Running Demands Research Articles

Match-play running demands of professional female Rugby Sevens: Comparison of ball-in-play, worst-case scenarios and game phases in Super Sevens 2023

A gray area remains about the intensity of efforts performed in Sevens competitions, especially during the worst-case scenarios (WCS - longest effort during a match). For this reason, the analysis of demands during the ball-in-play (BIP) is increasing in team sports like Rugby Sevens. Through this method, we can also identify the WCS and the demands of distinct phases of play (attack, defense, and transition). Thus, this study aimed to (i) investigate and compare the BIP and WCS external load (EL) demands (distance per minute, sprint distance per minute, and accelerations per minute) during matches; and (ii) compare the BIP running demands across different game phases (attack, defense, and transition). Twenty-one female professional Rugby Sevens players participated, with their running demands analyzed during every BIP phase in all 20 matches of the Super Sevens 2023 using individual GPS tracking. The results indicated no significant differences in any EL variables between WCS and BIP averages. Furthermore, there were no differences in EL experienced by athletes during different phases and actions. In summary, our findings suggest that both the WCS and the BIP methods result in similar EL values across matches. Additionally, the EL remains consistent across different game periods (first half vs. second half) and actions (defense, attack, and transition). These results offer practical guidance for coaches when planning training sessions for female Rugby Sevens athletes, suggesting that preparation focused on WCS may effectively prepare athletes for the entire game.

Preseason and In-Season High-Speed Running Demands of 2 Professional Australian Rules Football Teams.

Australian Rules Football athletes complete long preseasons, yet injuries occur frequently at early stages of the competitive season. Little is known about the high-speed running (HSR) prescription during a preseason or whether players are adequately prepared for competition. This study described absolute and relative preseason and in-season HSR demands of 2 professional Australian football teams. HSR and sprinting volumes are significantly lower in elite Australian Rules football athletes during in-season compared with preseason. Cohort study. Level 3. During the 2019 season, HSR volume was collected for 2 professional Australian football teams (n = 55). Individual maximum speeds (Vmax) were captured to calculate relative running speed thresholds, as reported in 5% increments from 70%Vmax to 100%Vmax. Weekly volume of running above 70%Vmax (P = 0.01; r = 0.56) and 80%Vmax (P = 0.01; r = 0.58) was significantly greater in the preseason than the in-season. The weekly volume completed above 90%Vmax was not significantly greater in the preseason than the in-season (P = 0.10; r = 0.22). Individual variation in the distance completed at specific percentages of Vmax expressed as a coefficient of variation was reported as 51% at 71% to 80%Vmax, 39% at 81% to 90%Vmax, and 41% at 91% to 100%Vmax. The volume of HSR completed by athletes is far greater in the initial 4 weeks of the preseason than in any other point in preseason or competitive phases. At the individual level, there is substantial variation in the distance covered. This supports the concept of a heavily individualized approach to high-speed prescription and monitoring. Practitioners should carefully consider individual variation regarding sprinting volume during both preseason and in-season when prescribing and monitoring training to improve on-field performance and reduce the risk of injury.

Marathon Health Pitfalls: What Every Runner Needs to Know

Introduction and Purpose: Long-distance running, especially marathons, tests human endurance and physical limits. While the benefits of marathon running are well-documented, the associated health risks often go unnoticed. This review aims to synthesize current knowledge on the health risks and complications faced by marathon runners, providing crucial insights for both amateur and professional athletes.State of Knowledge: Marathon running imposes significant stress on the cardiovascular system, musculoskeletal structure, and metabolic processes. Issues such as acute myocardial injury, overhydration leading to hyponatremia, and musculoskeletal injuries are prevalent. The review also examines less common but severe risks like rhabdomyolysis and marathon-related cardiac arrests. Despite the robust fitness levels of runners, these health risks remain a serious concern, necessitating preventive strategies and proper health monitoring.Summary: Marathon runners must be aware of the potential health risks associated with prolonged endurance activities. Precautionary measures, including tailored training programs, dietary adjustments, and regular medical check-ups, are essential to mitigate these risks. Additionally, further research is required to develop more effective interventions and guidelines that can safeguard the health of marathon participants. This review underscores the need for a balanced approach that respects the physiological demands of marathon running while ensuring the health and safety of the runners.

Stability of Running Stride Biomechanical Parameters during Half-Marathon Race

This study explores the stability of biomechanical parameters of the running stride of male trained athletes during a half-marathon competition. Using a field-based descriptive design, eight male athletes from a local training group were monitored throughout an official half-marathon race under identical conditions, assessing biomechanical parameters including ground contact time (GCT), leg spring stiffness (LSS), vertical oscillation (VO), and stride length (SL) recorded via the Stryd Summit Power Meter. A repeated measures analysis of variance (RM ANOVA) was conducted to detect significant changes in biomechanical parameters as the race progressed. Results demonstrated minimal changes in all parameters, with no significant differences observed for GCT (F = 0.96, p = 0.38), VO (F = 0.23, p = 0.87), and SL (F = 1.07, p = 0.35), and a small (η2 = 0.004) yet statistically significant difference in LSS (F = 5.52, p = 0.03) between the first and second segments, indicating that athletes were able to maintain stable biomechanical parameters throughout the race. The conclusion highlights the need for personalized training programs tailored to the unique biomechanical adaptations and demands of endurance running.

Critical speed models of high-resolution speed-duration profiles describe peak running demands in soccer

The purpose of this study was to characterize critical speed (CS) models for summarizing high-resolution speed-duration profiles from GPS tracking data obtained from soccer players. GPS data from 15 male NCAA Division I soccer players were collected during practices and games over a 6-week period. Moving averages of the speed data were computed for each file for duration windows spanning 0.1 to 600 seconds at 0.1-second resolution. Speed-duration profiles for each session and for the entire sampling period (“global”) were generated for each player by selecting the maximal mean speeds for each duration. Four models were fit to the profiles: the two-parameter CS (CS2) model, the three-parameter CS (CS3) model, the omni-domain speed-duration (OmSD) model, and the five-parameter logistic (5PL) model. The 5PL, CS3, and OmSD models exhibited similar goodness of fits, and all outperformed the CS2 model. Similar CS estimates were obtained for each model, whereas maximum speed ( Smax) estimates were lower for OmSD compared to the 5PL. Players exhibited a range of parameter values for CS, D′, and Smax. Smax and CS estimated from session-specific speed-duration profiles were on average higher for games compared to practices. We conclude that CS models are useful for empirically describing speed-duration profiles and for assessing peak running demands for soccer practices and games. The proposed approach could help coaches design practice activities to better mimic game demands.

Match-play running demands in a female soccer professional club: From academy to professional team

The objective of the study was to examine the match-running load of female soccer players competing at distinct age groups (U15, U18 and senior cohorts) belonging to the same professional club, over a competitive season. The external load variables of the official matches were monitored with Global Positioning System (GPS) technology: total distance (TD), at >18 km·h−1 (running), at >21 km·h−1 (high-speed running, HSR) and at >24 km·h−1 (sprint, SPR) distances, efforts at >85% of the maximal sprint speed (>85% MSS), acceleration load (aLoaD), accelerations (ACC2 and ACC3, >2 and >3 m·s−2) and decelerations (DEC2 and DEC3 <−2 and <−3 m·s−2). Overall, distances covered at running, HSR and sprinting were greater for senior players than their younger peers (U15 and U18; p < 0.05). Regarding HSR and sprints, no difference was found for sprints accumulated by central defender (CD) players in comparison to U18 and U15 ( p > 0.05). In addition, U18 and senior players engaged more often in ACC and DEC, >2 and >3 m·s−2, respectively, than U15 players ( p < 0.05). In conclusion, older female soccer players are exposed to higher match load than their younger peers. These findings could be useful for soccer coaches to design specific speed development programmes across the long-term athletic development pathway.

Aerobic Endurance - Finding Optimal Rowing Ergometer Settings to Match Physiological Demands of Running

Assessing aerobic endurance is crucial for evaluating fitness levels, with the Cooper 12-minute test widely recognized as a benchmark. However, indoor rowing on the Concept2 rowing ergometer lacks a standardized equivalent, prompting this study to explore the potential of a 12-minute rowing test as an alternative. Despite differences in muscle groups, rowing shares foundational aerobic capacities with running. The investigation centers around the rowing drag factor, hypothesizing its role in aligning rowing performance with the physiological demands of running. The study involved 56 healthy male soldiers (age: 22.89 ± 2.28 years) undergoing 12-minute running and three drag factor rowing tests. While basic anthropometrics showed limited influence, height correlated positively with rowing performances, and weight negatively affected both running and rowing at low resistance and positively at higher resistances. The closest correlation between running and various drag factor rowing tests, and also the only one with no statistically significant difference in distance covered, was found at damper setting 1 of the ergometer, representing the lowest drag factor. The relatively low coefficient of determination (r2 = 0,18) suggests diversity in the performance foundations of the 12-minute running and rowing. Therefore, further analysis is needed before the rowing test can be considered a valid alternative to the Cooper test.

Analysis of Differences in Running Demands between Official Matches and Transition Games of Young Professional Soccer Players according to the Playing Position.

The aim of this study was to compare the running demands of transition games (TGs) and official matches, analysing their requirements according to the performance of each position. An observational design was used to examine the activity of 20 soccer players during official matches and TGs. GPS technology was used to monitor the total distance covered (DC), distance at speeds between 14-17.9 km•h-1, 18-21 km•h-1, and above 21 km•h-1, peak speed, accelerations and decelerations above 2.5 m•s-2, and Player Load for both activities. All players were assigned to groups: centre-backs (CBs), fullbacks (FBs), defensive midfielders (DMFs), offensive midfielders (OMFs), wide midfielders (WMFs) and strikers (Ss). TGs showed greater total DC, DC 14-17.9 km•h-1, DC 18-21 km•h-1, DC >21 km•h-1, accelerations and decelerations >2.5 m•s-2, and Player Load (p < 0.01). CBs, FBs and Ss showed more DC, DC 14-17.9 km•h-1, DC 18-21 km•h-1, DC >21 km•h-1, accelerations and decelerations >2.5 m•s-2 and Player Load in TGs (p < 0.01). In the midfielder positions, transition game players showed greater DC 18-21 km•h-1, DC >21 km•h-1, accelerations and decelerations >2.5 m•s-2 than in matches (p < 0.05). DMFs showed higher total DC (p < 0.05) and WMFs greater DC and DC 14-17.9 km•h-1 (p < 0.01) in these drills. During transition games CBs showed greater DC 14-17.9 km•h-1 than FBs, and greater DC than Ss (p < 0.05). FBs performed more decelerations >2.5 m•s-2 than DMFs and OMFs (p < 0.05). TGs produced a homogenized load in soccer players, independent of their position, which exceeded the external load of official matches.

Relationships between physical fitness and match running demands during a futsal congested-weeks training camp.

This study examines the relationships between body composition, anthropometry and physical fitness measures, and internal and external load (match physical and running demands) during a congested period of an overseas futsal training camp. Eleven under-20 national futsal players participated in a eleven-day training camp. During the matches, exercise heart rate (HR) and locomotion profiles were recorded via a Polar Team Pro system as the players' internal and external load. The friendly matches were scheduled on the training camp's 2nd, 4th, 6th, 8th, and 10th days. A repeated-measures analysis of variance (ANOVA) and Pearson's correlation coefficient were used for statistical analysis. The results revealed significant differences in sprint (F = 2.74, p = 0.04, η2 = 0.21), accelerations (F = 3.63, p = 0.04, η2 = 0.27), and decelerations (F = 2.73, p = 0.04, η2 = 0.21) performance between the five matches (p < 0.05). Also, the overall body composition and physical fitness measures had large to very large correlations with match running demands during congested periods of futsal competition (p < 0.05). In conclusion, the baseline body composition and the overall physical fitness measures may be essential factors in match running demands during a congested futsal match period. Futsal players who perform better in the 30-15 Intermittent Fitness Test can sustain a greater volume of high-intensity accelerations during a congested period.

Hamstring muscle injury is preceded by a short period of higher running demands in professional football players.

The aim of this study was to examine match running patterns before a hamstring muscle injury occurs during a match in male professional football players. A total of 281 male professional football players belonging to 7 teams from LaLiga were prospectively monitored over three seasons. Among these, 36 players suffered a non-contact hamstring muscle injury during an official match. The injuries were recorded by the medical staff, including the minute when the injury occurred. Running distances at different speed thresholds for 5 min and 15 min before the injury were compared to mean values of the previous 5 matches for the same time points. There were a total of 44 non-contact hamstring muscle injuries, which represents a hamstring muscle injury incidence of 3.34 injuries/1000 h of match exposure. The average time loss for these injuries was 33 ± 28 days (range 7 to 117 days). In the 15 min prior to the injury, players ran a similar distance as in control matches (p from 0.22 to 0.08). However, players ran a greater distance in the 5-min period before the injury than in control matches at 21.0-23.9 km/h (p < 0.001) and at ≥ 24 km/h (p < 0.001). The odds ratio for a hamstring muscle injury was 7.147 for those players who ran > 30.0 m at ≥ 21 km/h in a 5-min period (p < 0.001). Hamstring muscle injuries during competition were preceded by 5 min of higher running demands at > 21 km/h, compared with control matches. This suggests that a short period of unusual running increases the risk of hamstring muscle injury in professional football players.

Possession or position games: What is the key in soccer?

The aims of this study were to compare the running performance of possession and position games and to describe the external load of the same position game played on pitches of different dimensions. Using a GPS system (WIMU Pro, RealTrack Systems, Almería, Spain), the running demands of 25 professional soccer players were monitored during 18 possession (without a standardized role position) and 18 positional (with a specific role position) games of 9 vs. 9 + 2 floaters. Each format was developed in small (< 60 m2 per payer), medium (60-90 m2 per player) and large (> 90 m2 per player) sizes. Position games obtained significantly lower distance covered, peak speed and player load values than possession games (all p < 0.05). However, position games obtained significantly higher values of maximal acceleration, maximal deceleration, accelerations higher than 3 m · s-2 and decelerations lower than -3 m · s-2 than possession games (all p < 0.05). Likewise, large position games obtained significantly higher values of distance covered, distance covered > 21 km · h-1, peak speed and player load than small and medium sizes. Large size also showed significantly higher values of maximal acceleration and deceleration than small size, significantly fewer accelerations and decelerations, and fewer accelerations lower than 3 m · s-2 and decelerations higher than -3 m · s-2 compared to medium and small size (all p < 0.05). Practitioners should keep in mind the use of these games and their size to modify the external load of the players during their training.

Effect of the phase of the season and contextual variables on match running performance in Spanish LaLiga football teams.

This study aimed to examine the intra-season variation and the effects of contextual variables on total distance (TD), high-intensity running distance (HIRD) and high-speed distance (HSD) covered by Spanish football teams. The sample included 20 professional teams that competed in the Spanish LaLiga during the 2021-2022 season. Data were recorded using the TRACAB (ChyronHego, New York, USA) multicamera computerized optical tracking system. Multilevel linear mixed models were used to examine the effects of five contextual variables (1: phase of the season in six periods, 2: match location, 3: opponent ranking, 4: team ranking and 5: congested schedule) on TD, HIRD and HSD. Teams increased the running performance from period 1 to 5 of the season in TD (+2.2%; P < 0.05) and from period 1 to 4 in HIRD (+7.2%; P < 0.05), while a declining effect was found in period 6 for both TD (-1.2%; P < 0.05) and HIRD (-5.8%; P < 0.05). More HIRD (+1.5) and HSD (+5.3) were covered at home (P < 0.05), and more TD and HIRD were covered when playing against opponents ranked in the first (+2.4% and +5.3%, respectively; P < 0.05) and second quartile (+1.2% and +5.0%, respectively; P < 0.05), compared to teams from the fourth quartile. Football coaches and fitness specialists should note that running performance of Spanish teams increased throughout the season, but it declined during the last matches of the competition. Additionally, home matches and highranked opponents elicited higher running demands.

Peak Running Demands in Elite Women's Rugby Sevens and Rugby Union Match Play: A Comparative Study.

In women's rugby, players regularly interchange between the rugby sevens (R7) and rugby union (RU) formats. Yet, the game demands and particularly the physical aspects respective to both formats vary and players must be able to respond accordingly. The aim of this study was to compare peak running demands in R7 and RU players. A total of 51 international women players participated. HSBC World Sevens Series (n = 19) and Six Nations Rugby Union tournament matches (n = 10) were analyzed for a total of 437 individual match observations. Global positioning systems were utilized to measure total (in meters) and high-speed (above 16km·h-1, in meters) distance and frequency of accelerations (above 2.5m·s-2, n) during different rolling-average periods (1-7min) to obtain peak running activity values. Power law modeling was used to obtain slope and intercept. For all variables, peak values and the value at the 90th percentile (P90) were analyzed. No intercept difference (P = .25; -0.12 ± 0.17) was observed between formats for total distance (161 vs 155m·min-1). In contrast, R7 players reported a higher intercept (P = .01; -0.29 ± 0.17) for high-speed distance (66 vs 51m·min-1), while the intercept was higher (P = .01; 0.31 ± 0.20) in RU for accelerations performed (6.1 vs 5.4n·min-1). Regarding P90, higher values (P < .001) were observed in R7 for total and high-speed distance and accelerations. While peak overall intensity was similar, P90 on the high-speed spectrum was higher in R7. Information on the most demanding match-play periods specific to both women's rugby formats can inform training specificity by tailoring sessions to ensure sufficient exposure to these peak demands and, consequently, aid transitioning betweenformats.

Effect of increased running speed and weight carriage on peak and cumulative tibial loading.

Tibial stress injuries are a burdensome injury among military recruits. Military activities include running and the carriage of additional weight, and this may be related to the high risk of bone stress injuries. The aim of this study was to quantify tibial loading when running at two different speeds, with and without additional weight, and to quantify their combined influence. Fourteen male distance runners who ran at least 40 km per week ran barefoot on a force-instrumented treadmill in four conditions representing preferred running speed (mean (SD) 3.1 (0.3) m/s) and 20% increased running speed (3.8 (0.4) m/s), with and without 20% of body weight carried in a weight vest. Kinematics and kinetics were synchronously collected. Bending moments were estimated about the medial-lateral axis of the tibial centroid located 1/3rd of the length from distal to proximal. Static equilibrium was ensured at each 1% of stance. Peak bending moments were obtained in addition to cumulative-weighted loading, where weighted loading accounted for the relative importance of the magnitude of the bending moment and the quantity of loading using a bone-dependent weighting factor. There were no interaction effects for running speed and weight carriage on peak or cumulative tibial loading. Running at a 20% faster speed increased peak and cumulative loading per kilometer by 8.0% (p < 0.001) and 4.8% (p < 0.001), respectively. Carriage of an additional 20% of body weight increased peak and cumulative loading per kilometer by 6.6% (p < 0.001) and 8.5% (p < 0.001), respectively. Increasing the physical demand of running by increasing speed or weight carriage increased peak tibial loading and cumulative tibial loading per kilometer, and this may increase the risk of tibial stress injury. Running speed and weight carriage independently influenced tibial loading.

Running demands and tactical individual actions of wingers appear to depend on the playing formations within an amateur football team

We examine the differences in running performance demands and tactical individual actions for male amateur football wingers in four tactical formations: 4-2-3-1, 4-4-2, 3-5-2 and 3-4-2-1 during an entire season. Running demands were assessed in terms of: total distance run; distance traveled at 3 different speed ranges (Jogging, Running, and Sprinting); and number of accelerations registered in two different magnitude bands (Medium and High) while tactical individual actions were assessed through 3269 team match observations. 3-5-2 formation entails the highest running demands, exhibiting significant disparities in Jogging when compared to 4-2-3-1 and 3-5-2, in Sprinting when comparing 4-2-3-1 with both the 3-5-2 and the 3-4-2-1 formations. Moreover, the wingers in the 3-5-2 formation demonstrate the lowest scores in various tactical individual actions, including Shots: 3-5-2 vs. 3-4-2-1; Goal Area Shots: 3-5-2 vs. 3-4-2-1; and Dribbles: 3-5-2 vs. 3-4-2-1. Finally, wingers registered the highest levels of defensive tactical individual actions in 4-4-2 and 3-5-2. Findings suggest it would be of benefit for coaches to focus on formulating specific training plans to address the specific demands placed on wingers playing in these amateur matches and running performance demands and tactical individual actions should be considered together with tactical formation.

Peak Running, Mechanical, and Physiological Demands of Professional Men's Field Hockey Matches.

The aim of this study was to investigate the peak running, mechanical, and physiological demands of players of different positions in professional men's field hockey matches. Eighteen professional male field hockey players participated in the study, and data were collected in eleven official matches. Players wore GPS units (Vector S7, Catapult Sports) and heart rate (HR) monitors (Polar H1, Polar Electros) to collect physical and physiological data. Physical and physiological output of forwards, midfielders, and defenders in full matches and during 1-min peak periods was analysed. For all metrics and positions, the values identified for the 1-min peak periods were greater than the average values of match play (p < 0.05). In terms of 1-min peak period Player Load, all three positions were significantly different from each other. Forwards achieved the highest Player Load per minute, while defenders the lowest. The distance per minute, high-speed distance per minute, and the relative average heart rate of defenders were significantly lower than of midfielders and forwards (p < 0.05). The current study revealed the peak running, mechanical, and physiological demands of professional men's field hockey matches. It is recommended when prescribing training programmes, to consider not only match average demands, but also peak demands. Forwards and midfielders displayed similar peak demands, while defenders had the lowest demands in all metrics except the number of accelerations and decelerations per minute. Player Load per minute can be used to identify the differences in peak mechanical demands between forwards and midfielders.

Flat Versus Simulated Mountain Trail Running: A Multidisciplinary Comparison in Well-Trained Runners

This paper compares cardiopulmonary and neuromuscular parameters across three running aerobic speeds in two conditions that differed from a treadmill's movement: flat condition (FC) and unpredictable roll variations similar to mountain trail running (URV). Twenty well-trained male runners (age 33 ± 8 years, body mass 70.3 ± 6.4 kg, height 1.77 ± 0.06 m, V˙O2max 63.8 ± 7.2 mL·kg-1·min-1) voluntarily participated in the study. Laboratory sessions consisted of a cardiopulmonary incremental ramp test (IRT) and two experimental protocols. Cardiopulmonary parameters, plasma lactate (BLa-), cadence, ground contact time (GT) and RPE values were assessed. We also recorded surface electromyographic (sEMG) signals from eight lower limb muscles, and we calculated, from the sEMG envelope, the amplitude and width of peak muscle activation for each step. Cardiopulmonary parameters were not significantly different between conditions (V˙O2: p = 0.104; BLa-: p = 0.214; HR: p = 0.788). The amplitude (p = 0.271) and width (p = 0.057) of sEMG activation peaks did not change between conditions. The variability of sEMG was significantly affected by conditions; indeed, the coefficient of variation in peak amplitude (p = 0.003) and peak width (p < 0.001) was higher in URV than in FC. Since the specific physical demands of running can differ between surfaces, coaches should resort to the use of non-traditional surfaces, emphasizing specific surface-related motor tasks that are normally observed in natural running environments. Seeing that the variability of muscle activations was affected, further studies are required to better understand the physiological effects induced by systematic surface-specific training and to define how variable-surface activities help injury prevention.

Methods of performance analysis in women's Australian football: a scoping review.

The first women's Australian football (AF) professional competition was established in 2017, resulting in advancement in performance analysis capabilities within the sport. Given the specific constraints of women's AF, it is currently unclear what match-play performance analysis methods and techniques are implemented. Therefore, the aim of this scoping review was to describe and critically appraise physical, technical, and tactical performance analysis methods that have been employed in women's and girls' AF match-play. A systematic search was conducted on the 27th of June 2022 through five databases. Eligibility criteria were derived from the PCC framework with the population (P) of women and girls AF players, of any level of play; concepts (C) of interest which were measures, data, and methods related to the sport's physical, technical, and tactical performance; and the context (C) of methods that analysed any match-play performance. A narrative synthesis was conducted using extracted study characteristic data such as sample size, population, time period, collection standards, evaluation metrics for results, and application of thematic categorisations of previous sports performance reviews. Critical appraisal of eligible studies' methodologies was conducted to investigate research quality and identify methodological issues. From 183 studies screened, twelve eligible studies were included, which examined match-play through physical (9/12, 75%), technical (4/12, 33%), and tactical analysis (2/12, 17%). Running demands and game actions analysis were the most researched in senior women's AF. Research into junior girls' AF match-play performance has not been investigated. No research has been conducted on non-running physical demands, contact demands, acceleration, and tactical aspects of women's AF. All studies utilised either inferential statistics or basic predictive models. Critical appraisal deemed most studies as low risk of bias (11/12, 92%), with the remaining study having satisfactory risk. Future research utilising increased longitudinal and greater contextual data is needed to combat the prominent issue of data representativeness to better characterise performance within women's and girls' AF. Additionally, research involving junior and sub-elite AF players across the talent pathways is important to conduct, as it provides greater context and insight regarding development to support the evolving elite women's AF competition. Women's AF has been constrained by its resource environment. As such, suggestions are provided for better utilisation of existing data, as well as for the creation of new data for appropriate future research. Greater data generation enables the use of detailed machine learning predictions, neural networks, and network analysis to better represent the intertwined nature of match-play performance from technical, physical, and tactical data.

Peak match acceleration demands differentiate between elite youth and professional football players.

Youth footballers need to be developed to meet the technical, tactical, and physical demands of professional level competition, ensuring that the transition between competition levels is successful. To quantify the physical demands, peak match intensities have been measured across football competition tiers, with team formations and tactical approaches shown to influence these physical demands. To date, no research has directly compared the physical demands of elite youth and professional footballers from a single club utilising common formations and tactical approaches. The current study quantified the total match and peak match running demands of youth and professional footballers from a single Australian A-League club. GPS data were collected across a single season from both a professional (n = 19; total observations = 199; mean ± SD; 26.7 ± 4.0 years) and elite youth (n = 21; total observations = 59; 17.9 ± 1.3 years) team. Total match demands and peak match running demands (1-10 min) were quantified for measures of total distance, high-speed distance [>19.8 km·h-1] and average acceleration. Linear mixed models and effect sizes identified differences between competition levels. No differences existed between competition levels for any total match physical performance metric. Peak total and high-speed distances demands were similar between competitions for all moving average durations. Interestingly, peak average acceleration demands were lower (SMD = 0.63-0.69) in the youth players across all moving average durations. The data suggest that the development of acceleration and repeat effort capacities is crucial in youth players for them to transition into professional competition.

Revealing the Mutual Information between Body-Worn Sensors and Metabolic Cost in Running.

Running power is a popular measure to gauge objective intensity. It has recently been shown, though, that foot-worn sensors alone cannot reflect variations in the exerted energy that stems from changes in the running economy. In order to support long-term improvement in running, these changes need to be taken into account. We propose leveraging the presence of two additional sensors worn by the most ambitious recreational runners for improved measurement: a watch and a heart rate chest strap. Using these accelerometers, which are already present and distributed over the athlete's body, carries more information about metabolic demand than a single foot-worn sensor. In this work, we demonstrate the mutual information between acceleration data and the metabolic demand of running by leveraging the information bottleneck of a constrained convolutional neural network. We perform lab measurements on 29 ambitious recreational runners (age = 28 ± 7 years, weekly running distance = 50 ± 25 km, V˙O2max = 60.3 ± 7.4 mL · min-1·kg-1). We show that information about the metabolic demand of running is contained in kinetic data. Additionally, we prove that the combination of three sensors (foot, torso, and lower arm) carries significantly more information than a single foot-worn sensor. We advocate for the development of running power systems that incorporate the sensors in watches and chest straps to improve the validity of running power and, thereby, long-term training planning.