Jocelyn K. Mara

Periodization and Physical Performance in Elite Female Soccer Players

PURPOSE To investigate the variation in training demands, physical performance, and player well-being across a womens soccer season. METHODS Seventeen elite female players wore GPS tracking devices during every training session (N=90) throughout 1 national-league season. Intermittent high-speed-running capacity and 5-, 15-, and 25-m-sprint testing were conducted at the beginning of preseason, end of preseason, midseason, and end of season. In addition, subjective well-being measures were self-reported daily by players over the course of the season. RESULTS Time over 5 m was lowest at the end of preseason (mean 1.148 s, SE 0.017 s) but then progressively deteriorated to the end of the season (P<.001). Sprint performance over 15 m improved by 2.8% (P=.013) after preseason training, while 25-m-sprint performance peaked at midseason, with a 3.1% (P=.05) improvement from the start of preseason, before declining at the end of season (P=.023). Training demands varied between phases, with total distance and high-speed distance greatest during preseason before decreasing (P<.001) during the early- and late-season phases. Endurance capacity and well-being measures did not change across training phases. CONCLUSIONS Monitoring training demands and subsequent physical performance in elite female soccer players allow coaches to ensure that training periodization goals are being met and related positive training adaptations are being elicited.

Validity of a Wearable Accelerometer Device to Measure Average Acceleration Values During High-Speed Running.

Abstract Alexander, JP, Hopkinson, TL, Wundersitz, DWT, Serpell, BG, Mara, JK, and Ball, NB. Validity of a wearable accelerometer device to measure average acceleration values during high-speed running. J Strength Cond Res 30(11): 3007–3013, 2016—The aim of this study was to determine the validity of an accelerometer to measure average acceleration values during high-speed running. Thirteen subjects performed three sprint efforts over a 40-m distance (n = 39). Acceleration was measured using a 100-Hz triaxial accelerometer integrated within a wearable tracking device (SPI-HPU; GPSports). To provide a concurrent measure of acceleration, timing gates were positioned at 10-m intervals (0–40 m). Accelerometer data collected during 0–10 m and 10–20 m provided a measure of average acceleration values. Accelerometer data was recorded as the raw output and filtered by applying a 3-point moving average and a 10-point moving average. The accelerometer could not measure average acceleration values during high-speed running. The accelerometer significantly overestimated average acceleration values during both 0–10 m and 10–20 m, regardless of the data filtering technique (p < 0.001). Body mass significantly affected all accelerometer variables (p < 0.10, partial &eegr;2 = 0.091–0.219). Body mass and the absence of a gravity compensation formula affect the accuracy and practicality of accelerometers. Until GPSports-integrated accelerometers incorporate a gravity compensation formula, the usefulness of any accelerometer-derived algorithms is questionable.

Attacking Strategies That Lead to Goal Scoring Opportunities in High Level Women's Football

This study identified the attacking strategies that lead to goal scoring opportunities in womens football (soccer). All regular season games (n = 34) of the 2010/2011 W-League football competition were coded using performance analysis. Variables described the attacking strategies employed by teams and their association with goal scoring. It was shown that 24% (p < .001) of goals were the result of a cross (a distribution made from a wide area to a central area in front of goal). Further analysis demonstrated that 26% of corner kicks resulted in a shot at goal (p < .001). It was concluded that attacking through the wide areas of the field followed by a cross into a central zone inside the 18-yard box was the most effective strategy for creating goal scoring opportunities in womens football.

The acceleration and deceleration profiles of elite female soccer players during competitive matches

OBJECTIVES The aim of this study was to determine the acceleration (≥2ms-2) and deceleration (≤-2ms-2) profiles of elite female soccer players during competitive matches. DESIGN Single cohort, observational study. METHODS An Optical Player Tracking system was used to determine acceleration (≥2ms-2) and deceleration (≤-2ms-2) variables for twelve elite female players across seven competitive matches. RESULTS In total, players performed 423 (±126) accelerations and 430 (±125) decelerations per match. It was shown that the number of accelerations (p=0.003-0.034, partial η2=0.229-321) and decelerations (p=0.012-0.031, partial η2=0.233-275) at different intensities (based on the start and final velocity) varied according to player position. Mean and maximum distance per effort was 1-4m and 2-8m, respectively, and differed between each intensity category (p<0.001, partial η2=0.753-0.908). The mean time between efforts was 14s for both accelerations (±5s) and decelerations (±4s) and fluctuated between 15min time periods (p<0.001, partial η2=0.148-0.206). CONCLUSIONS The acceleration and deceleration profiles varied according to player position and time period of the match. The results of this study can be used to design match-specific acceleration and deceleration drills to enhance change of speed ability.

Quantifying the High-speed Running and Sprinting Profiles of Elite Female Soccer Players During Competitive Matches Using an Optical Player Tracking System

The aim of this study was to determine the high-speed running and sprinting profiles of elite female soccer players during competitive matches using a new Optical Player Tracking system. Eight stationary video cameras were positioned at vantage points surrounding the soccer field so that when each camera view was combined, the entire field could be viewed simultaneously. After each match, an optical player tracking system detected the coordinates (x, y) of each player for every video frame. Algorithms applied to the x and y coordinates were used to determine activity variables for 12 elite female players across 7 competitive matches. Players covered 9,220-10,581 m of total distance, 1,772-2,917 m of high-speed running (3.4-5.3 m·s) distance, and 417-850 m of sprinting (>5.4 m·s) distance, with variations between positional groups (p < 0.001; partial η = 0.444-0.488). Similarly, the number of high-speed runs differed between positional groups (p = 0.002; partial η = 0.342), and a large proportion of high-speed runs (81-84%) and sprints (71-78%) were performed over distances less than 10 m. Mean time between high-speed runs (13.9 ± 4.4 seconds) and sprints (86.5 ± 38.0 seconds) varied according to playing position (p < 0.001; partial η = 0.409) and time of the match (p < 0.001; partial η = 0.113-0.310). The results of this study can be used to design match-specific conditioning drills and shows that coaches should take an individualized approach to training load monitoring according to position.The aim of this study was to determine the high-speed running and sprinting profiles of elite female soccer players during competitive matches using a new Optical Player Tracking System. Eight stationary video cameras were positioned at vantage points surrounding the soccer field so that when each camera view was combined the entire field could be viewed simultaneously. Following each match, an optical player tracking system detected the coordinates (x,y) of each player for every video frame. Algorithms applied to the x and y coordinates were used to determine activity variables for twelve elite female players across seven competitive matches. Players covered 9,220-10,581 m of total distance, 1,772-2,917 m of high-speed running (3.4-5.3 m·s) distance and 417-850 m of sprinting (>5.4 m·s) distance, with variations between positional groups (p < 0.001, partial η = 0.444-0.488). Similarly, the number of high-speed runs differed between positional groups (p = 0.002, partial η = 0.342) and a large proportion of high-speed runs (81-84 %) and sprints (71-78 %) were performed over distances less than 10 m. Mean time between high-speed runs (13.9 s ± 4.4) and sprints (86.5 s ± 38.0) varied according to playing position (p < 0.001, partial η = 0.409) and time period of the match (p < 0.001, partial η = 0.113 - 0.310). The results of this study can be used to design match-specific conditioning drills, and shows that coaches should take an individualised approach to training load monitoring according to position.

Assessing the Energy Expenditure of Elite Female Soccer Players: A Preliminary Study

Abstract Mara, JK, Thompson, KG, and Pumpa, KL. Assessing the energy expenditure of elite female soccer players: A preliminary study. J Strength Cond Res 29(10): 2780–2786, 2015—The aim of this study was to assess the total and exercise energy expenditure of elite female soccer players during a training week. Eight elite female soccer players wore SenseWear Mini Armbands (SWAs) for 7 consecutive days during the preseason phase of a national league competition. In addition, players wore 15-Hz GPSports tracking devices during 4 training sessions and a friendly game. Total energy expenditure, exercise energy expenditure, and training and game demands were collected from the SWA and GPSports devices. Mean daily energy expenditure for the game day, training days, and rest days were 12,242 kJ (SD = 603 kJ), 11,692 (SD = 274 kJ), and 9,516 (SD = 369 kJ), respectively, with significant differences shown between activities (p < 0.001, partial &eegr;2 = 0.357), as well as between individual days (p < 0.001, partial &eegr;2 = 0.517). Mean values for energy expenditure during the friendly game (mean = 2,695 kJ, SD = 301 kJ) and training sessions (mean = 2,538 kJ, SD = 316 kJ) were similar (p = 0.278, Cohens d = 0.5). However, there were significant differences found between individual training sessions (p = 0.001–0.035). Total and exercise energy expenditure differs throughout the week in female soccer players. Nutritional intake should be adjusted accordingly to avoid energy imbalances for optimal performance and recovery.

Collective team behaviour of Australian Rules football during phases of match play

ABSTRACT Using the spatiotemporal characteristics of players, the primary aim of this study was to determine whether differences in collective team behaviour exist in Australian Rules football during different phases of match play. The secondary aim was to determine the extent to which collective team behaviour differed between competing teams and match half. Data was collected via 10 Hz global positioning system devices from a professional club during a 2 × 20 min, 15-v-15-match simulation drill. Five spatiotemporal variables from each team (x centroid, y centroid, length, width, and surface area) were collected and analysed during offensive, defensive, and contested phases. A multivariate analysis of variance comparing phase of match play (offensive, defensive, contested), Team (A & B), and Half (1 & 2) revealed that x-axis centroid and y-axis centroid showed considerable variation during all phases of match play. Length, width, and surface area were typically greater during the offensive phase comparative to defensive and contested phases. Clear differences were observed between teams with large differences recorded for length, width, and surface area during all phases of match play. Spatiotemporal variables that describe collective team behaviour may be used to understand team tactics and styles of play.

The Accuracy and Reliability of a New Optical Player Tracking System for Measuring Displacement of Soccer Players

Abstract Recently, a novel optical player tracking system has been developed to determine positional information of athletes in a non-invasive manner. The aim of this study was to measure the accuracy and reliability of displacement estimates derived from the system. Participants completed five soccer-specific running courses at three different speeds three times each, while being filmed using the multi-camera system. The participant’s x,y field positions were determined by the optical player tracking system and displacement was estimated using Euclidean distance, and compared with real distance. On average, the difference between actual distance and estimated displacement was 0.25% (mean absolute difference = 0.79 ± 0.56m) with a slightly larger coefficient of variation during 90° turns (4.89%) when compared with straight line running (4.09%). In addition, there were strong correlations between actual distance and measured displacement (r = 0.986 – 0.988). Collectively, the typical error (0.25 – 0.36 m), typical error as a coefficient of variation (1.06 – 1.75%) and intraclass correlation coefficient (0.88 – 0.93) showed high levels of intra-operator reliability. The optical player tracking system provides accurate and reliable estimates of displacement of players on a soccer field. This system provides non-invasive position detections for players and opposition players during soccer matches.