Australian Rules Football Players Research Articles

REGULAR LOW-DOSE CAFFEINE SUPPLEMENTATION DURING TRAINING DOES NOT PROVIDE ADDITIONAL BENEFIT TO SUBSEQUENT EXERCISE PERFORMANCE IN AUSTRALIAN RULES FOOTBALL ATHLETES

INTRODUCTION & AIMS Acute caffeine supplementation can improve exercise types like those completed by Australian Rules football (ARF) players during training. Hypothetically athletes could implement caffeine supplementation prior to training, allowing them to complete more training volume, improving adaptation and subsequent exercise performance. This study aimed to investigate the effect of regular low-dose caffeine ingestion pre-training during a training block on subsequent exercise performance. METHODS Twenty-nine male semi-professional ARF players were randomly allocated to a caffeine or placebo group. The four-week intervention period involved participants ingesting 2 mg·kg·BM-1 of caffeine or a placebo 60 min prior to two of their three weekly training sessions, which incorporated sport-specific conditioning and skills training. To assess exercise performance, a battery of tests was used before and after the intervention period including the Yo-Yo Intermittent Recovery Test Level 2 (YYIRT2), 20 m sprint and vertical jump (VJ). Performance differences were assessed using a linear mixed-effect model. RESULTS Mean session rating of perceived exertion (p = .24) and total training load (p =.53) were not different between caffeine and placebo groups over the intervention. There were no significant time x condition interaction effects for YYIRT2 accumulated distance (p = .87), or 5, 10 and 20 m sprint times (p =.06 - .44), however both caffeine and placebo groups improved YYIRT2 distance and sprint times following four weeks of training (p < 0.01). There was a significant effect for time showing decreased VJ performance (p < 0.01), with greater reductions in the placebo group (p = .03). CONCLUSION It is more beneficial to implement an effective training program for athletes rather than focusing effort on regular low-dose caffeine supplementation to augment the training stimulus. The training stimulus itself is typically greater for developing endurance and sprint effort performance, with supplemental caffeine showing no additional performance benefit.

Predicting successful draft outcome in Australian Rules football: Model sensitivity is superior in neural networks when compared to logistic regression.

Using logistic regression and neural networks, the aim of this study was to compare model performance when predicting player draft outcome during the 2021 AFL National Draft. Physical testing, in-game movement and technical involvements were collected from 708 elite-junior Australian Rules football players during consecutive seasons. Predictive models were generated using data from 465 players (2017 to 2020). Data from 243 players were then used to prospectively predict the 2021 AFL National Draft. Logistic regression and neural network models were compared for specificity, sensitivity and accuracy using relative cut-off thresholds from 5% to 50%. Using factored and unfactored data, and a range of relative cut-off thresholds, neural networks accounted for 73% of the 40 best performing models across positional groups and data configurations. Neural networks correctly classified more drafted players than logistic regression in 88% of cases at draft rate (15%) and convergence threshold (35%). Using individual variables across thresholds, neural networks (specificity = 79 ± 13%, sensitivity = 61 ± 24%, accuracy = 76 ± 8%) were consistently superior to logistic regression (specificity = 73 ± 15%, sensitivity = 29 ± 14%, accuracy = 66 ± 11%). Where the goal is to identify talented players with draft potential, model sensitivity is paramount, and neural networks were superior to logistic regression.

Tau PET: utility as a biomarker for chronic traumatic encephalopathy

AbstractBackgroundChronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by tau deposition in the depths of the sulci associated with exposure to repetitive head impacts (RHI). It is a post‐mortem diagnosis. We previously reported a frontotemporal predominant tau 18F‐MK6240 PET pattern resembling the distribution of CTE in a retired Australian Rules Football player in the context of a moderate amyloid‐beta plaque burden.1 This study aimed to investigate the utility of 18F‐MK6240 PET as a potential biomarker for CTE in contact sports players with exposure to RHI (sRHI).MethodsRHI (n = 33) and age‐matched healthy controls (HC) (n = 32) completed amyloid (18F‐NAV4694) and tau (18F‐MK6240) PET scans. Amyloid PET was quantified in Centiloids. 18F‐MK240 standardized uptake value ratios (SUVRs) were generated for the dorsolateral prefrontal cortex and composite regions of interest (ROI) (frontal; mesial temporal; temporoparietal).ResultFor sRHI, the primary contact sport was Australian Rules Football (n = 17), boxing/kickboxing/martial arts (n = 11), rugby (n = 4) and soccer (n = 1), with 36.4% participating at a professional level. sRHI had a mean age of 54.2 (±9.2) (vs HC 53.0±9.5, p = 0.61), and 94% were male (vs HC 78%, p = 0.08). sRHI did not differ from HC in years of education (p = 0.46) but had more impaired MMSE (28.1±1.9 vs 29.3±0.8, p = 0.006, d = ‐0.80) and Clinical Dementia Rating scores (0.21±0.3 vs 0±0, p<0.001, d = 1.25). sRHI and HC did not differ in mean Centiloid values (2.9±8.4 vs 3.0±8.2). sRHI and HC did not differ in 18F‐MK6240 SUVR in the regions examined, and no differences were observed between professional and amateur sRHI.ConclusionContact sports players with exposure to repetitive head impacts did not differ from age‐matched healthy controls on 18F‐MK6240 SUVR in frontal, mesial temporal, and temporoparietal brain regions. Study limitations include the small sample size, heterogeneity in sports type and highest level of participation, and participants with relatively mild cognitive and functional impairments. Additionally, while 18F‐MK6240 has high affinity for 3R/4R tau in Alzheimer’s disease, its affinity in CTE, particularly important at early stages, remains unclear.

Tau PET: utility as a biomarker for chronic traumatic encephalopathy

AbstractBackgroundChronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by tau deposition in the depths of the sulci associated with exposure to repetitive head impacts (RHI). It is a post‐mortem diagnosis. We previously reported a frontotemporal predominant tau 18F‐MK6240 PET pattern resembling the distribution of CTE in a retired Australian Rules Football player in the context of a moderate amyloid‐beta plaque burden.1 This study aimed to investigate the utility of 18F‐MK6240 PET as a potential biomarker for CTE in contact sports players with exposure to RHI (sRHI).MethodsRHI (n = 33) and age‐matched healthy controls (HC) (n = 32) completed amyloid (18F‐NAV4694) and tau (18F‐MK6240) PET scans. Amyloid PET was quantified in Centiloids. 18F‐MK240 standardized uptake value ratios (SUVRs) were generated for the dorsolateral prefrontal cortex and composite regions of interest (ROI) (frontal; mesial temporal; temporoparietal).ResultFor sRHI, the primary contact sport was Australian Rules Football (n = 17), boxing/kickboxing/martial arts (n = 11), rugby (n = 4) and soccer (n = 1), with 36.4% participating at a professional level. sRHI had a mean age of 54.2 (±9.2) (vs HC 53.0±9.5, p = 0.61), and 94% were male (vs HC 78%, p = 0.08). sRHI did not differ from HC in years of education (p = 0.46) but had more impaired MMSE (28.1±1.9 vs 29.3±0.8, p = 0.006, d = ‐0.80) and Clinical Dementia Rating scores (0.21±0.3 vs 0±0, p<0.001, d = 1.25). sRHI and HC did not differ in mean Centiloid values (2.9±8.4 vs 3.0±8.2). sRHI and HC did not differ in 18F‐MK6240 SUVR in the regions examined, and no differences were observed between professional and amateur sRHI.ConclusionContact sports players with exposure to repetitive head impacts did not differ from age‐matched healthy controls on 18F‐MK6240 SUVR in frontal, mesial temporal, and temporoparietal brain regions. Study limitations include the small sample size, heterogeneity in sports type and highest level of participation, and participants with relatively mild cognitive and functional impairments. Additionally, while 18F‐MK6240 has high affinity for 3R/4R tau in Alzheimer’s disease, its affinity in CTE, particularly important at early stages, remains unclear.

Associations between hamstring strain and knee ligament injuries with isometric trunk and hip strength and morphology in professional Australian rules football and rugby league players

Associations between hamstring strain and knee ligament injuries with isometric trunk and hip strength and morphology in professional Australian rules football and rugby league players

Influence of a COVID-19 induced reduction in game time on the match activity profiles of elite Australian Rules Football players

Assess the influence of a 20% reduction in game time on the volume and intensity of elite AF players’ match activity profiles. GPS technology was used to analyse the movement demands of 45 AF players from the same AFL club during 43 matches across the 2019 and 2020 seasons. GPS data were categorised into measures of volume (total match time [TMT] and total distance [TD]) and intensity (metres per minute [m.min-1], high-intensity running [HIR] distance and m.min-1 [>17 km·h-1], and very-high intensity running [VHIR] distance and m.min-1 [>23 km·h-1]). Volume decreased in 2020 with reductions in TMT (effect size [ES] ± 95% confidence interval [CI] = -1.8 ± 0.2; p < .001) and TD (ES = -1.8 ± 0.2; p < .001) overall, across all positional groups, and quarters. Intensity increased, evidenced by increases in HIR m.min-1 (ES = 0.3 ± 0.1; p < .001), and VHIR m.min-1 (ES = 0.3 ± 0.2; p = .006). HIR m.min-1 increased for midfielders (ES = 0.6 ± 0.3; p = .017). Defenders exhibited increases in HIR m.min-1 (ES = 0.2 ± 0.2; p = .007), and VHIR m.min-1 (ES = 0.4 ± 0.2; p = .010). Intensity of third quarters decreased at a greater rate in 2020 with reductions in m.min-1 (ES = -0.2 ± 0.1; p = .004) and HIR m.min-1 (ES = -0.2 ± 0.1; p = .037) compared to Q1. Systematic reductions in volume were found overall, across positional groups, and quarters. Average movement speed remained relatively stable overall, across quarters and positional groups. Increases in intensity were defined predominately by increases at high and very-high intensity speeds per minute, with defenders exhibiting the greatest increase in intensity and change to their match activity profiles. Longer quarter and three-quarter time breaks, and time between goals preserved intensity.

Surgical treatment of high-grade acute intramuscular hamstring tendon injuries in athletes leads to predictable return to sports and no re-injuries.

The purpose of this study was to assess the post-operative return to sport and re-injury rates following surgical repair of acute, first-time, high-grade intramuscular hamstring tendon injuries in high level athletes. Patients were identified using the databases of two sports surgeons. Once patients were identified their clinical notes and imaging were reviewed to confirm that all patients had injuries to the intramuscular portion of the distal aspect of the proximal biceps femoris tendon. All imaging was reviewed by an experienced musculoskeletal radiologist to confirm diagnosis. Surgery for such injuries was indicated in high-level athletes presenting with acute hamstring injuries. All patients were operated on within 4weeks. Outcomes included Tegner scores, return to sport, Lower Extremity Functional Score (LEFS), current hamstring symptoms and complications including re-injury. Eleven injuries (10 patients) were included in the study. All patients were male and Australian Rules Football players. Six patients were professional athletes and 4 semi-professional athletes. Median age was 24.5 (range 21-29) and median follow-up period was 33.7months (range; 16-65). 91% were British Athletic Muscle Injury Classification (BAMIC) 3c and 9% were BAMIC 4c. 91% were classed as MR2 and 9% as MR3 on the simplified four-grade injury classification. Athletes achieved return to play (RTP) at an average of 3.1months (SD 1.0) post repair. All but one patient achieved a Tegner score equal to pre-injury levels. Maximum LEFS was achieved by all patients. Minor pain scores (all with VAS < 1/10) on sciatic and functional stretch were recorded in 36% and 27% of patients respectively, with subtle neural symptoms (9%) and subjective tightness (36%) also noted. There were no surgical complications in our patient cohort. No patients had a re-injury or re-operation. Surgical repair of high-grade intramuscular tendon injuries of the biceps femoris hamstring muscle in athletes resulted in high levels of return to pre-injury sporting levels and no re-injuries. The intra-muscular tendon should be scrutinized when assessing hamstring injuries in elite sport and offer surgery in high-grade cases. IV.

Comparative Effects of Contrast Training and Progressive Resistance Training on Strength and Power-Related Measures in Subelite Australian Rules Football Players.

Schneiker, KT, Fyfe, JJ, Teo, SYM, and Bishop, DJ. Comparative effects of contrast training and progressive resistance training on strength and power-related measures in subelite Australian Rules Football players. J Strength Cond Res 37(7): 1440-1448, 2023-The aim of this study was to determine whether contrast training (CST) elicits superior strength-related and power-related outcomes compared with progressive resistance training (PRT). Sixteen male amateur Australian Rules Football players (age, 19 ± 2 years; height, 183 ± 8 cm; body mass, 78.5 ± 8.8 kg; mean ± SD ) completed 2 weeks of standardized resistance training followed by 6 weeks of either CST or PRT. Both CST and PRT improved absolute (20 and 19%) and relative (19 and 16%) 1 repetition maximum (1RM) half squat strength, absolute (8.7 and 8.7%, respectively) and relative (8.2 and 6.1%, respectively) squat jump peak power, and 20-m sprint performance (5.4 and 4.7%, respectively), including both 0 to 5 m (15 and 14%, respectively) and 0 to 10 m (8.6 and 7.5%, respectively) splits. Vertical jump height only improved with CST (6.5%), whereas body mass only increased after PRT (1.9%). There were negative associations between the baseline power-to-strength ratio (PSR) and improvements in both absolute ( r2 = 0.51 and 0.72 for CST and PRT, respectively) and relative ( r2 = 0.65 and 0.60 for CST and PRT, respectively) squat jump peak power. There were no statistically significant (i.e., p ≥ 0.05) between-group differences for all training outcomes. Both interventions improved various strength-related and power-related measures, although a lower baseline PSR was associated with greater improvements in power-related outcomes after both interventions. Contrast training is therefore an effective alternative to progressive resistance training during relatively short-term (6-8 weeks) training periods in young, male, team-sport athletes, particularly in those with a lower power-to-strength ratio.

Epidemiology of quadriceps muscle strain injuries in elite Australian rules football players.

INTRODUCTION: Quadriceps muscle strain injuries are prevalent in the Australian Football League (AFL) with each team recording 1-2 new quadriceps strain injuries per season. Little is known about the epidemiology and recovery time frames for quadriceps muscle strain injuries especially when compared to other common muscle injuries in football. This study aimed to describe the epidemiology of quadriceps muscle strain injuries in AFL players. We also aimed to describe recovery milestones and to investigate the influence of clinical factors such as injury type (index or re injury), the primary muscle injured, and the mechanism of injury on recovery timeframes.

Comparison of hip strength in football players with hip and/or groin-related pain and healthy controls

Introduction: Muscle weakness and atrophy have been associated with longstanding joint pathology, and strength testing is often recommended during the physical examination of patients with hip/groin pain. The aim of this study was to compare peak strength in football players (soccer and Australian football) presenting with hip and/or groin-related pain with healthy controls. Methods: Male and female football players were recruited across Melbourne and Brisbane, Australia. Demographic information and two questionnaires; the Copenhagen Hip and Groin Outcome Score (HAGOS) and the International Hip Outcome Tool 33 (iHOT) were collected. Hand-held dynamometry was utilised to test isometric hip muscle strength across flexion, extension, abduction, adduction, internal and external rotation planes. Peak strength (N) and torque (Nm) were normalised to body mass and linear mixed effects models were used to investigate the relationship between strength and symptomatic hips. Results: 191 football players with hip and/or groin-related pain (mean [+/- SD] age, 27.8 ± 6.3 years) and 69 controls (mean [+/- SD] age, 27.3 ± 5.6 years) were include in this study. Of this, 293 symptomatic hips and 138 control hips were used for analyses. Results demonstrated peak adduction (-0.18 Nm/kg: 95% CI -0.27 to -0.08, P 0.001), external rotation (-0.06 Nm/kg: 95% CI -0.09 to -0.02, P 0.003) and internal rotation strength (-0.06 Nm/kg: 95% CI -0.10 to -0.03, P 0.001) were lower in symptomatic hips than control hips. Abduction strength was lower in symptomatic Australian football players hips than controls (-0.20 Nm/kg: 95% CI -0.33 to -0.06, P 0.004) but this was not observed in symptomatic soccer players hips (-0.05 Nm/kg: 95% CI -0.15 to 0.06, P 0.382). No difference was found between peak flexion strength (0.07 Nm/kg: 95% CI -0.15 to 0.01, P 0.103) or peak extension strength (-0.07 Nm/kg: 95% CI -0.18 to 0.05, P 0.249) in symptomatic hips and control hips. Discussion: The findings from this research suggest that hip adduction, internal and external rotation are lower in footballers with hip and/or groin related pain than controls irrespective of the sport played. Hip abduction strength was lower in symptomatic Australian Rules football players but not observed in soccer. Impact:•Findings from this research suggest common impairments are found in hip adduction, internal and external rotation in football players with hip and/or groin related pain than controls regardless of sport played.•Hip abduction strength was lower in symptomatic Australian Rules football players but not observed in soccer. My co-authors and I acknowledge this research was supported by an Australian National Health and Medical Research Council (NHMRC) project grant 1088683.

Upper limb performance and neuromuscular asymmetries in Australian Rules Footballers following shoulder stabilisation surgery

Introduction: Shoulder dislocations are prevalent in Australian Rules Football (ARF) with many requiring shoulder stabilisation surgery. Following surgery, most athletes desire to return to sport (RTS) at their pre-injury level of performance. However, residual inter-limb deficits in strength and neuromuscular performance may delay RTS, and contribute to poor outcomes. The aim of this study was to investigate inter-limb deficits at the time of clearance to RTS during long-lever isometric tests in patients after stabilisation surgery, compared to an uninjured control group of ARF players.

Examining the Eye Movement Behaviors Associated With Skilled Decision-Making by Elite Australian Rules Football Players

Exploration of eye-movement behaviors of humans can provide insight into the processes used to inform and make decisions, with a large body of research revealing general trends, especially in the sporting context. Despite this some questions remain within the sport context particularly for elite groups engaged in diverse sports, and the potential for this information to provide for training, development, and performance. Therefore, the purpose of this study was to examine the critical fixation points and durations associated with superior decision-making within an elite group of Australian Rules football players. To achieve this eye-movement behavior (fixations) and associated decision-making skills of (N = 27; Mage = 25.0 ± 3.7 yrs) elite Australian Rules (AR) football players were measured while they watched game-based video clips. The most skilled players made significantly faster decisions compared to less skilled players (p < 0.001), who also had significantly shorter total fixation duration (p < 0.0001). Further, analysis showed that the most skilled players spent more time fixating on potential options within an area of interest (p = 0.003). Thus, within a group of highly skilled group of athletes, distinctions can be made on perceptual-cognitive skills, for outcome decisions and decision processes. That is, skilled decision-makers appear to have more efficient visual search strategies, which may help them process visual information more effectively. Further, examination of these behaviors may aid sport science and coaching staff identify the process that can be refined to increase player ability between and within various teams.

The effect of planning time on penultimate and ultimate step kinematics and subsequent knee moments during sidestepping.

Frontal plane postures during the ultimate step of sidestepping are linked to increased anterior cruciate ligament injury risk. However, there is a lack of research detailing the kinematic strategies present in the penultimate step. This study, therefore, investigated penultimate and ultimate step kinematics of planned sidestepping (pSS) and unplanned sidestepping (upSS) to further understand the effect of planning time on known ultimate step kinematic and kinetic differences. Sixty male amateur Australian Rules football players performed three trials of straight-line running (RUN), pSS, and upSS in a randomized order. Mediolateral foot placement and three-dimensional joint kinematics for the knee, pelvis, and trunk were measured at final foot contact of the penultimate step and initial foot contact of the ultimate step. Peak knee moments were measured during the weight acceptance phase of the ultimate step. In pSS, at the penultimate step final foot contact, the support foot was placed across the midline of the center of mass, in the frontal plane, contralateral to the sidestep direction. Greater trunk lateral flexion toward the sidestep direction and greater negative pelvic lateral tilt were observed in pSS compared with upSS and RUN. Differences between pSS and upSS frontal plane kinematics at penultimate step final foot contact suggest preparatory reorientation strategies are likely constrained by the amount of planning time available. As there are clear differences in preparatory kinematics, we recommend that planning time be considered when training and assessing sidestepping maneuvers and planned and unplanned maneuvers not be treated as interchangeable skills.

Strength and Biomechanical Risk Factors for Noncontact ACL Injury in Elite Female Footballers: A Prospective Study.

This study aimed to determine if a preseason field-based test battery was prospectively associated with noncontact anterior cruciate ligament (ACL) injury in elite female footballers. In total, 322 elite senior and junior female Australian Rules Football and soccer players had their isometric hip adductor and abductor strength, eccentric knee flexor strength, countermovement jump (CMJ) kinetics, and single-leg hop kinematics assessed during the 2019 preseason. Demographic and injury history details were also collected. Footballers were subsequently followed for 18 months for ACL injury. Fifteen noncontact ACL injuries occurred during the follow-up period. Prior ACL injury (odds ratio [OR], 9.68; 95% confidence interval (95% CI), 2.67-31.46), a lower isometric hip adductor to abductor strength ratio (OR, 1.98; 95% CI, 1.09-3.61), greater CMJ peak take-off force (OR, 1.74; 95% CI, 1.09-3.61), and greater single-leg triple vertical hop average dynamic knee valgus (OR, 1.97; 95% CI, 1.06-3.63) and ipsilateral trunk flexion (OR, 1.60; 95% CI, 1.01-2.55) were independently associated with an increased risk of subsequent ACL injury. A multivariable prediction model consisting of CMJ peak take-off force, dynamic knee valgus, and ACL injury history that was internally validated classified ACL injured from uninjured footballers with 78% total accuracy. Between-leg asymmetry in lower limb strength and CMJ kinetics were not associated with subsequent ACL injury risk. Preseason field-based measures of lower limb muscle strength and biomechanics were associated with future noncontact ACL injury in elite female footballers. These risk factors can be used to guide ACL injury screening practices and inform the design of targeted injury prevention training in elite female footballers.

Evening Whey Protein Intake, Rich in Tryptophan, and Sleep in Elite Male Australian Rules Football Players on Training and Nontraining Days.

To investigate the effect of evening whey protein supplementation, rich in tryptophan, on sleep in elite male Australian Rules Football players. Double-blinded, counterbalanced, randomized, cross-over study. Sleep was assessed using wrist activity monitors and sleep diaries in 15 elite male Australian Football League players on two training and nontraining days following evening consumption of an isocaloric whey protein supplement or placebo in preseason. A 5-day preintervention period was implemented to determine habitual dietary intake and baseline sleep measures. These habitual data were used to inform the daily dietary intake and timing of ingestion of the evening whey protein supplement or placebo on the intervention days. The whey protein supplement or placebo was consumed 3hr prior to habitual bedtime. Separate one-way repeated-measures analyses of covariance revealed no differences between the whey protein supplement and the placebo on sleep duration, sleep onset latency, sleep efficiency, or wake after sleep onset on either training or nontraining days. Evening whey protein supplementation, rich in tryptophan, does not improve acute sleep duration or quality in elite male Australian Football League players. However, elite athletes may be able to ingest a high protein/energy intake close to bedtime without impairing sleep, which is important for athlete recovery. Future research should investigate the effect of evening protein intake, high in tryptophan, on sleep duration and quality, including sleep staging during periods of restricted sleep and in poor-sleeping athletes.

Serum Protein Biomarkers of Inflammation, Oxidative Stress, and Cerebrovascular and Glial Injury in Concussed Australian Football Players.

Clinical decisions related to sports-related concussion (SRC) are challenging, because of the heterogenous nature of SRC symptoms coupled with the current reliance on subjective self-reported symptom measures. Sensitive and objective methods that can diagnose SRC and determine recovery would aid clinical management, and there is evidence that SRC induces changes in circulating protein biomarkers, indicative of neuroaxonal injury. However, potential blood biomarkers related to other pathobiological responses linked to SRC are still poorly understood. Therefore, here we analyzed blood samples from concussed (male = 30; female = 9) and non-concussed (male = 74; female = 27) amateur Australian rules football players collected during the pre-season (i.e., baseline), and at 2, 6, and 13 days post-SRC to determine time-dependent changes in serum levels of biomarkers related to glial (i.e., brain lipid-binding protein [BLBP]; phosphoprotein enriched in astrocytes 15) and cerebrovascular injury (i.e., von Willebrand factor, claudin-5), inflammation (i.e., fibrinogen, high mobility group box protein 1), and oxidative stress (i.e., 4-hydroxynoneal). In females, BLBP levels were significantly decreased at 2 days post-SRC compared with their pre-season baseline; however, area under the receiver operating characteristic curve (AUROC) analysis found that BLBP was unable to distinguish between SRC and controls. In males, AUROC analysis revealed a statistically significant change at 2 days post-SRC in the serum levels of 4-hydroxynoneal, however the associated AUROC value (0.6373) indicated little clinical utility for this biomarker in distinguishing SRC from controls. There were no other statistically significant findings. These results indicate that the serum biomarkers tested in this study hold little clinical value in the management of SRC at 2, 6, and 13 days post-injury.

Rates and Determinants of Returning to Australian Rules Football in Male Nonprofessional Athletes After Anterior Cruciate Ligament Reconstruction.

Background:Return to sport is a goal for most patients who undergo anterior cruciate ligament (ACL) reconstruction. However, at a nonelite level, there are limited sport-specific data regarding rates or factors associated with return to play.Purpose:To report rates and determinants of returning to play Australian Rules football after ACL reconstruction in male nonprofessional athletes.Study Design:Case-series; Level of evidence, 4.Methods:A total of 354 male nonprofessional Australian Rules football players who had undergone primary ACL reconstruction were asked to complete detailed sports activity questions at 12 months and 2 to 5 years (mean, 3 years) after surgery. Rates of return to play were calculated for both timepoints, along with preoperative patient expectations and postoperative sport performance. The following predictors of return to play were examined: age at surgery; height; weight; frequency of weekly football participation; sport participation level; psychological readiness to return to sport; and knee-related quality of life. Further ACL injuries were also documented. Descriptive statistics were used to summarize return-to-play data and contingency analysis for predictors of return to sport.Results:The rate of return to any level of play was 35% (95% CI, 30%-41%; n = 284) at the 12-month follow-up and 78% (95% CI, 72%-83%; n = 233) at the 2- to 5-year follow-up. Overall, 64% (95% CI, 57%-70%) of the patients were able to return to their same or higher level of play. Before surgery, 92% of the patients expected to return to their same preinjury level of Australian Rules football participation. At the 2- to 5-year follow-up, 61% who returned to play felt that they could perform as well as they could before their ACL injury. A greater psychological readiness to return to sport preoperatively and higher level of sport participation were significant predictors of a return at 2 to 5 years. Further ACL injuries were sustained by 21% of the cohort (15% graft rupture; 6% contralateral ACL injury).Conclusion:Most male athletes who participate in Australian Rules football returned to some level of play after ACL reconstruction; however, only 64% returned to preinjury levels. Preoperative expectations were not met, and high reinjury rates are a cause for concern.

Decrease in Plasma miR-27a and miR-221 After Concussion in Australian Football Players

Introduction:Sports-related concussion (SRC) is a common form of brain injury that lacks reliable methods to guide clinical decisions. MicroRNAs (miRNAs) can influence biological processes involved in SRC, and measurement of miRNAs in biological fluids may provide objective diagnostic and return to play/recovery biomarkers. Therefore, this prospective study investigated the temporal profile of circulating miRNA levels in concussed male and female athletes.Methods:Pre-season baseline blood samples were collected from amateur Australian rules football players (82 males, 45 females). Of these, 20 males and 8 females sustained an SRC during the subsequent season and underwent blood sampling at 2-, 6- and 13-days post-injury. A miRNA discovery Open Array was conducted on plasma to assess the expression of 754 known/validated miRNAs. miRNA target identified were further investigated with quantitative real-time PCR (qRT-PCR) in a validation study. Data pertaining to SRC symptoms, demographics, sporting history, education history and concussion history were also collected.Results:Discovery analysis identified 18 candidate miRNA. The consequent validation study found that plasma miR-221-3p levels were decreased at 6d and 13d, and that miR-27a-3p levels were decreased at 6d, when compared to baseline. Moreover, miR-27a and miR-221-3p levels were inversely correlated with SRC symptom severity.Conclusion:Circulating levels of miR-27a-3p and miR-221-3p were decreased in the sub-acute stages after SRC, and were inversely correlated with SRC symptom severity. Although further studies are required, these analyses have identified miRNA biomarker candidates of SRC severity and recovery that may one day assist in its clinical management.

Innovative Task Design: Becoming a Reader Involves More than Reading Strategies

ABSTRACT This paper looks at students’ motivation and engagement in the context of the Read Like a Demon (RLAD) project across a two-year period, in Melbourne, Victoria. This RLAD project was shaped over several years and targeted to students aged between 8 and 11 years. It utilized innovative reading experiences, including the influence of Australian Rules Football players as reading role models for students. The project aimed to promote wider reading among these students, many of whom are statistically likely to disengage from reading practices. The authors introduced new aspects to the project to broaden the avenues of influence for reading. Data from students and teachers were analyzed using the Engagement Model of Reading Development to explore the question “How did attention to classroom instruction affect students’ motivation and engagement during the RLAD project experiences?” The project found that an interplay of role models, authentic audience and choice positively affects students’ motivation and engagement. Findings from this article will provide classroom teachers with insights into how project design can bring increased attention to the affective aspects of becoming a reader.

Development of a Machine-Learning-Based Classifier for the Identification of Head and Body Impacts in Elite Level Australian Rules Football Players.

Background: Exposure to thousands of head and body impacts during a career in contact and collision sports may contribute to current or later life issues related to brain health. Wearable technology enables the measurement of impact exposure. The validation of impact detection is required for accurate exposure monitoring. In this study, we present a method of automatic identification (classification) of head and body impacts using an instrumented mouthguard, video-verified impacts, and machine-learning algorithms.Methods: Time series data were collected via the Nexus A9 mouthguard from 60 elite level men (mean age = 26.33; SD = 3.79) and four women (mean age = 25.50; SD = 5.91) from the Australian Rules Football players from eight clubs, participating in 119 games during the 2020 season. Ground truth data labeling on the captures used in this machine learning study was performed through the analysis of game footage by two expert video reviewers using SportCode and Catapult Vision. The visual labeling process occurred independently of the mouthguard time series data. True positive captures (captures where the reviewer directly observed contact between the mouthguard wearer and another player, the ball, or the ground) were defined as hits. Spectral and convolutional kernel based features were extracted from time series data. Performances of untuned classification algorithms from scikit-learn in addition to XGBoost were assessed to select the best performing baseline method for tuning.Results: Based on performance, XGBoost was selected as the classifier algorithm for tuning. A total of 13,712 video verified captures were collected and used to train and validate the classifier. True positive detection ranged from 94.67% in the Test set to 100% in the hold out set. True negatives ranged from 95.65 to 96.83% in the test and rest sets, respectively.Discussion and conclusion: This study suggests the potential for high performing impact classification models to be used for Australian Rules Football and highlights the importance of frequencies <150 Hz for the identification of these impacts.