Latest research in football - week 43 - 2015

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

Following studies were retrieved for this week:


#1 Influence of preparation and football skill level on injury incidence during an amateur football tournament
Reference: Arch Orthop Trauma Surg. 2015 Oct 23. [Epub ahead of print]
Authors: Koch M, Zellner J, Berner A, Grechenig S, Krutsch V, Nerlich M, Angele P, Krutsch W
Summary: Scientific studies on injury characteristics are rather common in professional football but not in amateur football despite the thousands of amateur football tournaments taking place worldwide each year. The purpose of this study was to evaluate the preparation and injury patterns of players of two different football skill levels who participated in an international amateur football tournament. In a prospective cohort study, an international amateur football tournament of medical doctors in 2011 was analysed with regard to training and warm-up preparation, the level of football played before the tournament and injury data during the tournament by means of standardised injury definitions and data samples for football. Amateur players of registered football clubs had higher training exposure before the tournament (p < 0.001) than recreational players and had more frequently performed warm-up programmes (p < 0.001). Recreational football players showed a significantly higher overall injury incidence (p < 0.002), particularly of overuse injuries (p < 0.001), during the tournament than amateur players. In almost 75 % of players in both groups, the body region most affected by injuries and complaints was the lower extremities. Orthopaedic and trauma surgeons had the lowest overall injury incidence and anaesthetists the highest (p = 0.049) during the tournament. For the first time, this study presents detailed information on the injury incidence and injury patterns of an amateur football tournament. Less-trained recreational players sustained significantly more injuries than better-trained amateur players, probably due to the lack of sufficient preparation before the tournament. Preventive strategies against overuse and traumatic injuries of recreational football players should start with regular training and warm-up programmes in preparation for a tournament.

#2 A new injury prevention programme for children's football - FIFA 11+ Kids - can improve motor performance: a cluster-randomised controlled trial
Reference: J Sports Sci. 2015 Oct 27:1-8. [Epub ahead of print]
Authors: Rössler R, Donath L, Bizzini M, Faude O
Summary: The present study evaluated the effects of a newly developed injury prevention programme for children's football ("FIFA 11+ Kids") on motor performance in 7-12-year-old children. We stratified 12 football teams (under-9/-11/-13 age categories) into intervention (INT, N = 56 players) and control groups (CON, N = 67). INT conducted the 15-min warm-up programme "FIFA 11+ Kids" twice a week for 10 weeks. CON followed a standard warm-up (sham treatment). Pre- and post-tests were conducted using: single leg stance; Y-balance test; drop and countermovement jump; standing long jump; 20-m sprint; agility run; slalom dribble; and wall volley test. We used magnitude-based inferences and linear mixed-effects models to analyse performance test results. We observed likely beneficial effects favouring INT in Y-balance (right leg; +3.2%; standardised mean difference (SMD) = 0.34; P = 0.58) and agility run (+3.6%; SMD = 0.45; P = 0.008). Possibly beneficial effects were found in Y-balance, drop jump reactive strength index, drop jump height, countermovement jump, standing long jump, slalom dribble and wall volley test. At least possibly beneficial improvements in favour of "FIFA 11+ Kids" were observed in nearly all parameters. Most effects were small, but slight improvements in motor performance may potentially contribute to a reduction of injury risk.

#3 Creatine Supplementation Increases Total Body Water in Soccer Players: a Deuterium Oxide Dilution Study
Reference: Int J Sports Med. 2015 Oct 28. [Epub ahead of print]
Authors: Deminice R, Rosa FT, Pfrimer K, Ferrioli E, Jordao AA, Freitas E
Summary: This study aimed to evaluate changes in total body water (TBW) in soccer athletes using a deuterium oxide dilution method and bioelectrical impedance (BIA) formulas after 7 days of creatine supplementation. In a double-blind controlled manner, 13 healthy (under-20) soccer players were divided randomly in 2 supplementation groups: Placebo (Pla, n=6) and creatine supplementation (CR, n=7). Before and after the supplementation period (0.3 g/kg/d during 7 days), TBW was determined by deuterium oxide dilution and BIA methods. 7 days of creatine supplementation lead to a large increase in TBW (2.3±1.0 L) determined by deuterium oxide dilution, and a small but significant increase in total body weight (1.0±0.4 kg) in Cr group compared to Pla. The Pla group did not experience any significant changes in TBW or body weight. Although 5 of 6 BIA equations were sensitive to determine TBW changes induced by creatine supplementation, the Kushner et al. 16 method presented the best concordance levels when compared to deuterium dilution method. In conclusion, 7-days of creatine supplementation increased TBW determined by deuterium oxide dilution or BIA formulas. BIA can be useful to determine TBW changes promoted by creatine supplementation in soccer athletes, with special concern for formula choice.

#4 Developing Legacy: Health Planning in the Host City of Porto Alegre for the 2014 Football World Cup
Reference: Prehosp Disaster Med. 2015 Oct 21:1-5. [Epub ahead of print]
Authors: Witt RR, Kotlhar MK, Mesquita MO, Lima MA, Marin SM, Day CB, Bandeira AG, Hutton A
Summary: The purpose of the study was to describe the process adopted to identify, classify, and evaluate legacy of health care planning in the host city of Porto Alegre for the Football World Cup 2014. There is an emerging interest in the need to demonstrate a sustainable health legacy from mass gatherings investments. Leaving a public health legacy for future host cities and countries is now an important part of planning for these events. Process The Ministry of Sports initiated and coordinated the development of projects in the host cities to identify actions, projects, and constructions to be developed to prepare for the World Cup. In Porto Alegre, a common structure was developed by the coordinating team to instruct legacy identification, classification, and evaluation. This structure was based on international documentary analysis (including official reports, policy documents, and web-based resources) and direct communication with recognized experts in the field. Findings and Interpretation Sixteen total legacies were identified for health surveillance (5) and health services. They were classified according to the strategic area, organizations involved, dimension, typology, planned or unplanned, tangible or intangible, territorial coverage, and situation prior to the World Cup. Possible impacts were then assessed as positive, negative, and potentiating, and mitigating actions were indicated. The project allowed the identification, classification, and development of health legacy, including risk analysis, surveillance, mitigation measures, and provision of emergency medical care. Although the project intended the development of indicators to measure the identified legacies, evaluation was not possible at the time of publication due to time.

#5 The influence of soccer match play on physiological and physical performance measures in soccer referees and assistant referees
Reference: J Sports Sci. 2015 Nov 2:1-7. [Epub ahead of print]
Authors: Castillo D, Yanci J, Cámara J, Weston M
Summary: The aim of this study was to quantify the acute impact of soccer match officiating on selected physiological and physical performance measures. Twenty-four officials from the Spanish National 3rd Division participated in this study. External global positioning system and internal (heart rate) load data were collected for each match official during 8 official matches. Pre- and post-matches, the referees were assessed for tympanic temperature, blood lactate, 15- and 30-m sprint speeds and unilateral (dominant and non-dominant legs) and bilateral vertical jump performances. For referees, the acute physiological and physical performance effects of officiating (post-match value minus pre-match value) were large increases in blood lactate (1.7 mmol · l-1; ±90% confidence limit, 0.9 mmol · l-1; effect size, ES = 4.35), small increases in 15-m sprint (0.09; ±0.04 s; ES = 0.53) and 30-m sprint speeds (0.14; ±0.08 s; ES = 0.39) and a small increase in non-dominant leg jump performance (2.1; ±1.4 cm; ES = 0.31). For assistant referees, there was a small decrease in tympanic temperature (-0.3°C; ±0.2°C; ES = -0.65) and small increases in blood lactate (0.4; ±0.3 mmol · l-1; ES = 0.66), 15-m sprint speed (0.06; ±0.04 s; ES = 0.47), 30-m sprint speed (0.11; ±0.16 s; ES = 0.49) and bilateral countermovement jump height (3.4; ±1.5 cm; ES = 0.45). Taken together, these data demonstrate that the physical demands of soccer officiating are sufficient to elicit increases in blood lactate and small decrements in sprint performance and, thereby, provide some evidence for match-related fatigue.

#6 Bilateral piriformis syndrome in two elite soccer players: Report of two cases
Reference: Orthop Traumatol Surg Res. 2015 Oct 27. pii: S1877-0568(15)00262-5. doi: 10.1016/j.otsr.2015.07.022. [Epub ahead of print]
Authors: Zeren B, Canbek U, Oztekin HH, İmerci A, Akgün U
Summary: Piriformis syndrome, a relatively rare condition, is described as entrapment of a sciatic nerve at the level of the piriformis muscle. There have been a few reports of bilateral piriformis syndrome in literature. In this study, we present bilateral piriformis syndrome in two professional soccer players from different teams who are symptom free at last follow-up after surgery. In both patients, resting EMG records were read normal, however EMG recording during the activity revealed prolonged H-reflexes. Both patients had no relief from conservative treatment and rehabilitation, therefore surgical treatment was performed. Preoperative mean visual analogue scale (VAS) value was 7, and decreased to 3 at the sixth month follow-up visit and at the longer term follow-up, mean 85months (74-96) it was valued at 1. Both soccer players returned to their active sports lives in the sixth postoperative month. According to Benson's functional evaluation scale, in long-term follow-up, there have been excellent results and both patients resumed their professional carrier for many years (mean 7 years).

#7 Treatment of Anterior Cruciate Ligament Injuries by Major League Soccer Team Physicians
Reference: Orthop J Sports Med. 2014 Nov 24;2(11):2325967114559892. doi: 10.1177/2325967114559892. eCollection 2014.
Authors: Farber J, Harris JD, Kolstad K, McCulloch PC
Download link: linkL
Summary: The treatment and rehabilitation procedures of anterior cruciate ligament (ACL) injuries in elite soccer players are controversial. Points of debate include surgical timing, technique, graft choice, rehabilitation, and return-to-sport criteria and timing. The purpose of the study was to identify practice preferences among current Major League Soccer (MLS) team orthopaedic surgeons for ACL injuries. The survey was administered at the MLS team physician annual meeting in January 2013. At least 1 orthopaedic surgeon representative from each of the 19 clubs (16 from the United States, 3 from Canada) was in attendance. Teams with more than 1 affiliated orthopaedic surgeon were given an additional survey to be completed either at the meeting or returned via e-mail. Descriptive statistics, Wilcoxon Mann-Whitney (return-to-play parameters, running, and ball drills), and Fisher exact tests (graft selection, bracing, continuous passive motion) were applied to the various data sets from the survey responses. A 100% survey participation rate was achieved (22 team orthopaedic surgeons representing 19 MLS teams). A single-incision, arthroscopically assisted, single-bundle reconstruction was the most common technique (91%). Surgeons were split regarding femoral tunnel drilling (50% transtibial, 46% accessory medial). Autograft bone-patellar tendon-bone (BPTB) was the most common preferred graft choice (68%). The biggest concerns about BPTB autograft and hamstring autograft were anterior knee pain (76%) and hamstring weakness (46%), respectively. Most surgeons did not recommend postoperative continuous passive motion (64%) or functional bracing (68%). Most surgeons permitted return to sport without restrictions at 6 to 8 months following surgery (82%). Surgeons who routinely used functional bracing after ACL surgery more frequently used hamstring autograft than those who used BPTB autograft (P = .04). This article successfully describes current management of ACL injuries among MLS team orthopaedic surgeons. The preference for single-bundle BPTB autograft is similar to published data in the National Football League and National Basketball Association.

#8 Erratum: "Eating and Nutrition Habits in Young Competitive Athletes: A Comparison Between Soccer Players and Cyclists".
Reference: Transl Med UniSa. 2014 Sep 1;12:1-3.
Authors: Galanti G, Stefani L, Scacciati I, Mascherini G, Buti G, Maffulli N
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#9 Quantification of training load during one-, two- and three-game week schedules in professional soccer players from the English Premier League: implications for carbohydrate periodisation
Reference: J Sports Sci. 2015 Nov 4:1-10. [Epub ahead of print]
Authors: Anderson L, Orme P, Di Michele R, Close GL, Morgans R, Drust B, Morton JP
Summary: Muscle glycogen is the predominant energy source for soccer match play, though its importance for soccer training (where lower loads are observed) is not well known. In an attempt to better inform carbohydrate (CHO) guidelines, we quantified training load in English Premier League soccer players (n = 12) during a one-, two- and three-game week schedule (weekly training frequency was four, four and two, respectively). In a one-game week, training load was progressively reduced (P < 0.05) in 3 days prior to match day (total distance = 5223 ± 406, 3097 ± 149 and 2912 ± 192 m for day 1, 2 and 3, respectively). Whilst daily training load and periodisation was similar in the one- and two-game weeks, total accumulative distance (inclusive of both match and training load) was higher in a two-game week (32.5 ± 4.1 km) versus one-game week (25.9 ± 2 km). In contrast, daily training total distance was lower in the three-game week (2422 ± 251 m) versus the one- and two-game weeks, though accumulative weekly distance was highest in this week (35.5 ± 2.4 km) and more time (P < 0.05) was spent in speed zones >14.4 km · h-1 (14%, 18% and 23% in the one-, two- and three-game weeks, respectively). Considering that high CHO availability improves physical match performance but high CHO availability attenuates molecular pathways regulating training adaptation (especially considering the low daily customary loads reported here, e.g., 3-5 km per day), we suggest daily CHO intake should be periodised according to weekly training and match schedules.

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