Latest research in football - week 47 - 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 Z-scores-based methods and their application to biological monitoring: an example in professional soccer players
Reference: Biostatistics. 2017 Nov 15. doi: 10.1093/biostatistics/kxx044. [Epub ahead of print]
Authors: Sauliere G, Dedecker J, Marquet LA, Rochcongar P, Toussaint JF, Berthelot G
Summary: The clinical and biological follow-up of individuals, such as the biological passport for athletes, is typically based on the individual and longitudinal monitoring of hematological or urine markers. These follow-ups aim to identify abnormal behavior by comparing the individual's biological samples to an established baseline. These comparisons may be done via different ways, but each of them requires an appropriate extra population to compute the significance levels, which is a non-trivial issue. Moreover, it is not necessarily relevant to compare the measures of a biomarker of a professional athlete to that of a reference population (even restricted to other athletes), and a reasonable alternative is to detect the abnormal values by considering only the other measurements of the same athlete. Here we propose a simple adaptive statistic based on maxima of Z-scores that does not rely on the use of an extra population. We show that, in the Gaussian framework, it is a practical and relevant method for detecting abnormal values in a series of observations from the same individual. The distribution of this statistic does not depend on the individual parameters under the null hypothesis, and its quantiles can be computed using Monte Carlo simulations. The proposed method is tested on the 3-year follow-up of ferritin, serum iron, erythrocytes, hemoglobin, and hematocrit markers in 2577 elite male soccer players. For instance, if we consider the abnormal values for the hematocrit at a 5% level, we found that 5.57% of the selected cohort had at least one abnormal value (which is not significantly different from the expected false-discovery rate). The approach is a starting point for more elaborate models that would produce a refined individual baseline. The method can be extended to the Gaussian linear model, in order to include additional variables such as the age or exposure to altitude. The method could also be applied to other domains, such as the clinical patient follow-up in monitoring abnormal values of biological markers.


#2 Effects of detraining on breathing pattern and ventilatory efficiency in young soccer players
Reference: J Sports Med Phys Fitness. 2017 Nov 17. doi: 10.23736/S0022-4707.17.07619-8. [Epub ahead of print]
Authors: Alvero Cruz JR, Ronconi M, Garcia Romero J, Naranjo Orellana J
Summary: This study investigated the effects of detraining on breathing pattern. The aim of this study was to evaluate the effect of a sixweek detraining period on breathing patterns and ventilatory efficiency. Fourteen young soccer players were evaluated at the end of a competitive season and after a sixweek detraining period. Assessment of respiratory efficiency was based on VE/VCO2 slope changes below 70% of exercise intensity. All participants underwent twice an incremental graded exercise test up to exhaustion. No differences in breathing frequency and inspiratory time/ total time ratio (Ti/Ttot) were found after detraining (p>.05). Differences in tidal volume (VT), VT/Ti quotient and VE were significant (p<.05) at between 40 to 100% of exercise intensity. The VE/VCO2 slope did not change (p>.05) during a postdetraining maximal incremental test. A sixweek detraining period causes changes in inspiratory flow but does not affect the inspiratory time/total respiratory cycle time ratio. The overall ventilatory efficiency of the respiratory system remains constant and is not affected by detraining.


#3 Acoustic Analysis of Soccer Fans in Acute Phonotrauma After the Match
Reference: J Voice. 2017 Nov 13. pii: S0892-1997(17)30294-1. doi: 10.1016/j.jvoice.2017.10.004. [Epub ahead of print]
Authors: Pinarbasli MO, Kaya E, Ozudogru E, Gurbuz MK, Colak E, Aksoy MA, Birdane L, Guney FO
Summary: Acute phonotrauma is the result of sound production by shouting or straining one's voice. In this study, we aimed to investigate the acute changes in the vocal folds and voices of soccer fans who voluntarily applied to our clinic after the soccer match where they engaged in acute phonotrauma. There are no other studies in the literature conducted on a similar sample group. Videolaryngostroboscopic (VLS) examination, acoustic voice analysis, and Voice Handicap Index (VHI) questionnaire were performed on 29 voluntary soccer fans included to the study before the match and at the first hour after the match. The values obtained were compared statistically with each other and with 29 control groups without voice pathology. The jitter, shimmer, and normalized noise energy values measured after the match increased significantly statistically compared with the pre-match level, but harmonic noise ratio value decreased significantly (P < 0.05). VHI scores increased significantly after the match according to the pre-match scores (P < 0.05). In the VLS examinations, there was no difference in the images before and after the match. It has been concluded that people who are using their voices loudly and intensely by shouting during the match are exposed to sound changes after the match, and if this situation becomes persistent, it may cause permanent voice pathologies. It is thought that VHI and acoustic voice analysis should be done together with VLS for diagnosis and follow-up of voice changes for which the VLS examination alone is not sufficient.


#4 Sex Differences in Aerobic Fitness in Top-Class Soccer Referees
Reference: J Strength Cond Res. 2017 Nov 14. doi: 10.1519/JSC.0000000000002292. [Epub ahead of print]
Authors: Castagna C, Bizzini M, DʼOttavio S, Araujo Povoas SC
Summary: The aim of this study was to assess the aerobic-fitness differences between male and female top-class soccer field referees (FRs). This with the purpose to provide cutoff values useful for training prescription in female FRs. Forty female top-class FRs (age 34.18 ± 3.50 years and 5 ± 3.9 years international refereeing experience) and 52 male FRs (age 38.4 ± 3.3 years and 5 ± 3.5 years international refereeing experience) candidates in the preliminary open list developed by the FIFA Refereeing Department for the 2014 and 2015 World Cup Tournaments, participated in the study. The FRs were tested for aerobic fitness under laboratory conditions with a progressive speed treadmill test until exhaustion. Female FRs showed to possess, on average, lower (large effect) levels of aerobic fitness and performance compared with their male counterparts. The female FRs' V[Combining Dot Above]O2max (48.1 ± 4.4 ml·kg·min) was 7% (large effect) lower than the male FRs (51.9 ml·kg·min). Peak treadmill speed was 11% lower (large effect) in female FRs (16.27 ± 0.94 vs. 14.64 ± 0.96 km·h). The receiver operating characteristic curve analysis enabled cutoff values (47.8 ml·kg·min for V[Combining Dot Above]O2max) that may be used as preliminary cues to guide physiological selection and training prescription in female FRs aiming to officiate male-soccer matches. Only 2.5% of the female FRs showed V[Combining Dot Above]O2max higher than the mean values of male FRs when using the scaled notation (0.68). Female FRs aiming to officiate male competitions should consider training intensities at anaerobic threshold speed (13 km·h, 95% heart rate max) when developing aerobic fitness. Given the very large sex differences in aerobic performance, strength/power training should be proposed to perspective female top-class FRs.


#5 Return to Play After Hip Arthroscopic Surgery for Femoroacetabular Impingement in Professional Soccer Players
Reference: Am J Sports Med. 2017 Nov 1:363546517738741. doi: 10.1177/0363546517738741. [Epub ahead of print]
Authors: Locks R, Utsunomiya H, Briggs KK, McNamara S, Chahla J, Philippon MJ
Summary: Arthroscopic hip surgery has been shown to be effective in returning professional athletes back to play at a high level of performance in different sports. Limited information exists regarding professional soccer players and their return to play. The purpose of the study was to determine the rate and time to return to sport for professional soccer players after hip arthroscopic surgery for the treatment of femoroacetabular impingement (FAI) and to identify possible risk factors associated with a delay in returning to play. Professional soccer players who underwent hip arthroscopic surgery for FAI by a single surgeon between 2005 and 2015 were evaluated. Data retrieved from www.mlssoccer.com , www.fifa.com , www.transfermarkt.co.uk , and www.wikipedia.org included information on each player's professional career, participation on the national team, length of professional career before surgery, number of appearances (games) before surgery, time between surgery and first appearance in a professional game, and number of appearances after surgery. Other data were obtained from the patient's medical records. Twenty-four professional soccer players (26 hips) were included. The mean age at surgery was 25.0 ± 4.0 years (range, 19-32 years). A total of 96% of patients were able to return to play at the professional level. The mean time between surgery and the first professional game played was 9.2 months (range, 1.9-24.0 months). On average, players played in 70 games after surgery (range, 0-224). National team players were able to return to play significantly earlier than the rest of the players (median, 5.7 months vs 11.6 months, respectively; P = .018). Severe chondral damage and microfracture did not interfere with return to play. The arthroscopic management of FAI in symptomatic professional soccer players allowed 96% of them to return to play. Players with national team experience were able to return to play earlier than those without it. Severe chondral damage and microfracture did not interfere with return to play.


#6 Effects of an Interpersonal Style Intervention for Coaches on Young Soccer Players' Motivational Processes
Reference: J Hum Kinet. 2017 Oct 20;59:107-120. doi: 10.1515/hukin-2017-0151. eCollection 2017 Oct.
Authors: Pulido JJ, Sanchez-Oliva D, Leo FM, Matos S, Garcia-Calvo T
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5680690/pdf/hukin-59-107.pdf
Summary: The main goal of the study was to assess the effects of an intervention programme developed with soccer coaches, based on promoting strategies to optimise the satisfaction of the basic psychological needs of athletes. Eight soccer coaches, aged between 19 and 50 years (M = 32.5; SD = 14.34), participated in the study. They were selected intentionally (without academic or federative training) and divided equally into a control and an experimental group by random peer selection. Also, 109 soccer players, aged between 11 and 15 years (M = 13.78; SD = 1.38), divided into a control group (CG; n = 56) and an experimental group (EG; n = 53), participated in the experiment. The training programme (12 hours) was aimed to develop methodological and motivational strategies to promote autonomy, competence and relatedness need satisfaction among the players. The results showed that the participants in the EG decreased competence and relatedness control, while significantly increased (post-intervention) competence and relatedness needs satisfaction. Moreover, values for the EG did not decrease for autonomy, competence frustration and amotivation, while they increased for the sport commitment. Also, intrinsic motivation decreased in both groups (greater decrease in the CG). In conclusion, we can affirm the effectiveness of the training programme to create an environment of "bright side" motivation, and reduce thwarting styles, needs frustration and low self-determination levels.


#7 Mental Strategies Predict Performance and Satisfaction with Performance among Soccer Players
Reference: J Hum Kinet. 2017 Oct 20;59:79-90. doi: 10.1515/hukin-2017-0149. eCollection 2017 Oct.
Authors: Kruk M, Blecharz J, Boberska M, Zarychta K, Luszczynska A
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5680688/pdf/hukin-59-079.pdf
Summary: This study investigated the changes in mental strategies across the season and their effects on performance and satisfaction with individual performance. Data were collected three times: at the pre-season at Time 1 (T1; baseline), in the mid-season at Time 2 (T2; two-month follow-up), and at the end-of-season at Time 3 (T3; nine-month follow-up) among male soccer players (N = 97) aged 16-27. Athletes completed the questionnaires assessing the use of nine psychological strategies in competition and the level of satisfaction with individual performance. Endurance performance was measured objectively with a 300 m run. A high level of relaxation (T1) explained better 300 m run performance (T3) and a high level of self-talk explained a higher satisfaction with individual performance (T3). A rare use of distractibility and emotional control (T1) predicted a higher level of satisfaction with individual performance (T3). No predictive role of other psychological strategies was found. The use of emotional control, relaxation, and distractibility increased over the season, whereas the use of imagery and negative thinking declined. Besides the roles of self-talk, imagery, relaxation and goal-setting, the effects of distractibility and emotional control should be taken into account when considering athletes' mental training programs.


#8 Low perceptual sensitivity to altered video speed in viewing a soccer match
Reference: Sci Rep. 2017 Nov 13;7(1):15379. doi: 10.1038/s41598-017-15619-8.
Authors: de'Sperati C, Baud Bovy G
Download link: https://www.nature.com/articles/s41598-017-15619-8.pdf
Summary: When watching videos, our sense of reality is continuously challenged. How much can a fundamental dimension of experience such as visual flow be modified before breaking the perception of real time? Here we found a remarkable indifference to speed manipulations applied to a popular video content, a soccer match. In a condition that mimicked real-life TV watching, none of 100 naïve observers spontaneously noticed speed alterations up/down to 12%, even when asked to report motion anomalies, and showed very low sensitivity to video speed changes (Just Noticeable Difference, JND = 18%). When tested with a constant-stimuli speed discrimination task, JND was still high, though much reduced (9%). The presence of the original voice-over with compensation for pitch did not affect perceptual performance. Thus, our results document a rather broad tolerance to speed manipulations in video viewing, even under attentive scrutiny. This finding may have important implications. For example, it can validate video compression strategies based on sub-threshold temporal squeezing. This way, a soccer match can last only 80 min and still be perceived as natural. More generally, knowing the boundaries of natural speed perception may help to optimize the flow of artificial visual stimuli which increasingly surround us.


#9 A prospective investigation to evaluate risk factors for lower extremity injury risk in male youth soccer players
Reference: Scand J Med Sci Sports. 2017 Nov 11. doi: 10.1111/sms.13013. [Epub ahead of print]
Authors: Read PJ, Oliver JL, De Ste Croix MBA, Myer GD, Lloyd RS
Summary: There is an inherent risk of injury in male youth football; however, pertinent risk factors for injury have yet to be examined. This study used a prospective cohort design with 357 elite male youth football players (aged 10-18 years) assessed during the pre-season period and then monitored during the season recording all non-contact lower extremity injuries. Screening tests included: single leg hop for distance (SLHD); 75% of maximum hop and stick (75%Hop); single leg countermovement jump (SLCMJ); and the tuck jump assessment (TJ). Players were divided into sub-groups based on chronological age. SLCMJ peak landing vertical ground reaction force (pVGRF) asymmetry was the most prominent risk factor (U11-U12's, OR 0.90, p = 0.04; and U15-U16's, OR 0.91, p < 0.001). Maturational offset (OR 0.58, p = 0.04), lower right leg SLCMJ pVGRF relative to body weight (OR 0.36, p = 0.03) and advanced chronological age (OR 3.62, p = 0.04) were also significantly associated with heightened injury risk in the U13-U14's, U15-U16's and U18's respectively. Univariate analyses showed combinations of anthropometric and movement screening risk factors were associated with heightened risk of lower extremity injury; however, there was variability across the different chronological age groups. Greater SLCMJ pVGRF asymmetry, lower right leg SLCMJ pVGRF %BW, later maturation and advanced chronological age are potential risk factors for injury in elite male youth football players, although the strength of these relationships were often low to moderate. In addition, risk factors are likely to change at different stages of development.


#10 Kinematic analysis of pressing situations in female collegiate football games: New insight into ACL injury causation
Reference: Scand J Med Sci Sports. 2017 Nov 16. doi: 10.1111/sms.13018. [Epub ahead of print]
Authors: Sasaki S, Koga H, Krosshaug T, Kaneko S, Fukubayashi T
Summary: The most common events during which anterior cruciate ligament (ACL) injuries occur in football are pressing situations. This study aimed to describe the knee and hip joint kinematics during pressing situations in football games in order to identify kinematic patterns in actions with a high risk for ACL injuries. We filmed 5 female collegiate football matches and identified 66 pressing situations. Five situations with a large distance between the trunk and foot placements in the sagittal plane were analysed using a model-based image-matching technique. The mean knee flexion angle at initial contact (IC) was 13° (range, 8°-28°), and increased by 11° (95% confidence interval [CI], 3°-14°) at 40 ms after IC. As for knee adduction and rotation angles, the knee positions were close to neutral at IC, and only minor knee angular changes occurred later in the sequences. The mean hip flexion was 25° (range, 8°-43°) at IC, and increased by 22° (95% CI, 11°-32°) after 100 ms. The hip was also externally rotated by 7° (range, -19° to 3°) at IC, and gradually rotated internally, reaching 10° of internal rotation (range, -5° to 27°) at 100 ms after IC. This study suggests that the observed knee valgus, internal hip and knee rotation, and static hip flexion previously reported in non-contact ACL injury events are unique to injury situations. In contrast, neither rapid knee valgus nor increased internal rotation was seen in non-injury pressing manoeuvres.


#11 The prognostic value of physiological and physical characteristics in youth soccer: A systematic review
Reference: Eur J Sport Sci. 2017 Nov 21:1-13. doi: 10.1080/17461391.2017.1386719. [Epub ahead of print]
Authors: Murr D, Raabe J, Honer O
Download link: http://www.tandfonline.com/doi/abs/10.1080/17461391.2017.1386719?needAccess=true#aHR0cDovL3d3dy50YW5kZm9ubGluZS5jb20vZG9pL3BkZi8xMC4xMDgwLzE3NDYxMzkxLjIwMTcuMTM4NjcxOT9uZWVkQWNjZXNzPXRydWVAQEAw
Summary: Talent identification and selection in soccer is typically based on subjective evaluations of experienced coaches. Recently, there has been a trend to complement these subjective assessments with objective tests. However, there is currently no comprehensive overview of the prognostic relevance of objective measurements in youth soccer. Therefore, the primary purpose of the current study was to systematically review published empirical studies related to the prognostic relevance of physiological (e.g. endurance and speed) and physical characteristics (i.e. height and weight). Of 6876 initially identified studies, nine articles were included. In those studies, endurance (nine studies), change of direction (seven), height (seven), and weight (seven) received the most meaningful consideration within the literature. In regard to physiological predictors, between 16 and 29 effect sizes were tested for endurance, sprint, and change of direction, and about half of them were found to be significant with small to moderate effects (0.37 ≤ Mdn(d) ≤ 0.57). In addition, while only investigated in two studies all tested effect sizes for repeated sprint ability were found to be significant. Despite their frequent consideration in the literature, low numbers of significant effect sizes (≤ 26%) and magnitude (0.23 ≤ Mdn(d) ≤ 0.29) were found for the physical predictors height and weight. Overall, results appear to be dependent on the respective study design and, in particular, moderator variables (i.e. soccer development stage, performance level T1/T2, prognostic period, and sample size). Consequently, additional research seems warranted to more comprehensively investigate the predictive relevance of the individual characteristics using more homogeneous study designs.



American Football
#1 Associations between BMI Change and Cardiometabolic Risk in Retired Football Players
Reference: Med Sci Sports Exerc. 2017 Nov 14. doi: 10.1249/MSS.0000000000001492. [Epub ahead of print]
Authors: Trexler ET, Smith-Ryan AE, DeFreese JD, Marshall SW, Guskiewicz KM, Kerr ZY
Summary: Elevated rates of cardiometabolic diseases have been observed in former American football players. The current study sought to determine if change in body mass index (ΔBMI) following retirement influences the prevalence of coronary heart disease (CHD), diabetes, or high blood pressure (HBP) in former professional football players. Retired professional football players (n=3,729) were sent a survey with questions regarding health status, playing history, and demographic information. Self-reported BMI at the time of retirement was subtracted from current self-reported BMI to calculate ΔBMI. Prevalence of CHD, diabetes, and HBP were determined by asking participants if they had ever been diagnosed by a healthcare professional. Binomial regression with a Poisson residual and robust variance estimation was used to compute crude prevalence ratios (PRs) and 95% confidence intervals (CI) for each outcome. Adjusted PRs were calculated by adjusting for BMI at the time of retirement, age, years of football experience, race, exercise habits, alcohol use, steroid history, smoking history, and playing position. Complete data were available for 2,062 respondents. Prevalence of CHD increased 25-31% for each 5-point increase in ΔBMI following retirement (Crude PR: 1.25; 95%CI: 1.03-1.52; p=0.026; Adjusted PR: 1.31; 95%CI: 1.11-1.55; p=0.001). Diabetes prevalence increased 69-88% for each 5-point ΔBMI increase (Crude: 1.88; 95%CI: 1.45-2.44; p<0.001; Adjusted: 1.69; 95%CI: 1.32-2.15; p<0.001). A 5-point increase in ΔBMI was associated with a 35-40% increase in HBP prevalence (Crude: 1.40; 95%CI: 1.27-1.53; p<0.001; Adjusted: 1.35; 95%CI: 1.24-1.47; p<0.001). After controlling for relevant covariates, post-retirement ΔBMI was positively and independently associated with prevalence of CHD, diabetes, and HBP. Post-retirement interventions using diet and/or exercise to influence body composition may improve long-term health in retired football players.


#2 Calling Injury Timeouts for the Medical Evaluation of Concussion: Determinants of Collegiate Football Officials' Behavior
Reference: J Athl Train. 2017 Nov 8. doi: 10.4085/1062-6050-52.11.17. [Epub ahead of print]
Authors: Kroshus E, Parsons J, Hainline B
Summary: Sports officials can play an important role in concussion safety by calling injury timeouts so that athletic trainers can evaluate athletes with possible concussions. Understanding the determinants of whether officials call an injury timeout when they suspect a concussion has important implications for the design of interventions that better support officials in this role. The objective of the study was to assess the knowledge of US collegiate football officials about concussion symptoms and to determine the associations between knowledge, perceived injunctive norms, and self-efficacy and calling injury timeouts for suspected concussions in athletes. 3074 US collegiate football officials contacted, 1324 (43% response rate) participated.  Concussion knowledge, injunctive norms (belief about what others would want them to do), and behavioral self-efficacy (confidence in their ability to call injury timeouts for suspected concussions in athletes during challenging game-day conditions) were used as outcome measures. Officials reported calling approximately 1 injury timeout for a suspected concussion every 4 games during the 2015 season. Structural equation modeling indicated that officials with more concussion-symptom knowledge had greater behavioral self-efficacy. Independent of an official's symptom knowledge, injunctive norms that were more supportive of calling an injury timeout were associated with greater self-efficacy. Concussion education for officials is important because when officials are aware of concussion symptoms, they are more confident in calling injury timeouts. Beyond increasing symptom knowledge, fostering sports environments that encourage concussion safety in all stakeholder groups can support officials in calling injury timeouts. Athletic trainers can help create sports environments that support proactive concussion identification by educating stakeholders, including officials, about the importance of concussion safety. When officials believe that other stakeholders support concussion safety, they are more likely to call injury timeouts if they suspect a concussion has occurred.


#3 Postmortem Autopsy-Confirmation of Antemortem [F-18]FDDNP-PET Scans in a Football Player With Chronic Traumatic Encephalopathy
Reference: Neurosurgery. 2017 Nov 10. doi: 10.1093/neuros/nyx536. [Epub ahead of print]
Authors: Omalu B, Small GW, Bailes J, Ercoli LM, Merrill DA, Wong KP, Huang SC, Satyamurthy N, Hammers JL, Lee J, Fitzsimmons RP, Barrio JR
Summary: Currently, only presumptive diagnosis of chronic traumatic encephalopathy (CTE) can be made in living patients. We present a modality that may be instrumental to the definitive diagnosis of CTE in living patients based on brain autopsy confirmation of [F-18]FDDNP-PET findings in an American football player with CTE. [F-18]FDDNP-PET imaging was performed 52 mo before the subject's death. Relative distribution volume parametric images and binding values were determined for cortical and subcortical regions of interest. Upon death, the brain was examined to identify the topographic distribution of neurodegenerative changes. Correlation between neuropathology and [F-18]FDDNP-PET binding patterns was performed using Spearman rank-order correlation. Mood, behavioral, motor, and cognitive changes were consistent with chronic traumatic myeloencephalopathy with a 22-yr lifetime risk exposure to American football. There were tau, amyloid, and TDP-43 neuropathological substrates in the brain with a differential topographically selective distribution. [F-18]FDDNP-PET binding levels correlated with brain tau deposition (rs = 0.59, P = .02), with highest relative distribution volumes in the parasagittal and paraventricular regions of the brain and the brain stem. No correlation with amyloid or TDP-43 deposition was observed. [F-18]FDDNP-PET signals may be consistent with neuropathological patterns of tau deposition in CTE, involving areas that receive the maximal shearing, angular-rotational acceleration-deceleration forces in American football players, consistent with distinctive and differential topographic vulnerability and selectivity of CTE beyond brain cortices, also involving midbrain and limbic areas. Future studies are warranted to determine whether differential and selective [F-18]FDDNP-PET may be useful in establishing a diagnosis of CTE in at-risk patients.


#4 Intracranial Ischemic Infarct Due to Blunt Force Trauma in a High School Football Player
Reference: Cureus. 2017 Sep 7;9(9):e1659. doi: 10.7759/cureus.1659.
Authors: Esianor BI, Haider AS, Engelhardt MI, Osumah T, Vayalumkal S, Thakur R, Leonard D, Haithcock J, Layton KF
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5675602/pdf/cureus-0009-00000001659.pdf
Summary: Ischemic stroke is an uncommon cause of death among teenagers and young adults; however, the etiologies differ when compared to ischemic strokes in older individuals. Large-vessel atherosclerosis and small-vessel disease causing ischemic stroke are rare for the teenage population, while cervicocerebral arterial dissections account for up to 20% of ischemic strokes. Here, we present the case of a 16-year-old male who developed internal carotid artery dissection (ICAD) after a head injury and subsequently developed ischemic stroke and seizures.


#6 Posterolateral Corner Injuries of the Knee at the National Football League Combine: An Imaging and Outcomes Analysis
Reference: Arthroscopy. 2017 Nov 13. pii: S0749-8063(17)31162-3. doi: 10.1016/j.arthro.2017.08.303. [Epub ahead of print]
Authors: Chahla J, Kennedy NI, Cinque ME, Sanchez G, Logan C, Vopat BG, Beaulieu-Jones B, Price M, Whalen J, LaPrade RF, Provencher MT
Summary: (1) To determine the epidemiology, examination findings, imaging findings, and associated injuries of posterolateral corner (PLC) injuries in players participating in the National Football League (NFL) Combine and (2) to evaluate the impact of PLC injuries on performance compared with matched controls. All PLC injuries identified at the NFL Combine between 2009 and 2015 were reviewed. The inclusion criteria were any player who had clinical findings or a previous surgical procedure consistent with a PLC injury and who participated in medical and performance testing at the NFL Combine. PLC injuries were identified by evaluating the side-to-side difference in lateral-compartment laxity with varus stress and reviewing magnetic resonance imaging studies. NFL performance outcomes (draft position and number of games played or started within the first 2 years) were compared with matched controls. Of the 2,285 players assessed at the NFL Combine, 16 (0.7%) were identified with a history of a grade II or III PLC tear and surgical management whereas 7 additional players (0.3%) had a PLC injury diagnosed on clinical examination, for 23 total PLC injuries (1%). On examination, 13 of 22 knees (59%) were shown to be stable; however, most of those managed surgically had significantly improved stability (13 of 15 stable) versus none of those managed nonsurgically (0 of 7 stable). Surgically managed PLC-injured athletes started significantly fewer games than controls (5.3 vs 10.5, P = .03); the mean draft position for players with surgically treated PLC injuries was 139.7 versus controls' mean draft position of 111.3. Of the 16 athletes treated operatively, 2 reported a PLC injury recurrence; both were managed nonoperatively. A small percentage of players at the NFL Combine had evidence of a previous PLC injury (1%), with 0.4% having residual varus asymmetry on clinical examination. A worse overall mean draft position for isolated PLC-injured athletes versus controls was found: 132.8 versus 111.3 (P = .02). It is recommended that the use of varus stress radiographs be considered for NFL Combine athletes to objectively determine their grade of injury. LEVEL OF EVIDENCE: Level IV, retrospective case series.


Australian Football
#1 Phases of match-play in professional Australian Football: Descriptive analysis and reliability assessment
Reference: J Sci Med Sport. 2017 Oct 23. pii: S1440-2440(17)31671-7. doi: 10.1016/j.jsams.2017.10.021. [Epub ahead of print]
Authors: Rennie MJ, Watsford ML, Spurrs RW, Kelly SJ, Pine MJ
Summary: The purpose was to examine the frequency and time spent in the phases of Australian Football (AF) match-play and to assess the intra-assessor reliability of coding these phases of match-play. Video footage of 10 random quarters of AF match-play were coded by a single researcher. Phases of offence, defence, contested play, umpire stoppage, set shot and goal reset were coded using a set of operational definitions. Descriptive statistics were provided for all phases of match-play. Following a 6-month washout period, intra-coder reliability was assessed using typical error of measurement (TEM) and intra-class correlation coefficients (ICC). A quarter of AF match-play involved 128±20 different phases of match-play. The highest proportion of match-play involved contested play (25%), followed by offence (18%), defence (18%) and umpire stoppages (18%). The mean duration of offence, defence, contested play, umpire stoppage, set shot and goal reset were 14, 14, 10, 11, 28 and 47s, respectively. No differences were found between the two coding assessments (p>0.05). ICCs for coding the phases of play demonstrated very high reliability (r=0.902-0.992). TEM of the total time spent in each phase of play represented moderate to good reliability (TEM=1.8-9.3%). Coding of offence, defence and contested play tended to display slightly poorer TEMs than umpire stoppages, set shots and goal resets (TEM=8.1 vs 4.5%). Researchers can reliably code the phases of AF match-play which may permit the analysis of specific elements of competition.


#2 Eight Week Return to Play following Latarjet Shoulder Reconstruction in an Australian Football Player: A Case Report
Reference: J Sport Rehabil. 2017 Nov 15:1-28. doi: 10.1123/jsr.2017-0194. [Epub ahead of print]
Authors: Murphy M, Stockden M, Withers K, Breidahl W, Charlesworth J
Summary: Anterior shoulder dislocations are a common injury in many sports resulting in extended time lost from play with an extremely high recurrence rate in young athletes playing high risk sport. Latarjet shoulder reconstruction is a common surgical procedure used to prevent subsequent dislocation with an expected rehabilitation timeframe of between four to six months before return to play. A 21-year-old male Australian football player experienced two left sided shoulder dislocations before undergoing a left Latarjet shoulder reconstruction. He was assessed clinically and with magnetic resonance imaging which revealed significant tearing of the anterior labrum. We theorized maximal glenohumeral stability occurs after bony healing of the coracoid onto the glenoid at six weeks. The patient then underwent an eight-week structured and graduated rehabilitation program aimed at preventing loss of shoulder range of motion, muscle and functional capacity and returned to play at eight weeks post injury with no complications or recurrence at twelve month follow-up. This is the first time an eight-week rehabilitation following Latarjet shoulder reconstruction has been reported. In athletes with anterior glenohumeral dislocation who require accelerated return to play, a Latarjet reconstruction with an eight-week rehabilitation protocol can be considered.


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