Latest research in football - week 27 - 2017

As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases.

Following studies were retrieved for this week:

#1 Laboratory and Match Physiological Data from an Elite Male Collegiate Soccer Athlete
Reference: J Strength Cond Res. 2017 Jun 22. doi: 10.1519/JSC.0000000000002063. [Epub ahead of print]
Authors: Sapp RM, Aronhalt L, Landers-Ramos RQ, Spangenburg EE, Wang MQ, Hagberg JM
Summary: This study compared physiological data from an elite collegiate soccer player to that of his teammates over two seasons. The player of special interest (Player A) was the winner of the MAC Hermann trophy and was therefore considered the top player in NCAA division I soccer for each of the two seasons in which data was collected. Maximal oxygen consumption (VO2max) was measured during preseasons and heart rate was recorded during competitive matches. Polar training loads (PTL) were calculated by the Polar Team2 Pro (Polar USA) system based on time spent in HR zones. Player A had a lower VO2max than the team average in 2012 (56 vs. 61.5 ± 4.3 ml/kg/min) and a similar value in 2013 (54 vs. 56.9 ± 5.1 ml/kg/min). During matches, Player A showed consistent significant differences from the team in percentage of time spent at 70-79% HRmax (12.8 ± 5.5% vs. 10.1 ± 4.0%), 80-89% HRmax (54.3 ± 11.5% vs. 29.3 ± 6.8%), and 90-100% HRmax (23.1 ± 10.6% vs. 45.4 ± 8.5%). This led to a consistently lower PTL/min accumulated by Player A compared to his teammates (3.6 ± 0.4 vs. 4.4 ± 0.3), which may be beneficial over a season and may be related to his success. Thus, the ability to regulate moments of maximal exertion is useful in reducing training load and may be a characteristic of elite players, though whether our findings relate to differences in the playing style, position, or aerobic capacity of Player A, are unknown.

#2 Pitch size and Game Surface in Different Small-Sided Games. Global Indicators, Activity Profile and Acceleration of Female Soccer Players
Reference: J Strength Cond Res. 2017 Jun 22. doi: 10.1519/JSC.0000000000002090. [Epub ahead of print]
Authors: Lopez-Fernandez J, Gallardo L, Fernandez-Luna A, Villacanas V, Garcia-Unanue J, Sanchez-Sanchez J.
Summary: The aim of this research was to evaluate the influence of game surface and pitch size on the movement profile in female soccer players during Small-Sided-Games (SSGs) of 4 v 4. 16 women played three different 4-a-side (400 m, 600 m and 800 m) on three surfaces (ground [GR], artificial turf [AT] and natural grass [NG]). Time-motion variables were assessed through GPS devices (Spi Pro X, GPSports, Australia). GR had the worst outputs on most variables. NG achieved higher results than AT in terms of total distance [SSG 400 (+37.000 m; p=0.006); SSG 600 (+59.989 m; p<0.001); SSG 800 (+42.284 m; p=0.001)]. On the other hand, the smaller SSG (400) had the lowest values on most variables. However, while the middle SSG (600) presented higher output than the bigger one (800) for Body Load [NG (+7.745 a.u.; p<0.001); AT (+8.207 a.u.; p<0.001); GR (+5.879 a.u.; p<0.001)], it had lower results for High Intensity Distance [NG (-13.15 m; p=0.025); AT (-13.59 m; p=0.026)]. Despite women's performance being higher on AT than GR, the NG surface still showed the highest outcomes in the most intense SSG. Moreover, although the performance increase in bigger pitches, if the size is too large the outputs could be reduced.

#3 User Survey of 3 Ankle Braces in Soccer, Volleyball, and Running: Which Brace Fits Best?
Reference: J Athl Train. 2017 Jun 29. doi: 10.4085/1062-2050-52.4.06. [Epub ahead of print]
Authors: Janssen K, Van Den Berg A, Van Mechelen W, Verhagen E
Summary: Recurrence rates for ankle sprains are high. Therefore, preventive measures such as ankle bracing during sports are recommended. The study’s objective was to systematically evaluate the perceived ease of use, quality, comfort, stability, and hindrance of and the overall satisfaction with 3 contemporary brace types in 3 types of sports. Young adult recreational athletes (29 soccer players, 27 volleyball players, and 31 runners) participated in this study. Semirigid brace (SB), lace-up brace (LB), and compression brace (CB) were utilized Rating of perceived ease of use, quality, comfort, stability, and hindrance of and overall satisfaction with the brace types during sports on a 5-point Likert scale. The secondary outcome measure was participants' willingness to buy the tested brace. Overall, the 3 brace types received high mean scores for ease of use and quality. Soccer players preferred the CB over both alternatives, considering the higher scores for comfort (CB = 4.0, LB = 3.5, SB = 2.8), hindrance (CB = 3.7, LB = 2.9, SB = 2.8), overall satisfaction (CB = 3.6, LB = 3.0, SB = 2.5), and highest willingness to buy this brace. Volleyball players preferred the LB over both alternatives, considering the higher scores for stability (LB = 4.2, CB = 3.2, SB = 3.3), overall satisfaction (LB = 3.8, CB = 3.0, SB = 3.0), and greatest willingness to buy this brace. Runners preferred the CB over both alternatives considering the better score for hindrance (CB = 3.6, LB = 2.8, SB = 2.9) and greatest willingness to buy this brace. All 3 ankle brace types scored high on perceived ease of use and quality. Regarding the brace types, soccer players, volleyball players, and runners differed in their assessments of subjective evaluation of comfort, stability, hindrance, overall satisfaction, and willingness to buy the brace. Soccer players and runners preferred the CB, whereas volleyball players preferred the LB.

#4 Impact of a Soccer Game on Cardiac Biomarkers in Adolescent Players
Reference: Pediatr Exerc Sci. 2017 Jun 29:1-16. doi: 10.1123/pes.2017-0060. [Epub ahead of print]
Authors: Hosseini SM, Azizi M, Samadi A, Talebi N, Hannes G, Burtscher M
Summary: Biochemical markers such as cardiac troponin I (cTnI) and N-terminal pro B-type natriuretic peptide (NT-proBNP) have become indispensable tools for the diagnosis of myocardial injury, providing highly sensitive and specific information about cardiac cell damage and wall stress. The purpose of the present research was to examine the response of cardiac biomarkers to a soccer game in adolescent male soccer players. 22 trained adolescent male soccer players (14-16 years) were selected in a purposive manner. Blood samples were taken before, immediately after, and 2 and 24 hours after the game for the determination of cTnI and NT-proBNP. Serum concentration of cTnI and NT-proBNP were increased immediately and 2 hour after the soccer game (P<0.001). After 24 hours, the levels of cTnI had dropped but remained above baseline (p=0.002) whereas serum NT-proBNP levels had returned to baseline. At any time point, none of the values exceeded the upper reference value. This is the first study to investigate acute responses of cardiac biomarkers to a soccer game in adolescent male players. The post-game elevation of cardiac biomarkers and their rapid recovery are indicative of a physiological rather than a pathological response.

#5 Winners' Cup: a national football tournament brings together adolescent patients with cancer from all over Italy
Reference: Tumori. 2017 Jun 26:0. doi: 10.5301/tj.5000655. [Epub ahead of print]
Authors: Silva M, Chisari M, Signoroni S, Bassani A, Tagliabue L, Ricci A, Daversa M, Achini M, Spreafico F, Murelli M, Milano GM, Bisogno G, Coccoli L, Conte M, Garaventa A, Indolfi P, Perrotta S, Spinelli M, Mercolini F, Soloni P, Pierobon M, Di Cataldo A, Perillo T, Mascarin M, Coassin E, Veneroni L, Casanova M, Massimino M, Ferrari A
Summary: Società Scientifiche Italiane Insieme per gli Adolescenti con Malattie Onco-ematologiche (SIAMO) is an Italian nationwide scheme that focuses on adolescent patients with cancer. Some of its activities include promoting dedicated local projects at the various oncology centers all over the country and organizing events to improve awareness regarding cancer in adolescence. It is with these aims in mind that it organized the Winners' Cup, a football tournament between Italian adolescents who had (or had had) pediatric cancers. There were 144 young people 15 to 24 years old who arrived from 16 different treatment centers around the country to take part in the tournament and share their stories. Such an event had never been attempted before, in Italy at least. The Winners' Cup was a great success and an opportunity to focus attention on the particular clinical, psychological, and social needs of cancer patients in this age group.

#6 Online news media reporting of football-related fatalities in Australia: A matter of life and death
Reference: J Sci Med Sport. 2017 Jun 21. pii: S1440-2440(17)30479-6. doi: 10.1016/j.jsams.2017.06.015. [Epub ahead of print]
Authors: Fortington LV, Bekker S, Finch CF
Summary: While deaths in sports settings are rare, they do occur. To develop an understanding of the sports and people most at risk, and to identify opportunities for prevention, routine and systematic data detailing the occurrence of these fatalities is required. There is currently no routine reporting of data of this nature in Australia. As there is often strong community interest in these incidents, the media offers an opportunity for surveillance. However before this can occur, understanding of the terminology used by the media is required. The aim of this study was to identify the terminology most frequently used in online Australian news media coverage of football-related deaths. Three databases were searched for online news media reports of people who died while participating in football (all football codes) in Australia. A descriptive analysis of terminology was undertaken to identify the common language applied. Thirty-four football-related fatalities in Australia were identified between 2010-2016, via 149 separate articles. The most frequent terms identified in the media items were: Family; Club; Rugby; Football; Player; League; Died; Game; Death; Life; Loved; Hospital; Match; Young; Community; Playing; Friends; Sport; Heart; AFL [Australian Football League]. This study identified terminology used in reporting football-related fatalities in Australia, identifying common reference to terms relating to 'death' as metaphors and the frequent celebration of 'life.' The findings suggest that a reliance on researcher-generated terminology will be insufficient to reflect media discourse in prospective monitoring of sports deaths for surveillance.

#7 Effects of different re-warm up activities in football players' performance
Reference: PLoS One. 2017 Jun 29;12(6):e0180152. doi: 10.1371/journal.pone.0180152. eCollection 2017.
Authors: Abade E, Sampaio J, Goncalves B, Baptista J, Alves A, Viana J
Summary: Warm up routines are commonly used to optimize football performance and prevent injuries. Yet, official pre-match protocols may require players to passively rest for approximately 10 to 15 minutes between the warm up and the beginning of the match. Therefore, the aim of this study was to explore the effect of different re-warm up activities on the physical performance of football players. Twenty-Two Portuguese elite under-19 football players participated in the study conducted during the competitive season. Different re-warm up protocols were performed 6 minutes after the same standardized warm up in 4 consecutive days in a crossover controlled approach: without, eccentric, plyometric and repeated changes of direction. Vertical jump and Sprint performances were tested immediately after warm up and 12 minutes after warm up. Results showed that repeated changes of direction and plyometrics presented beneficial effects to jump and sprint. Different practical implications may be taken from the eccentric protocol since a vertical jump impairment was observed, suggesting a possibly harmful effect. The absence of re-warm up activities may be detrimental to players' physical performance. However, the inclusion of re-warm up prior to match is a complex issue, since the manipulation of volume, intensity and recovery may positively or negatively affect the subsequent performance. In fact, this exploratory study shows that eccentric exercise may be harmful for physical performance when performed prior a football match. However, plyometric and repeated changes of direction exercises seem to be simple, quick and efficient activities to attenuate losses in vertical jump and sprint capacity after warm up. Coaches should aim to develop individual optimal exercise modes in order to optimize physical performance after re warm activities.

#8 Alcohol Marketing during the UEFA EURO 2016 Football Tournament: A Frequency Analysis
Reference: Int J Environ Res Public Health. 2017 Jun 29;14(7). pii: E704. doi: 10.3390/ijerph14070704.
Authors: Purves RI, Critchlow N, Stead M, Adams J, Brown K
Summary: This study examined the frequency and nature of alcohol marketing references in broadcasts of the 2016 UEFA (Union of European Football Associations) European Championships football tournament in the United Kingdom (UK). Eighteen matches from across the tournament were recorded in full as broadcast in the UK, including all four matches featuring the English national team and all seven featuring the French national team. All visual and verbal references to alcohol marketing were recorded using a tool with high inter-rater reliability. A total of 2213 alcohol marketing references were recorded, an average of 122.94 per broadcast and 0.65 per broadcast minute (0.52 per minute in-play and 0.80 per minute out-of-play). Almost all references were visual (97.5%), with 77.9% occurring around the pitch border. Almost all (90.6%) were indirect references to alcohol brands (e.g., references to well-known slogans), compared to only 9.4% direct references to brands (e.g., brand names). The frequency of references to alcohol marketing was high. Although the overall proportion of direct brand references was low, the high proportion of indirect references demonstrates that alcohol producers were able to circumvent the French national law governing alcohol marketing (the Loi Évin) using indirect "alibi marketing". To ensure the spirit of the Loi Évin regulations are achieved, stricter enforcement may be required to limit exposure to alcohol marketing, particularly for young people.

#9 A systematic review of the technology-based assessment of visual perception and exploration behaviour in association football
Reference: J Sports Sci. 2017 Jun 26:1-20. doi: 10.1080/02640414.2017.1344780. [Epub ahead of print]
Authors: McGuckian TB, Cole MH, Pepping GJ
Summary: The purpose was to visually perceive opportunities for action, athletes rely on the movements of their eyes, head and body to explore their surrounding environment. To date, the specific types of technology and their efficacy for assessing the exploration behaviours of association footballers have not been systematically reviewed. This review aimed to synthesise the visual perception and exploration behaviours of footballers according to the task constraints, action requirements of the experimental task, and level of expertise of the athlete, in the context of the technology used to quantify the visual perception and exploration behaviours of footballers. A systematic search for papers that included keywords related to football, technology, and visual perception was conducted. All 38 included articles utilised eye-movement registration technology to quantify visual perception and exploration behaviour. The experimental domain appears to influence the visual perception behaviour of footballers, however no studies investigated exploration behaviours of footballers in open-play situations. Studies rarely utilised representative stimulus presentation or action requirements. To fully understand the visual perception requirements of athletes, it is recommended that future research seek to validate alternate technologies that are capable of investigating the eye, head and body movements associated with the exploration behaviours of footballers during representative open-play situations.

American Football
#1 Osteoarthritis Prevalence in Retired National Football League Players With a History of Concussion and Lower Extremity Injury
Reference: J Athl Train. 2017 Jun 2;52(6):518-525. doi: 10.4085/1062-6050-52.2.03.
Authors: Lynall RC, Pietrosimone B, Kerr ZY, Mauntel TC, Mihalik JP, Guskiewicz KM
Summary: Dynamic balance deficits have been described postconcussion, even after athletes return to play. Lower extremity (LE) musculoskeletal injury rates increase for up to 1 year after concussion, but the long-term musculoskeletal implications of concussion are unclear. The objective was to (1) examine the association of concussion and LE injury histories with osteoarthritis (OA) prevalence in retired National Football League players and (2) examine the association of concussion and LE injury histories with OA prevalence in those ≤55 years of age. We administered the Health Survey of Retired National Football League Players, which collects information about demographics, OA, LE injury, and concussion history. Twelve discrete categories were created based on concussion and LE injury history, ranging from 0 concussions and 0 LE injuries (referent group) to 3+ concussions and 2+ LE injuries. Binomial regression analysis modeled lifetime OA prevalence. Covariates were body mass index, age at the time of the survey, and total years playing professional football. Complete data were available for 2696 participants. Lifetime OA prevalence was smallest in the referent group (21.1%) and largest in the 3+ concussion and 2+ LE group (50.6%; 2.5 times the referent; 95% confidence interval [CI] = 2.1, 3.1). Participants in all concussion groups (1, 2, 3+) who reported a history of 0 LE injuries had a greater OA prevalence than the referent group. When participants were stratified by age, the ≤55 years of age, 3+ concussions, and 2+ LE injuries group prevalence ratio (3.6; 95% CI = 2.7, 5.2) was larger than that of the >55 years of age, 3+ concussions, and 2+ LE injuries group (1.8; 95% CI = 1.3, 2.4) compared with the respective referent groups. Concussion with or without a history of LE injury may be an important moderator of OA. Future researchers should seek to better understand the mechanisms that influence the association among concussion, LE injury, and OA.

Australian Football
#1 Subsequent Injuries Are More Common Than Injury Recurrences: An Analysis of 1 Season of Prospectively Collected Injuries in Professional Australian Football
Reference: Am J Sports Med. 2017 Jul;45(8):1921-1927. doi: 10.1177/0363546517691943. Epub 2017 Mar 9.
Authors: Finch CF, Cook J, Kunstler BE, Akram M, Orchard J
Summary: It is known that some people can, and do, sustain >1 injury over a playing season. However, there is currently little high-quality epidemiological evidence about the risk of, and relationships between, multiple and subsequent injuries. The purpose was to describe the subsequent injuries sustained by Australian Football League (AFL) players over 1 season, including their most common injury diagnoses. Within-player linked injury data on all date-ordered match-loss injuries sustained by AFL players during 1 full season were obtained. The total number of injuries per player was determined, and in those with >1 injury, the Subsequent Injury Classification (SIC) model was used to code all subsequent injuries based on their Orchard Sports Injury Classification System (OSICS) codes and the dates of injury. There were 860 newly recorded injuries in 543 players; 247 players (45.5%) sustained ≥1 subsequent injuries after an earlier injury, with 317 subsequent injuries (36.9% of all injuries) recorded overall. A subsequent injury generally occurred to a different body region and was therefore superficially unrelated to an index injury. However, 32.2% of all subsequent injuries were related to a previous injury in the same season. Hamstring injuries were the most common subsequent injury. The mean time between injuries decreased with an increasing number of subsequent injuries. When relationships between injuries are taken into account, there is a high level of subsequent (and multiple) injuries leading to missed games in an elite athlete group.

Gaelic Football
#1 The Positional Anthropometric and Performance Profile of Elite Gaelic Football Players
Reference: J Strength Cond Res. 2017 Jun 22. doi: 10.1519/JSC.0000000000002071. [Epub ahead of print]
Authors: Shovlin A, Roe M, Malone S, Collins K
Summary: The aim of the current investigation was to evaluate the variation in the anthropometric and performance characteristics of elite Gaelic football players with respect of position. One hundred and forty-eight elite Gaelic footballers underwent anthropometric (height, body mass, sum of seven skinfolds, % adipose tissue) and performance [counter movement jump height (CMJ), CMJ peak power, CMJ relative peak power, squat jump height (SJ), SJ peak power, SJ relative peak power, 5-, 10- and 20 m sprint times and Yo-Yo Intermittent Recovery Test Level 2 (Yo-YoIRT2)] during 'the early in-season' phase. Data were split into five positional groups (full-back, half-back, midfield, half-forward and full-forward). Higher %AT was observed in full forwards when compared to the half backs (p = 0.001), midfielders (p = 0.035) and half forwards (p = 0.021). Full forwards had significantly greater SJ (p = 0.036) and CMJ (p = 0.013) when compared to the midfielders with no other positional differences observed. No significant variation in sprint times was observed across positions. When Yo-YoIRT2 was considered, full forwards and full backs completed significantly lower distances compared to the middle three positional lines of, half backs, midfielders and half forwards (p = 0.00). The current study is the first to provide normative data for anthropometric and performance values of elite Gaelic football players which in turn can be utilised by coaches to generate appropriate training regimes to maximise position specific preparation for competitive match-play.

The Training Manager -