Latest research in football - week 25,5 - 2018

#1 Seasonal Variation of Agility, Speed and Endurance Performance in Young Elite Soccer Players
Reference: Sports (Basel). 2017 Feb 4;5(1). pii: E12. doi: 10.3390/sports5010012.
Authors: Dragijsky M, Maly T, Zahalka F, Kunzmann E, Hank M
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969008/pdf/sports-05-00012.pdf
Summary: The aim of this study was to investigate changes in the linear running speed (LRS) for 30 m, change of direction speed (CODS), and endurance in young elite Czech soccer players. The following tests were conducted to assess CODS and endurance: Agility 505 turning toward the dominant (A505DL) and non-dominant lower limb (A505NL); Illinois Agility Test (IAT); and intermittent test (Yo-Yo IRT1). During the soccer season, we investigated performance at the following time periods: the start (t₁) and the end of the pre-season period (t₂); during (t₃) and at the end of the competitive period (t₄). Repeated measurement analysis of variance revealed a significant effect of time period on selected fitness parameters (p < 0.05). Post hoc analysis for test A505DL revealed significant improvements of performance at t₃ (2.71 ± 0.08 s) and t₄ (2.72 ± 0.06 s) compared to t₁ (2.81 ± 0.09 s). A505NL was significantly different between t₁ (2.83 ± 0.09 s) and t₂ (2.76 ± 0.09 s), t₃ (2.7 ± 0.07 s) and t₄ (2.71 ± 0.09 s). Performance of CODS at t₁ for the IAT (18.82 ± 0.56 s) was significantly lower (p < 0.05) than any other time period (t₂ = 18.52 ± 0.63 s, t₃ = 17.94 ± 0.51 s, t₄ = 17.89 ± 0.66 s). The power of LRS was significantly different at t₃ (4.99 ± 0.15 s), and t₄ (4.98 ± 0.17 s) compared to t₁ (5.15 ± 0.21 s), and t₂ (5.07 ± 0.14 s). For the Yo-Yo IRT1 test, we observed a significant increase in performance between t₁ (625.26 ± 170.34 m), t₂ (858.95 ± 210.55 m), and t₃ (953.68 ± 229.88 m). These results show the impact of soccer season time period on young soccer player performance and may further serve as a basis for comparison with similar research conducted by peers. These results may aid sports practice for clinicians, conditioning coaches, soccer coaches and physiotherapeutic coaches.


#2 Seasonal Variation of Agility, Speed and Endurance Performance in Young Elite Soccer Players
Reference: Sports (Basel). 2017 Feb 4;5(1). pii: E12. doi: 10.3390/sports5010012.
Authors: Dragijsky M, Maly T, Zahalka F, Kunzmann E, Hank M
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969008/pdf/sports-05-00012.pdf
Summary: The aim of this study was to investigate changes in the linear running speed (LRS) for 30 m, change of direction speed (CODS), and endurance in young elite Czech soccer players. The following tests were conducted to assess CODS and endurance: Agility 505 turning toward the dominant (A505DL) and non-dominant lower limb (A505NL); Illinois Agility Test (IAT); and intermittent test (Yo-Yo IRT1). During the soccer season, we investigated performance at the following time periods: the start (t₁) and the end of the pre-season period (t₂); during (t₃) and at the end of the competitive period (t₄). Repeated measurement analysis of variance revealed a significant effect of time period on selected fitness parameters (p < 0.05). Post hoc analysis for test A505DL revealed significant improvements of performance at t₃ (2.71 ± 0.08 s) and t₄ (2.72 ± 0.06 s) compared to t₁ (2.81 ± 0.09 s). A505NL was significantly different between t₁ (2.83 ± 0.09 s) and t₂ (2.76 ± 0.09 s), t₃ (2.7 ± 0.07 s) and t₄ (2.71 ± 0.09 s). Performance of CODS at t₁ for the IAT (18.82 ± 0.56 s) was significantly lower (p < 0.05) than any other time period (t₂ = 18.52 ± 0.63 s, t₃ = 17.94 ± 0.51 s, t₄ = 17.89 ± 0.66 s). The power of LRS was significantly different at t₃ (4.99 ± 0.15 s), and t₄ (4.98 ± 0.17 s) compared to t₁ (5.15 ± 0.21 s), and t₂ (5.07 ± 0.14 s). For the Yo-Yo IRT1 test, we observed a significant increase in performance between t₁ (625.26 ± 170.34 m), t₂ (858.95 ± 210.55 m), and t₃ (953.68 ± 229.88 m). These results show the impact of soccer season time period on young soccer player performance and may further serve as a basis for comparison with similar research conducted by peers. These results may aid sports practice for clinicians, conditioning coaches, soccer coaches and physiotherapeutic coaches.


#3 Functional Assessment and Injury Risk in a Professional Soccer Team
Reference: Sports (Basel). 2017 Jan 22;5(1). pii: E9. doi: 10.3390/sports5010009.
Authors: Gomez-Piqueras P, Gonzalez-Villora S, Sainz de Baranda Andujar MDP, Contreras-Jordan OR
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969000/pdf/sports-05-00009.pdf
Summary: At the last World Conference on Sport and Physical Therapy celebrated in Bern (Switzerland, 2015), it was confirmed that the functional skills of an athlete are a very important variable to be considered in the recovery of an injury. On the other hand, its use as a predictive risk tool still lacks solid evidence. The purpose of this study was to determine whether a battery of functional tests (FPT) could be used as a preliminary measure for the season in order to identify the injury risk in a professional soccer team in the Spanish Second Division B League. Fifty-two soccer players (ages of 25.3 ± 4.6 years, 10.33% ± 0.9% fat) were functionally assessed during two seasons (2012⁻2013 and 2013⁻2014) and analyzed from an injury perspective. A total of 125 injuries were recorded. The sample was grouped based on the number of injuries and the required absence days. Except for the bipodal vertical jump (CMJ), none of the functional tests revealed differences among the groups. The correlation study between the functional condition and the suffered injuries did not show any significant results.


#4 Soccer and Relative Age Effect: A Walk among Elite Players and Young Players
Reference: Sports (Basel). 2017 Jan 11;5(1). pii: E5. doi: 10.3390/sports5010005.
Authors: Sierra-Diaz MJ, Gonzalez-Villora S, Pastor-Vicedo JC, Serra-Olivares J
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969014/pdf/sports-05-00005.pdf
Summary: Grouping people according to chronological age is popular in fields such as education and sport. Athletes who are born in the first months of the year usually have cognitive and physical development differences in contrast to those born in the last months of the same year. That is why competitive teams tend to select older players more often than youngsters. Age differences between athletes born in the same year as well as an over-representation of older players are known as the Relative Age Effect. This effect is extensively described in young and elite team sports such as basketball, volleyball or, ice-hockey, as well as in soccer. The purpose of this study is to examine the state-of-the-art of the Relative Age Effect in youth and elite soccer players. This review summarizes recent research articles on the Relative Age Effect related to competitive soccer from 2010 to 2016. The systematic literature search was conducted in four databases: SPORTDiscus, Medline, EBSCO host and Google Scholar. Although causes and final solutions have not been clearly achieved yet, it is necessary to continue investigating this phenomenon in order to provide a starting point for future research.


#5 Goal Format in Small-Sided Soccer Games: Technical Actions and Offensive Scenarios of Prepubescent Players
Reference: Sports (Basel). 2016 Nov 25;4(4). pii: E53. doi: 10.3390/sports4040053.
Authors: Pulling C, Twitchen A, Pettefer C
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968898/pdf/sports-04-00053.pdf
Summary: The aim of this study was to investigate the influence of the number of goal-posts and the positioning of goal-posts used within small-sided games on the frequency of technical actions and offensive scenarios performed by prepubescent players within soccer. The participants were eight male prepubescent soccer players (12.1 ± 0.5 years). The participants were video recorded for 20 min playing four different formats of 4v4 small-sided games: (1) standard two goal game; (2) four goal game, one goal in each corner; (3) two goal game with goal-posts positioned 9.14 m/10 yd infield, scoring only through the back of the goal; (4) four goal-game, one goal positioned 9.14 m/10 yd infield in each corner, scoring through either the front or back of each goal. Chi-squared tests of independence were utilized to statistically explore the impact of the different small-sided game formats. There were significant associations (p < 0.05) observed between the different small-sided game formats and the frequency of turns, dribbles, shots, goals and overlaps performed. For example, players performed more turns in small-sided game format two and more shots during small-sided game format four. It is suggested coaches should consider using a variation of the number and positioning of goal-posts in small-sided games as an effective training tool in the development of prepubescent soccer players. This will enable coaches to vary the focus of sessions, and develop specific technical and tactical actions within a situation similar to that of real match-play.


#6 Relationship between Procedural Tactical Knowledge and Specific Motor Skills in Young Soccer Players
Reference: Sports (Basel). 2016 Nov 17;4(4). pii: E52. doi: 10.3390/sports4040052.
Authors: Aquino R, Marques RFR, Petiot GH, Goncalves LGC, Moraes C, Santiago PRP, Puggina EF
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968894/pdf/sports-04-00052.pdf
Summary: The purpose of this study was to investigate the association between offensive tactical knowledge and the soccer-specific motor skills performance. Fifteen participants were submitted to two evaluation tests, one to assess their technical and tactical analysis. The motor skills performance was measured through four tests of technical soccer skills: ball control, shooting, passing and dribbling. The tactical performance was based on a tactical assessment system called FUT-SAT (Analyses of Procedural Tactical Knowledge in Soccer). Afterwards, technical and tactical evaluation scores were ranked with and without the use of the cluster method. A positive, weak correlation was perceived in both analyses (rho = 0.39, not significant p = 0.14 (with cluster analysis); and rho = 0.35; not significant p = 0.20 (without cluster analysis)). We can conclude that there was a weak association between the technical and the offensive tactical knowledge. This shows the need to reflect on the use of such tests to assess technical skills in team sports since they do not take into account the variability and unpredictability of game actions and disregard the inherent needs to assess such skill performance in the game.


#7 Comparıson of the Heart Rate and Blood Lactate Responses of Different Small Sided Games in Young Soccer Players
Reference: Sports (Basel). 2016 Sep 29;4(4). pii: E48. doi: 10.3390/sports4040048.
Authors: Koklu Y, Alemdaroglu U
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968902/pdf/sports-04-00048.pdf
Summary: The purpose of this study was to compare the percentage of maximum heart rate (%HRmax), blood lactate (La-), and rating of perceived exertion (RPE, CR-10) responses across different formats of small-sided games (SSG) in elite young soccer players. Fourteen players (average age 16.7 ± 0.6 years; height 177.6 ± 4.1 cm; body mass 66.3 ± 4.7 kg; average training age 6.7 ± 1.6 years; percentage of body fat 8.4 ± 2.6%) volunteered to perform the YoYo intermittent recovery test (level 1) and eight bouts of soccer drills including 2-a-side, 3-a-side, and 4-a-side games without goalkeepers in random order at two-day intervals. Heart rates were monitored throughout the SSGs, whereas the RPE and venous blood lactate were determined at the end of the last bout of each SSG. The differences in La-, %HRmax, and RPE either across the different SSGs or between the bouts were identified using 3 × 8 (games × exercise bouts) two-way analysis of variance with repeated measures. Significant differences were found in terms of La-, RPE, and %HRmax among the different types of SSG (p ≤ 0.05). 3-a-side and 4-a-side games elicited significantly higher responses than 2-a-side games in terms of %HRmax (p ≤ 0.05), whereas 4-a-side games resulted in significantly lower La- and RPE responses compared to 2-a-side and 3-a-side games. The results of this study show that physiological responses differ according to the numbers of players involved in small-sided games. Therefore, it can be concluded that 3-a-side and 4-a-side games could be more effective in improving high intensity aerobic performance than 2-a-side games, which in turn are more appropriate for developing anaerobic performance.


#8 Physiological Characteristics of Incoming Freshmen Field Players in a Men's Division I Collegiate Soccer Team
Reference: Sports (Basel). 2016 Jun 8;4(2). pii: E34. doi: 10.3390/sports4020034.
Authors: Lockie RG, Davis DL, Birmingham-Babauta SA, Beiley MD, Hurley JM, Stage AA, Stokes JJ, Tomita TM, Torne IA, Lazar A
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968924/pdf/sports-04-00034.pdf
Summary: Freshmen college soccer players will have lower training ages than their experienced teammates (sophomores, juniors, seniors). How this is reflected in field test performance is not known. Freshmen (n = 7) and experienced (n = 10) male field soccer players from the same Division I school completed soccer-specific tests to identify potential differences in incoming freshmen. Testing included: vertical jump (VJ), standing broad jump, and triple hop (TH); 30-m sprint, (0⁻5, 5⁻10, 0⁻10, and 0⁻30 m intervals); 505 change-of-direction test; Yo-Yo Intermittent Recovery Test Level 2 (YYIRT2); and 6 × 30-m sprints to measure repeated-sprint ability. A MANOVA with Bonferroni post hoc was conducted on the performance test data, and effect sizes and z-scores were calculated from the results for magnitude-based inference. There were no significant between-group differences in the performance tests. There were moderate effects for the differences in VJ height, left-leg TH, 0⁻5, 0⁻10 and 0⁻30 m sprint intervals, and YYIRT2 (d = 0.63⁻1.18), with experienced players being superior. According to z-score data, freshmen had meaningful differences below the squad mean in the 30-m sprint, YYIRT2, and jump tests. Freshmen soccer players may need to develop linear speed, high-intensity running, and jump performance upon entering a collegiate program.


#9 Heart Rate Responses during Small Sided Games and Official Match-Play in Soccer
Reference: Sports (Basel). 2016 May 30;4(2). pii: E31. doi: 10.3390/sports4020031.
Authors: Asci A
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968916/pdf/sports-04-00031.pdf
Summary: Small sided games (SSGs) are a match specific type of training. In addition, there is an insufficient number of studies that compare heart rate (HR) responses of SSGs and official match-play (OM). The purpose of this study was to investigate the heart rate responses during SSGs and OM in young soccer players. Twenty-two male soccer players (mean ± SD; age 17.4 ± 0.9 years, height 174.9 ± 6.6 cm, body weight 67.7 ± 8.1 kg) volunteered to participate in this study. The first session included anthropometric measurements and a maximum running test (RT). Following the RT session, all players participated in five different randomly ordered SSG sessions (3-, 4-, 5-, 7- and 9-a-side with goalkeepers). OMs were also monitored in the fourth week of the study. A one-way multivariate repeated-measures analysis of variance (MANOVA) was then conducted to evaluate the differences between the SSGs and OM. The results showed that 3-a-side elicited significantly higher HR and %HRmax than other SSGs and OM, whereas 9-a-side resulted in significantly lower HR and %HRmax compared to other SSG formats and OM (p < 0.05). In conclusion, 3-a-side, 4-a-side and 5-a-side SSG formats provide players with the opportunity to spend sufficient proportion of time spent in high intensity zones that are specific to match demands.


#10 Relationship of Two Vertical Jumping Tests to Sprint and Change of Direction Speed among Male and Female Collegiate Soccer Players
Reference: Sports (Basel). 2016 Feb 16;4(1). pii: E11. doi: 10.3390/sports4010011.
Authors: McFarland IT, Dawes JJ, Elder CL, Lockie RG
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968930/pdf/sports-04-00011.pdf
Summary: In collegiate level soccer acceleration, maximal velocity and agility are essential for successful performance. Power production is believed to provide a foundation for these speed qualities. The purpose of this study was to determine the relationship of change of direction speed, acceleration, and maximal velocity to both the counter movement jump (CMJ) and squat jump (SJ) in collegiate soccer players. Thirty-six NCAA Division II soccer players (20 males and 16 females) were tested for speed over 10 and 30 m, CODS (T-test, pro agility) and power (CMJ, SJ). Independent t-tests (p ≤ 0.05) were used to derive gender differences, and Pearson's correlations (p ≤ 0.05) calculated relationships between the different power and speed tests. Female subjects displayed moderate-to-strong correlations between 30 m, pro agility and T-test with the CMJ (r = -0.502 to -0.751), and SJ (r = -0.502 to -0.681). Moderate correlations between 10 and 30 m with CMJ (r = -0.476 and -0.570) and SJ (r = -0.443 and -0.553, respectively) were observed for males. Moderate to strong relationships exist between speed and power attributes in both male and female collegiate soccer players, especially between CMJ and maximal velocity. Improving stretch shortening cycle (SSC) utilization may contribute to enhanced sport-specific speed.

#11 Effect of New Zealand Blackcurrant Extract on Performance during the Running Based Anaerobic Sprint Test in Trained Youth and Recreationally Active Male Football Players
Reference: Sports (Basel). 2017 Sep 15;5(3). pii: E69. doi: 10.3390/sports5030069.
Authors: Godwin C, Cook MD, Willems MET
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968969/pdf/sports-05-00069.pdf
Summary: It was observed previously that New Zealand blackcurrant (NZBC) extract reduced slowing of the maximal 15 m sprint speed during the Loughborough Intermittent Shuttle Test. We examined the effect of NZBC extract on the performance of the Running Based Anaerobic Sprint Test (RAST, 6 × 35-m sprints with 10 seconds passive recovery) in trained youth and recreationally active football players. Fifteen recreationally active (University team) (age: 20 ± 1 years, height: 174 ± 19 cm, body mass: 80 ± 13 kg) and nine trained youth players (English professional club) (age: 17 ± 0 years, height: 178 ± 8 cm, body mass: 69 ± 9 kg, mean ± SD) participated in three testing sessions. Prior to the RASTs, participants consumed two capsules of NZBC extract (600 mg∙day-1 CurraNZ®) or placebo (P) for 7 days (double blind, randomised, cross-over design, wash-out at least 14 days). Ability difference between groups was shown by sprint 1 time. In the placebo condition, trained youth players had faster times for sprint 1 (5.00 ± 0.05 s) than recreationally active players (5.42 ± 0.08 s) (p < 0.01). In trained youth players, there was a trend for an effect of NZBC extract (p = 0.10) on the slowing of the sprint 1 time. NZBC extract reduced slowing of the sprint 5 time (P: 0.56 ± 0.22 s; NZBC: 0.35 ± 0.25, p = 0.02) and this was not observed in recreationally active players (P: 0.57 ± 0.48 s; NZBC: 0.56 ± 0.33, p = 0.90). For fatigue index, expressed as a % change in fastest sprint time, there was a strong trend to be lower in both trained youth and recreationally active players combined by NZBC extract (P: -13 ± 7%; NZBC: -11 ± 6%, p = 0.06) with 12 participants (five trained youth) experiencing less fatigue. New Zealand blackcurrant extract seems to benefit repeated sprint performance only in trained football players.


#12 Body Composition Evaluation Issue among Young Elite Football Players: DXA Assessment
Reference: Sports (Basel). 2017 Feb 23;5(1). pii: E17. doi: 10.3390/sports5010017.
Authors: Leao C, Simoes M, Silva B, Clemente FM, Bezerra P, Camoes M
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969018/pdf/sports-05-00017.pdf
Summary: Accurate assessment of body composition is an important issue among athletes. Different methodologies generate controversial results, leading to a deep uncertainty on individual exercise prescriptions. Thus, this study aims to identify the differences between field methods, such as bioelectrical impedance (BIA) and skinfold assessment, with a clinical method, highly accurate, dual-energy X-ray absorptiometry (DXA), among elite young football players. Thirty-eight male football players with a mean (sd) age of 16.7 (0.87) years, involved in the Portuguese national competition of U16 (n = 13) and U19 (n = 25), were evaluated and objective measures of body composition, muscle strength and football skills were collected by trained specialists. Body composition was assessed using BIA (Tanita BC-418, Tanita Corp., Tokyo, Japan), in agreement with all the evaluation premises. Additionally, all athletes were evaluated using the clinical method DXA (Hologic Inc., Waltham, MA, USA). Among the U19 athletes, three skinfold sites (SKF) were assessed: chest, abdomin and thigh. The Spearman correlation coefficients and the mean difference between methods were calculated. The agreement between both methods was analyzed using Bland-Altman plots. Among the evaluated athletes, lower mean values of body fat % were found using BIA as a method of body composition assessment compared with DXA (12.05 vs. 15.58 for U16; 11.97 vs. 14.16 for U19). Despite the moderate correlation between methods (r = 0.33) to estimate the percentage of total fat, the median of the difference (DXA vs. BIA) was relevant in clinical terms, with 2.90% and 1.47% for U16 and U19 athletes, respectively. Stronger correlations were found between the sum of the SKF and DXA fat estimation (r = 0.68). The Bland-Altman plots showed a clear underestimation in the evaluations using the BIA, namely among athletes with better body composition profiles (8%⁻12% of fat). Using BIA, an underestimation of body fat assessment was observed among 94.5% of the athletes with less than 12% body fat mass. Among the evaluated athletes, fat mass was underestimated at a median value of 2.21% using BIA in comparison with DXA. The sum of the SKF showed a stronger correlation with the reference method (DXA) (r = 0.68) than BIA.


#13 Content Validity and Psychometric Properties of the Nomination Scale for Identifying Football Talent (NSIFT): Application to Coaches, Parents and Players
Reference: Sports (Basel). 2017 Jan 1;5(1). pii: E2. doi: 10.3390/sports5010002.
Authors: Prieto-Ayuso A, Pastor-Vicedo JC, Contreras-Jordan O
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969006/pdf/sports-05-00002.pdf
Summary: The identification of football talent is a critical issue both for clubs and the families of players. However, despite its importance in a sporting, economic and social sense, there appears to be a lack of instruments that can reliably measure talent performance. The aim of this study was to design and validate the Nomination Scale for Identifying Football Talent (NSIFT), with the aim of optimising the processes for identifying said talent. The scale was first validated through expert judgment, and then statistically, by means of an exploratory factor analysis (EFA), confirmatory factor analysis (CFA), internal reliability and convergent validity. The results reveal the presence of three factors in the scale's factor matrix, with these results being confirmed by the CFA. The scale revealed suitable internal reliability and homogeneity indices. Convergent validity showed that it is teammates who are best able to identify football talent, followed by coaches and parents. It can be concluded that the NSIFT is suitable for use in the football world. Future studies should seek to confirm these results in different contexts by means of further CFAs.


#14 The Effect of Recovery Duration on Technical Proficiency during Small Sided Games of Football
Reference: Sports (Basel). 2016 Jul 8;4(3). pii: E39. doi: 10.3390/sports4030039.
Authors: McLean S, Kerherve H, Naughton M, Lovell GP, Gorman AD, Solomon C
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968888/pdf/sports-04-00039.pdf
Summary: The aim of this study was to determine the effect of increasing the duration of the recovery periods separating serial bouts of small sided games (SSG) of football on technical skills (TS). Twelve semi-professional footballers (mean ± SD; age 21 ± 3 years; VO2peak 64 ± 7 mL∙min∙kg-1; playing experience 15 ± 3 years) completed two SSG sessions, consisting of 3 vs. 3 players and 6 bouts of 2 min, separated by either 30 s recovery (REC-30) or 120 s recovery (REC-120). Sixteen TS, including passing, possession, and defensive related variables, and exercise intensity (heart rate, rating of perceived exertion, time motion descriptors) during the bouts were measured. Repeated measures ANOVA were used to determine differences between-conditions, for TS. The number of successful tackles was significantly higher, and the average time each team maintained possession was significantly lower in REC-120 compared to REC-30. There were no significant differences for all other TS variables, or exercise intensity measures between REC-30 and REC-120. Overall, a four-fold increase in the duration of recovery separating SSG bouts did not alter the technical skill execution of players. The experience and skill level of the players, combined with an apparent regulation of effort through pacing, may have assisted in the maintenance of technical skill execution.


#15 Analysis of Physiological, Technical, and Tactical Analysis during a Friendly Football Match of Elite U19
Reference: Sports (Basel). 2016 Jun 16;4(2). pii: E35. doi: 10.3390/sports4020035.
Authors: Ortega JI, Evangelio C, Clemente FM, Martins FML, Gonzalez-Villora S
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968927/pdf/sports-04-00035.pdf
Summary: The main objective was to analyze a friendly match of youth elite soccer players identifying the variance of tactical and physiological response parameters during the game. In addition, detecting the impact of both halves on player performance. For the purposes of this study twenty-two U19 players were analyzed playing 11v11. Activity profile, heart rate (HR and HRmax), grouped in five different zones were analyzed via Bluetooth technology, technical performance was analyzed by the Team Sport Assessment Procedure (TSAP), and tactical performance was measured by Social Network Analysis. A comparison of heart rate responses showed significant main effects in the halves (p = 0.001; η p 2 = 0.623). A comparison between tactical position and technical performance had significant main effects (p = 0.001; η p 2 = 0.390). Tactical position showed statistically significant effects on tactical prominence (p = 0.002; η p 2 = 0.296). Therefore, fatigue is a component distinguished in technical/tactical parameters, such as volume of play and efficiency index. Results suggest that fatigue effects may constrain technical performance and, for that reason, the use of instruments to monitor the fatigue effect during matches may be suggested.


#16 "You're Not Born with Talent" Talented Girls' and Boys' Perceptions of Their Talents as Football Players
Reference: Sports (Basel). 2016 Jan 27;4(1). pii: E6. doi: 10.3390/sports4010006.
Authors: Saether SA, Mehus I
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968932/pdf/sports-04-00006.pdf
Summary: Generally in sports, there is a strong assumption of a connection between skill level in young age and adulthood. Studies have mainly focused on the coaches' understanding and role in identifying and developing talent. In this article we turn our attention towards the athletes' perspectives, interviewing talented young football players (five boys and five girls) about their perceptions of their own talent and development. The objective of the article is to investigate how boys and girls perceive their talent and to discuss how various perceptions influence coaching practice in talent development. We introduce the following questions: (a) do the players use a static or dynamic perception of their own talent and (b) do the players consider specific or general skills to be most important in their skill development? Results show that the boys have a more static perception of talent compared to the girls. Furthermore, the boys in this study stress the importance of highly specified skills. The girls have a more balanced view on what is important, but tend to stress the importance of basic skills. The study suggests two potential implications. First, the coaches should be aware of the possible vulnerability following players' static perception of talent. Second, an exclusive focus on specified skills might make for less optimal preparation for the changing demands young players meet when moving through the different levels of play on their way to high level football. In future research it would be interesting to investigate how players with a lower skill level, not yet regarded as talent, perceive their talent and skill development.


#17 Effects of Video-Based Visual Training on Decision-Making and Reactive Agility in Adolescent Football Players
Reference: Sports (Basel). 2015 Dec 31;4(1). pii: E1. doi: 10.3390/sports4010001.
Authors: Nimmerichter A, Weber NJR, Wirth K, Haller A
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968940/pdf/sports-04-00001.pdf
Summary: This study investigated the trainability of decision-making and reactive agility via video-based visual training in young athletes. Thirty-four members of a national football academy (age: 14.4 ± 0.1 years) were randomly assigned to a training (VIS; n = 18) or a control group (CON; n = 16). In addition to the football training, the VIS completed a video-based visual training twice a week over a period of six weeks during the competition phase. Using the temporal occlusion technique, the players were instructed to react on one-on-one situations shown in 40 videos. The number of successful decisions and the response time were measured with a video-based test. In addition, the reactive-agility sprint test was used. VIS significantly improved the number of successful decisions (22.2 ± 3.6 s vs. 29.8 ± 4.5 s; p < 0.001), response time (0.41 ± 0.10 s vs. 0.31 ± 0.10 s; p = 0.006) and reactive agility (2.22 ± 0.33 s vs. 1.94 ± 0.11 s; p = 0.001) pre- vs. post-training. No significant differences were found for CON. The results have shown that video-based visual training improves the time to make decisions as well as reactive agility sprint-time, accompanied by an increase in successful decisions. It remains to be shown whether or not such training can improve simulated or actual game performance.