Recreational Football Training Increases Leg-Extensor Velocity Production in 55- To 70-Year Old Adults: A Randomized Controlled Trial.

This study investigated the effects of 10 weeks of recreational football training on the leg-extensor force-velocity (F-V) profile in 55- to 70-year-old adults. Simultaneous effects on functional capacity, body composition and endurance exercise capacity were examined. Forty participants (age 63.5 ± 3.9 years; 36♂ 4♀) were randomized in a football training (FOOT, n = 20) and a control (CON, n = 20) group. FOOT performed 45-min to 1-h of football training sessions with small-sided games twice a week. Pre- and post-intervention assessments were performed. The results revealed a greater increase in maximal velocity (d = 0.62, pint = 0.043) in FOOT compared to CON. No interaction effects were found for maximal power and force (pint > 0.05). 10-m fast walk improved more (d = 1.39, pint < 0.001), 3-step stair ascent power (d = 0.73, pint = 0.053) and body fat percentage (d = 0.61, pint = 0.083) tended to improve more in FOOT than in CON. RPE and HR values at the highest speed level during a submaximal graded treadmill test decreased more in FOOT compared to CON (RPE: d = 0.96, pint = 0.005; HR: d = 1.07, pint = 0.004). Both the number of accelerations and decelerations as well as the distance spent in moderate- and high-speed zones increased markedly throughout the 10-week period (p < 0.05). Participants perceived the sessions as very enjoyable and feasible. In conclusion, recreational football training resulted in improved leg-extensor velocity production, which translated to a better performance on functional capacity tests that rely on a high execution velocity. Simultaneously, exercise tolerance was improved and body fat percentage tended to reduce. It appears that short-term recreational football training can induce broad-spectrum health benefits in 55- to 70-year-old adults with only 2 hours of training per week.

Video assistant referees (VAR): The impact of technology on decision making in association football referees.

The use of technology has been proposed to improve decision-making in sport officials. The implementation of the video Assistant Referee (VAR) in association football is one example of how technology can be used to assist decision making, although its impact remains unknown. In 2195 competitive football matches across 13 countries, the VAR conducted 9732 checks for potential match-changing incidents, with the median duration of a check being 22 seconds. The checks resulted in a total of 795 reviews, with a median duration of 62.0 s for on-field reviews (N = 534) and 15.0 s for VAR-only reviews (N = 261).We report that the predictive odds for making the correct decision after VAR intervention were significantly higher than for the initial referee's decision, with accuracy increasing from 92.1% to 98.3%. Findings have implications for the current debate about the introduction of technology in association football and may help set guidelines regarding the use of technology across other sports and professional domains.

The Constituent Year Effect in European Track and Field Masters Athletes: Evidence of Participation and Performance Advantages.

Inequalities in relative age distribution have previously been demonstrated to influence participation and performance achievements in Masters athletes. The purpose of the present study was to examine the participation- and performance-related constituent year effect among Masters athletes (N = 2,474) from the European Masters Track and Field Championships across subdisciplines and age. The results indicated that a participation-related constituent year effect was observed. The likelihood of participation was significantly higher for athletes in their first year of any 5-year age category (χ2 = 149.8, p < .001) and decreased significantly when they were in the fourth or fifth year. The results also indicated a performance-related constituent year effect. Masters athletes in their first year won significantly more medals than expected based on observed participation rate (χ2 = 23.39, p < .001). We compare our results with the existing literature and discuss potential mechanisms for this constituent year effect.

Effects of wrist tendon vibration and eye movements on manual aiming.

In the present study, we investigated whether visual information mediates a proprioceptive illusion effect induced by muscle tendon vibration in manual aiming. Visual information was gradually degraded from a situation in which the targets were present and participants (n = 20; 22.3 ± 2.7 years) were permitted to make saccadic eye movements to designated target positions, to a condition in which the targets were not visible and participants were required to perform cyclical aiming while fixating a point between the two target positions. Local tendon vibration applied to the right wrist extensor muscles induced an illusory reduction of 15% in hand movement amplitude. This effect was greater in the fixation than in the saccade condition. Both anticipatory control and proprioceptive feedback are proposed to contribute to the observed effects. The primary saccade amplitude was also reduced by almost 4% when muscle tendon vibration was locally applied to the wrist. These results confirm a tight link between eye movements and manual perception and action. Moreover, the impact of the proprioceptive illusion on the ocular system indicates that the interaction between systems is bidirectional.

Does Visual Attention Impact on Decision Making in Complex Dynamic Events?

In recent years, several publications examined the underlying mechanisms that might have an impact on decision-making processes under time pressure. This study investigated how individual differences in attentional capability relate to decision making in complex dynamic offside events. A total of 24 professional football assistant referees (ARs) performed an offside decision-making task and an attention-demanding task. ARs with higher attentional capability along the horizontal meridian of their attentional focus made fewer mistakes when judging offside situations in football than ARs with lower capability. This implies that being able to rely on high-attentional capabilities in situations requiring conscious perception of multiple processes is likely to be beneficial for the ultimate decision-making performance.

Using web-based training to enhance perceptual-cognitive skills in complex dynamic offside events.

In association football, the difficulty in making offside decisions depends on both perceptual and cognitive processes. Therefore, the objectives of the present study were to enhance the decision-making skills of assistant referees by further developing their ability to (1) time slice the incoming information flow into series of isolated time frames during an ongoing offside situation and (2) use this information to mentally read off the spatial positions of the key-role players. Training (n = 10) and control groups (n = 10) were exposed to a pre- and post-test, consisting of an offside decision-making and frame recognition test. In the latter, assistant referees were asked to indicate which of five photos best represented the spatial position of the defender and attacker at the moment of the pass. Only the training group received 12 web-based offside training sessions. First, the training group improved in mentally freezing, holding and scanning the mental picture of the offside situation in short-term memory from pre- to post-test, as evidenced by an increased recognition accuracy. Second, the improvement in recognition accuracy resulted in enhanced performance on the offside decision-making task. The benefits of web-based training are highlighted.

Factors underlying age-related changes in discrete aiming.

Age has a clear impact on one's ability to make accurate goal-directed aiming movements. Older adults seem to plan slower and shorter-ranged initial pulses towards the target, and rely more on sensory feedback to ensure endpoint accuracy. Despite the fact that these age-related changes in manual aiming have been observed consistently, the underlying mechanism remains speculative. In an attempt to isolate four commonly suggested underlying factors, young and older adults were instructed to make discrete aiming movements under varying speed and accuracy constraints. Results showed that older adults were physically able to produce fast primary submovements and that they demonstrated similar movement-programming capacities as young adults. On the other hand, considerable evidence was found supporting a decreased visual feedback-processing efficiency and the implementation of a play-it-safe strategy in older age. In conclusion, a combination of the latter two factors seems to underlie the age-related changes in manual aiming behaviour.

The impact of age and physical activity level on manual aiming performance.

Older adults traditionally adapt their discrete aiming movements, thereby traveling a larger proportion of the movement under closed-loop control. As the beneficial impact of a physically active lifestyle in older age has been described for several aspects of motor control, we compared the aiming performance of young controls to active and sedentary older adults. To additionally determine the contribution of visual feedback, aiming movements were executed with and without saccades. Results showed only sedentary older adults adopted the typical movement changes, highlighting the impact of a physically active lifestyle on manual aiming in older age. In an attempt to reveal the mechanism underlying the movement changes, evidence for an age-related decline in force control was found, which in turn resulted in an adapted aiming strategy. Finally, prohibiting saccades did not affect older adults' performance to a greater extent, suggesting they do not rely more on visual feedback than young controls.

The use of 2D and 3D information in a perceptual-cognitive judgement task.

We examined whether the use of three-dimensional (3D) simulations in an off-field offside decision-making task is beneficial compared to the more widely available two-dimensional (2D) simulations. Thirty-three assistant referees, who were all involved in professional football, participated in the experiment. They assessed 40 offside situations in both 2D and 3D formats using a counterbalanced design. A distinction was made between offside situations near (i.e., 15 m) and far (i.e., 30 m) from the touchline. Subsequently, a frame recognition task was performed in which assistant referees were asked to indicate which of the five pictures represented the previous video scene. A higher response accuracy score was observed under 3D (80.0%) compared to 2D (75.0%) conditions, in particular for the situations near the touchline (3D: 81.8%; 2D: 72.7%). No differences were reported between 2D and 3D in the frame recognition task. Findings suggest that in highly dynamic and complex situations, the visual system can benefit from the availability of 3D information, especially for relatively fine, metric position judgements. In the memory task, in which a mental abstraction had to be made from a dynamic situation to a static snapshot, 3D stereo disparities do not add anything over and beyond 2D simulations. The specific task demands should be taken into account when considering the most appropriate format for testing and training.

Experts in offside decision making learn to compensate for their illusory perceptions.

In association football, the flash-lag effect appears to be a viable explanation for erroneous offside decision making. Due to this spatiotemporal illusion, assistant referees (ARs) perceive the player who receives the ball ahead of his real position. In this experiment, a laboratory decision-making task was used to demonstrate that international top-class ARs, compared with amateur soccer players, do not have superior perceptual sensitivity. They clearly modify their decision criterion according to the contextual needs and, therefore, show a higher response bias toward not responding to the stimulus, in particular in the most difficult situations. Thus, international ARs show evidence for response-level compensation, resulting in a specific cost (i.e., more misses), which clearly reflects the use of particular (cognitive) strategies. In summary, it appears that experts in offside decision making can be distinguished from novices more on the cognitive or decision-making level than on the perceptual level.

The assessment of the match performance of association football referees: Identification of key variables.

The purpose of this study was to understand the contribution of each performance indicator to evaluate match performance of football referees. Thirty-four elite Referee Match Observers (RMOs) from the Portuguese FA participated voluntarily in the study. From the official assessment sheet of each game, the referee's game score was categorized in two groups according to referee's game score: i) Referees with a Low Score (LFS) and ii) Referees with High Score (HFS). A multivariable binary logistic regression model was used to assess the relationship between the Performance Indicators (PIs) of the dimensions i) game difficulty and game intervention and ii) disciplinary actions and game management in relation to the referee's match assessment score. The model proposed revealed that only the PIs negative application of the laws of the game and referee teamwork, from the dimension disciplinary actions and game management, significantly defined the final game referee's assessment score. This study suggests that the PIs scored by the RMOs contributed in a different way to the referee's game score. The model explains 60.4% of the referee's game score based on the variables referee teamwork and negative application of the laws of the game.

The relationships between relative age effect, personality constructs and achievement level in soccer.

Introduction: Youth soccer academies are challenged with the constant recruitment process of young talented players to select those who will achieve long-term success as an athlete. Youth soccer academies strive to enhance the physical and technical skill development as well as personality development of talented players because psychological characteristics play a crucial role in players' future success in their transition to professional soccer. The least mature players and relatively young players may have a greater need to possess superior technical/tactical or psycho-behavioral skills than those relatively older counterparts because of the higher selection rates of early maturing players. Due to RAEs, a significant decrease in the overall quality of professional soccer teams might be observed because of the loss of talent of physically smaller, but psychologically stronger and more versatile relatively young players who possess proper technical and tactical attributes at an early age. The first objective of this study was to examine any possible relationship between RAE and personality constructs. A second objective was to identify factors and effects that can help in the further improvement of talent selection and equal opportunities for elite youth soccer players based on their underlying RAE. The third objective was to consider the impact of RAE on long-term career development. Methods: In this retrospective observational study, 151 elite youth soccer players between 15 and 18 years of age were first grouped in birth quartiles. Personality constructs were then assessed, using a combination of observations, interviews, and a self-assessment questionnaire. Next competition level after 8 years was evaluated to identify RAEs, differences in personality characteristics and opportunities to reach professional soccer player status between relatively older vs. younger players. Results: A clear significant RAE was observed for the whole database (Q1 = 38.4% vs. Q4 = 13.9%) with OR of 2.61 (χ2 = 19.46, p < 0.01, r = -0.85). Relatively young players had higher median scores on personality constructs such as self-confidence (p = 0.04), while relatively old players had higher median scores on personality constructs such as team orientation (p = 0.03). In the long term, more players of the youngest birth quartile were signed as professional players (76.2%), compared with relatively old players (46.6%). 65.0% of the 20 players had the highest total score on personality constructs developed as a professional soccer player, vs. 35.0% of the 20 players with the lowest scores. Discussion: In conclusion, this study showed not only further evidence of the RAE but also provided evidence supporting "the underdog hypothesis" in national elite youth teams. Relatively young players were also more likely to get higher value senior professional contracts in the long term. We propose that this may be due to the relatively young players developing superior psychological skills and technical expertise to compensate for their early physical disadvantage. This in turn suggests the need for greater awareness of the importance of personality constructs in the future development of youth elite soccer players. Therefore, the crux of the issue is how youth soccer academies elicit the "best of both worlds" ie. moderating RAE whilst also gaining the benefits of the underdog hypothesis by creating the right environment for every player to develop to their full potential in elite youth soccer academies.

A lab-based comparison of differential ratings of perceived exertion between a run and jump protocol involving low or high impacts on the lower extremities.

The rating of perceived exertion method (RPE) allows to describe training intensity in a single value. To better understand the underlying components, the separate rating of perceived breathlessness (RPE-B) and leg-muscle exertion (RPE-L) has been proposed. Here we hypothesised that the separation between the two components may (partly) be determined by the impacts on the lower extremities. In this study, we aimed to experimentally evaluate the differential effect of high versus low impact running and jumping on RPE-B and RPE-L in team sport activities by manipulating the movement strategy (heel strike and passive landing pattern versus forefoot strike and active landing pattern). Eighteen recreational team sport players participated in two submaximal tests consisting of a sequence of running and jumping bouts, whilst ground reaction forces (GRF) were collected. RPE-B and RPE-L data were collected after each bout using the CR100 scale. Paired-samples t-tests were used to analyse between-session differences in these variables. GRF analysis showed that absorption mechanics differed considerably between the two sessions. RPE-L was on average 6.50 AU higher in the low impact session (p = 0.006). However, RPE-B was also increased by 4.96 AU with low impact (p = 0.009). We conclude that the extent to which the lower extremities are being exposed to high or low impacts does not explain a possible separation between the two RPE types.HighlightsThe separate rating of the different underlying components of RPE (e.g. variables related to the cardiorespiratory and the muscular system) may provide more insight in the relationship between training load and training outcomes, which likely differs between these components.The findings of this study do not support the idea that the separation in rating between perceived breathlessness (RPE-B, cardiorespiratory) and leg-muscle exertion (RPE-L, muscular) is also rooted in the extent to which musculoskeletal structures in the lower extremities are being exposed to high or low impacts.

Hemispheric asymmetries in goal-directed hand movements are independent of hand preference.

Asymmetries in the kinematics and neural substrates of voluntary right and left eye-hand coordinated movements have been accredited to differential hemispheric specialization. An alternative explanation for between-hand movement differences could result from hand preference related effects. To test both assumptions, an experiment was conducted with left- and right-handers performing goal-directed movements with either hand paced by a metronome. Spatiotemporal accuracy was comparable between hands, whereas hand peak velocity was reached earlier when moving with the left compared to the right hand. The underlying brain activation patterns showed that both left- and right-handers activated more areas involved in visuomotor attention and saccadic control when using their left compared to the right hand. Altogether, these results confirm a unique perceptuomotor processing specialization of the left brain/right hand system that is independent of hand preference.

The relative age effect in European professional soccer: did ten years of research make any difference?

The relative age effect (RAE) refers to an asymmetry in the birth-date distribution favouring players born early in the selection year and discriminating against participants born later in the year. While the RAE effect was initially reported in sport more than two decades ago, there have been few attempts to examine whether player selection strategies have changed over time in light of our improved understanding of the phenomenon. We compared the birth-date distributions of professional soccer players in ten European countries over a 10-year period involving the 2000-2001 and 2010-2011 competitive seasons, respectively. Chi-square goodness-of-fit tests were used to compare differences between the observed and expected birth-date distributions across selection years. Generally, results indicated no change in the RAE over the past 10 years in professional soccer, emphasizing the robust nature of this phenomenon. We propose a change in the structure of youth involvement in soccer to reduce the impact of the RAE on talent identification and selection.

Leveling the Playing Field: A New Proposed Method to Address Relative Age- and Maturity-Related Bias in UK Male Academy Soccer Players.

Relative age selection bias persists within all major soccer leagues and youth soccer academies across the globe, with the relative age effect (RAE) being typically characterized as the over selection of relatively older players (who have sometimes also been shown to be early maturing). The aim of this study was to examine if a new allocation method (i) eliminates the RAE, and (ii) reduces the presence of any additional maturity-related differences in anthropometric and physical fitness characteristics which may exist between players within the same selection category. In the first phase, 1,003 academy soccer players [under (U) 9-16] from 23 UK professional soccer clubs were sampled and a clear RAE per birth quarter (Q) was observed for the overall sample (Q1 = 45.0% vs. Q4 = 9.8%) as well as for the different age categories. Using the newly suggested reallocation method, youth players were divided by allocation date which was defined as the midway point between the chronological age and the estimated developmental (ED) birthdate. Stature was used as an anthropometric reference point on the P50 of the growth curve to determine the developmental birthdate for this new method. After the reallocation of the players using ED, the distribution of players was more equally spread (Q1 = 25.3%, Q2 = 25.6%, Q3 = 22.4%, Q4 = 26.7%). After reallocation, the mean delta stature was reduced by 16.6 cm (from 40.3 ± 7.08 to 23.7 ± 4.09 cm, d = 2.87). The mean delta body mass difference after allocation was reduced by 6.7kg (from 33.2 ± 6.39 to 26.5 ± 4.85 kg, d = 1.18). The mean age difference increased from 1.8 to 3.9 years. A total of 42.7% of the sample would have been reallocated to a different age group compared to the current one. After reallocation, 45% of the anthropometric and physical fitness comparisons showed reductions in the within-group variation expressed as a percentage of coefficient of variation (CV%). The U10 players demonstrated the largest reduction in CV% (-7.6%) of the anthropometric characteristics. The U10 squad also showed the largest reduction in CV% for various physical fitness characteristics (-7.5%). By both eliminating the RAE and reducing temporary maturity-related anthropometric and physical fitness differences, soccer academies across the world may diversify and increase the size of the talent pool both for clubs and national youth teams. In conclusion, this study provides further evidence that the newly proposed allocation method shows the potential to remove the RAE and to create a more "leveled playing field" by reducing the within-group variation of anthropometric and physical fitness characteristics affording relatively younger, and eventually, late-maturing players the opportunity to develop their talent fairly.

Differential Ratings of Perceived Exertion: Relationships With External Intensity and Load in Elite Men's Football.

PURPOSE: To examine the utility of differential ratings of perceived exertion (dRPE) for monitoring internal intensity and load in association football. METHODS: Data were collected from 2 elite senior male football teams during 1 season (N = 55). External intensity and load data (duration × intensity) were collected during each training and match session using electronic performance and tracking systems. After each session, players rated their perceived breathlessness and leg-muscle exertion. Descriptive statistics were calculated to quantify how often players rated the 2 types of rating of perceived exertion differently (dRPEDIFF). In addition, the association between dRPEDIFF and external intensity and load was examined. First, the associations between single external variables and dRPEDIFF were analyzed using a mixed-effects logistic regression model. Second, the link between dRPEDIFF and session types with distinctive external profiles was examined using the Pearson chi-square test of independence. RESULTS: On average, players rated their session perceived breathlessness and leg-muscle exertion differently in 22% of the sessions (range: 0%-64%). Confidence limits for the effect of single external variables on dRPEDIFF spanned across largely positive and negative values for all variables, indicating no conclusive findings. The analysis based on session type indicated that players differentiated more often in matches and intense training sessions, but there was no pattern in the direction of differentiation. CONCLUSIONS: The findings of this study provide no evidence supporting the utility of dRPE for monitoring internal intensity and load in football.

Monitoring Elite Youth Football Players' Physiological State Using a Small-Sided Game: Associations With a Submaximal Running Test.

PURPOSE: To examine the utility of a standardized small-sided game (SSG) for monitoring within-player changes in mean exercise heart rate (HRex) when compared with a submaximal interval shuttle-run test (ISRT). METHODS: Thirty-six elite youth football players (17 [1] y) took part in 6 test sessions across an in-season period (every 4 wk). Sessions consisted of the ISRT (20-m shuttles, 30″:15″ work:rest ratio, 70% maximal ISRT) followed by an SSG (7v7, 80 × 56 m, 6 min). HRex was collected during both protocols, with SSG external load measured as high-speed running distance (>19.8 km·h-1) and acceleration distance (>2 m·s-2). Data were analyzed using linear mixed-effect models. RESULTS: Controlling for SSG external load improved the model fit describing the SSG-ISRT HRex relationship (χ2 = 12.6, P = .002). When SSG high-speed running distance and SSG acceleration distance were held constant, a 1% point change in SSG HRex was associated with a 0.5% point change in ISRT HRex (90% CI: 0.4 to 0.6). Inversely, when SSG HRex was held constant, the effects of a 100-m change in SSG high-speed running distance and a 21-m change in SSG acceleration distance on ISRT HRex were -1.0% (-1.5 to -0.4) and -0.6% points (-1.1 to 0.0), respectively. CONCLUSIONS: An SSG can be used to track within-player changes in HRex for monitoring physiological state. Given the uncertainty in estimates, we advise to only give meaning to changes in SSG HRex >2% points. Additionally, we highlight the importance of considering external load when monitoring SSG HRex.

Building a transdisciplinary expert consensus on the cognitive drivers of performance under pressure: An international multi-panel Delphi study.

Introduction: The ability to perform optimally under pressure is critical across many occupations, including the military, first responders, and competitive sport. Despite recognition that such performance depends on a range of cognitive factors, how common these factors are across performance domains remains unclear. The current study sought to integrate existing knowledge in the performance field in the form of a transdisciplinary expert consensus on the cognitive mechanisms that underlie performance under pressure. Methods: International experts were recruited from four performance domains [(i) Defense; (ii) Competitive Sport; (iii) Civilian High-stakes; and (iv) Performance Neuroscience]. Experts rated constructs from the Research Domain Criteria (RDoC) framework (and several expert-suggested constructs) across successive rounds, until all constructs reached consensus for inclusion or were eliminated. Finally, included constructs were ranked for their relative importance. Results: Sixty-eight experts completed the first Delphi round, with 94% of experts retained by the end of the Delphi process. The following 10 constructs reached consensus across all four panels (in order of overall ranking): (1) Attention; (2) Cognitive Control-Performance Monitoring; (3) Arousal and Regulatory Systems-Arousal; (4) Cognitive Control-Goal Selection, Updating, Representation, and Maintenance; (5) Cognitive Control-Response Selection and Inhibition/Suppression; (6) Working memory-Flexible Updating; (7) Working memory-Active Maintenance; (8) Perception and Understanding of Self-Self-knowledge; (9) Working memory-Interference Control, and (10) Expert-suggested-Shifting. Discussion: Our results identify a set of transdisciplinary neuroscience-informed constructs, validated through expert consensus. This expert consensus is critical to standardizing cognitive assessment and informing mechanism-targeted interventions in the broader field of human performance optimization.

Load Monitoring Practice in European Elite Football and the Impact of Club Culture and Financial Resources.

Load monitoring is considered important to manage the physical training process in team sports such as Association Football. Previous studies have described the load monitoring practices of elite English football clubs and clubs with an established sports-science department. An examination of a broader international sample is currently not available. In addition, previous research has suggested factors that may improve the implementation of load monitoring practices, such as a strong club belief on the benefit of evidence-based practice (EBP) and high club financial resources. However, no study has examined yet the actual impact of these factors on the monitoring practices. Therefore, this study aims (1) to provide an overview of load monitoring practices in European elite football and (2) to provide insight into the differences in implementation between clubs by examining the impact of the club beliefs on the benefit of EBP and the club financial resources. An online survey, consisting of multiple choice and Likert scale questions, was distributed among sports-science and sports-medicine staff (n = 99, 50% response rate). Information was asked about the types of data collected, collection purposes, analysis methods, and staff involvement. The results indicated that external load data (e.g., global navigation satellite system, accelerometer…) was collected the most whilst respondents also indicated to collect internal load (e.g., heart rate, rating of perceived exertion…) and training outcome data (e.g., aerobic fitness, neuromuscular fatigue…) for multiple purposes. Considerable diversity in data analysis was observed suggesting that analysis is often limited to reporting the gathered data. Sports-science staff were responsible for data collection and analysis. Other staff were involved in data discussion to share decision-making. These practices were positively impacted by a stronger club belief on the benefit of EBP and greater financial resources. Creating an organizational culture, characterized by a strong belief on the benefit of EBP, is important to increase the impact of load monitoring. However, the actual potential may still be largely determined by financial resources. High-level clubs could therefore play a leading role in generating and sharing knowledge to improve training practices and player health.