIMP, and external training load was operationalized by distance covered in 3 velocity ranges. A linear mixed-effects model with athlete as a random effect was fit to RPE-TRIMP with total distance covered at ≤69.99% (low-velocity running [LVR]), 70% to 84.99% (high-velocity running [HVR]), and 85% to 100% (very-high-velocity running [VHVR]) of individual maximum velocity.

RESULTS

Increased running distance in all 3 velocity ranges (LVR, HVR, and VHVR) resulted in a significant (P < .001) increase in RPE-TRIMP. Coefficients (95% CIs) were .10 (.08-.11) for LVR, .23 (.18-.28) for HVR, and .44 (.35-.53) for VHVR. A 50-m increase in running distance covered in the LVR, HVR, and VHVR velocity ranges was associated with increases in RPE-TRIMP of 5, 11.5, and 22 arbitrary units, respectively.

CONCLUSIONS

Internal training load, calculated as RPE-TRIMP, increased with increases in total distance covered in the LVR, HVR, and VHVR velocity ranges (P < .001). RPE-TRIMP can be a practical solution for monitoring global training-session load in elite sprinters.

Player Activity and Load Profiling with Hidden Markov Models: A Novel Application in Rugby League

Player movement in rugby league is complex, being spatiotemporal and multifaceted. Modeling this complexity to provide robust measures of player activity and load has proved difficult, with important aspects of player movement yet to be considered. These include the influence of time-varying covariates on player activity and the combination of different dimensions of player movement. Few studies have simultaneously categorized player activity into different activity states and investigated factors influencing the transition between states, or compared player activity and load profiles between matches and training. This study applied hidden Markov models (HMMs)-a data-driven, multivariate approach-to rugby league training and match GPS data to i) demonstrate how HMMs can combine multiple variables in a data-driven way to effectively categorize player movement states, ii) investigate the influence of two time-varying covariates, score difference and elapsed match time on player activity states, and iii) compare player activity and load profiles within and between training and match modalities. HMMs were fitted to player GPS, accelerometer and heart rate data of one English Super League team across 60 training sessions and 35 matches. Distinct activity states were detected for both matches and training, with transitions between states in matches influenced by score difference and elapsed time and clear differences in activity and load profiles between training and matches. HMMs can model the complexity of player movement to effectively profile player activity and load in rugby league and have the potential to facilitate new research across several sports.

Analyzing soccer match sprint distances: A comparison of GPS-based absolute and relative thresholds

This study compared the most common absolute sprint threshold (> 25.2 km/h) with relative and individualized thresholds (> 70%, > 75%, > 80%, > 85% and > 90% of peak match speed). Twenty elite soccer players, competing in the first division of the Portuguese League, were monitored using GNSS equipment during thirty-four official matches. Peak match speed was retrieved as the individual maximal speed reached during the full season. Distances were registered when speed overcame the absolute and the relative thresholds. Mean ± SD of peak speeds and distances covered were calculated, and Pearson correlation (r) and mean paired differences were performed to analyze relationships and differences between thresholds. The peak match speed was 32.9 ± 1.4 km/h. Correlations between distances covered using the absolute and relative thresholds varied from very strong (> 70%: r = 0.84, p < .001; > 75%: r = 0.89, p < .001; and > 80%: r = 0.88, p < .001), strong (> 85%: r = 0.79, p < .001), to moderate (> 90%: r = 0.59, p < .001). Overall, the > 75% (ES: 0.23 [95% CI: 0.16, 0.31]) and the > 90% (ES: -1.65 [95%CI: -1.85, -1.48]) relative thresholds presented the smallest and largest differences, respectively, with the absolute threshold. Differences were also found when considering the playing positions. While the distances covered by central midfielders were similar between the absolute and > 80% thresholds (-0.03 [-0.16, 0.10]), fullbacks covered largely more distance -1.88 [-2.42 -1.50]) in the absolute threshold than in the > 80% threshold. The distances covered by players varied based on the selected threshold, affecting the distances covered by different playing positions. Being the highest speed threshold within displacements thresholds, the absolute sprint threshold showed greater similarity to lower rather than higher relative thresholds.

The Relationship Between Individually Assessed High-Intensity Accelerations, High-Intensity Decelerations, Sprints, and Technical Performances During Soccer Matches: A Full Season Analysis

Purpose: This longitudinal study analyzed the relationship between players' physical (sprint distances, number of high-intensity accelerations and decelerations assessed with individual and relative thresholds) and technical (retrieved from SofaScore platform) performances during competition. Methods: Twenty elite players were monitored across a full season. Physical performances were monitored with GNSS devices, retrieving time (s), velocity (km.h-1) and distance (m). Sprint distances were calculated as > 80% of the match peak speed registered across the season. High-intensity accelerations and decelerations were calculated as >75% of the peak values registered across the season. Pearson (r) correlations (with 95% confidence intervals) were calculated to assess the relationship among different physical performance variables and between the physical and technical performance variables. Results: Sprint distances correlated with the number of ball touches (r = -0.36 [-0.49, -0.23], p < .001), accurate passes (r = -0.45 [-0.56, -0.32], p < .001), and dribble attempts (r = 0.30 [0.16, 0.43], p < .001). If players touched the ball more frequently and pass the ball more accurately, they covered shorter sprint distances. However, if players attempted more dribbles, they covered longer sprint distances. Conclusion: Practitioners can develop tactical strategies considering the relationship between sprint distances and technical variables such as ball touches, accurate passes, and dribble attempts.

Internal and External Load Profile during Beach Invasion Sports Match-Play by Electronic Performance and Tracking Systems: A Systematic Review

Beach variants of popular sports like soccer and handball have grown in participation over the last decade. However, the characterization of the workload demands in beach sports remains limited compared to their indoor equivalents. This systematic review aimed to: (1) characterize internal and external loads during beach invasion sports match-play; (2) identify technologies and metrics used for monitoring; (3) compare the demands of indoor sports; and (4) explore differences by competition level, age, sex, and beach sport. Fifteen studies ultimately met the inclusion criteria. The locomotive volumes averaged 929 ± 269 m (average) and 16.5 ± 3.3 km/h (peak) alongside 368 ± 103 accelerations and 8 ± 4 jumps per session. The impacts approached 700 per session. The heart rates reached 166-192 beats per minute (maximal) eliciting 60-95% intensity. The player load was 12.5 ± 2.9 to 125 ± 30 units. Males showed 10-15% higher external but equivalent internal loads versus females. Earlier studies relied solely on a time-motion analysis, while recent works integrate electronic performance and tracking systems, enabling a more holistic quantification. However, substantial metric intensity zone variability persists. Beach sports entail intermittent high-intensity activity with a lower-intensity recovery. Unstable surface likely explains the heightened internal strain despite moderately lower running volumes than indoor sports. The continued integration of technology together with the standardization of workload intensity zones is needed to inform a beach-specific training prescription.

If You Want to Prevent Hamstring Injuries in Soccer, Run Fast: A Narrative Review about Practical Considerations of Sprint Training

Hamstring strain injuries (HSIs) are one of the most common injuries in sprint-based sports. In soccer, the ability to sprint is key, not only because of its relation to performance but also due to its possible protective effect against HSIs. Although many authors have focused on the "how", "when", and "what" training load should be implemented, there is a lack of practical proposals for sprint training in a high-level professional environment. The objective of this narrative review is, after a deep review of the scientific literature, to present a practical approach for sprint training, trying to answer some of the questions that most strength and conditioning coaches ask themselves when including it in soccer. Once the literature published on this topic was reviewed and combined with the practical experience of the authors, it was concluded that sprint training in soccer, although it presents an obvious need, is not something about which there is methodological unanimity. However, following the practical recommendations from this narrative review, strength and conditioning coaches can have a reference model that serves as a starting point for optimal management of the internal and external training load when they wish to introduce sprint training in the competitive microcycle in professional soccer players, with the aim of reducing HSIs.

The use of wearable resistance and weighted vest for sprint performance and kinematics: a systematic review and meta-analysis

Wearable resistance (WR) and weighted vests (WV) can be used in almost all training conditions to enhance sprint performance; however, positioning and additional mass are different in WV and WR strategies, affecting performance and kinematics differently. We aimed to systematically review the literature, searching for intervention studies that reported the acute or chronic kinematic and performance impact of WV and WR and comparing them. We analyzed Pubmed, Embase, Scopus, and SPORTDiscuss databases for longitudinal and cross-over studies investigating sprint performance or kinematics using an inverse-variance with a random-effect method for meta-analysis. After the eligibility assessment, 25 studies were included in the meta-analysis. Cross-over WR and WV studies found significantly higher sprint times and higher ground contact times (CT) compared to unloaded (UL) conditions. However, WR presented a lower step frequency (SF) compared to UL, whereas WV presented a lower step length (SL). Only one study investigated the chronic adaptations for WR, indicating a superiority of the WR group on sprint time compared to the control group. However, no difference was found chronically for WV regarding sprint time, CT, and flight time (FT). Our findings suggest that using WV and WR in field sports demonstrates overload sprint gesture through kinematic changes, however, WR can be more suitable for SF-reliant athletes and WV for SL-reliant athletes. Although promising for chronic performance improvement, coaches and athletes should carefully consider WV and WR use since there is no supporting evidence that WV or WR will impact sprint performance, CT, and FT.

The influence of match status on the conditional characteristics of tactical sprint actions in professional soccer players

This study aimed to analyse the influence of the match status on the conditional characteristics of tactical sprint actions among Spanish professional soccer players, considering playing positions. Thirty-two Spanish male professional soccer players from a LaLiga Spanish Second Division (LaLiga SmarthBank) team participated in this study. Actions above 85% of the players' maximum velocity were analysed based on their tactical purpose. These findings provide valuable information regarding the tactical aspects of sprinting in soccer, emphasizing the influence of playing positions and match status on the distribution of tactical sprint actions. No effects of match status were observed for any game phase. However, when tactical actions were individually studied, it was observed that the maximum velocity in Chase actions was higher when the team was winning, while in Press actions, the maximum velocity was higher when the team was losing and in in Run in behind/Penetrate, the maximum velocity was higher in drawing situations compared to losing situations. No effects of match status on the distance covered during sprinting were observed, and regarding duration, significant differences were only observed in Recovery run actions. In addition, the influence of match status is higher when playing positions are considered, although the within playing positions analysis revealed significant differences only in CM players. These findings provide valuable information for the design of specific training drills considering playing positions, suggesting the need to analyse the previous match in order to structure the training load of the microcycle in a comprehensive manner.

Engineering Features from Raw Sensor Data to Analyse Player Movements during Competition

Research in field sports often involves analysis of running performance profiles of players during competitive games with individual, per-position, and time-related descriptive statistics. Data are acquired through wearable technologies, which generally capture simple data points, which in the case of many team-based sports are times, latitudes, and longitudes. While the data capture is simple and in relatively high volumes, the raw data are unsuited to any form of analysis or machine learning functions. The main goal of this research is to develop a multistep feature engineering framework that delivers the transformation of sequential data into feature sets more suited to machine learning applications.

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.

Changing the criteria applied to acceleration and deceleration efforts changes the types of player actions detected

This study identified and profiled the types of player actions of Australian football players executed during high acceleration and/or deceleration efforts and identified how the duration exceeding the acceleration or deceleration threshold influenced the identified executed player actions. The commencing speed of the acceleration and deceleration efforts were also assessed. Acceleration and deceleration efforts of 22 Australian football players monitored with a 10-Hz GNSS device across two matches were analysed. Synchronised video footage of the matches was used to identify the player actions executed during acceleration and deceleration efforts. Linear mixed models were conducted to examine the relationship between commencing speed, player action, and duration exceeding the effort threshold. 'Linear movement' and 'jump' were the most frequently executed player actions for high accelerations and 'stop' and 'being tackled' for high decelerations. Significant differences were observed in commencing speed between player actions for the high deceleration efforts. Furthermore, it was found that a higher commencing speed was associated with an increased duration exceeding the deceleration threshold. These findings will help practitioners and researchers with selecting minimum-duration criteria for acceleration and deceleration efforts and provide an understanding of the types of player actions executed during these efforts.

Thoracic-Worn Accelerometers Detect Fatigue-Related Changes in Vertical Stiffness During Sprinting

ABSTRACT

Horsley, BJ, Tofari, PJ, Halson, SL, Kemp, JG, Johnston, RD, and Cormack, SJ. Thoracic-worn accelerometers detect fatigue-related changes in vertical stiffness during sprinting. J Strength Cond Res 38(2): 283-289, 2024-Thoracic-mounted accelerometers are valid and reliable for analyzing gait characteristics and may provide the opportunity to assess running-related neuromuscular fatigue (NMF) during training and competition without the need for additional tests, such as a countermovement jump (CMJ). However, their sensitivity for detecting fatigue-related changes in gait across different speeds is unclear. We, therefore, assessed the changes in accelerometer-derived gait characteristics, including vertical stiffness (K vert ), following a repeated sprint protocol (RSP). Sixteen recreationally active subjects performed single and repeated CMJs on a force plate and 40 m run throughs overground at 3-4, 5-6, and 7-8 m·s -1 pre-post a 12 × 40 m RSP. Gait characteristics (contact time, step frequency, step length, K vert , etc.) were derived from an accelerometer contained within a global navigation satellite system unit on the thoracic spine using a validated algorithm. Changes in running gait and CMJ performance were assessed using a linear mixed-effects model (95% confidence interval [95% CI]; effect size [ES]). Significance was set at p < 0.05. A significant reduction in K vert occurred at 7-8 m·s -1 following the RSP (-8.51 kN·m -1 [-13.9, -3.11]; p = 0.007; ES [95% CI] = -0.39 [-0.62, -0.15]) which coincided with a decreased jump height (-0.03 m [-0.04, -0.01]; p = 0.002; ES [95% CI] = -0.87 [-1.41, -0.30]). However, all other gait characteristics were not significantly different irrespective of speed. Thoracic-worn accelerometers can detect changes in K vert at 7-8 m·s -1 which may be useful for monitoring NMF during sprinting. However, a RSP does not result in altered gait mechanics in subsequent running at lower speeds.

Application of arbitrary and individualized load quantification strategies over the weekly microcycle in professional soccer players

The aims of this study were to: (a) determine the differences in external load quantification between arbitrary and individual speed thresholds over the weekly microcycle in professional soccer players, and (b) analyse the association between internal load and different external load quantification strategies (ELQSs). Ten professional outfield players were monitored during training sessions and official matches using 10 Hz GPS devices over a 6-week in-season period. The absolute and relative ("R" before the distance category) distances covered were calculated for the following external load variables: medium-intensity running distance (MIR), high-intensity running (HIR), sprint distance (SD), and very high-intensity running (VHIR). Individualized thresholds were determined based on maximal sprinting speed (MSS) and the last speed achieved during the 30-15 Intermittent Fitness Test (VIFT) of each player. In terms of match-day workload, significant differences (p < 0.05) were observed between arbitrary and individualized strategies (i.e., MSS and VIFT) for the distance covered in MIR, HIR, SD, VHIR, RHIR, RSD, and RVHIR. The MSS strategy compared to arbitrary thresholds revealed significant differences (p < 0.05) for distance covered in HIR, RHIR, and VHIR during all training sessions. The present results showed that arbitrary thresholds lead to underestimation of external load absolute and relative metrics compared to the MSS strategy throughout the microcycle. The VIFT strategy mainly revealed differences in external load quantification regarding MD compared to arbitrary thresholds. Individualized speed threshold strategies did not achieve better associations with internal load measures in comparison with arbitrary thresholds in professional soccer players.

Quantifying demands on the hamstrings during high-speed running: A systematic review and meta-analysis

INTRODUCTION

Hamstring strain injury (HSI) remains a performance, economic, and player availability burden in sport. High-speed running (HSR) is cited as a common mechanism for HSI. While evidence exists regarding the high physical demands on the hamstring muscles in HSR, meta-analytical synthesis of related activation and kinetic variables is lacking.

METHODS

A systematic search of Medline, Embase, Scopus, CINAHL, SportDiscus, and Cochrane library databases was conducted in accordance with the PRISMA 2020 guidelines. Studies reporting hamstring activation (electromyographic [EMG]) or hamstring muscle/related joint kinetics were included where healthy adult participants ran at or beyond 60% of maximum speed (activation studies) or 4 m per second (m/s) (kinetic studies).

RESULTS

A total of 96 studies met the inclusion criteria. Run intensities were categorized as "slow," "moderate," or "fast" in both activation and kinetic based studies with appropriate relative, and raw measures, respectively. Meta-analysis revealed pooled mean lateral hamstring muscle activation levels of 108.1% (95% CI: 84.4%-131.7%) of maximal voluntary isometric contraction (MVIC) during "fast" running. Meta-analysis found swing phase peak knee flexion internal moment and power at 2.2 Newton meters/kilogram (Nm/kg) (95% CI: 1.9-2.5) and 40.3 Watts/kilogram (W/kg) (95% CI: 31.4-49.2), respectively. Hip extension peak moment and power was estimated as 4.8 Nm/kg (95% CI: 3.9-5.7) and 33.1 W/kg (95% CI: 17.4-48.9), respectively.

CONCLUSIONS

As run intensity/speed increases, so do the activation and kinetic demands on the hamstrings. The presented data will enable clinicians to incorporate more objective measures into the design of injury prevention and return-to-play decision-making strategies.

Improved physical performance of elite soccer players based on GPS results after 4 days of carbohydrate loading followed by 3 days of low carbohydrate diet

BACKGROUND

Carbohydrate loading is an established sports nutrition strategy for endur- 16 ance exercise performance. We tested if carbohydrate loading could improve the performance of 17 elite soccer players under ecologically valid circumstances using Global Positioning System (GPS) data.

METHODS

Twenty-two adult Iran Premier league soccer players were divided into a carbohydrate-loading group (CLG) and Control group (CG). The carbohydrate loading group restricted carbohydrate intake for three days to 1.5 g/kg/d while increasing exercise intensity. From days four to seven, exercise intensity was decreased and carbohydrate intake was considerably increased up to 7.5 g/kg/d on the day of the match, during which performance was analyzed using GPS data. The control group performed the same exercise training but maintained their habitual carbohydrate intake of 5-6 g/kg/d. The data were analyzed using a univariate ANCOVA with baseline data from a pre-intervention match as the control variable.

RESULTS

The carbohydrate loading team scored significantly higher on running distance, maximum speed and the number of top and repeated sprints; the carbohydrate loading group scored significantly lower on player load, metabolic power and running imbalance compared to the control team during their match.

CONCLUSIONS

Our findings suggest carbohydrate loading enabled elite soccer players to achieve greater running outputs with greater metabolic efficiency and lower fatigue compared to their habitual diets.

Linear and Change of Direction Repeated Sprint Ability Tests: A Systematic Review

ABSTRACT

Kyles, A, Oliver, JL, Cahill, MJ, Lloyd, RS, and Pedley, J. Linear and change of direction repeated sprint ability tests: a systematic review. J Strength Cond Res 37(8): 1703-1717, 2023-The ability to repeatedly sprint is important in many sports, but there is no established protocol for measuring repeated sprint ability (RSA). The purpose of this review was to identify overground RSA protocols previously reported in the literature and to recommend standardized protocols. A systematic review of the literature was used to identify studies that have used an RSA test, with data describing protocol design extracted. One hundred eight studies were included in the review, across which 47 unique protocols were identified. Eighteen protocols included at least one change of direction (COD), and this increased mean sprint time compared with linear RSA tests (7.26 ± 1.84 vs. 4.48 ± 1.02 seconds). There was considerable variability across protocols regarding sprint distance (20-40 m), sprint repetitions (3-15), recovery duration (10-60 seconds), recovery type (active vs. passive), and work-to-rest ratio (≤1:1.4-19.2). Separate protocols are needed for linear and COD tests, and these should reflect the brief nature of intense periods of competition and stress the ability to recover. Based on data across studies for protocol design and to ensure a demanding work-to-rest ratio, it is suggested that a linear RSA should comprise 6 × 30 m sprints separated by 15 seconds of active recovery. To provide some parity to linear tests, to keep work duration brief and to maintain a demanding work-to-rest ratio, a COD RSA should comprise 6 × 30 m shuttle sprints (15 + 15 m), providing one change of direction (180° COD), and maintaining a 15-second active recovery.

Arbitrary absolute vs. individualized running speed thresholds in team sports: A scoping review with evidence gap map

The aims of this scoping review were (i) to characterize the main methodological approaches to assessing individualized running speed thresholds in team sports players; (ii) to assess the use of traditional arbitrary (absolute) thresholds compared to individualized running speed thresholds in team sports players; (iii) to provide an evidence gap map (EGM) about the approaches and study designs employed in investigations in team sports and (iv) to provide directions for future research and practical applications for the strength and conditioning field. Methods studies were searched for in the following databases: (i) PubMed; (ii) Scopus; (iii) SPORTDiscus and (iv) Web of Science. The search was conducted on 15/07/2022. Risk of bias was assessed using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). From 3,195 potentially relevant articles, 36 were eligible for inclusion in this review. Of the 36 included articles, 27 (75%) focused on the use of arbitrary and individualized running speed thresholds to describe the locomotor demands (e.g., high intensity running) of players. Thirty-four articles used individualized speed running thresholds based on physical fitness assessments (e.g., 40-m linear sprint) or physical performance (e.g., maximal acceleration). This scoping review supported the need for a greater focus to be placed on improving the methodological aspects of using individualized speed running thresholds in team sports. More than just creating alternatives to arbitrary thresholds, it is essential to increase the replicability of methodological conditions whilst ensuring that research comparing the most adequate measures and approaches to individualization takes into consideration the population and context of each study.

Position-Specific Running and Technical Demands During Male Elite-Junior and Elite-Senior Australian Rules Football Match-Play

ABSTRACT

Jennings, J, Štaka, Z, Wundersitz, DW, Sullivan, CJ, Cousins, SD, Čustović, E, and Kingsley, MI. Position-specific running and technical demands during male elite-junior and elite-senior Australian rules football match-play. J Strength Cond Res 37(7): 1449-1455, 2023-The aim of this study was to compare position-specific running and technical demands of elite-junior and elite-senior Australian rules football match-play to better inform practice and assist transition between the levels. Global positioning system and technical involvement data were collated from 12 Victorian U18 male NAB League ( n = 553) and 18 Australian Football League ( n = 702) teams competing in their respective 2019 seasons. Players were grouped by position as nomadic, fixed, or ruck, and data subsets were used for specific analyses. Relative total distance ( p = 0.635, trivial effect), high-speed running (HSR) distance ( p = 0.433, trivial effect), acceleration efforts ( p = 0.830, trivial effect), deceleration efforts ( p = 0.983, trivial effect), and efforts at >150 m·min -1 ( p = 0.229, trivial effect) and >200 m·min -1 ( p = 0.962, trivial effect) did not differ between elite-junior and elite-senior match-play. Elite juniors covered less total and HSR distance during peak periods (5 seconds-10 minutes) of demand ( p ≤ 0.022, small-moderate effects). Within both leagues, nomadic players had the greatest running demands followed by fixed position and then rucks. Relative disposals ( p = 0.330, trivial effect) and possessions ( p = 0.084, trivial effect) were comparable between the leagues. During peak periods (10 seconds to 2 minutes), elite juniors had less technical involvements than elite seniors ( p ≤ 0.001, small effects). Although relative running demands and positional differences were comparable between the leagues, elite juniors perform less running, HSR, and technical involvements during peak periods when compared with elite seniors. Therefore, coaching staff in elite-senior clubs should maintain intensity while progressively increasing the volume of training that recently drafted players undertake when they have transitioned from elite-junior leagues.

High-intensity Actions in Elite Soccer: Current Status and Future Perspectives

Over the years, soccer has become more physically demanding; the number and frequency of high-intensity actions have increased, and these activities are decisive in determining the match outcome. Importantly, the reductionist approach commonly used to analyze high-intensity actions does not contemplate a more contextualized perspective on soccer performance. Traditionally, most investigations have only provided quantitative data regarding sprints (i. e. time, distances, frequency) without examining "how" (e. g. type of trajectory or starting position) and "why" (e. g. tactical role) soccer players sprint. In fact, other high-intensity actions, apart from running, are not even mentioned (i. e. curve sprints, change of direction, and specific-jump tasks). This has led to the use of tests and interventions that do not accurately reflect real game actions. Given the true technical-tactical-physical demands of each playing position, this narrative review collected a wide-spectrum of current soccer-related articles and provided a discussion regarding high-intensity actions, with a positional-based approach. In this narrative review, practitioners are encouraged to contemplate and consider the different elements that characterize high-intensity actions in soccer, in order to assess and train soccer players under a more sport-specific and integrative perspective.

Relative Individual Sprint in Most Demanding Passages of Play in Spanish Professional Soccer Matches

(1) Background: The objective of this research was to analyse the most demanding passages (MDP) considering the sprint variable relative to the maximum level of sprint ability of each player as a function of player position, final outcome and part of the match during the competitive phase of a professional soccer season. (2) Methods: Global positioning system (GPS) data were collected from 22 players according to their playing position in the last 19 match days of the Spanish La Liga professional soccer in the 2020/2021 season. MDP were calculated from 80% of the maximum sprint speed of each player. (3) Results: Wide midfielders covered the greatest distance at >80% of the maximum speed (2.4 ± 1.63 seg) and the longest duration (21.91 ± 13.35 m) in their MDP. When the whole team was losing, it demonstrated greater distances (20.23 ± 13.04 m) and longer durations (2.24 ± 1.58 seg) compared to games in which it was winning. When the team ended up drawing, the relative sprint distance covered in the second half was significantly greater than in the first (16.12 ± 21.02; SD = 0.26 ± 0.28 (-0.03/-0.54). (4) Conclusions: Different demands of MDP, according to the sprint variable relative to the maximum individual capacity in competition, are required when contextual game factors are considered.

Physical Match Demands of International Women's Rugby Union: A Three-Year Longitudinal Analysis of a Team Competing in The Women's Six Nations Championship

There is a paucity of studies describing the physical match demands of elite international women's rugby union, which limits coaches' ability to effectively prepare players for the physical demands required to compete at the elite level. Global positioning system technologies were used to measure the physical match demands of 53 international female rugby union players during three consecutive Women's Six Nations Championships (2020-2022), resulting in 260 individual match performances. Mixed-linear modelling was used to investigate differences in physical match demands between positions. Significant effects (p < 0.05) of the position were observed for all variables, with the exception of relative distances (m.min^-1) at velocities of 1.01-3.00 m·s^-1 (p = 0.094) and 3.01-5.00 m·s^-1 (p = 0.216). This study provides valuable data on the physical match demands of elite international women's rugby union match play that may aid practitioners in the physical preparation of players to compete at this level. Training methodologies for elite-level female rugby union players should consider the unique demands across positional groups with specific considerations of high-velocity running and collision frequency.

The Contribution of Energy Systems in Repeated-Sprint Protocols: The Effect of Distance, Rest, and Repetition

Purpose: This study aims to investigate the effects of rest intervals, sprint distance, and number of repetitions on performance variables, physiological responses, and energy system contributions in repeated-sprint protocols when total distance variable was the controlled (300 m). Method: Sixteen male soccer players participated in this study. The four protocols, each totaling a distance of 300 m, consisted of the combination of 15 and 30 m sprints with 30 s rest intervals (15meters30sec and 30meters30sec, respectively) and 1:5 work-rest ratios (15meters12sec and 30meters22sec, respectively). Aerobic, glycolytic, and phosphagen energy systems' contributions were calculated from the oxygen consumption (VO2) during the exercise, net lactate production, and the recovery VO2 kinetics using mono-exponential models. Repeated measures ANOVA with the Bonferroni correction was applied to examine the hypothesized differences. Results: The findings indicated that total sprint duration (F3:45=281.14; p<0.001), percentage of performance decline (F3:45=16.58; p<0.001), delta lactate (F3:45=39.72, p<0.001), rating of perceived exertion (F3:45=28.64; p<0.001), energy demand (F3:45=101.6; p<0.001), VO2 during the rest intervals (F3:45=42.72; p<0.001), and the absolute contribution of glycolytic (F3:45=119.6; p<0.001) and phosphagen energy systems (F3:45=72.9; p<0.001) were lowest in the 15meters30sec compared to other protocols. However, the relative contribution of aerobic system was greatest in the 15meters30sec compared to other protocols (F3:45=28.1, p<0.001). Both absolute (F3:45=119.6; p<0.001) and relative contribution of glycolytic system (F3:45=88.5, p<0.001) were greatest in the 30meters22sec compared to other protocols. Conclusion: This study showed that increasing sprint distance when rest interval is equal and decreasing rest interval when sprint distance is equal can increase the glycolytic system contribution.

How do soccer players sprint from a tactical context? Observations of an English Premier League soccer team

The aim of this study was to quantify and tactically contextualise (i.e., phase of play and tactical outcome [TO]) sprints (≥7.0 m/s) of an English Premier League (EPL) soccer team during match-play. Videos of 901 sprints (10 matches) were evaluated using the Football Sprint Tactical-Context Classification System. Sprints occurred within a variety of phases of play (attacking/defensive organisation and transitions) and TOs, both out- and in-possession, with position-specific differences. Most sprints were completed out-possession (58%), with "closing down" the most observed TO (28%). In-possession, "run the channel" (25%) was the most observed TO. Centre backs predominantly performed "ball down the side" sprints (31%), whereas central midfielders mostly performed "covering" sprints (31%). Central forwards and wide midfielders mostly performed "closing down" (23% and 21%) and "run the channel" (23% and 16%) sprints when out- and in-possession, respectively. Full backs most frequently performed "recovery" and "overlap" runs (14% each). This study provides insights into the specific physical-tactical characteristics of sprints performed from an EPL soccer team. This information can be used to assist in the development of position-specific physical preparation programmes, and more ecologically valid and contextualised gamespeed and agility sprint drill construction to better reflect the demands of soccer.

High-speed running and sprinting in professional adult soccer: Current thresholds definition, match demands and training strategies. A systematic review

The aims of this systematic review were (1) to summarize the evidence on absolute velocity thresholds used to classify high-speed running and sprinting, (2) to examine the existing evidence about the individualized thresholds approach, (3) to describe high-speed and sprint running distance match demands, and (4) to provide training strategies for eliciting HSR and sprinting during training sessions in professional adult soccer. This systematic review was conducted following the PRISMA 2020 guidelines. After the authors' screening, 30 studies were included in this review. This review found that, to date, there is no consensus on the absolute thresholds defining high-speed and sprint running in adult soccer players. Until international standards are defined, it is reasonable to set absolute thresholds considering the range of values found in the literature collected in this review. Relative velocity thresholds could be considered for specific training sessions whose goal is to reach near maximal velocity exposure. During official matches, high-speed and sprint running distances ranged from 911 to 1,063 m and 223-307 m, respectively, in professional female soccer players, while ranges from 618 to 1,001 m and 153-295 m, respectively, in professional male soccer players. During training, game-based drills designed in formats using relative areas per player greater than 225 m2 and 300 m2 appear to be adequate for achieving high-speed running and sprinting exposure, respectively, for male players. The combination of game-based, running exercises and soccer circuit-based drills is advisable to ensure adequate high-speed and sprint running exposure both at a team and individual level.

When and How Do Soccer Players From a Semi-Professional Club Sprint in Match Play?

The aims of this study were to investigate the periods in which sprints occurred during official matches and analyze these sprints considering the effect of the playing position and different contextual variables. Electronic performance and tracking systems were used for the analysis of all sprints performed by players. Matches were recorded by video and synchronized with performance tracking data. A total of 252 sprints were analyzed. The greatest frequency of sprints was observed in the period 1 (0’–15’), followed by period 2 (15’–30’) and period 6 (75’–90’), regardless of the playing position (χ2 = 31.35; p = 0.051). Most sprints were non-linear (non-linear sprints: 97.6%; linear sprints: 2.4%) and without ball possession (without ball possession: 95.2%; with ball possession: 4.8%) for all playing positions, but the role of the sprint and the field area in which the sprint occurred were dependent on the position (p < 0.001). Specifically, players covered ~17.55 m per sprint, starting at ~10.34 km/h, reaching ~26.74 km/h, maximally accelerating at ~2.73 m/s2, and decelerating at ~3.61 m/s2. Overall, the playing position and contextual variables had no significant effect on physical performance variables analyzed during these sprints. Therefore, this study allows performance practitioners to have a better understanding of when and how soccer players sprint in match-play. In this regard, this study presents some training and testing strategies that may be considered to improve performance and decrease injury risk.

Responses of soccer players performing repeated maximal efforts in simulated conditions of the FIFA World Cup Qatar 2022: A holistic approach

This study aimed to assess the capacity for repeated maximal effort (RME) of soccer players in the thermo-natural conditions (NC) and in simulated conditions for the 2022 FIFA World Cup in Qatar (QSC). Twenty-four semi-professional soccer players participated in the study. The exercise test consisted of ten 6-second maximal efforts on a cycloergometer. A 90-second passive rest interval was used. The test was performed in a Weiss Technik WK-26 climate test chamber in two different conditions: 1) thermo-neutral conditions (NC-20.5°C; 58.7% humidity); and 2) simulated conditions for the 2022 World Cup in Qatar (QSC-28.5 ± 1.92°C; 58.7 ± 8.64% humidity). Power-related, physiological, psychomotor, blood, and electrolyte variables were recorded. Results showed that (1) players achieved higher peak power (max 1607,46 ± 192,70 [W] - 3rd rep), needed less time to peak power (min 0,95 ± 0,27 [s] - 3rd rep), and had a higher fatigue slope (max 218,67 ± 59,64 [W/sek] - 7th rep) in QSC than in NC (in each repetition of study protocol); (2) between the 1st repetition and subsequent repetitions a number of significants in among physiological, blood-related, and electrolyte variables were noted, but their direction was similar in both simulated conditions (e.g. V'O2/kg 37,59 ± 3,96 vs 37,95 ± 3,17 [ml/min/kg] - 3rd rep, LAC 13,16 ± 2,61 vs 14,18 ± 3,13 [mg/dl] - 10th rep or K 4,54 ± 0,29 vs 4,79 ± 0,36 [mmol/l] - 2nd rep when compare QCS and NC respectively); (3) an 8°C of temperature difference between the climatic conditions did not significantly affect the soccer players' physical and physiological responses in RME. The study results can be used in the design of training programs aimed to increase players' physiological adaptations by simulating soccer-specific conditions of play in terms of anaerobic capacity, in particular, repetitive maximal efforts. These findings will be useful during the upcoming 2022 World Cup in Qatar and in locations where high ambient temperatures are customary.

A classification of specific movement skills and patterns during sprinting in English Premier League soccer

The aim of this study was to quantify and contextualize sprinting actions (≥ 7.0 m/s) of English Premier League (EPL) soccer match-play with respect to the movement skills and patterns employed. Video footage (3.2.6, Premier League DVMS, ChyronHego) and raw video-based locomotor coordinates of 901 sprint efforts from 10 matches of an EPL soccer team (2017-2018), were evaluated using the Football Sprint Movement Classification System pertaining to transition, initiation, and actualisation of sprint movement skills and patterns. The results from a one-way ANOVA or independent t-test revealed that, generally, most sprinting actions begun from a linear initiation position compared to lateral or rear (63%, d = 5.0-5.3, p < 0.01), without a change of direction (COD) (48%, d = 4.9-5.6, p < 0.01) compared to lateral, front-back, back-front, and from forward travelling (linear and diagonal) transition movements (68%, d = 2.1-5.7, p < 0.01) compared to lateral or rear. Additionally, most sprints were initiated with a rolling acceleration (66%, d = 3.2, p < 0.01) compared to explosive acceleration, often performed with a degree of curvature (86%, d = 7.2, p < 0.01) compared to linear, with torso rotation (62%, d = 2.7, p < 0.01) compared to no rotation, and typically end with an action such as duelling with an opponent or involvement with the ball (49%). Additionally, the sprint movement characteristics proportions slightly differed across playing positions. Overall, this study confirms that sprints during EPL soccer matches are initiated from and performed with a variety of different movement skills and patterns in relation to different sport-specific outcomes. This data can be used to assist in the development of more effective physical preparation programmes, inform position-specific contextualized sprinting drills to achieve better specificity and potential transfer of training, while also informing speed testing protocols.

Effect of playing position and microcycle days on the acceleration speed profile of elite football players

The aim of this study was to analyse the differences in the A-S profile of elite football players induced by playing position and the microcycle day. Players belonged to a second division club in the Spanish La Liga competition. They were classified into five playing positions: central defenders (CD), full backs (FB), midfielders (MF), wide midfielders (WMF) and forwards (FW). Microcycle days were categorised according to the days until matchday (MD, MD-1, MD-2, MD-3, MD-4 and MD-5). Data was collected along six microcycles, including one match per microcycle. The variables analysed were: maximal theoretical acceleration (A₀), maximal theoretical speed (S₀), maximal acceleration (ACC_max), maximal speed (S_max) and A-S slope (AS_slope). Significant differences were found within positions and microcycle day for all variables (p < 0.05). Match day (MD) showed greater values than the training sessions in A₀, ACC_max and S_max (p < 0.05). The highest values for variables associated with acceleration capabilities were found in CD on MD, whereas speed variables were higher in WMF. MD-2 showed the lowest values in all variables except for AS_slope. Maximal acceleration and sprint abilities are therefore affected by playing position. Wide positions showed the highest speed capacity, and CD presented a likely acceleration profile. Higher values for all variables concerning the microcycle day, were achieved on MD, and were not reproduced during training with the consequent injury risk and performance decrease it takes.

FIFA World Cup Qatar 2022: Solutions to the Physical Fitness Challenge

In 2022, the FIFA World Cup has been scheduled to take place in Qatar in November and December, months which coincide with the in-season period of the European soccer season. This will be challenging for the staff of the participating national teams and the domestic clubs to which participating players are attached. The aim of this letter to the editor is to propose solutions on how to manage the associated challenges. Regular training and competition over the course of a season in European professional soccer is generally characterized by a pre-competition preparation period of five to six weeks, followed by two competition phases, interspersed with a winter break (Eliakim et al., 2018). Certain leagues such as the English Premier League do not typically have a winter break meaning that games are played almost continuously across the season. During World Cup years, there is usually an average of four to five weeks between the end of national domestic championships and the start of the World Cup tournament (Table 1, Figure 1) which traditionally takes place during the off-season period. However, in 2022, the FIFA World Cup has been scheduled to take place in November and December, months which coincide with the in-season period of the European soccer season (Figure 1). With the World Cup being staged during this part of the season, many national team players (notably those in the major European Leagues) will have just one week of preparation between the last match of their domestic leagues and the start of the World Cup tournament (November 20th, 2022). More precisely, the major European soccer leagues will interrupt match schedules between November 9th and 13th with differences in the number of games completed at this time of the season ranging from 14 to 17 across the various leagues (Table 2). The physical and mental demands placed on modern professional players have steadily risen over recent years due to an increase in the number of matches played during congested periods across the season (Anderson et al., 2016). Since the number of matches is not evenly distributed across the typical 40-week season, players can often compete in as many as three matches in a seven-day period. Aside from the physical and mental demands that are imposed during a match, players might experience insufficient recovery between these games; in part due to extensive travelling which can disrupt the sleep/wake cycle (Lastella et al., 2019). Indeed, poor quality of sleep and the stress induced by a match can negatively affect physical fitness and may even increase the risk of sustaining injuries and/or infections (Clemente et al., 2021) in the period leading up to the World Cup. National teams are composed of players from different leagues who have varying levels of exposure to match-play (e.g., starters, non-starters) in terms of the average weekly volume of soccer matches at their clubs (“Rapports - Observatoire du football CIES”). Moreover, both starters and non-starters are exposed to different external match and training loads (Anderson et al., 2016). External loads have previously been defined as the overall volume of activity that a player performs during both training sessions and matches (Ravé et al., 2020). There is evidence that this metric correlates with a player’s physical fitness status (Clemente et al., 2019) and their injury risk (Malone et al., 2017). Accordingly, it will be challenging for national teams to manage the fitness of players such that they are physically ready to play at the World Cup tournament. This is especially applicable to individuals who play in the major European leagues and we note a significant contrast between European match schedules and those on other continents. For example, in Major League Soccer (MLS) in North America, match schedules will be interrupted from November 5th, 15 days before the World Cup tournament begins. Similarly, in the Japanese J-League in Asia, Saudi Pro League and Qatar Star League, matches will be interrupted one month before the World Cup tournament begins, leaving more time for players on these continents to prepare. It is also important to note that the French, Spanish and English domestic championships will resume their match schedules on December 27th which is just ten days after the end of the World Cup (Figure 1). Clubs will clearly want their players to return uninjured and with sufficient fitness levels to resume domestic competition but these goals could be compromised by the aforementioned scheduling of the World Cup tournament.

Monitoring the post-match neuromuscular fatigue of young Turkish football players

Neuromuscular fatigue tests have been used in previous studies to organize post-match training programs and to minimize injuries. The aim of this study is to describe the neuromuscular fatigue that occurs after a football match and to examine the relationship between internal and external load values in the match and fatigue parameters obtained at different time intervals. Twenty male U19 academy league soccer players (age: 19; height: 181.3 ± 4.3; weight: 73.4 ± 6.7) participated in the study. The countermovement jump (CMJ) test was applied to the players 24 h before, as well as 24, 48, 72, 96, and 120 h after a football match. During the CMJ tests, the maximum velocity of each player during the jump was recorded by using the GymAware linear position transducer. The CMJ maximum velocity values 24 h before and 24 h after the match, as well as the CMJ height values (Cohen's d: 1.210; p < 0.001), were statistically different from the values recorded 24 h before and 24 and 48 h after the match (Cohen's d: 1.578; p < 0.001; Cohen's d: 0,922; p < 0.009). The correlation values were not statistically significant. The results suggest, CMJ height and CMJ maximum velocity values, which determine neuromuscular fatigue after a football match, can be used by practitioners to display post-match neuromuscular fatigue measurements.

When and How do Professional Soccer Players Experience Maximal Intensity Sprints in Laliga?

This study aimed to 1) examine the periods in which maximal intensity sprints occurred during professional soccer matches and 2) analyze the maximal intensity sprints registered in match play considering the effect of playing position and other contextual variables. A total of 1252 match observations were collected from 277 male professional soccer players. Sprinting actions at maximal intensity were analyzed during 30 official matches, and both contextual and performance variables were collected using electronic performance and tracking systems. Maximal intensity sprints were more frequent in the first and last periods of the match (0'-15'; 75'-90'), regardless of the playing position (χ²=23.01; p=0.29; ES=0.07). These sprints were usually non-linear actions without possession of the ball and had different tactical purposes depending on the playing position. In addition, regarding the physical performance required by maximal intensity sprints, that the mean sprint duration ranged from ~4.9 s to ~9 s, the mean distance covered ranged from ~30 m to ~55 m, while the mean maximum velocity was between ~30.12 and ~32.80 km/h depending on the tactical purpose and playing position. In conclusion, professional soccer players need to be prepared during warm-ups for maximal intensity sprints in the first period of the match as well as maximal intensity sprints under high fatigue conditions given the frequency of sprints in the last period of the match. Also, training drills should be designed with a special focus on non-linear sprints without possession of the ball, based on the main tactical purpose of each position (e.g., CD: interceptions; MF: recovery runs; FB, WMF and FW: run the channel).

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.

Running Performance of Male Versus Female Players in Australian Football Matches: A Systematic Review

BACKGROUND

Australian Football is a fast paced, intermittent sport, played by both male and female populations. The aim of this systematic review was to compare male and female Australian Football players, competing at elite and sub-elite levels, for running performance during Australian Football matches based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

METHODS

Medline, SPORTDiscus, and Web of Science searches, using search terms inclusive of Australian Football, movement demands and microsensor technology, returned 2535 potential manuscripts, of which 33 were included in the final analyses.

RESULTS

Results indicated that male athletes performed approximately twice the total running distances of their female counterparts, which was likely due to the differences in quarter length (male elite = 20 min, female elite = 15 min (plus time-on). When expressed relative to playing time, the differences between males and females somewhat diminished. However, high-speed running distances covered at velocities > 14.4 km·h-1 (> 4 m·s-1) were substantially greater (≥ 50%) for male than female players. Male and female players recorded similar running intensities during peak periods of play of shorter duration (e.g., around 1 min), but when the analysis window was lengthened, females showed a greater decrement in running performance.

CONCLUSION

These results suggest that male players should be exposed to greater training volumes, whereas training intensities should be reasonably comparable across male and female athletes.

An Analysis of Acceleration, Deceleration and High-Intensity Skating during Elite Bandy Match-Play: A Case Study

Profiles of physical workload in sports are useful to optimize performance and reduce the risk of injury. The aim of the study was to investigate physical workload in 10 elite bandy players by describing acceleration, deceleration, and high-intensity skating during bandy match-play. During 13 home matches, 10 male elite bandy players wore a GPS unit to measure changes in the total distance, total distance skating in two speed zones, and total distance of acceleration and deceleration. A within-subject design was used to measure changes over time during match-play by comparing first and second halves as well as comparisons for consecutive 15 min intervals. No significant differences were observed for high-intensity or very high-intensity acceleration and deceleration for comparisons by halves or for 15-min intervals. For comparisons by halves, a significant time-dependent effect was observed on very fast skating (1337.6 m vs. 1160.9 m), sprint skating (300.0 m vs. 272.0 m), low-intensity acceleration (342.7 m vs. 333.0 m), and total distance covered (10,916.9 m vs. 10,450.3 m). These variables, along with low-intensity deceleration, were also significant for the 15 min interval comparisons. The results show that there is no time-dependent reduction in high-intensity acceleration and deceleration in elite bandy match-play. However, elite bandy players do not maintain the distance of high-intensity skating throughout a whole match.

Sequential movement pattern-mining (SMP) in field-based team-sport: A framework for quantifying spatiotemporal data and improve training specificity?

Athlete external load is typically quantified as volumes or discretised threshold values using distance, speed and time. A framework accounting for the movement sequences of athletes has previously been proposed using radio frequency data. This study developed a framework to identify sequential movement sequences using GPS-derived spatiotemporal data in team-sports and establish its stability. Thirteen rugby league players during one match were analysed to demonstrate the application of the framework. The framework (Sequential Movement Pattern-mining [SMP]) applies techniques to analyse i) geospatial data (i.e., decimal degree latitude and longitude), ii) determine players turning angles, iii) improve movement descriptor assignment, thus improving movement unit formation and iv) improve the classification and identification of players' frequent SMP. The SMP framework allows for sub-sequences of movement units to be condensed, removing repeated elements, which offers a novel technique for the quantification of similarities or dis-similarities between players and playing positions. The SMP framework provides a robust and stable method that allows, for the first time the analysis of GPS-derived data and identifies the frequent SMP of field-based team-sport athletes. The application of the SMP framework in practice could optimise the outcomes of training of field-based team-sport athletes by improving training specificity.

Integrating video tracking and GPS to quantify accelerations and decelerations in elite soccer

The aim of this study was to analyze the degree of agreement comparing number and distance covered in different acceleration and deceleration sections registered by a video tracking system (MEDIACOACH) and a GPS device (WIMU PRO) during official competition. Data from a Spanish professional club were registered over the course of a season. First, the descriptive statistics presented more bursts of accelerations and decelerations in WIMU PRO than in MEDIACOACH, whereas the distances covered recorded by both systems were similar. Second, negative relationships were found (i.e., negative bias) comparing WIMU PRO to MEDIACOACH in the number of accelerations and decelerations between 0/1 m/s² and ½ m/s² (p < 0.05), and in the distances covered in accelerations and decelerations (p < 0.05) between 0/1 m/s² and in accelerations and decelerations registered between 2/3 m/s² and more than 3 m/s². Moreover, the differences in means (i.e., standardized mean bias) across the two devices were trivial (> 0.19) and small (0.2-0.59) for most variables. The standardized typical errors in the estimate (TEE) were moderate (0.3-0.59) and small to moderate (0.1-0.29 to 0.3-0.59), respectively. Also, the Intra class Correlation Coefficients (ICCs) for agreement and consistency between systems showed good and excellent values (> 0.90). The magnitude of change in means (%) between systems, defined as the percentage change between the numbers or values, was below 14% and 7% for number and distances covered, respectively. All scores in the smallest worthwhile change were lower than 9% and in the coefficients of variation were lower than 95% and 15%, respectively. Thus, both systems demonstrated an acceptable degree of agreement and could be useful in analyzing players' acceleration demands in professional soccer. However, caution is required when interpreting the results and a comparison with a gold standard is required in order to validate both systems.

The Quantification of Acceleration Events in Elite Team Sport: a Systematic Review

BACKGROUND

Wearable tracking devices are commonly utilised to quantify the external acceleration load of team sport athletes during training and competition. The ability to accelerate is an important attribute for athletes in many team sports. However, there are many different acceleration metrics that exist in team sport research. This review aimed to provide researchers and practitioners with a clear reporting framework on acceleration variables by outlining the different metrics and calculation processes that have been adopted to quantify acceleration loads in team sport research.

METHODS

A systematic review of three electronic databases (CINAHL, MEDLINE, SPORTDiscus), was performed to identify peer-reviewed studies that published external acceleration load in elite team sports during training and/or competition. Articles published between January 2010 and April 2020 were identified using Boolean search phrases in relation to team sports (population), acceleration/deceleration (comparators), and competition and/or training (outcome). The included studies were required to present external acceleration and/or deceleration load (of any magnitude) from able-bodied athletes (mean age ≥ 18 years) via wearable technologies.

RESULTS

A total of 124 research articles qualified for inclusion. In total, 113/124 studies utilised GPS/GNSS technology to outline the external acceleration load of athletes. Count-based metrics of acceleration were predominant of all metrics in this review (72%). There was a lack of information surrounding the calculation process of acceleration with 13% of studies specifying the filter used in the processing of athlete data, whilst 32% outlined the minimum effort duration (MED). Markers of GPS/GNSS data quality, including horizontal dilution of precision (HDOP) and the average number of satellites connected, were outlined in 24% and 27% of studies respectively.

CONCLUSIONS

Team sport research has predominantly quantified external acceleration load in training and competition with count-based metrics. Despite the influence of data filtering processes and MEDs upon acceleration, this information is largely omitted from team sport research. Future research that outlines acceleration load should present filtering processes, MEDs, HDOP, and the number of connected satellites. For GPS/GNSS systems, satellite planning tools should document evidence of available satellites for data collection to analyse tracking device performance. The development of a consistent acceleration filtering method should be established to promote consistency in the research of external athlete acceleration loads.

Evaluation of Performance Characteristics and Internal and External Training Loads in Female Collegiate Beach Volleyball Players

ABSTRACT

Bozzini, BN, McFadden, BA, Scruggs, SK, and Arent, SM. Evaluation of performance characteristics and internal and external training loads in female collegiate beach volleyball players. J Strength Cond Res 35(6): 1559-1567, 2021-Although women's beach volleyball is the fastest growing collegiate sport, the training demands and performance characteristics have yet to be determined. The purpose of this study was to evaluate internal and external training loads throughout a competitive season and to quantify the performance characteristics of National Collegiate Athletic Association Division I women's beach volleyball players. Female beach volleyball players (N = 20) were monitored throughout the 6-week competitive season (T1-T6) using integrative global positioning systems (GPS) and heart rate (HR)-monitoring technology, which was individualized based on preseason testing, for the determination of workload metrics. In addition to team data, all variables were analyzed between travel (n = 11, regular match participation) and non-travel (n = 7) squad athletes (p < 0.05). Team performance metrics demonstrated the explosive power emphasis of the sport, with travel squad players exhibiting significantly greater vertical jump and jump velocity abilities than their non-travel counterparts (p < 0.05). Although few time main effects from T1 to T6 were observed for team workload metrics, follow-ups revealed significant time × group interactions for training load (TL), exercise energy expenditure (EEE), total distance covered, and minutes spent in HR zones (HRZ1-Z5) over the season (p < 0.05). Finally, although average workloads were greater in practices than in matches, when accounting for pre-match warm-ups, competition load was greater than practice (p < 0.05). National Collegiate Athletic Association Division I women's beach volleyball is a demanding, explosive power sport characterized by overall large TL and EEE, particularly in-season when athletes compete in 4 matches per weekend. The workloads observed point to the need to assess and manage training loads and fueling requirements to optimize performance and decrease injury risk.

Specific Absolute Velocity Thresholds during Male Basketball Games Using Local Positional System; Differences between Age Categories

The aim of this study was (I) to establish absolute specific velocity thresholds during basketball games using local positional system (LPS) and (II) to compare the speed profiles between various levels of competitions. The variables recorded were total distance (TD); meters per minute (m·min); real time (min); maximum speed (Km h−1), distance (m), percentage distance, and percentage duration invested in four speed zones (standing–walking; jogging; running; and high-speed running). Mean and standard deviation (±SD) were calculated, and a separate one-way analysis of variance was undertaken to identify differences between competitions. TD (3188.84 ± 808.37 m) is covered by standing–walking (43.51%), jogging (36.58%), running (14.68%), and sprinting (5.23%) activities. Overall, 75.22% of the time is invested standing–walking, jogging (18.43%), running (4.77%), and sprinting (1.89%). M·min (large effect size), % duration zone 2 (moderate effect size); distance zone 4 (large effect size), and % distance zone 4 (very large effect size) are significantly higher during junior than senior. However, % distance zone 1 (large effect size) and % duration zone 1 (large effect size) were largely higher during senior competition. The findings of this study reveal that most of the distance and play time is spent during walking and standing activities. In addition, the proportion of time spent at elevated intensities is higher during junior than in senior competition.

Varying Demands and Quality of Play Between In-Conference and Out-of-Conference Games in Division I Collegiate Women's Soccer

Bozzini, BN, McFadden, BA, Walker, AJ, and Arent, SM. Varying demands and quality of play between in-conference and out-of-conference games in Division I collegiate women's soccer. J Strength Cond Res 34(12): 3364-3368, 2020-The purpose of this study was to assess differences in physical workloads, physiological responses, and performance variables between in-conference (IC) and out-of-conference (OC) games during a collegiate women's soccer season. Female field players (N = 11), who played a minimum of 45 minutes for >50% of games, were evaluated using an integrative GPS and HR monitoring system to determine training load (TL), exercise energy expenditure (EEE), total distance covered (DIS), sprints, time spent in HR zones 4 and 5 (HRZ4 = 80-89% HRmax; HRZ5 = 90-100% HRmax), and distance covered in speed zones 4 and 5 (DISZ4 = 15.0-19.9 km·h; DISZ5 = ≥20 km·h). In addition, percent passing accuracy (PA%), dribbling success (DS%), tackling success (TS%), and challenges won (CW%) were generated for all games. Workload data were analyzed as a rate per minute playing time (PT) per game to account for differences in game duration and PT between OC (n = 7) and IC games (n = 11). Repeated-measures multivariate analyses of variance with univariate follow-ups and effect sizes (Hedges' g) were conducted to compare conditions (OC vs. CON) (p < 0.05). There were significantly greater TL, DIS, EEE, and HRZ5 per minute PT in OC versus IC games (Hedges' g: TL = 0.48; DIS = 0.20, EEE = 0.55; HRZ5 = 0.83; p < 0.05). Further analysis found significant differences in first half play favoring OC games (p < 0.05), but not second half play (p > 0.05). Based on these findings, OC games seem to be more demanding compared to IC, particularly during first half play. Emphasis should be placed on tailoring TL to the accumulating in-season demands through athlete-monitoring technology to prevent declines in performance in the latter half of the season.

Implementing High-speed Running and Sprinting Training in Professional Soccer

High-speed running and sprinting training play an important role in the development of physical capabilities, sport-specific performance and injury prevention among soccer players. This commentary aims to summarize the current evidence regarding high-speed running and sprinting training in professional soccer and to inform its implementation in research and applied settings. It is structured into four sections: 1) Evidence-based high-speed running and sprinting conditioning methodologies; 2) Monitoring of high-speed running and sprinting performance in soccer 3) Recommendations for effective implementation of high-speed running and sprinting training in applied soccer settings; 4) Limitations and future directions. The contemporary literature provides preliminary methodological guidelines for coaches and practitioners. The recommended methods to ensure high-speed running and sprinting exposure for both conditioning purposes and injury prevention strategies among soccer players are: high-intensity running training, field-based drills and ball-drills in the form of medium- and large-sided games. Global navigation satellite systems are valid and reliable technologies for high-speed running and sprinting monitoring practice. Future research is required to refine, and advance training practices aimed at optimizing individual high-speed running and sprinting training responses and associated long-term effects.

Comparison of Internal and External Training Loads in Male and Female Collegiate Soccer Players During Practices vs. Games

McFadden, BA, Walker, AJ, Bozzini, BN, Sanders, DJ, and Arent, SM. Comparison of internal and external training loads in male and female collegiate soccer players during practices vs. games. J Strength Cond Res 34(4): 969-974, 2020-The purpose of this study was to compare the internal and external training loads (TLs) in men and women throughout a Division I soccer season during practices versus games. Players were evaluated during all practices and regulation game play using the Polar TeamPro system, utilizing Global Positioning Satellite technology and heart rate (HR) monitoring to determine TL, time spent in HR zones expressed as a percent of HRmax (HRZ1-Z5), calories expended per kilogram body mass (Kcal·kg), distance covered (DIS), sprints, average speed (SPDAVG), and distance covered in speed zones (DISZ1-Z5). During games, no significant differences were seen between men and women for TL, Kcal·kg, HRZ1-Z5, SPDAVG, DIS, DISZ1, DISZ3, and DISZ4. However, men accumulated a significantly greater number of sprints and DISZ5 (p < 0.05) during games, whereas women accumulated a greater DISZ2 (p < 0.05). During practice, no differences were observed for TL, DIS, sprints, Kcal·kg, DISZ2, DISZ3, HRZ1-Z5, but men exhibited higher SPDAVG, (p < 0.05), DISZ1 (p < 0.05), DISZ4 (p < 0.05), and DISZ5 (p < 0.05). The parallels in Kcal·kg, total DIS, HR, and TL indicate a similar relative workload between men and women. However, distance covered in higher speed zones was found to be greater in men than women across practice and games likely reflecting inherent sex differences in the ability to achieve those speeds. Monitoring techniques that track relative player workloads throughout practices and games may enhance player health and performance during the season. An individualized approach to tracking high-intensity running may improve workload prescriptions on a per player basis.