Seasonal changes in the force velocity sprint profile of Spanish youth football players across age categories.

The purpose of this study was to investigate the changes in the force-velocity (F-V) profile and 30-metres sprint times of youth football players over a competitive season and across different age groups. Sixty-four players were categorized into five age groups (Under-10 (U10), Under-12 (U12), Under-14 (U14), Under-16 (U16), Under-18 (U18)) and assessed at three time points during the season: the pre-season (P1), mid-season (P2), and end season (P3) using GNSS/GPS technology. Results showed that the theoretical maximum force (F0) increased by the end of the season compared to the baseline in U14, U16, and U18 (p < 0.

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%).

A Change-Point Method to Detect Meaningful Change in Return-to-Sport Progression in Athletes.

Purpose: To explore how the change-point method can be used to analyze complex longitudinal data and detect when meaningful changes (change points) have occurred during rehabilitation.

Method: This design is a prospective single-case observational study of a football player in a professional club who sustained an acute lower-limb muscle injury during high-speed running in training. The rehabilitation program was entirely completed in the football club under the supervision of the club's medical team.

Judgement and Decision Making in Clinical and Return-to-Sports Decision Making: A Narrative Review.

Making return-to-sport decisions can be complex and multi-faceted, as it requires an evaluation of an individual's physical, psychological, and social well-being. Specifically, the timing of progression, regression, or return to sport can be difficult to determine due to the multitude of information that needs to be considered by clinicians. With the advent of new sports technology, the increasing volume of data poses a challenge to clinicians in effectively processing and utilising it to enhance the quality of their decisions.

Exploration of collective tactical variables in elite netball: An analysis of team and sub-group positioning behaviours.

Collective tactical behaviours are aspects of player interactions that are particularly important in netball, due to its unique restrictions on player movement (players unable to move when in possession of the ball and positional spatial restrictions). The aim of this study was to explore variables representing collective tactical behaviours in netball. A local positioning system provided player positions of one team throughout seven elite-level netball matches.

Challenges and considerations in determining the quality of electronic performance & tracking systems for team sports.

Electronic performance & tracking systems (EPTS) are commonly used to track the location and velocity of athletes in many team sports. A range of associated applications using the derived data exist, such as assessment of athlete characteristics, informing training design, assisting match adjudication and providing fan insights for broadcast. Consequently the quality of such systems is of importance to a range of stakeholders.

Exploring football coaches' views on coach education, role, and practice design: An Australian perspective.

Despite the importance placed on the design and delivery of formal coach education programs by Football Australia, there remains a lack of research relating to how formal coach education strategies support Australian football (i.e., soccer) coaches and their coaching practices.

A Framework for Clinicians to Improve the Decision-Making Process in Return to Sport.

Return-to-sport (RTS) decisions are critical to clinical sports medicine and are often characterised by uncertainties, such as re-injury risk, time pressure induced by competition schedule and social stress from coaches, families and supporters. RTS decisions have implications not only for the health and performance of an athlete, but also the sports organisation. RTS decision-making is a complex process, which relies on evaluating multiple biopsychosocial factors, and is influenced by contextual factors.

Characteristics of Complex Systems in Sports Injury Rehabilitation: Examples and Implications for Practice.

Complex systems are open systems consisting of many components that can interact among themselves and the environment. New forms of behaviours and patterns often emerge as a result. There is a growing recognition that most sporting environments are complex adaptive systems.

Moving Toward a More Comprehensive Analysis of Acceleration Profiles in Elite Youth Football.

In football, having greater acceleration ability may decide the most important moments within matches. Up to now, commonly used acceleration variables have typically been investigated in isolation, with each variable suffering from unique limitations. Subsequently, any findings may provide a limited representation of what specific acceleration demands had actually occurred.

Positional Differences in the Most Demanding Scenarios of External Load Variables in Elite Futsal Matches.

The aims of this study were to analyze the peak physical demands in elite futsal by quantifying the most demanding scenarios of match play and to identify the differences between playing positions (defenders, wingers, and pivots) and the seasonal trend for five different rolling average time windows (30, 60, 120, 180, and 300 s). The most demanding scenarios of external load from distance, speed, acceleration, and deceleration variables were obtained from 14 elite futsal players using a local positioning system during 15 official matches in the premier Spanish Futsal League (2018-2019 season). The results showed an extremely large effect of the time window for all dependent variables in all positional groups.

Convergent Validity of CR100-Based Session Ratings of Perceived Exertion in Elite Youth Football Players of Different Ages.

Purpose: To assess the convergent validity of internal load measured with the CR100 scale in youth football players of 3 age groups.

Methods: A total of 59 players, age 12-17 years, from the youth academy of a professional football club were involved in this study. Convergent validity was examined by calculating the correlation between session ratings of perceived exertion (sRPE) and Edwards load, a commonly used load index derived from the heart rate, with the data originating from 1 competitive season.

Criterion Validity of Catapult ClearSky T6 Local Positioning System for Measuring Inter-Unit Distance.

The validity of a local positioning system (LPS) to measure inter-unit distance was investigated during a team sport movement circuit. Eight recreationally active, female indoor team-sport players completed a circuit, comprising seven types of movements (walk, jog, jump, sprint, 45° change of direction and shuffle), on an indoor court. Participants wore a receiver tag (ClearSky T6, Catapult Sports) and seven reflective markers, to allow for a comparison with the reference system (©Vicon Motion Systems, Oxford Metrics, UK).

Match analysis in Rugby Union: performance indicators of Rugby Championship and Super Rugby teams.

Background: A number of key performance indicators (KPIs) have been found to discriminate between winning and losing performances in Rugby Union competitions. This study aimed to investigate the KPIs of winning and losing teams during recent Rugby Championship and Super Rugby seasons.

Methods: Data from 139 matches during the 2014-2015 Rugby Championship and 2015 Super Rugby were extracted from the SANZAAR website and retrospectively analyzed.

Interunit Reliability and Effect of Data-Processing Methods of Global Positioning Systems.

Purpose: To establish the interunit reliability of a range of global positioning system (GPS)-derived movement indicators, to determine the variation between manufacturers, and to investigate the difference between software-derived and raw data.

Methods: A range of movement variables were obtained from 27 GPS units from 3 manufacturers (GPSports EVO, 10 Hz, n = 10; STATSports Apex, 10 Hz, n = 10; and Catapult S5, 10 Hz, n = 7) that measured the same team-sport simulation session while positioned on a sled. The interunit reliability was determined using the coefficient of variation (%) and 90% confidence limits, whereas between-manufacturers comparisons and comparisons of software versus raw processed data were established using standardized effect sizes and 90% confidence limits.

Validity of Session Rating of Perceived Exertion Assessed via the CR100 Scale to Track Internal Load in Elite Youth Football Players.

Purpose: To assess the convergent validity of the Borg CR100® scale to track internal training load (TL) in youth football players.

Methods: A total of 19 youth football players (age = 15 [1] y, height = 175.9 [12.

Running Intensities in Elite Youth Soccer by Age and Position.

Duthie, GM, Thornton, HR, Delaney, JA, Connolly, DR, and Serpiello, FR. Running intensities in elite youth soccer by age and position. J Strength Cond Res 32(10): 2918-2924, 2018-The purpose of this investigation was to examine differences between the peak running speed, acceleration, and metabolic power of elite youth soccer across a range of age levels by position.

The Occurrence of Repeated High Acceleration Ability (RHAA) in Elite Youth Football.

The aim of the present study was to investigate the occurrence of Repeated High-Acceleration Ability (RHAA) bouts in elite youth football games using 10-Hz GPS devices and two relative thresholds derived from players' actual maximal acceleration. Thirty-six outfield soccer players (age 14.9±0.

Futsal task constraints promote transfer of passing skill to soccer task constraints.

This study investigated how learning a passing skill with futsal or soccer task constraints influenced transfer to a new task. Futsal (n = 24, 13.6 ± 1.

Different Training Modalities Improve Energy Cost and Performance in Master Runners.

The aim of this study was to compare the effects of continuous moderate-intensity and discontinuous high-intensity training on running performance in master runners. Thirty-four male master runners (47.2 ± 7.

Acute exercise alters skeletal muscle mitochondrial respiration and H2O2 emission in response to hyperinsulinemic-euglycemic clamp in middle-aged obese men.

Obesity, sedentary lifestyle and aging are associated with mitochondrial dysfunction and impaired insulin sensitivity. Acute exercise increases insulin sensitivity in skeletal muscle; however, whether mitochondria are involved in these processes remains unclear. The aim of this study was to investigate the effects of insulin stimulation at rest and after acute exercise on skeletal muscle mitochondrial respiratory function (JO2) and hydrogen peroxide emission (JH2O2), and the associations with insulin sensitivity in obese, sedentary men.

Long-term Practice with Domain-Specific Task Constraints Influences Perceptual Skills.

The long-term impact of practice with different task constraints on perceptual skill is relatively un-explored. This study examined the influence of extensive practice, i.e.

Acute High-Intensity Interval Exercise-Induced Redox Signaling Is Associated with Enhanced Insulin Sensitivity in Obese Middle-Aged Men.

Obesity and aging are associated with increased oxidative stress, activation of stress and mitogen activated protein kinases (SAPK), and the development of insulin resistance and metabolic disease. In contrast, acute exercise also increases oxidative stress and SAPK signaling, yet is reported to enhance insulin sensitivity and reduce the risk of metabolic disease. This study explored this paradox by investigating the effect of a single session of high-intensity interval-exercise (HIIE) on redox status, muscle SAPK and insulin protein signaling in eleven middle-aged obese men.