Impaired pre-competition wellbeing measures can negatively impact running performance in developmental youth female soccer players.

This study aimed to determine the association between pre-competition perceived player wellbeing measures and subsequent relative and peak running performance of developmental youth female soccer players (n = 15, age: 16 ± 1 years). Total distance (TD), high-speed (> 3.5 m/s) (HSRD) and very high-speed (> 5.3 m/s) running (VHSRD) were expressed using 1-, 2- and 5-minute epochs and relative (per minute) calculations. Fatigue, sleep quality, upper and lower-body muscle soreness, stress, and mood wellbeing measures were collected via a self-reported questionnaire (1-5 Likert scale). Menstrual cycle phase was collected via a calendar-based countback method. Results demonstrated that reductions in stress was associated with decreased relative and peak TD in all epochs (p = 0.008-0.040), relative and peak HSRD (p = 0.006-0.039) in 2- and 5-minute epochs as well as VHSRD in 2-minute epochs (p = 0.026). For example, a one-point reduction of 'normal' to 'relaxed' is associated with a decrease of 7 m/min in peak TD for 1-minute epochs. One-point increase in fatigue (e.g., 'normal' to 'more tired than normal') displayed a decrease of 7 m/min peak TD for 2-minute (p = 0.048) and 9 m/min for 5-minute (p = 0.007) rolling epochs. Likewise, one-point increase in lower-body muscle-soreness (e.g., 'normal' to 'increase in soreness/tightness') was associated with a reduction of 6 m/min peak VHSRD for 1-minute epochs (p = 0.034). Results suggest that perceived player wellbeing can influence running performance. However, the magnitude of the change in player wellbeing should be considered in a practical sense.

Gender and socioecological level differences in stakeholders' perceptions of athlete attrition factors in an Australian high-performance pathway system.

OBJECTIVES: This study aimed to build on previous work by the authors. It examines how socioecological level and gender influence high-performance sport system (HPSS) stakeholders' perspectives of the relative importance and feasibility to address athlete attrition factors within an Australian high-performance pathway system (HPPS). DESIGN: Mixed methods. METHODS: Sub-analysis was conducted of rating data from 30 participants who had contributed to identifying 83 statements in 13 clusters in a previous Concept Mapping study. The 13 clusters were statistically analysed in 'R' using cumulative link mixed models (CLMMs) to determine differences in perceived importance and feasibility between 1) socioecological levels, and 2) genders. RESULTS: Mean ratings for 11 and three of the 13 clusters were statistically significantly different between at least two of the five socioecological levels, for importance and feasibility, respectively. Athletes had the largest variation in mean ratings from the most (athlete health 4.59), to least (performance potential 2.83) important cluster, when compared to the other four socioecological levels. There were statistically significant differences between the ratings between genders (Men/Women) for two clusters for each rating scale: Importance: 'athlete health' (M3.33:W3.84 [p 0.012]); 'performance potential' (M3.35:W2.57; [p 0.001]), Feasibility: 'abuse and mismanagement of health' (M2.97:W3.68; [p 0.000]) and 'athlete health' (M2.54:W3.33; [p 0.000]). CONCLUSIONS: This study highlights the need to implement more robust athlete attrition monitoring protocols. It also highlights the importance of listening to youth athletes' voices, and enabling equal gender representation to ensure holistically tailored environments are created to retain talented athletes in high-performance pathway programmes.

The Effects of a Field-Based Priming Session on Perceptual, Physiological, and Performance Markers in Female Rugby Sevens Players.

PURPOSE: This study aimed to determine the effects of a field-based priming session on perceptual, physiological, and performance responses in female rugby sevens athletes. METHODS: Thirteen highly trained female rugby sevens players (age: 20.7 [2.0] y; height: 169.3 [4.8] cm; weight: 68.8 [7.9] kg) completed either a 20-minute field-based priming session or a control condition. Perceptual, physiological, and performance variables were collected at baseline (PRE) and 5 (POST5), 30 (POST30), and 120 minutes (POST120) postintervention. Data were analyzed using Bayesian mixed effects models. RESULTS: The priming protocol had a larger increase in mental readiness (maximum a posteriori [MAP] = 20, 95% high-density intervals [HDI] = -4 to 42, probability of direction [PD]% = 95, % in region of practical equivalence [ROPE] = 9.7), physical readiness (MAP = 20.1, 95% HDI = -4.6 to 42.1, PD% = 93, % in ROPE = 10.6), and testosterone (MAP = 14.9, 95% HDI = 0.5 to 27.7, PD% = 98, % in ROPE = 5.6) than the control POST30. Cognitive performance decreased POST120 in the priming condition for congruent (MAP = 0.02, 95% HDI = -0.06 to 0.00, PD% = 95, % in ROPE = 6.4) and incongruent tasks (MAP = 0.00, 95% HDI = -0.07 to 0.00, PD% = 98, % in ROPE = 3.2) when compared with the control. CONCLUSIONS: Perceptual and physiological markers improved POST30 in the priming condition. Findings indicate that perceptual and physiological responses to priming were not coupled with performance improvements. Priming was not accompanied by perceptual, physiological, or performance improvements at POST120.

Predicting the unpredictable: analysing the entropy and spatial distribution of ball movement patterns in field hockey.

Analysing the ball movement patterns of team invasion sports provides practical insight into successful strategies by identifying how and where to move the ball to create goal scoring opportunities. The aim of this study was to analyse the entropy and spatial distribution of ball movement patterns in international field hockey teams. A notational analysis system was developed in SportsCode to analyse 131 matches (n = 57 men, n = 74 women) from the 2019 Pro League tournament. The start and end location of each ball movement and the outcome of each play was recorded. Calculated variables included game possession (%), entropy, possession per zone (%) and progression rates. Decision trees identified that higher circle possession and direct movements to goal from deep attack, and lower build attack and build defence entropy, were the strategies most likely to lead to goal shots. However, teams should be unpredictable when the opposition are organised to maintain possession and unbalance the defence. Match context only had small effects on ball movement strategies highlighting there is more than one way to be successful. Executing strategies that exploit these factors should lead to greater attacking opportunities and success. Analysing the dynamic, complexity of international hockey allows coaches to prepare specific strategies for individual teams.

Substitute running outputs in elite youth male soccer players: less peak but greater relative running outputs.

Coaches consider substitute players to be a substantial factor in influencing the outcome of a soccer match. Substitute players are expected to make physical impact on the match by superseding the running output of the player they replaced and are a key tool for managing in-game fatigue and influencing the outcome of a game. This study investigated the physical impact and internal response of substitute players, compared to starting and full-match players. We also sought to determine if differences between substitution statuses were influenced by playing position. Players wore 15-Hz global positioning system tracking devices across 29 competition matches and were categorised according to their substitution status (full-match, starters, substitutes) and playing position (external defender, midfield, external attacker and central attacker). Peak total (TD) and high-speed running (> 5.0 m/s) distance (HSRD) were calculated using 1-, 2- and 5-minute rolling epochs. Relative running demands were reported as TD and HSRD per minute of total playing time. Substitute players performed less peak TD and HSRD in 1-, 2- and 5-minute epochs, and reported lower RPE compared to starting and full-match players. In contrast, substitutes performed greater relative HSRD per minute than starting and full-match players (p < 0.001, |d| range = 0.35-1.34). In conclusion, substitute players may have a relative physical impact but do not replicate or supersede the peak demands of full-match players. Coaches and practitioners should implement targeted warm-up interventions to enhance substitute readiness to meet the peak running demands in order to have a more effective physical impact.

Do conditioning focused various-sided training games prepare elite youth male soccer players for the demands of competition?

Relative metrics (i.e. distance covered per minute of match time) are regularly used to quantify soccer player movement demands. However, limited literature is available concerning the peak player demands during training. This study aimed to compare the relative and peak demands of conditioning-focused various-sided training games (VSG) to competition matches in elite youth male soccer players according to playing position. Data from twenty-nine competition matches (national) and twenty-two VSGs (small, medium, and large) were collected for twenty-three elite under-17 soccer players using 15-Hz portable global positioning system tracking devices (GPSports, Canberra, Australia). Relative player movements were reported as total distance (TD) and high-speed running distance (HSRD) (> 5.0 m/s) per minute of total playing time. Peak player movements were calculated using a 1-minute rolling epoch length, reported as the maximum TD and HSRD. Linear mixed models demonstrated interactions between VSG type and player position for relative TD (p < 0.001) and HSRD (p < 0.001), and peak TD (p = 0.010) and HSRD (p = 0.003). The relative TD of VSGs were greater than match-play for all player positions. However, only Central Defenders demonstrated similar HSRD in MSGs and LSGs compared to match-play when analysed using relative calculations. External Attackers also replicated match-play relative HSRD demands in LSGs. No VSG type was found to replicate or supersede the peak player movements of match-play across any playing position. Consequently, VSGs should be supplemented with high-speed running training to prepare players for the peak running requirements of match-play.

Women with larger breasts are less satisfied with their breasts: Implications for quality of life and physical activity participation.

INTRODUCTION: Although low breast satisfaction has been associated with a range of potential negative health implications, little is known about key factors that influence breast satisfaction across the lifespan. This study aimed to determine the impacts of age, body mass and breast size on breast satisfaction and how breast satisfaction impacts psychosocial and sexual well-being-related quality of life outcomes and physical activity behaviours. METHODS: Three hundred and forty-five women (age range: 18.1-83.7 years) had their body mass (kg), standing height (cm) and breast volume (ml) measured. A 13-item questionnaire comprising the Breast-Q and Active Australia Survey was used to assess breast satisfaction, quality of life outcomes and participation in physical activity. RESULTS: Breast satisfaction was influenced by breast size, such that women with larger breasts were less satisfied with their breasts compared to their counterparts with smaller breasts. Greater breast satisfaction was associated with improved psychosocial and sexual well-being-related measures of quality of life, and time spent participating in physical activity. CONCLUSION: Interventions to improve breast satisfaction among women across the breast size spectrum should be encouraged in public health initiatives to better engage and encourage positive health behaviours and reduce potential adverse health implications.

Capture, analyse, visualise: An exemplar of performance analysis in practice in field hockey.

The goal of performance analysis is to capture the multitude of factors that affect sports strategy, and present them in an informative, interpretable, and accessible format. The aim of this study was to outline a performance analysis process in field hockey that captures, analyses and visualises strategy in layers of detail culminating in the creation of an RStudio Shiny application. Computerised notational analysis systems were developed to capture in-game events and ball tracking data of 74 matches from the Women's Pro League 2019. Game styles were developed using k-means cluster analysis to reduce detailed in-game events into practical profiles to identify the attack types, game actions and tempo of a team's strategy. Ball movement profiles were developed to identify the predictability (entropy) and direction (progression rates) of ball movements, and consequent distribution of possession in different attacking zones. The Shiny application, an interactive web-platform, links the information from simple game profiles with detailed game variables to understand each teams' holistic game plan, how they are different, and how to exploit these differences. The process outlined can be applied to any team invasion sport to understand, develop and communicate successful strategies under different match situations.

Identifying and analysing game styles and factors influencing a team's strategy in field hockey.

Characterising a team's game style is a performance analysis approach that captures game events, and groups them into profiles using clustering techniques to identify the consistent (and winning) strategies a team implements. The aim of this study was to identify the game styles of international hockey teams. Video footage from the 2019 Pro League tournament (n = 74 female and n = 57 male matches) were analysed retrospectively using a notational analysis system in SportsCode™. Variables were arranged into six game style categories (established attack game actions, counter attack game actions, established attack success, counter attack success, set pieces, tempo) and two game style types identified per category using a k-means clustering algorithm. Decision trees were used to identify the influence of extrinsic and intrinsic match factors on the probability of a team playing a particular game style. Opposition and other reference team game style categories were shown to be more important in predicting a game style category than contextual factors. Examination of team profiles highlights how different strategies are successful for different teams such as high-intensity attack or absorbing pressure and counter attacking. This performance analysis process provides practical insights into the holistic performance of international hockey teams.

Identifying women at risk of weight gain after a breast cancer diagnosis: Results from a cohort of Australian women.

ISSUES ADDRESSED: This study aimed to identify risk factors associated with weight gain post a diagnosis of breast cancer in a cohort of Australian women. METHODS: In this retrospective clinical audit, objectively measured weight, age and menopause status, treatment type/s, grade, stage, oestrogen receptor and progesterone receptor (PR) status were extracted for 73 breast cancer patients from an ongoing breast cancer treatment quality assurance project. Weight gain or loss was classified as a body mass increase or decrease of ≥5% of weight at diagnosis. RESULTS: When compared to weight at diagnosis, 57% of patients maintained, 22% gained, and 21% lost weight at 24 months post-diagnosis. Factors associated with weight gain were a diagnosis of grade II (P < .001) or grade III (P < .001) compared to grade I breast cancer, and refusal of radiotherapy (P < .001). Factors associated with weight loss were being postmenopausal compared to premenopausal (P = .033), PR positive compared to PR negative (P < .001), refusal of chemotherapy (P < .001) and radiotherapy recommended (P < .001). CONCLUSIONS: The maintenance of weight in a majority of women in this cohort is a novel finding. Early identification of women at risk of weight gain post a breast cancer diagnosis can assist health professionals identify, and therefore assisting patients in the prevention and management of weight gain and associated sequela. Investigating the weight-related communications between a patient and specialist, their access to allied health professionals and social support may assist in understanding the overall positive changes in this cohort.

How Do the Habitual Sleep Patterns of Elite Female Basketball and Soccer Athletes Compare With the General Population?

PURPOSE: To compare the habitual sleep of female basketball and soccer athletes to age- and sex-matched controls and to characterize the sleep of basketball and soccer athletes at different competition locations and on the days surrounding competition. METHODS: Using an observational case-control design, 41 female participants were recruited to participate, consisting of 11 basketball athletes (mean [SD]: age = 24.1 [4.9] y), 10 soccer athletes (24.8 [6.4] y), and 20 nonathletic controls (24.2 [2.8] y). Sleep was monitored using actigraphy for four 7-day periods throughout the preseason and subsequent competition season. Generalized linear models were used to analyze the effect of group and competition situation (eg, Home or Away) on sleep. RESULTS: During habitual conditions, basketball athletes had longer sleep durations (7.4 [1.5] h) than soccer athletes (7.0 [1.2] h, P < .001) and controls (7.3 [1.2] h, P = .002). During competition, basketball and soccer athletes had longer sleep durations following home (7.7 [1.7] and 7.2 ± 1.3 h) compared with away games (6.8 [1.8] and 7.0 [1.3] h). In addition, basketballers went to bed earlier (23:49 [01:25]) and woke earlier (07:22 [01:59]) following away games compared with soccer athletes (00:10 [01:45] and 08:13 [01:45]). CONCLUSIONS: Basketballers had longer habitual sleep durations compared with soccer athletes and nonathletic controls. During competition, basketballers had earlier bed and wake times compared with soccer athletes following away games, highlighting the need for individualized sleep strategies.

Relationship between heart rate variability and body mass index: A cross-sectional study of preschool children.

Reduced heart rate variability (HRV) is associated with overweight and obesity in adults. However, little is known about this relationship in early childhood. We investigated the relationship between resting vagally-mediated HRV and body mass index (BMI) in Australian preschool children. Children were recruited from 13 non-government early learning centres located in Queensland and New South Wales, Australia. From this population-based sample, data from 146 healthy children (58 females) between 3 and 5 years of age (mean age 4.35 ± 0.44 years) were analysed. BMI was calculated from child body weight and height. Physical activity was recorded using an Actigraph wGT3x accelerometer worn at the waist of participants over 3 consecutive days. A Polar H10 chest strap measured seated, resting RR intervals for the calculation of HRV with the root mean square of successive differences (RMSSD) reflecting vagally-mediated activity. The relationship between HRV and BMI was analysed using a linear mixed model adjusted for age, sex and physical activity. Analysis revealed that RMSSD (ln) demonstrated a significant inverse relationship with BMI (ß = -0.06; 95% CI = -0.12 - -0.01; p = 0.032), and the model accounted for 23% of the variance in RMSSD (ln). Notably, a one unit increase in BMI resulted in a reduction in RMSDD (ln) of 0.06. This investigation demonstrated evidence for a significant inverse linear relationship between vagally-mediated HRV and BMI in 3 - 5-year-old Australian children, similar to that of adults. Furthermore, this relationship was independent of age, sex and physical activity levels. Results may indicate that the cardiometabolic health of preschool children is, in part, influenced by the relationship between vagally-mediated HRV and weight status.

Methods of performance analysis in team invasion sports: A systematic review.

The objective of this review was to systematically describe the traditional and contemporary data capture and analytic methods employed in performance analysis research in team invasion sports, evaluate the practicality of these methods, and formulate practical recommendations on methods for analysing tactics and strategies in team invasion sports. A systematic search of the databases SPORTDiscus, Web of Science, Scopus, MEDLINE and PubMed was performed. Keywords addressed performance analysis methods and team invasion sports, with all other disciplines of sports science excluded. A total of 537 articles were included in the review and six main themes of research identified. Themes included game actions, dynamic game actions, movement patterns, collective team behaviours, social network analysis and game styles. Performance analysis research has predominantly focused on identifying key performance indicators related to success by analysing differences in game actions between successful and less successful teams. However, these measures are outcome-focused and only provide limited insight into winning team's strategy. Team invasion sports are now viewed as dynamic, complex systems with opposing teams as interacting parts. Strategies and tactics should be analysed using a holistic process-orientated approach by recording dynamic actions, collective team behaviours and passing networks, and viewing them in game styles.

The influence of match phase and field position on collective team behaviour in Australian Rules football.

This study investigated the influence of match phase and field position on collective team behaviour in Australian Rules football (AF). Data from professional male athletes (years 24.4 ± 3.7; cm 185.9 ± 7.1; kg 85.4 ± 7.1), were collected via 10 Hz global positioning system (GPS) during a competitive AFL match. Five spatiotemporal metrics (x-axis centroid, y-axis centroid, length, width, and surface area), occupancy maps, and Shannon Entropy (ShannEn) were analysed by match phase (offensive, defensive, and contested) and field position (defensive 50, defensive midfield, forward midfield, and forward 50). A multivariate analysis of variance (MANOVA) revealed that field position had a greater influence on the x-axis centroid comparative to match phase. Conversely, match phase had a greater influence on length, width, and surface area comparative to field position. Occupancy maps revealed that players repositioned behind centre when the ball was in their defensive half and moved forward of centre when the ball was in their forward half. Shannon Entropy revealed that player movement was more variable during offence and defence (ShannEn = 0.82-0.93) compared to contest (ShannEn = 0.68-0.79). Spatiotemporal metrics, occupancy maps, and Shannon Entropy may assist in understanding the game style of AF teams.

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

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.

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 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.

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

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 η = 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.

Physical and Physiological Characteristics of Various-Sided Games in Elite Women's Soccer.

PURPOSE: To investigate the physical and physiological response to different formats of various-sided games. METHODS: Eighteen elite women's soccer players wore 15-Hz global positioning system devices and heart-rate (HR) monitors during various-sided games (small, 4 vs 4 and 5 vs 5; medium, 6 vs 6 and 7 vs 7; large, 8 vs 8 and 9 vs 9). RESULTS: Players covered more relative sprinting distance during large-sided games than in small-sided (P < .001, d = 0.69) and medium-sided (P < .001, d = 0.54) games. In addition, a greater proportion of total acceleration efforts that had a commencement velocity <1 m/s were observed in small-sided games (44.7% ± 5.5%) than in large-sided games (36.7% ± 10.6%) (P = .018, d = 0.94). This was accompanied by a greater proportion of acceleration efforts with a final velocity equivalent to the sprint threshold in large-sided games (15.4% ± 7.7%) than in small-sided games (5.2% ± 2.5%) (P < .001, d = 1.78). The proportion of time spent in HR zone 4 (>85% maximum HR) was greater during small-sided games (69.8% ± 2.5%) than in medium- (62.1% ± 2.8%, d = 2.90) and large-sided games (54.9% ± 3.1%) (P < .001, d = 5.29). CONCLUSIONS: The results from this study demonstrate that coaches can use small-sided games as an aerobic conditioning stimulus and to develop players' explosiveness and repeat-sprint ability over short durations. Large-sided games can be used to maintain aerobic capacity and develop maximum speed over longer distances.

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

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 η2 = 0.357), as well as between individual days (p < 0.001, partial η2 = 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, Cohen's 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.