Latest research in football - week 46 - 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 Hamstring Injuries in Professional Soccer Players: Extent of MRI-Detected Edema and the Time to Return to Play
Reference: Sports Health. 2017 Nov 1:1941738117741471. doi: 10.1177/1941738117741471. [Epub ahead of print]
Authors: Crema MD, Godoy IRB, Abdalla RJ, de Aquino JS, Ingham SJM, Skaf AY
Summary: Discrepancies exist in the literature regarding the association of the extent of injuries assessed on magnetic resonance imaging (MRI) with recovery times. Thr hypothesis was that MRI-detected edema in grade 1 hamstring injuries does not affect the return to play (RTP). Grade 1 hamstring injuries from 22 professional soccer players were retrospectively reviewed. The extent of edema-like changes on fluid-sensitive sequences from 1.5-T MRI were evaluated using craniocaudal length, percentage of cross-sectional area, and volume. The time needed to RTP was the outcome. Negative binomial regression analysis tested the measurements of MRI-detected edema-like changes as prognostic factors. The mean craniocaudal length was 7.6 cm (SD, 4.9 cm; range, 0.9-19.1 cm), the mean percentage of cross-sectional area was 23.6% (SD, 20%; range, 4.4%-89.6%), and the mean volume was 33.1 cm3 (SD, 42.6 cm3; range, 1.1-161.3 cm3). The mean time needed to RTP was 13.6 days (SD, 8.9 days; range, 3-32 days). None of the parameters of extent was associated with RTP. The extent of MRI edema in hamstring injuries does not have prognostic value.

#2 Hip Strength as a Predictor of Ankle Sprains in Male Soccer Players: A Prospective Study
Reference: J Athl Train. 2017 Nov 8. doi: 10.4085/1062-6050-52.11.18. [Epub ahead of print]
Authors: Powers CM, Ghoddosi N, Straub RK, Khayambashi K
Summary: Diminished hip-abductor strength has been suggested to increase the risk of noncontact lateral ankle sprains. The purpose was to determine prospectively whether baseline hip-abductor strength predicts future noncontact lateral ankle sprains in competitive male soccer players. Two hundred ten competitive male soccer players participated in this study.  Before the start of the sport season, isometric hip-abductor strength was measured bilaterally using a handheld dynamometer. Any previous history of ankle sprains, body mass index, age, height, and weight was documented. During the sport season (30 weeks), ankle injury status was recorded by team medical providers. Injured athletes were further classified based on the mechanism of injury. Only data from injured athletes who sustained noncontact lateral ankle sprains were used for analysis. Postseason, logistic regression was used to determine whether baseline hip strength predicted future noncontact lateral ankle sprains. A receiver operating characteristic curve was constructed for hip strength to determine the cutoff value for distinguishing between high-risk and low-risk outcomes. A total of 25 noncontact lateral ankle sprains were confirmed, for an overall annual incidence of 11.9%. Baseline hip-abductor strength was lower in injured players than in uninjured players (P = .008). Logistic regression indicated that impaired hip-abductor strength increased the future injury risk (odds ratio = 1.10 [95% confidence interval = 1.02, 1.18], P = .010). The strength cutoff to define high risk was ≤33.8% body weight, as determined by receiver operating characteristic curve analysis. For athletes classified as high risk, the probability of injury increased from 11.9% to 26.7%. Reduced isometric hip-abductor strength predisposed competitive male soccer players to noncontact lateral ankle sprains.

#3 Nonsurgical Management of an Anterior Cruciate Ligament-Deficient Knee in a Women's Soccer Player: A Validation Clinical Case Report
Reference: J Athl Train. 2017 Nov 8. doi: 10.4085/1062-6050.52.11.21. [Epub ahead of print]
Authors: Gray CE, Hummel C, Lazenby T
Summary: A collegiate women's soccer player sustained an isolated anterior cruciate ligament (ACL) tear and expressed a desire to continue her season without surgical intervention. Using the results of a randomized controlled trial and published clinical guidelines, the clinicians classified the patient as an ACL-deficient coper. The patient completed her soccer season without incident, consistent with the findings of the established clinical guidelines. However, 6 months later, she sustained a meniscal tear, which was not unexpected given that 22% of ACL-deficient copers in the randomized controlled trial incurred a meniscal tear within 24 months of ACL injury.

#4 Risk Factors for Lower Extremity Overuse Injuries in Female Youth Soccer Players
Reference: Orthop J Sports Med. 2017 Oct 23;5(10):2325967117733963. doi: 10.1177/2325967117733963. eCollection 2017 Oct.
Authors: O'Kane JW, Neradilek M, Polissar N, Sabado L, Tencer A, Schiff MA
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Summary: Youth soccer injuries are common and of increasing concern, with sport specialization occurring at younger ages. Limited research is available regarding overuse injuries and risk factors in young female athletes. The purpose was to identify the number and rate of overuse injuries in female soccer players (ages 12-15 years), describe the anatomic location and type of injury, and evaluate contributing risk factors. A total of 351 female youth soccer players, ages 12 to 15 years, from Washington State were evaluated from 2008 to 2012. Players with lower extremity overuse injuries were identified through weekly emails and were interviewed by telephone to obtain data on injury type and body region. We evaluated the association between overuse injuries and preseason risk factors, including joint hypermobility, hip and knee muscle strength, and jump biomechanics, using Poisson regression to estimate relative risk (RR) and 95% CIs. The incidence rate for first-time lower extremity overuse injuries was 1.7 per 1000 athlete-exposure hours (AEH; 95% CI, 1.4-2.2), and that for repeat injuries was 3.4 per 1000 AEH (95% CI, 2.1-5.6). Knee injuries accounted for 47% of overuse injuries. Increased valgus was associated with a 3.2-fold increased risk (95% CI, 1.52-6.71) for knee injury. A 1-standard deviation (SD) increase in hamstring strength was associated with a 35% decreased risk (RR, 0.65; 95% CI, 0.46-0.91) for overuse knee injuries, and a 1-SD increase in quadriceps strength was associated with a 30% decreased risk (RR, 0.70; 95% CI, 0.50-0.98). A 1-SD increase in hip flexor strength was associated with a 28% decreased risk (RR, 0.72; 95% CI, 0.51-1.00) for overuse knee injuries, and a 1-SD increase in external rotation strength was associated with a 35% decreased risk (RR, 0.65; 95% CI, 0.46-0.91). Playing on more than 1 soccer team was associated with a 2.5-fold increased risk (95% CI, 1.08-5.35) for overuse knee injuries, and participating in other physical activities was associated with a 61% decreased risk (odds ratio, 0.39; 95% CI, 0.15-0.81). In this study, lower extremity overuse injuries in female youth soccer players affected primarily the knee. Lower knee separation distance, decreased lower extremity strength, and playing on more than 1 soccer team increased injury risk.

#5 Comparison of body fat percentage of male soccer players of different competitive levels, playing positions and age groups: a meta-analysis
Reference: J Sports Med Phys Fitness. 2017 Nov 7. doi: 10.23736/S0022-4707.17.07941-5. [Epub ahead of print]
Authors: Slimani M, Znazen H, Hammami A, Bragazzi NL
Summary: The aim of the present meta-analysis was to compare the body fat percentage (%) between male soccer players of different competitive levels, playing positions and age groups. The systematic search was conducted using different databases and according to the Population/Intervention or Exposure/Comparison/Outcome(s) [PICO] criteria. Higher % values of body fat in lower-level soccer players than higher-level counterparts (ES=0.18, 95% CI -0.86 to -0.14, p=0.006) were noted. Higher body fat % values in goalkeepers than defenders (ES=0.21, 95% CI -1.17 to -0.34, p<0.001), midfielders (ES=0.26, 95% CI -1.50 to -0.45, p<0.001) and forwards (ES=0.18, 95% CI -1.26 to -0.53, p<0.001) were observed. There was no significant association between % of body fat and age (p=0.86). In conclusion, body fat % clearly distinguished higher- from lower-level soccer players. These findings also imply that body fat % differ as a function of positional role in soccer and that sports scientists, coaches, and strength and conditioning professionals need to be aware of the specific positional requirements in soccer in terms of body fat. However, due to some limitations of the present meta-analysis (high statistically significant heterogeneity and evidence of publication bias), further studies are urgently needed in the field.

#6 Muscle injury rate in professional football is higher in matches played within 5 days since the previous match: a 14-year prospective study with more than 130000 match observations
Reference: Br J Sports Med. 2017 Nov 3. pii: bjsports-2016-097399. doi: 10.1136/bjsports-2016-097399. [Epub ahead of print]
Authors: Bengtsson H, Ekstrand J, Walden M, Hägglund M
Summary: The association between match congestion and injury rates in professional football has yielded conflicting results. The aim was to analyse associations between match congestion on an individual player level and injury rates during professional football matches. Data from a prospective cohort study of professional football with 133 170 match observations were analysed with Poisson regressions. Associations between short-term match congestion, defined as number of days between two match exposures (≤3, 4, 5, 6 and 7-10 days) and injury rates were analysed. To analyse the influence of long-term match congestion, defined as individual match exposure hours in the 30 days preceding a match, observations were categorised into three groups (low, ≤4.5; medium, >4.5 to ≤7.5; and high, >7.5 hours). No differences in total match injury rates were found between the reference category (≤3 days) and the other categories of short-term congestion. Muscle injury rates were significantly lower in matches preceded by 6 (rate ratio (RR) 0.79; 95% CI 0.65 to 0.95) or 7-10 days (RR 0.81; 95% CI 0.71 to 0.93) compared with ≤3 days since the last match exposure. No differences in total and muscle injury rates between the three long-term match congestion groups were found. In this study of male professional football players, there were no match congestion-related differences in total match injury rates, but muscle injury rates during matches were lower when players were given at least 6 days between their match exposures.

#7 Change in knee flexor torque after fatiguing exercise identifies previous hamstring injury in football players
Reference: Scand J Med Sci Sports. 2017 Nov 8. doi: 10.1111/sms.13007. [Epub ahead of print]
Authors: Lord C, Ma'ayah F, Blazevich AJ
Summary: Muscular fatigue and inter-limb strength asymmetry are factors known to influence hamstring injury risk, however limb-specific exacerbation of knee flexor (hamstrings) torque production after fatiguing exercise has previously been ignored. To investigate changes in muscular force production before and after sport-specific (repeated-sprint) and non-specific (knee extension-flexion) fatiguing exercise, and explore the sensitivity and specificity of isokinetic endurance (i.e. muscle-specific) and single-leg vertical jump (i.e. whole limb) tests to identify previous hamstring injury. 20 Western Australia State League footballers with previous unilateral hamstring injury and 20 players without participated. Peak concentric knee extensor and flexor (180°∙s-1 ) torques were assessed throughout an isokinetic endurance test, which was then repeated alongside a single-leg vertical jump test (SLVJ) before and after maximal repeated-sprint exercise. Greater reductions in isokinetic knee flexor torque (-16%) and the concentric hamstring:quadriceps peak torque ratio (-15%) were observed after repeated-sprint running only in the injured (kicking) leg and only in the previously injured subjects. Changes in (1) peak knee flexor torque after repeated-sprint exercise, and (2) the decline in knee flexor torque during the isokinetic endurance test measured after repeated-sprint exercise, correctly identified the injured legs (N=20) within the cohort (N=80) with 100% specificity and sensitivity. Decreases in peak knee flexor torque and knee flexor torque during an isokinetic endurance test after repeated-sprint exercise identified previous hamstring injury with 100% accuracy. Changes in knee flexor torque, but not SLVJ, should be tested to determine its prospective ability to predict hamstring injury in competitive football players.

#8 Effects of special exercise programs on functional movement screen scores and injury prevention in preprofessional young football players
Reference: J Exerc Rehabil. 2017 Oct 30;13(5):535-540. doi: 10.12965/jer.1735068.534. eCollection 2017 Oct.
Authors: Dinc E, Kilinc BE, Bulat M, Erten YT, Bayraktar B
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Summary: To increase movement capacity and to reduce injury risk in young soccer players by implementing a special functional exercise program based on functional movement screen (FMS) and correctives. 67 young male athletes 14-19 years of age from a Super League Football Club Academy participated in the study. Functional movement patterns were evaluated with FMS assessment protocol. Deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability push-up, and rotatory stability were examined in FMS. Considering the FMS scores the number of intervention and control groups were defined as 24 and 43, respectively. Intervention program was composed of 1 hr twice a week sessions in total of 12 weeks with 4 weeks of mobility, 4 weeks of stability, and 4 weeks of integration exercises. At the end of 12-week intervention and control groups were re-evaluated with FMS protocol. Contact and noncontact sports injuries recorded during one season. In intervention group there was statistically significant difference in increase in total FMS scores (P<0.01), deep squat (P≤0.001), hurdle step (P<0.05), inline lunge (P<0.01), and trunk stability push-up (P<0.01). In control group total FMS, deep squat, and trunk stability push-up scores increased with a statistical difference (P<0.01, P<0.05, P≤0.01, respectively). The incidence of noncontact injury in control group was higher than intervention group (P<0.05). Periodic movement screening and proper corrections with functional training is valuable in order to create better movement capacity to build better physical performance and more effective injury prevention.

#9 Heads Up: The Presentation of Schizoaffective Disorder in an Elite College Soccer Player with Prior Concussion
Reference: Harv Rev Psychiatry. 2017 Nov/Dec;25(6):302-310. doi: 10.1097/HRP.0000000000000147.
Authors: Adelsky SJ, Ducharme S, Wilner EK, Yudkoff B, Lejeune S.

American Football
#1 Is Big Truly Bad? Aortic Dilation in Former National Football League Players
Reference: Circ Cardiovasc Imaging. 2017 Nov;10(11). pii: e007157. doi: 10.1161/CIRCIMAGING.117.007157.
Authors: Churchill TW, Baggish AL

#2 Ascending Aortic Dimensions in Former National Football League Athletes
Reference: Circ Cardiovasc Imaging. 2017 Nov;10(11). pii: e006852. doi: 10.1161/CIRCIMAGING.117.006852.
Autors: Gentry JL 3rd, Carruthers D, Joshi PH, Maroules CD, Ayers CR, de Lemos JA, Aagaard P, Hachamovitch R, Desai MY, Roselli EE, Dunn RE, Alexander K, Lincoln AE, Tucker AM, Phelan DM
Summary: Ascending aortic dimensions are slightly larger in young competitive athletes compared with sedentary controls, but rarely >40 mm. Whether this finding translates to aortic enlargement in older, former athletes is unknown. This cross-sectional study involved a sample of 206 former National Football League (NFL) athletes compared with 759 male subjects from the DHS-2 (Dallas Heart Study-2; mean age of 57.1 and 53.6 years, respectively, P<0.0001; body surface area of 2.4 and 2.1 m2, respectively, P<0.0001). Midascending aortic dimensions were obtained from computed tomographic scans performed as part of a NFL screening protocol or as part of the DHS. Compared with a population-based control group, former NFL athletes had significantly larger ascending aortic diameters (38±5 versus 34±4 mm; P<0.0001). A significantly higher proportion of former NFL athletes had an aorta of >40 mm (29.6% versus 8.6%; P<0.0001). After adjusting for age, race, body surface area, systolic blood pressure, history of hypertension, current smoking, diabetes mellitus, and lipid profile, the former NFL athletes still had significantly larger ascending aortas (P<0.0001). Former NFL athletes were twice as likely to have an aorta >40 mm after adjusting for the same parameters. Ascending aortic dimensions were significantly larger in a sample of former NFL athletes after adjusting for their size, age, race, and cardiac risk factors. Whether this translates to an increased risk is unknown and requires further evaluation.

#3 Total And Segmental Body Composition Examination In Collegiate Football Players Using Multifrequency Bia And Dxa
Reference: J Strength Cond Res. 2017 Nov 6. doi: 10.1519/JSC.0000000000002320. [Epub ahead of print]
Authors: Raymond CJ, Dengel DR, Bosch TA
Summary: The current study examined the influence of player position on the agreement between multi-frequency bioelectrical impedance analysis (MfBIA) and dual X-ray absorptiometry (DXA) when assessing total and segmental percent body fat (BF%), fat mass (FM), and fat-free mass (FFM) in NCAA Division I collegiate football athletes. Forty-four male collegiate athletes (age=19±1 yrs; height=1.9±1.0 m; weight=106.4±18.8 kg) participated. Player positions included: offensive linemen (OL; n=7), tight ends (TE; n=4), wide receivers (WR; n=9), defensive linemen (DL; n=6), defensive backs (DB; n=8), linebackers (LB; n=6), and running backs (RB; n=4). Total and segmental body composition measured using MfBIA were compared with values obtained using DXA. Compared to DXA, MfBIA underestimated BF% (3.0±3.8%), total FM (2.5±4.3 kg), arm FM (0.4±0.8 kg), arm FFM (1.4±0.9 kg), leg FM (2.8±2.0 kg), and leg FFM (5.4±2.4 kg) (all p<0.001; arm FM p=0.002) and overestimated total FFM (-2.4±4.5 kg) (p<0.001). Limits of agreement (LOAs) were: ±7.39% (BF%), ±8.50 kg (total FM), ±1.50 kg (arm FM), ±1.83 kg (arm FFM), ±3.83 kg (leg FM), ±4.62 kg (leg FFM), and ±8.83 kg (total FFM). No significant differences were observed between devices for trunk FM (-0.3±3.0 kg; p = 0.565) and trunk FFM (0.4±2.4 kg; p=0.278), with LOAs of ±5.92 kg and ±4.69 kg, respectively. Player position significantly affected all between-device mean body composition measurement differences (adjusted p<0.05), with OL demonstrating the greatest effect on each variable. Therefore, MfBIA does not appear accurate in examining between-player body composition in college football players.

#4 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.XX. [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 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. Of the 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) was 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.

#5 Effects of Intravenous Cold Saline on Hyperthermic Athletes Representative of Large Football Players and Small Endurance Runners
Reference: Clin J Sport Med. 2017 Oct 27. doi: 10.1097/JSM.0000000000000505. [Epub ahead of print]
Authors: Morrison KE, Desai N, McGuigan C, Lennon M, Godek SF
Summary: The purpose was to evaluate the cooling effects of intravenous (IV) cold normal (0.9%) saline on hyperthermic athletes. Twelve male participants who were representative of a collegiate cross-country (6) and American football (6) population. Participants underwent body composition analysis using a BodPod. They were placed in an environmentally controlled chamber and brought to a Tc of 39.5°C with dynamic exercise. When temperatures were reached, they were treated with either 2 L of cold saline (CS) (4°C) or intravenous room temperature (22°C) saline (RS) over a ∼30-minute period. Tre was measured with a rectal temperature probe every minute during the treatment period. Total ΔTre (ending Tre - starting Tre) and cooling rate (total change in Tre/time) were measured for each condition, and body composition variables calculated included body surface area (BSA), BSA-to-mass ratio (BSA/mass), lean body mass, and body fat percentage (%BF) (P < 0.05). Statistically significant differences were found in the total ΔTre and cooling rate between the CS and RS trials. The cooling rate for the CS trials was significantly correlated to mass, BSA, BSA/mass, and %BF. In hyperthermic athletes, core temperature was reduced more effectively using chilled saline during IV infusion. Body composition had a significant impact on overall cooling revealing that the smaller and leaner participants cooled at a greater rate. When indicated, CS infusion could be considered for cooling hyperthermic individuals when other methods are not available.

#6 Meniscectomy and Resultant Articular Cartilage Lesions of the Knee Among Prospective National Football League Players: An Imaging and Performance Analysis
Reference: Am J Sports Med. 2017 Nov 1:363546517737991. doi: 10.1177/0363546517737991. [Epub ahead of print]
Authors: Chahla J, Cinque ME, Godin JA, Sanchez G, Lebus GF, Whalen JM, Price MD, Kennedy NI, Moatshe G, LaPrade RF, Provencher MT
Summary: The effect of prior meniscectomy and the resulting reduction in meniscal tissue on a potential National Football League (NFL) player's articular cartilage status and performance remain poorly elucidated. Purpose/Hypothesis: (1) To determine the epidemiology, imaging characteristics, and associated articular cartilage pathology of the knee among players with a previous meniscectomy who were participating in the NFL Combine and (2) to evaluate the effect of these injuries on performance as compared with matched controls. The hypothesis was that players with less meniscal tissue would have worse cartilage status and inferior performance metrics in their first 2 NFL seasons. All athletes with a history of a meniscectomy and magnetic resonance imaging scan of the knee who participated in the NFL Combine (2009-2015) were identified. Medical records and imaging were analyzed, and surgical history, games missed in college, position played, and draft position were documented. The conditions of the meniscus and cartilage were graded with modified ISAKOS scores (International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine) and ICRS scores (International Cartilage Repair Society), respectively. Players with a previous meniscectomy of at least 10% of total medial or lateral meniscal volume excised (ISAKOS meniscus grade ≤8) and matched controls without a significant pre-Combine injury were similarly evaluated and compared by position of play through analysis of draft position, number of games played and started, and how many eligible plays they participated in (snap percentage) within the first 2 NFL seasons. Of the 2285 players who participated in the NFL Combine (2009-2015), 287 players (322 knees) had a prior meniscectomy (206 lateral, 81 medial). Among these players, 247 (85%) had a total of 249 chondral lesions, most commonly on the lateral femoral condyle (111 lesions, 45%). There was a significant inverse correlation found between the ISAKOS medial and lateral meniscus grade and the corresponding compartment chondral lesion grade ( P = .001). A poorer meniscus score was also associated with worse chondral pathology, especially in the lateral compartment. After controlling for position of play, the injury-free control group had a significantly greater number of total games played and games started and higher snap percentage versus those with a prior meniscectomy of at least 10% volume (ISAKOS meniscus grade ≤8). Players with severe chondral lesions (ICRS grade 4) in the medial and lateral compartments had significantly worse performance metrics when compared with matched controls. Previous meniscectomy of at least 10% of total medial or lateral meniscus volume in prospective NFL players was significantly correlated with larger and more severe chondral lesions. Chondral and meniscal defects of the knee were found to result in a significant decrease in objective performance measures during a player's initial NFL career versus matched controls. Given these findings, players with a prior meniscectomy with evidence of chondral damage should be evaluated carefully for their overall functional levels; however, additional work is needed to fully clarify the effect of prior knee meniscal surgery on overall NFL performance.

#7 CranioSacral Therapy, Brain Injury, and American Football: Time for a Convergence
Reference: J Altern Complement Med. 2017 Nov 7. doi: 10.1089/acm.2017.0264. [Epub ahead of print]
Authors: Leskowitz E

#8 Correction to: Impact Performance of Modern Football Helmets
Reference: Ann Biomed Eng. 2017 Oct 25. doi: 10.1007/s10439-017-1948-8. [Epub ahead of print]
Authors: Viano DC, Withnall C, Halstead D
Summary: This erratum is to correct headings listing the impact location and speed in Figs. 5 and 6. The following provides corrected Figs. 5 and 6. The data is unchanged. The authors apologize for any inconvenience this might have caused.

#9 Clinical and Radiologic Outcomes After Scaphoid Fracture: Injury and Treatment Patterns in National Football League Combine Athletes Between 2009 and 2014
Reference: Arthroscopy. 2017 Nov 1. pii: S0749-8063(17)31071-X. doi: 10.1016/j.arthro.2017.08.259. [Epub ahead of print]
Authors: Moatshe G, Godin JA, Chahla J, Cinque ME, Kennedy NI, Sanchez G, Beaulieu-Jones BR, LaPrade RF, Provencher MT
Summary: The purpose was to report on the clinical and radiologic outcomes and complications after surgical treatment in National Football League (NFL) Combine athletes with a history of a scaphoid fracture. The medical records of 2,285 athletes participating in the NFL Combine from 2009 to 2015 were evaluated for a history of scaphoid, hand, or wrist injury. Clinical outcomes, including grip strength, pinch test, range of motion, and presence of pain and stiffness, were recorded. Imaging studies were evaluated for the percentage of healing, fixation treatment type, hardware complications, radiographic deformity, and presence of osteoarthritis. Of the 2,285 athletes evaluated, 56 presented with a history of a scaphoid fracture. Most fractures were in the middle and proximal aspects of the scaphoid. Of the scaphoid fractures, 76% (43 players) were treated with screw fixation. Of the athletes, 36 (72%) had normal range of motion of the affected wrist, 52 (93%) reported no pain, and 44 (83%) reported no stiffness in the affected wrist. The grip strength and pinch strength were 91% and 96%, respectively, of the uninjured side. The fracture was healed in 75% of the cases; however, 34% had degenerative changes. Hardware complications were found in 15% of the athletes. Good clinical outcomes can be achieved after scaphoid fractures in prospective NFL athletes. However, the rates of nonunion (25%), degenerative changes (34%), and hardware complications (15%) in this study suggest the need for close postoperative radiographic follow-up in this population of patients because their athletic demands may lead to higher rates of the aforementioned complications.

Australian Football
#1 Weak Relationships between Stint Duration, Physical and Skilled Match Performance in Australian Football
Reference: Front Physiol. 2017 Oct 23;8:820. doi: 10.3389/fphys.2017.00820. eCollection 2017.
Authors: Corbett DM, Sweeting AJ, Robertson S
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Summary: Australian Rules football comprises physical and skilled performance for more than 90 min of play. The cognitive and physiological fatigue experienced by participants during a match may reduce performance. Consequently, the length of time an athlete is on the field before being interchanged (known as a stint), is a key tactic which could maximize the skill and physical output of the Australian Rules athlete. This study developed two methods to quantify the relationship between athlete time on field, skilled and physical output. Professional male athletes (n = 39) from a single elite Australian Rules football club participated, with physical output quantified via player tracking systems across 22 competitive matches. Skilled output was calculated as the sum of involvements performed by each athlete, collected from a commercial statistics company. A random intercept and slope model was built to identify how a team and individuals respond to physical outputs and stint lengths. Stint duration (mins), high intensity running (speeds >14.4 km · hr-1) per minute, meterage per minute and very high intensity running (speeds >25 km·hr-1) per minute had some relationship with skilled involvements. However, none of these relationships were strong, and the direction of influence for each player was varied. Three conditional inference trees were computed to identify the extent to which combinations of physical parameters altered the anticipated skilled output of players. Meterage per minute, player, round number and duration were all related to player involvement. All methods had an average error of 10 to 11 involvements, per player per match. Therefore, other factors aside from physical parameters extracted from wearable technologies may be needed to explain skilled output within Australian Rules football matches.

Gaelic Football
#1 The Influence Of Team Rating On Running Performance In Elite Gaelic Football
Reference: J Strength Cond Res. 2017 Nov 6. doi: 10.1519/JSC.0000000000002316. [Epub ahead of print]
Authors: Mangan S, Malone S, Ryan M, Gahan JM, Warne J, Martin D, O'Neill C, Burns C, Collins K.
Summary: It is currently unknown how team rating influences running performance in Gaelic football. GPS technologies were used to quantify match-running performance within 5 elite Gaelic football teams over a period of 5 years (2012-2016). In total 780 player data sets were collected over 95 matches. Running performance variables included total distance, high-speed distance (≥17 km h) and the percentage of high-speed distance. Team ratings were determined objectively using the Elo Ratings System for Gaelic football. Reference team rating had trivial effects on total distance (p = 0.011, partial η2 = 0.008) and high-speed distance (p = 0.011, partial η2 = 0.008). Opposition team rating had small effects on total distance (p = 0.005, partial η2 = 0.016) and high-speed distance (p = 0.001, partial η2 = 0.020). Top tier teams cover greater total distances and high-speed distance than lower tier teams. Players cover considerably less total distance and high-speed distance against tier 3 and tier 4 teams. Tier 1 players ran a significantly higher percentage of distance at high-speed, than players who played for tier 2 teams (p = 0.020). The competitive advantage of top tier Gaelic football teams is closely linked with their ability to demonstrate a higher physical intensity than lower tier teams.

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