The Perils of Misinterpreting and Misusing "Publication Bias" in Meta-analyses: An Education Review on Funnel Plot-Based Methods.

Publication bias refers to a systematic deviation from the truth in the results of a meta-analysis due to the higher likelihood for published studies to be included in meta-analyses than unpublished studies. Publication bias can lead to misleading recommendations for decision and policy making. In this education review, we introduce, explain, and provide solutions to the pervasive misuses and misinterpretations of publication bias that afflict evidence syntheses in sport and exercise medicine, with a focus on the commonly used funnel-plot based methods. Publication bias is more routinely assessed by visually inspecting funnel plot asymmetry, although it has been consistently deemed unreliable, leading to the development of statistical tests to assess publication bias. However, most statistical tests of publication bias (i) cannot rule out alternative explanations for funnel plot asymmetry (e.g., between-study heterogeneity, choice of metric, chance) and (ii) are grossly underpowered, even when using an arbitrary minimum threshold of ten or more studies. We performed a cross-sectional meta-research investigation of how publication bias was assessed in systematic reviews with meta-analyses published in the top two sport and exercise medicine journals throughout 2021. This analysis highlights that publication bias is frequently misused and misinterpreted, even in top tier journals. Because of conceptual and methodological problems when assessing and interpreting publication bias, preventive strategies (e.g., pre-registration, registered reports, disclosing protocol deviations, and reporting all study findings regardless of direction or magnitude) offer the best and most efficient solution to mitigate the misuse and misinterpretation of publication bias. Because true publication bias is very difficult to determine, we recommend that future publications use the term "risk of publication bias".

Injury incidence rates in women's football: a systematic review and meta-analysis of prospective injury surveillance studies.

OBJECTIVE: To review the literature to establish overall, match and training injury incidence rates (IIRs) in senior (≥18 years of age) women's football (amateur club, elite club and international). DESIGN: Systematic review and meta-analysis of overall, match and training IIRs in senior women's football, stratified by injury location, type and severity. DATA SOURCES: MEDLINE via PubMed; EMBASE via Ovid; CINAHL via EBSCO and Web of Science were searched from earliest record to July 2021. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: (1) football players participating in a senior women's football league (amateur club or elite club) or a senior women's international football tournament; (2) the study had to report IIRs or provide sufficient data from which this outcome metric could be calculated through standardised equations; (3) a full-text article published in a peer-reviewed journal before July 2021; (4) a prospective injury surveillance study and (5) case reports on single teams were ineligible. RESULTS: 17 articles met the inclusion criteria; amateur club (n=2), elite club (n=10), international (n=5). Overall, match and training 'time-loss' IIRs are similar between senior women's elite club football and international football. 'Time-loss' training IIRs in senior women's elite club football and international football are approximately 6-7 times lower than their equivalent match IIRs. Overall 'time-loss' IIRs stratified by injury type in women's elite club football were 2.70/1000 hours (95% CI 1.12 to 6.50) for muscle and tendon, 2.62/1000 hours (95% CI 1.26 to 5.46) for joint and ligaments, and 0.76/1000 hours (95% CI 0.55 to 1.03) for contusions. Due to the differences in injury definitions, it was not possible to aggregate IIRs for amateur club football. CONCLUSION: Lower limb injuries incurred during matches are a substantial problem in senior women's football. The prevention of lower limb joint, ligament, muscle and tendon injuries should be a central focus of injury prevention interventions in senior women's amateur club, elite club and international football. PROSPERO REGISTRATION NUMBER: CRD42020162895.

Systematic Review of Pre-injury Migraines as a Vulnerability Factor for Worse Outcome Following Sport-Related Concussion.

Background: Individuals with migraine disorders may be affected differently by concussions compared to individuals without migraine disorders. Prior studies on this topic have had mixed results. The purpose of this study was to systematically examine clinical outcomes following a sport-related concussion in athletes who have a pre-injury history of migraines. Methods: All studies published prior to 15 May 2021 that examined pre-injury migraines as a possible predictor of clinical recovery from concussion were included. The search included (i) sport/athlete-related terms, (ii) concussion-related terms, and (iii) diverse predictor/modifier terms. After removing duplicates, 5,118 abstracts were screened, 538 full-text articles were reviewed, and 27 articles were included for narrative synthesis without meta-analysis (n = 25 with unique samples). Risk of bias was assessed using the domain-based Quality In Prognosis Studies (QUIPS) tool. Results: Most studies did not find pre-injury migraines to be associated with concussion outcome, but several of these studies had small or very small sample sizes, as well as other methodological weaknesses. Risk of bias varied greatly across studies. Some of the larger, better-designed studies suggested pre-injury migraines may be a risk factor for worse concussion outcome. Most articles examined pre-injury migraines as an exploratory/secondary predictor of concussion outcome; very few were designed to examine migraine as the primary focus of the study. Migraine history was predominantly based on self-report and studies included minimal information about migraine (e.g., age of onset, frequency/severity, past treatment). Effect sizes were usually not reported or able to be calculated from reported study data. Conclusion: There is some evidence to suggest that pre-injury migraines may be a vulnerability factor for a worse outcome following concussion, with studies having the lowest risk of bias reporting a positive association. Future studies should focus on improving methodological quality when assessing the relationship between pre-injury migraines and concussion outcome and better characterizing pre-injury migraine status. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019128292, identifier: PROSPERO 2019 CRD42019128292.

Implementing the 27 PRISMA 2020 Statement items for systematic reviews in the sport and exercise medicine, musculoskeletal rehabilitation and sports science fields: the PERSiST (implementing Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science) guidance.

Poor reporting of medical and healthcare systematic reviews is a problem from which the sports and exercise medicine, musculoskeletal rehabilitation, and sports science fields are not immune. Transparent, accurate and comprehensive systematic review reporting helps researchers replicate methods, readers understand what was done and why, and clinicians and policy-makers implement results in practice. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement and its accompanying Explanation and Elaboration document provide general reporting examples for systematic reviews of healthcare interventions. However, implementation guidance for sport and exercise medicine, musculoskeletal rehabilitation, and sports science does not exist. The Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science (PERSiST) guidance attempts to address this problem. Nineteen content experts collaborated with three methods experts to identify examples of exemplary reporting in systematic reviews in sport and exercise medicine (including physical activity), musculoskeletal rehabilitation (including physiotherapy), and sports science, for each of the PRISMA 2020 Statement items. PERSiST aims to help: (1) systematic reviewers improve the transparency and reporting of systematic reviews and (2) journal editors and peer reviewers make informed decisions about systematic review reporting quality.

Longitudinal Vestibular and Oculomotor Impairments Among Amateur Athletes 1 Year Following Sport-Related Concussion: A Prospective Follow-Up.

OBJECTIVES: To investigate (i) the presence of vestibular and oculomotor impairments and (ii) the self-perceived effects of concussion-associated dizziness on health-related quality of life among amateur athletes 6 months and 1 year following sport-related concussion compared with nonconcussed, control athletes. DESIGN: Prospective, matched-cohort study. SETTING: Clinical assessment laboratory. PARTICIPANTS: Amateur athletes who were diagnosed with sport-related concussion within 1 week of injury, and sex-, age-, and activity-matched nonconcussed, control athletes. MAIN MEASURES: Participants were evaluated 6 months and 1 year following sport-related concussion and enrollment in the longitudinal study using the Vestibular and Oculo-Motor Screening and the Dizziness Handicap Inventory. We performed multivariate analyses of variance and chi-square analyses to compare concussion and control group scores at each study assessment. RESULTS: Forty-seven participants with concussion and 47 control participants completed the study. The concussion group reported similar mean symptom provocation scores on the Vestibular and Oculo-Motor Screening and exhibited a similar near-point convergence distance compared with the control group at the 6-month and 1-year study assessments. The concussion and control groups had similar perceptions of the effects of dizziness on their health-related quality of life at both study assessments. CONCLUSION: Meaningful differences in vestibular and oculomotor symptom provocation and self-perceived effects of dizziness on everyday life were not observed between concussed and nonconcussed, control athletes 6 months and 1 year following sport-related concussion.

Age of First Exposure to Contact and Collision Sports and Later in Life Brain Health: A Narrative Review.

A controversial theory proposes that playing tackle football before the age of 12 causes later in life brain health problems. This theory arose from a small study of 42 retired National Football League (NFL) players, which reported that those who started playing tackle football at a younger age performed worse on selected neuropsychological tests and a word reading test. The authors concluded that these differences were likely due to greater exposure to repetitive neurotrauma during a developmentally sensitive maturational period in their lives. Several subsequent studies of current high school and collegiate contact/collision sports athletes, and former high school, collegiate, and professional tackle football players have not replicated these findings. This narrative review aims to (i) discuss the fundamental concepts, issues, and controversies surrounding existing research on age of first exposure (AFE) to contact/collision sport, and (ii) provide a balanced interpretation, including risk of bias assessment findings, of this body of evidence. Among 21 studies, 11 studies examined former athletes, 8 studies examined current athletes, and 2 studies examined both former and current athletes. Although the literature on whether younger AFE to tackle football is associated with later in life cognitive, neurobehavioral, or mental health problems in former NFL players is mixed, the largest study of retired NFL players (N = 3,506) suggested there was not a significant association between earlier AFE to organized tackle football and worse subjectively experienced cognitive functioning, depression, or anxiety. Furthermore, no published studies of current athletes show a significant association between playing tackle football (or other contact/collision sports) before the age of 12 and cognitive, neurobehavioral, or mental health problems. It is important to note that all studies were judged to be at high overall risk of bias, indicating that more methodologically rigorous research is needed to understand whether there is an association between AFE to contact/collision sports and later in life brain health. The accumulated research to date suggests that earlier AFE to contact/collision sports is not associated with worse cognitive functioning or mental health in (i) current high school athletes, (ii) current collegiate athletes, or (iii) middle-aged men who played high school football. The literature on former NFL players is mixed and does not, at present, clearly support the theory that exposure to tackle football before age 12 is associated with later in life cognitive impairment or mental health problems.

COVID-19 Prevention and Control Measures in Workplace Settings: A Rapid Review and Meta-Analysis.

Workplaces can be high-risk environments for SARS-CoV-2 outbreaks and subsequent community transmission. Identifying, understanding, and implementing effective workplace SARS-CoV-2 infection prevention and control (IPC) measures is critical to protect workers, their families, and communities. A rapid review and meta-analysis were conducted to synthesize evidence assessing the effectiveness of COVID-19 IPC measures implemented in global workplace settings through April 2021. Medline, Embase, PubMed, and Cochrane Library were searched for studies that quantitatively assessed the effectiveness of workplace COVID-19 IPC measures. The included studies comprised varying empirical designs and occupational settings. Measures of interest included surveillance measures, outbreak investigations, environmental adjustments, personal protective equipment (PPE), changes in work arrangements, and worker education. Sixty-one studies from healthcare, nursing home, meatpacking, manufacturing, and office settings were included, accounting for ~280,000 employees based in Europe, Asia, and North America. Meta-analyses showed that combined IPC measures resulted in lower employee COVID-19 positivity rates (0.2% positivity; 95% CI 0-0.4%) than single measures such as asymptomatic PCR testing (1.7%; 95% CI 0.9-2.9%) and universal masking (24%; 95% CI 3.4-55.5%). Modelling studies showed that combinations of (i) timely and widespread contact tracing and case isolation, (ii) facilitating smaller worker cohorts, and (iii) effective use of PPE can reduce workplace transmission. Comprehensive COVID-19 IPC measures incorporating swift contact tracing and case isolation, PPE, and facility zoning can effectively prevent workplace outbreaks. Masking alone should not be considered sufficient protection from SARS-CoV-2 outbreaks in the workplace.

Condition-specific health-related quality of life amongst amateur athletes six months and one-year following sport-related concussion: A prospective, follow-up.

OBJECTIVE: To prospectively investigate the condition-specific health-related quality of life (HRQoL) of athletes six months and one-year following sport-related concussion. DESIGN: Prospective, longitudinal study. SETTING: Clinical research centre at university school of public health. PARTICIPANTS: Amateur athletes who were diagnosed with sport-related concussion within one-week after presenting to a hospital emergency department were recruited along with sex-, age-, and activity-matched, non-concussed, control athletes. Concussion and control participants were assessed six months and one-year following sport-related concussion and study enrolment, respectively. MAIN OUTCOME MEASURES: Participants completed the Post-Concussion Symptom Scale and five condition-specific HRQoL patient-reported outcome measures - Headache Impact Test-6, Fatigue Severity Scale, Neck Disability Index, Generalised Anxiety Disorder-7, and Dizziness Handicap Inventory. We performed Frequentist and Bayesian mixed-design analyses of variance to compare the concussion group and control group at both assessments and quantify whether there was greater evidence in favour of the null hypothesis compared with the alternative hypothesis. RESULTS: At six-month and one-year assessments, the concussion group (n = 47; male = 72%; mean (SD) age = 22.68 (5.07)) and the control group (n = 47; male = 72%; mean (SD) age = 23.81 (4.60)) reported similar clinical symptom severity scores and condition-specific HRQoL. The proportion of athletes in the concussion group with clinically-impaired scores was similar to the proportion of non-concussed athletes with clinically-impaired scores. At six-month and one-year assessments, there was moderate-to-very strong evidence that there was no difference between concussion and control participants' perceptions of the effects of headache, fatigue, neck pain, anxiety, and dizziness on HRQoL. CONCLUSION: There was moderate-to-very strong evidence in favour of no difference between the concussion and control groups on symptom severity scores and condition-specific HRQoL patient-reported outcome measures at six-month and one-year assessments. These results suggest that condition-specific HRQoL returns to the levels of non-concussed individuals within six months following sport-related concussion.

Age of First Exposure to Football Is Not Associated With Later-in-Life Cognitive or Mental Health Problems.

Background: The purpose of this study was to determine if earlier age of first exposure to football is associated with worse brain health in middle-aged and older adult men who played high school football. Methods: Men from the United States, aged 35 and older, who reported playing high school football, completed a customized, online health survey via the Amazon Mechanical Turk (mTurk) platform. Survey items included physical, psychological, and cognitive symptoms over the past week and over the past year, sports participation history (including age of first exposure to football), medical history, and concussion history. Participants also completed the Patient Health Questionnaire-8 (PHQ-8) and the British Columbia Post-Concussion Symptom Inventory (BC-PSI). Results: There were 186 men (age M = 51.78, SD = 10.93) who participated in high school football, and 87 (46.8%) reported football participation starting before the age of 12 and 99 (53.2%) reported football participation at or after the age of 12. Those who started playing football at an earlier age reported a greater number of lifetime concussions (M = 1.95, SD = 1.79) compared to those who started playing at age 12 or later (M = 1.28, SD = 1.52; U = 3,257.5, p = 0.003). A similar proportion of men who played football before vs. after the age of 12 reported a lifetime history of being prescribed medications for depression, anxiety, chronic pain, headaches, or memory problems. When comparing men who played football before vs. after the age of 12, the groups did not differ significantly in their ratings of depression, anger, anxiety, headaches, migraines, neck or back pain, chronic pain, concentration problems, or memory problems over the past week or the past year. The two groups did not differ significantly in their ratings of current symptoms of depression (PHQ-8; U = 4,187.0, p = 0.74) or post-concussion-like symptoms (BC-PSI; U = 3,944.0, p = 0.53). Furthermore, there were no statistically significant correlations between the age of first exposure to football, as a continuous variable, and PHQ-8 or BC-PSI scores. Conclusion: This study adds to a rapidly growing body of literature suggesting that earlier age of first exposure to football is not associated with later-in-life brain health.

Participation in pre-injury level sport one-year following sport-related concussion: A prospective, matched cohort study.

OBJECTIVES: To estimate the times taken to receive clearance to return to sporting activity and to return to pre-injury level of sport competition following sport-related concussion, and to estimate the proportion of athletes who were participating at their pre-injury level of sport competition six months and one-year following sport-related concussion. DESIGN: Prospective cohort study. METHODS: Amateur, adult athletes (16-38 years old) were diagnosed with sport-related concussion at a university-affiliated hospital emergency department. Participants were assessed within one-week, upon medical clearance to return to sporting activity, two weeks following return to sporting activity, six months, and 12 months following sport-related concussion. We assessed sex-, age-, and activity-matched non-injured, control participants at matched time-points. Participants were asked during each study assessment whether they were participating in any sport, in a different sport than before their sport-related concussion, in the same sport but at a lower level of competition than before their sport-related concussion, or in the same sport at the same level of competition than before their sport-related concussion. RESULTS: Fifty concussed participants and 50 non-injured, control participants completed the study. The median times taken to receive clearance to return to sporting activity and to return to pre-injury level of sport competition following sport-related concussion were 13 days (95%CI=12,16) and 31 days (95%CI=28,32), respectively. One-year following sport-related concussion, 52% of participants reported that they were no longer participating in the same sport and at the same level of competition as they were before their sport-related concussion, compared with only 24% of participants in the non-injured, control group (p=0.003). CONCLUSIONS: A greater percentage of athletes in the concussion group were not participating at their perceived pre-injury level of sport competition one-year following sport-related concussion compared with a non-injured control group. Factors that explain the lower proportion of amateur athletes participating at their pre-injury level of sport competition one-year after sport-related concussion are likely multifaceted and should be considered in future investigations.

Using a Likelihood Heuristic to Summarize Conflicting Literature on Predictors of Clinical Outcome Following Sport-Related Concussion.

OBJECTIVE: To introduce a new methodology for summarizing the results from systematic reviews-a likelihood heuristic-to the field of sport-related concussion. DATA SOURCES: We applied the likelihood heuristic to the results of a systematic review published by Iverson et al (2017), containing 101 studies, on the predictors of worse clinical outcome following sport-related concussion. STUDY SELECTION: We re-examined 5 individual prognostic factors that are of clinical interest and for which there is conflicting literature (female sex = 44 studies, prior concussion history = 41 studies, loss of consciousness = 31 studies, post-traumatic amnesia = 25 studies, and retrograde amnesia = 10 studies). DATA EXTRACTION: For each prognostic factor, likelihood ratios were generated using the (1) number of significant and nonsignificant studies, (2) study power, (3) alpha level, and (4) prior probability that the alternative hypothesis was true. DATA SYNTHESIS: Assuming each study had 80% power and an alpha level of 5%, observing the reported number of conflicting studies for female sex, prior concussion history, and retrograde amnesia is substantially more likely if each prognostic factor is associated with worse clinical outcome following sport-related concussion. For loss of consciousness, the observed number of conflicting studies is more likely if loss of consciousness is not associated with worse clinical outcome following sport-related concussion. A secondary analysis incorporating potentially more realistic study parameters of statistical power (45%) and alpha level (25%) generates weaker likelihood evidence that the observed numbers of studies for each prognostic factor are associated with worse clinical outcome following sport-related concussion than they are not. CONCLUSIONS: Using a likelihood heuristic with 80% power and 5% alpha level, there is very strong likelihood evidence that female sex, prior concussion history, and retrograde amnesia are associated with worse clinical outcome following sport-related concussion. The strength of likelihood evidence that prognostic factors are associated with worse clinical outcome reduces when statistical power is lower and alpha level is inflated.

Clinical Detection and Recovery of Vestibular and Oculomotor Impairments Among Amateur Athletes Following Sport-Related Concussion: A Prospective, Matched-Cohort Study.

OBJECTIVE: To (1) quantify the diagnostic accuracy of the vestibular/oculomotor screening (VOMS), and (2) determine the recovery of vestibular and oculomotor impairments exhibited by concussed athletes compared with nonconcussed athletes using the VOMS. SETTING: Clinical assessment laboratory. PARTICIPANTS: Amateur athletes who were diagnosed with sport-related concussion by emergency department physicians, and non-concussed, control athletes. DESIGN: Prospective, longitudinal study. MAIN MEASURES: Participants were assessed 1 week following sport-related concussion, upon clearance to return-to-sporting activity, and 2 weeks following return-to-sporting activity by a study investigator who administered the VOMS. We calculated test sensitivity, specificity, and positive and negative predictive values to estimate the diagnostic accuracy of the VOMS. We performed a mixed-design analysis of variance to assess differences in VOMS symptom scores reported by concussed athletes compared with control athletes. RESULTS: Fifty concussion participants and 50 control participants completed the study. The VOMS demonstrated sensitivity and specificity of 96% and 46%, respectively, and produced positive and negative predictive values of 64% and 92%, respectively. The concussion group exhibited a significantly greater symptom provocation change score from baseline than the control group for all test domains of the VOMS only in the first week following concussion. CONCLUSION: The VOMS may be most useful as a clinical screening tool to rule out, rather than confirm, the presence of sport-related concussion. The VOMS may be appropriate to inform the recovery of vestibular and oculomotor impairments exhibited by concussed individuals over time.

Age of First Exposure to Football Is Not Associated with Midlife Brain Health Problems.

The purpose of this study was to determine if earlier age of first exposure (AFE) to football is associated with worse brain health in middle-aged men who played high school football. We assessed 123 men 35-55 years of age, who played high school football, using (1) a survey of demographic information as well as medical, sport participation, and concussion history; (2) the Patient Health Questionnaire-8 (PHQ-8); and (3) the British Columbia Post-Concussion Symptom Inventory (BC-PSI). Sixty-two (50.4%) men reported football participation starting before the age of 12 (i.e., AFE <12 years) and 61 (49.6%) reported football participation at or after the age of 12 (AFE > 12 years). Compared with those with AFE >12 years, a similar proportion of former high school football players who began playing tackle football before age 12 reported that they had been prescribed medications for mental health problems or that they had recently experienced symptoms of anxiety, depression, memory loss, chronic pain, or headaches. Moreover, there was no significant difference in their lifetime history of treatment by a mental health professional. The groups did not differ significantly on PHQ-8 (U = 1839.0, p = 0.791) or BC-PSI total scores (U = 1828.5, p = 0.751). These findings suggest that earlier AFE to football is not associated with worse brain health in middle-aged men in this sample who played high school football.

Using functional movement tests to investigate the presence of sensorimotor impairment in amateur athletes following sport-related concussion: A prospective, longitudinal study.

OBJECTIVE: To longitudinally investigate the presence of sensorimotor impairments in amateur athletes following sport-related concussion using two functional movement tests. DESIGN: Prospective, longitudinal study. SETTING: Human movement analysis laboratory. PARTICIPANTS: Athletes who presented to a hospital emergency department and were diagnosed with sport-related concussion, and sex-, age-, and activity-matched non-concussed, control athletes. Concussed participants were assessed within one-week following sport-related concussion, upon clearance to return-to-sporting activity (RTA), and two weeks after RTA. Control participants were assessed at an initial time-point and approximately two and four weeks following their initial study assessment. MAIN OUTCOMES MEASURES: At each laboratory assessment, participants completed two functional movement tests: the Star Excursion Balance Test to evaluate anterior reach distance (normalised for leg length) and fractal dimension (centre of pressure path complexity), and the Multiple Hop Test to evaluate corrective postural strategies and time-to-stabilisation. RESULTS: Fifty concussed athletes and 50 control athletes completed the study. There were no significant differences at any study assessment between the concussion and control group on the Star Excursion Balance Test anterior reach distance or fractal dimension (centre of pressure path complexity). During the Multiple Hop Test, the concussion group used a significantly greater number of corrective postural strategies than the control group one-week following sport-related concussion and upon clearance to RTA, but not two weeks following RTA. CONCLUSION: Recently concussed athletes made a greater number of corrective postural strategies than control participants during the Multiple Hop Test upon clearance to RTA but not two weeks after RTA. The Multiple Hop Test may offer a clinically useful tool for practitioners to examine the recovery of subtle sensorimotor impairments and related RTA readiness.

Headache- and Dizziness-Specific Health-Related Quality-of-Life Impairments Persist for 1 in 4 Amateur Athletes Who Are Cleared to Return to Sporting Activity Following Sport-Related Concussion: A Prospective Matched-Cohort Study.

OBJECTIVES: To prospectively investigate the recovery of athlete-reported symptoms and the condition-specific health-related quality of life (HRQoL) following sport-related concussion. DESIGN: Prospective matched-cohort study. METHODS: We recruited amateur athletes who were diagnosed with sport-related concussion by emergency department physicians. Study participants were assessed at 3 time points following sport-related concussion. At each assessment, participants completed 5 condition-specific HRQoL patient-reported outcome measures to evaluate participants' perceptions of the effects of specific concussion-related symptoms on their HRQoL. We performed log-linear analyses to assess the proportion of concussed participants with clinically impaired condition-specific HRQoL compared with the proportion of participants in the control group with clinically impaired condition-specific HRQoL. RESULTS: Fifty participants with sport-related concussion and 50 control participants matched by sex, age, and activity completed the study. Upon return to sporting activity, there was a significantly greater proportion of participants in the concussion group who perceived that headache, neck pain, and dizziness had an adverse effect on their HRQoL compared with the control group. Two weeks after return to sporting activity, there was still a significantly greater proportion of participants in the concussion group who perceived that headache (χ21 = 9.0; odds ratio [OR] = 4.4; 95% confidence interval [CI]: 1.5, 15.2; P = .003) and dizziness (χ21 = 9.5; OR = 13.5; 95% CI: 1.8, 604.9; P = .006) had an adverse effect on their HRQoL compared with the proportion of clinically impaired participants in the control group. CONCLUSION: Of concussed participants, 1 in 4 perceived that headache and dizziness had adverse effects on their HRQoL after returning to sporting activity following sport-related concussion compared with nonconcussed, control participants. J Orthop Sports Phys Ther 2020;50(12):692-701. doi:10.2519/jospt.2020.9485.

Are questionable research practices facilitating new discoveries in sport and exercise medicine? The proportion of supported hypotheses is implausibly high.

Questionable research practices (QRPs) are intentional and unintentional practices that can occur when designing, conducting, analysing, and reporting research, producing biased study results. Sport and exercise medicine (SEM) research is vulnerable to the same QRPs that pervade the biomedical and psychological sciences, producing false-positive results and inflated effect sizes. Approximately 90% of biomedical research reports supported study hypotheses, provoking suspicion about the field-wide presence of systematic biases to facilitate study findings that confirm researchers' expectations. In this education review, we introduce three common QRPs (ie, HARKing, P-hacking and Cherry-picking), perform a cross-sectional study to assess the proportion of original SEM research that reports supported study hypotheses, and draw attention to existing solutions and resources to overcome QRPs that manifest in exploratory research. We hypothesised that ≥ 85% of original SEM research studies would report supported study hypotheses. Two independent assessors systematically identified, screened, included, and extracted study data from original research articles published between 1 January 2019 and 31 May 2019 in the British Journal of Sports Medicine, Sports Medicine, the American Journal of Sports Medicine, and the Journal of Orthopaedic & Sports Physical Therapy We extracted data relating to whether studies reported that the primary hypothesis was supported or rejected by the results. Study hypotheses, methodologies, and analysis plans were preregistered at the Open Science Framework. One hundred and twenty-nine original research studies reported at least one study hypothesis, of which 106 (82.2%) reported hypotheses that were supported by study results. Of 106 studies reporting that primary hypotheses were supported by study results, 75 (70.8%) studies reported that the primary hypothesis was fully supported by study results. The primary study hypothesis was partially supported by study results in 28 (26.4%) studies. We detail open science practices and resources that aim to safe-guard against QRPs that bely the credibility and replicability of original research findings.

Concussed athletes walk slower than non-concussed athletes during cognitive-motor dual-task assessments but not during single-task assessments 2 months after sports concussion: a systematic review and meta-analysis using individual participant data.

OBJECTIVES: To determine whether individuals who sustained a sports concussion would exhibit persistent impairments in gait and quiet standing compared to non-injured controls during a dual-task assessment . DESIGN: Systematic review and meta-analysis using individual participant data (IPD). DATA SOURCES: The search strategy was applied across seven electronic bibliographic and grey literature databases: MEDLINE, EMBASE, CINAHL, SportDISCUS, PsycINFO, PsycARTICLES and Web of Science, from database inception until June 2017. ELIGIBILITY CRITERIA FOR STUDY SELECTION: Studies were included if; individuals with a sports concussion and non-injured controls were included as participants; a steady-state walking or static postural balance task was used as the primary motor task; dual-task performance was assessed with the addition of a secondary cognitive task; spatiotemporal, kinematic or kinetic outcome variables were reported, and; included studies comprised an observational study design with case-control matching. DATA EXTRACTION AND SYNTHESIS: Our review is reported in line with the Preferred Reporting Items for Systematic review and Meta-Analyses-IPD Statement. We implemented the Risk of Bias Assessment tool for Non-randomised Studies to undertake an outcome-level risk of bias assessment using a domain-based tool. Study-level data were synthesised in one of three tiers depending on the availability and quality of data: (1) homogeneous IPD; (2) heterogeneous IPD and (3) aggregate data for inclusion in a descriptive synthesis. IPD were aggregated using a 'one-stage', random-effects model. RESULTS: 26 studies were included. IPD were available for 20 included studies. Consistently high and unclear risk of bias was identified for selection, detection, attrition, and reporting biases across studies. Individuals with a recent sports concussion walked with slower average walking speed (χ2=51.7; df=4; p<0.001; mean difference=0.06 m/s; 95% CI: 0.004 to 0.11) and greater frontal plane centre of mass displacement (χ2=10.3; df=4; p=0.036; mean difference -0.0039 m; 95% CI: -0.0075 to -0.0004) than controls when evaluated using a dual-task assessment up to 2 months following concussion. SUMMARY/CONCLUSIONS: Our IPD evidence synthesis identifies that, when evaluated using a dual-task assessment, individuals who had incurred a sports concussion exhibited impairments in gait that persisted beyond reported standard clinical recovery timelines of 7-10 days. Dual-task assessment (with motion capture) may be a useful clinical assessment to evaluate recovery after sports concussion. PROTOCOL PRE-REGISTRATION: This systematic review was prospectively registered in PROSPERO CRD42017064861.