HealthyTrailsBR - The prevalence of running-related injuries and cramps, and the description of personal and running characteristics in Brazilian trail runners: a cross-sectional study.

BACKGROUND: Physical activity in natural environments, such as trail running, is a way to nurture physical and mental health. However, running has an inherent risk of musculoskeletal injuries. OBJECTIVES: To investigate the prevalence of running-related injuries (RRI) and cramps, and to describe the personal and training characteristics of Brazilian trail runners. METHODS: A total of 1068 trail runners were included in this observational cross-sectional study. The participants had at least six months of trail running experience. The data were collected between April 2019 and February 2020 through an online and self-reported survey. RESULTS: The point prevalence of RRIs was 39.2 % (95 % credible interval [CrI]: 36.3, 42.1). The body region with the highest point prevalence was the knee. The 12-month period prevalence of RRIs was 69.2 % (95 %CrI: 66.4, 72.0). The body region with the highest 12-month period prevalence was the lower leg. 1- and 12-month period prevalence of cramps was 19.5 % (95 %CrI: 17.1, 21.9) and 36.0 % (95 %CrI: 33.0, 38.8), respectively. Triceps surae was the muscle most affected by cramps. CONCLUSIONS: Two in 5 (40 %) trail runners reported being injured at the time of data collection, and about 2 of 3 reported previous RRIs in the last 12 months. The most prevalent injured body regions were the knee and the lower leg. One in 5 trail runners reported cramps in the last month, increasing to 36 % in the last 12 months. Knowing better the characteristics of the population and the burden of health conditions may inform better decisions regarding implementation actions toward trail running practice.

Two sides of the same runner! The association between biomechanical and physiological markers of endurance performance in distance runners.

BACKGROUND: The number of people who run to achieve competitive performance has increased, encouraging the scientific community to analyze the association of factors that can affect a runner performance. RESEARCH QUESTION: Is there association between running spatiotemporal and angular kinematics with the physiological markers of endurance performance during a cardiorespiratory exercise test? METHODS: This was an observational cross-sectional study with 40 distance runners simultaneously submitted to a running biomechanical analysis and cardiorespiratory exercise test on a treadmill. Mixed models were developed to verify the association between angular kinematic data obtained by the Movement Deviation Profile and the running spatiotemporal data with oxygen consumption and ventilatory thresholds. RESULTS: Spatiotemporal variables [.e., step frequency Odds Ratio 0.09 [0.06-0.12 95 % Confidence Interval], center of mass vertical displacement Odds Ratio 0.10 [0.07-0.14 95 % Confidence Interval], and step length [Odds Ratio -0.01 [-0.01 to -0.00 95 % Confidence Interval]] were associated with VO2. Also, step frequency Odds Ratio 1.03 [1.01-1.05 95 % Confidence Interval] was associated with the first ventilatory threshold, and angular running kinematics [Movement Deviation Profile analysis] Odds Ratio 1.47 [1.13-1.91 95 % Confidence Interval] was associated with peak of exercise during the cardiorespiratory exercise test. SIGNIFICANCE: Our findings demonstrated that: both higher step frequency and center of mass vertical displacement are associated with the increase of oxygen demand; step frequency is associated with the first ventilatory threshold, due to the entrainment mechanism and angular kinematic parameters are associated with peak aerobic speed. Future studies could also compare the biomechanical and physiological characteristics of different groups of distance runners. This could help identify the factors that contribute to oxygen demands during running and performance across different ages, genders, and levels of competition.

Artificial intelligence and Machine Learning approaches in sports: Concepts, applications, challenges, and future perspectives.

BACKGROUND: The development and application of Artificial Intelligence (AI) and Machine Learning (ML) in healthcare have gained attention as a promising and powerful resource to change the landscape of healthcare. The potential of these technologies for injury prediction, performance analysis, personalized training, and treatment comes with challenges related to the complexity of sports dynamics and the multidimensional aspects of athletic performance. OBJECTIVES: We aimed to present the current state of AI and ML applications in sports science, specifically in the areas of injury prediction, performance enhancement, and rehabilitation. We also examine the challenges of incorporating AI and ML into sports and suggest directions for future research. METHOD: We conducted a comprehensive literature review, focusing on publications related to AI and ML applications in sports. This review encompassed studies on injury prediction, performance analysis, and personalized training, emphasizing the AI and ML models applied in sports. RESULTS: The findings highlight significant advancements in injury prediction accuracy, performance analysis precision, and the customization of training programs through AI and ML. However, future studies need to address challenges such as ethical considerations, data quality, interpretability of ML models, and the integration of complex data. CONCLUSION: AI and ML may be useful for the prevention, detection, diagnosis, and treatment of health conditions. In this Masterclass paper, we introduce AI and ML concepts, outline recent breakthroughs in AI technologies and their applications, identify the challenges for further progress of AI systems, and discuss ethical issues, clinical and research opportunities, and future perspectives.

What is the influence of biomechanical variables on the Y balance test performance in recreational runners?

BACKGROUND: Asymmetries and poor Y balance test (YBT) performance are associated with an increased risk of injuries in athletes. The aim of this study was to investigate the association between YBT performance with biomechanical variables in runners. METHODS: The runners underwent the YBT, followed by the assessment of center of pressure, plank position, muscle strength (MS) of hip flexors, extensors, abductors, and external rotators, knee extensors, ankle dorsiflexion range of motion (ROM), Q angle, forefoot alignment, and passive hip internal rotation. Associations between variables were examined using multiple linear regression models with the Bayesian Information Criterion. RESULTS: 122 cases were analyzed. The R2 values were 0.38; 0.05; 0.06; and 0.15 for the anterior, posteromedial, posterolateral and composite directions models, respectively. The anterior reach in the YBT was associated with ankle dorsiflexion ROM [Sß 95%IC: 0.43 (0.32-0.55)], passive hip internal rotation [Sß 95%IC: 0.35 (0.24-0.47)], MS of the hip extensors [Sß 95%IC: 0.19 (0.07-0.31)] and forefoot alignment [Sß 95%IC: 0.14 (-0.25-0.02)]. The posteromedial and posterolateral reach were associated with MS of the hip flexors [Sß 95%IC: 0.23 (0.09-0.37) and 0.24 (0.11-0.38)], respectively. The composite score was associated with MS of the hip flexors [Sß 95%IC: 0.31 (0.18-0.45)], ankle dorsiflexion ROM [Sß 95%IC: 0.24 (0.10-0.37)] and Q angle [Sß 95%IC: 0.18 (0.04-0.31)]. CONCLUSION: YBT performance in different directions demonstrated specific associations with key biomechanical factors.

Exercise behavior, practice, injury, and symptoms of respiratory tract infection of 502 Brazilian adults during lockdown oscillations in two years (2021-2022) of the COVID-19 pandemic.

BACKGROUND: In the period between 2020 and 2023, during the COVID-19 (coronavirus disease 2019) pandemic, many countries released their restriction measures so that individuals were able to begin practicing physical exercises and outdoor sports again. The purpose of the current study was to evaluate the physical exercise behavior, symptoms of respiratory tract infection, and training practice, as well as aspects of pain and injuries in the lower limbs of adults during periods of lockdown oscillations in the two years of the COVID-19 pandemic in Brazil. METHODS: Cross-sectional study. PARTICIPANTS: A total of 502 adults were evaluated during two consecutive years of the COVID-19 pandemic, corresponding to the years 2021 and 2022. A virtual questionnaire was applied using the Google Forms platform through a link, or a Quick Response Code available in social media environments. The variables collected were: anthropometric characteristics, presence of comorbidities, clinical history for the diagnosis of COVID-19, and behavior related to physical exercise practices, divided into five topics: (1) physical exercise habits; (2) symptoms and health care utilization; (3) habit of practicing physical exercise in relation to the prevention of COVID-19; (4) preventive measures for COVID-19; and (5) feelings and reasons for practicing exercises. RESULTS: A total 79.0% of the participants returned to the practice of physical exercise after a period of social isolation due to COVID-19, with running (30.0%) and muscle strength training (50.0%) being the most prevalent modalities, in which 62.0% of practitioners carried out the activity individually, without any professional or technical monitoring. With regard to physical preparation, 61.0% reported performing pre-training stretching, 64.0% associated with muscular resistance training. Of these, 89% did not report current injuries or pain symptoms when returning to exercise (69.0%). Total of 60.5% reported experiencing respiratory tract symptoms of COVID-19 and seeking a consultation with a doctor, and 61.0% performed diagnostic test, with RT-PCR (Real time-polymerase chain reaction) being the most common test. Of those tested, 55.0% were positive for COVID-19, without the need for hospitalization (95.0%). The most commonly used measures for the prevention of COVID-19 were the fabric or surgical mask. The predominant feeling in the pandemic was anxiety (50.5%) and the reasons for practicing sports were: physical conditioning (30.9%), a feeling of pleasure (21.3%), and weight loss (20.3%). CONCLUSION: After two years of the COVID-19 pandemic (2021-2022), with periods of lockdown, there were low reports of injuries and pain symptoms after exercising on the return to physical exercise practices of running and strength training. However, the restrictions negatively affected the exercise behavior due to respiratory tract symptoms of COVID-19 and a reduction in training intensity, performed without any professional or technical supervision. The participants reported the use of a fabric or surgical mask for the prevention of COVID-19, and an increased feeling of anxiety. The reasons given for practicing physical exercise were physical conditioning, a feeling of pleasure, and weight loss.

Are alterations in running biomechanics associated with running injuries? A systematic review with meta-analysis.

BACKGROUND: No systematic review has investigated the main biomechanical variables as predictors of running-related injuries. OBJECTIVE: To investigate the main biomechanical variables associated with running-related injuries. METHODS: Medline via PubMed, EMBASE, SPORTDiscus, Web of Science, and CINAHL were searched from inception until 1 November 2021. Each study included must have investigated the association of at least one biomechanical variable (kinetics, kinematics, electromyography, or pressure distribution) with running injuries. The meta-analysis was conducted, and a modified version of the Downs and Black Quality Index was used for methodological quality evaluation. RESULTS: Across the 82 studies included, 5465 runners were investigated. The meta-analysis was conducted with 11 biomechanical variables from 51 articles (n=2395). The peak hip adduction angle was the sole biomechanical variable associated with running injury and was found to be higher in injured runners (0.57, 95% CI 0.21, 0.94) compared to uninjured runners. However, this result was highly influenced by two studies (out of five studies) conducted by the same group of authors. CONCLUSION: Clinicians, coaches, and runners should be aware that minimal evidence supports that alterations of running biomechanics are associated with running-related injuries. Heterogeneity in evaluation conditions and inconsistency in the naming and definitions of biomechanical variables make definitive conclusions challenging. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO, CRD42017068839.

Implementation of an online pain science education for chronic musculoskeletal pain in Brazilian public health system: protocol for a hybrid type III randomised controlled trial with economic evaluation.

BACKGROUND: Although clinical practice guidelines recommend pain education as the first-line option for the management of chronic musculoskeletal pain, there is a lack of pain education programmes in healthcare. Thus, digital health programmes can be an effective tool for implementing pain education strategies for public health. This trial will aim to analyse the implementation and effectiveness outcomes of three online pain science education strategies in the Brazilian public health system (SUS) for individuals with chronic musculoskeletal pain. METHODS: We will conduct a hybrid type III effectiveness-implementation randomised controlled trial with economic evaluation. We will include adult individuals with chronic musculoskeletal pain, recruited from primary healthcare in the city of Guarapuava, Brazil. Individuals will be randomised to three implementation groups receiving a pain science education intervention (EducaDor) but delivered in different modalities: group 1) synchronous online; group 2) asynchronous videos; and group 3) interactive e-book only. Implementation outcomes will include acceptability, appropriateness, feasibility, adoption, fidelity, penetration, sustainability, and costs. We will also assess effectiveness outcomes, such as pain, function, quality of life, sleep, self-efficacy, and adverse effects. Cost-effectiveness and cost-utility analyses will be conducted from the SUS and societal perspectives. The evaluations will be done at baseline, post-intervention (10 weeks), and 6 months. DISCUSSION: This study will develop and implement a collaborative intervention model involving primary healthcare professionals, secondary-level healthcare providers, and patients to enhance self-management of chronic pain. In addition to promoting better pain management, this study will also contribute to the field of implementation science in public health by generating important insights and recommendations for future interventions. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05302180; 03/29/2022).

Nasal dilator and physiological parameters associated to running performance: A systematic review and meta-analysis.

Nasal dilators were created to expand the nasal valve area. The aim of this systematic review was to verify physiological parameters associated to running performance with the use of nasal dilators. This study was registered in PROSPERO (CRD42021225795). According to the PICOS framework studies were included: Population: healthy subjects; Intervention: nasal dilators; Comparison: control group, placebo, minimal intervention, health education or other intervention; Outcomes: cardiorespiratory parameters and subjective perceptions; Study: randomized controlled trials, repeated measures or within-subjects design. The databases searched were MEDLINE, EMBASE, CENTRAL The Cochrane Library, CINAHL, SPORTDiscus, Web of Science, PEDro and Scopus. The descriptors "Running", "Nasal Dilator", "Randomized Controlled Trial", and synonyms were used. The risk of bias was assessed using the PEDro scale. Random effects Der Simonian and Laird model were used. The assessment of the certainty of the evidence was carried out using the GRADE approach. Eleven articles were included. There was a difference in favour of the nasal dilator when compared to placebo for maximal oxygen uptake and rating of perceived exertion. The certainty of the evidence was very low. Future studies will probably have an impact on estimation of the effect.

Effectiveness of a 3D bikefitting method in riding pain, fatigue, and comfort: a randomized controlled clinical trial.

To investigate the effects of bike fitting compared to qualitative-based riding posture recommendations on comfort, fatigue, and pain in amateur cyclists. This was a randomised controlled parallel trial of 162 amateur cyclists divided into two groups: bike fitting group (BFG) - participants received a bike fitting session based on 3D kinematic assessments; and a control group (QG) - participants who received a handout containing qualitative-based cycling posture recommendations. Primary outcomes were perceived comfort (FEEL Scale), perceived fatigue (OMNI Scale), and perceived pain (numeric rating pain scale, NRPS). Outcomes were assessed at baseline, when the interventions were delivered, and after 15 days. Intention-to-treat analyses were conducted using student t-tests between pre and post intervention on both groups. All dependent variables from BFG displayed significant statistical difference between both groups post-intervention (p < 0.05). FEEL Scale and OMNI Scale results showed the highest changes of all variables under analysis (mean differences of 3.12 and 3.95 points, respectively); while the body parts with more reduction in riding pain were Groin and Back (mean differences of 1.68 and 1.35, respectively). In conclusion, 3D kinematic bikefit demonstrated superior improvements over riding pain, comfort and fatigue compared to qualitative riding posture recommendations.

Physical Activity During Lockdowns Associated with the COVID-19 Pandemic: A Systematic Review and Multilevel Meta-analysis of 173 Studies with 320,636 Participants.

BACKGROUND: Many countries have restricted public life in order to contain the spread of the novel coronavirus (SARS-CoV2). As a side effect of related measures, physical activity (PA) levels may have decreased. OBJECTIVE: We aimed (1) to quantify changes in PA and (2) to identify variables potentially predicting PA reductions. METHODS: A systematic review with random-effects multilevel meta-analysis was performed, pooling the standardized mean differences in PA measures before and during public life restrictions. RESULTS: A total of 173 trials with moderate methodological quality (modified Downs and Black checklist) were identified. Compared to pre-pandemic, total PA (SMD - 0.65, 95% CI - 1.10 to - 0.21) and walking (SMD - 0.52, 95% CI - 0.29 to - 0.76) decreased while sedentary behavior increased (SMD 0.91, 95% CI: 0.17 to 1.65). Reductions in PA affected all intensities (light: SMD - 0.35, 95% CI - 0.09 to - 0.61, p = .013; moderate: SMD - 0.33, 95% CI - 0.02 to - 0.6; vigorous: SMD - 0.33, - 0.08 to - 0.58, 95% CI - 0.08 to - 0.58) to a similar degree. Moderator analyses revealed no influence of variables such as sex, age, body mass index, or health status. However, the only continent without a PA reduction was Australia and cross-sectional trials yielded higher effect sizes (p < .05). CONCLUSION: Public life restrictions associated with the COVID-19 pandemic resulted in moderate reductions in PA levels and large increases in sedentary behavior. Health professionals and policy makers should therefore join forces to develop strategies counteracting the adverse effects of inactivity.

Strength Level of Professional Elite Soccer Players after the COVID-19 Lockdown Period: A Retrospective Double-Arm Cohort Study.

BACKGROUND: It is well known that periods of inactivity generate a loss of muscle strength, a fundamental component of sports performance in soccer. However, little information is available on the decrease in strength levels in professional soccer players after the quarantine lockdown that occurred during the COVID-19 pandemic. AIM: To compare the isokinetic peak torque profiles of professional soccer players from different teams before and after the quarantine period generated by COVID-19. METHODS: A retrospective observational study was performed using data collected from two different professional elite-level soccer teams just before and immediately after the COVID-19 quarantine period. One team gave individual instructions to its players for conditioning maintenance at home during the quarantine period, while the other team used regular video calls to maintain the player's conditioning status on home training. The main outcomes were the mean peak torque of knee extensors and flexors, from concentric and eccentric contractions of each playing position. Analysis. A two-way ANOVA analysis was used to compare peak torque before and after the quarantine period and between both teams' strategies, showing a statistically significant reduction in eccentric knee flexor peak torque from the team that did not have remote monitoring. CONCLUSIONS: Remote monitoring programs are recommended so that athletes are less affected by the deleterious effects of confinement.

Train at home, but not alone: a randomised controlled multicentre trial assessing the effects of live-streamed tele-exercise during COVID-19-related lockdowns.

OBJECTIVE: Public life restrictions associated with the COVID-19 pandemic caused reductions in physical activity (PA) and decreases in mental and somatic health. Considering the interplay between these factors, we investigated the effects of digital home exercise (DHE) during government-enforced lockdowns. METHODS: A multicentre randomised controlled trial was performed allocating healthy individuals from nine countries (N=763; 523 female) to a DHE or an inactive control group. During the 4-week main intervention, DHE members engaged in live-streamed multicomponent home exercise. Subsequently, both groups had access to prerecorded workouts for an additional 4 weeks. Outcomes, assessed weekly, included PA level (Nordic Physical Activity Questionnaire-Short), anxiety (Generalized Anxiety Disorder Scale-7), mental well-being (WHO-5 Questionnaire), sleep quality (Medical Outcome Study Sleep Scale), pain/disability (Chronic Pain Grade Scale) and exercise motivation (Self-Concordance Scale). Mixed models were used for analysis. RESULTS: Live-streamed DHE consistently increased moderate PA (eg, week 1: 1.65 times more minutes per week, 95% CI 1.40 to 1.94) and vigorous PA (eg, week 1: 1.31 times more minutes per week, 95% CI 1.08 to 1.61), although the effects decreased over time. In addition, exercise motivation, sleep quality and anxiety were slightly improved for DHE in the 4-week live streaming period. The same applied to mental well-being (mean difference at week 4: +0.99, 95% CI 0.13 to 1.86), but an inverted trend was observed after live streaming was substituted by prerecorded exercise. CONCLUSIONS: Live-streamed DHE represents an efficacious method to enhance PA and selected markers of health during pandemic-related public life restrictions. However, research on implementation is warranted to reduce dropout rates. TRIAL REGISTRATION NUMBER: DRKS00021273.

What are the facilitators and barriers to develop a running-related injury prevention program? A qualitative study.

BACKGROUND: Knowing the facilitators and barriers of the development process of prevention programs in advance may prevent setbacks to occur and may even enable strategies to explore the facilitators and to deal with and/or avoid possible barriers. OBJECTIVE: To investigate the facilitators and barriers of the development process of a running-related injury (RRI) prevention program. METHODS: This was a qualitative study conducted with semi-structured face-to-face interviews with participants from the development of the RunIn3 RRI prevention program. The analysis on facilitators and barriers was performed following a content analysis approach. All participants enrolled in the development of the RunIn3 program were invited to participate in this study (n = 10). The interviews were conducted and recorded until saturation. Qualitative data from interview transcripts were grouped into condensed meaning units, codes, categories and themes, and were analyzed descriptively. RESULTS: Nine participants were included in this study. Overall, 17 categories were identified: six facilitators (35.3%) and 11 barriers (64.7%). The facilitators were reported 55.1% of the time (frequency of emerging themes [FET] = 43/78) and the barriers were reported 44.9% of the time (FET = 35/78). The most frequent categories classified as facilitators were 'group meeting' (32.6%, FET = 14/43) and 'form of contact' (20.9%, FET = 9/43). The most frequent categories classified as barriers were 'absence of participants' (22.9%, FET = 8/35) and 'ramblings' (20.0%, FET = 7/35). CONCLUSION: The facilitators were more frequently reported than the barriers related to the development of the RRI prevention program, based on FET. These results may help in future endeavors toward the development of sports injury prevention programs.

RunIn3: the development process of a running-related injury prevention programme.

BACKGROUND: Running is an important type of exercise to keep people physically active. However, running also carries a risk of developing running-related injuries (RRI). Therefore, effective and evidence-based RRI prevention programmes are desirable, but are scarce in practice. An approach to face this problem might be the application of methods to develop RRI prevention programmes based on theories of behaviour change. OBJECTIVE: The purpose of the study was to develop an RRI prevention programme based on perspectives of behavioural and social science theories, as well as taking a framework development approach. METHODS: This was a qualitative study using the Intervention Mapping (IM) framework held between February and March 2018 in São Paulo, Brazil. The participants were involved in running practice. The data collection was conducted during focus group meetings. The data analysis was based on semantic thematic approach using a content analysis orientation based on inductive reasoning. RESULTS: The target population of the RRI prevention programme identified was 'adult recreational runners'. The objectives of the RRI prevention programme were established in two broad actions: (1) to provide feedback on individual training characteristics and RRI risk; and (2) provide/enhance knowledge, skills and self-efficacy on RRI preventive behaviours. The programme is aimed to be delivered through an online system. CONCLUSION: An RRI prevention programme was developed using the IM framework and a participatory approach. The programme was named 'RunIn3', and it is based on providing feedback on running volume and RRI risk, as well as providing knowledge, skills and self-efficacy on RRI preventive behaviours.

Brazilian version of the OSTRC Questionnaire on health problems (OSTRC-BR): translation, cross-cultural adaptation and measurement properties.

BACKGROUND: The Oslo Sports Trauma Research Center - Questionnaire on Health Problems (OSTRC-QHP) has been shown to be a valid and reliable questionnaire for monitoring athletes with acute, overuse, and illness problems. OBJECTIVES: To translate and cross-culturally adapt the OSTRC-QHP into Brazilian-Portuguese (OSTRC-BR), and investigate the measurement properties of this version. METHODS: The original (Norwegian) questionnaire was translated and culturally adapted following existing guidelines. Measurement properties of the OSTRC-BR were investigated in 134 athletes followed for 13 weeks. Reliability was analyzed via internal consistency and test-retest reliability. Responsiveness was assessed by effect size (ES) estimations, correlation of the OSTRC-BR severity score with the Global Perceived Effect scale (GPE) and the Numeric Pain Rating Scale (NPRS), and by the Receiver Operating Characteristic (ROC) Curve test based on the area under the curve (AUC). RESULTS: The OSTRC-QHP has been translated and cross-culturally adapted successfully. The Cronbach's alpha was 0.93 (95% CI: 0.92, 0.94). Intrarater reliability (ICC2,1) of 0.96 (95% CI: 0.94, 0.98) was classified as excellent. ES estimation showed large effects (1.14 to 1.39). OSTRC-BR correlation was moderate (0.58 to 0.72) with the GPE and substantial (0.84 to 0.89) with the NPRS. The AUC values were above 0.70 when analysing all types of health problems. CONCLUSIONS: The OSTRC-BR presented adequate measurement properties. The OSTRC-BR is a valid, reliable, responsive, and, therefore, an adequate tool for monitoring Brazilian athletes from different sports during training and competitions.

The Association Between the Acute:Chronic Workload Ratio and Running-Related Injuries in Dutch Runners: A Prospective Cohort Study.

OBJECTIVE: To investigate the association between the acute:chronic workload ratio (ACWR) and running-related injuries (RRI). METHODS: This is a secondary analysis using a database composed of data from three studies conducted with the same RRI surveillance system. Longitudinal data comprising running exposure (workload) and RRI were collected biweekly during the respective cohorts' follow-up (18-65 weeks). ACWR was calculated as the most recent (i.e., acute) external workload (last 2 weeks) divided by the average external (i.e., chronic) workload of the last 4, 6, 8, 10 and 12 weeks. Three methods were used to calculate the ACWR: uncoupled, coupled and exponentially weighted moving averages (EWMA). Bayesian logistic mixed models were used to analyse the data. RESULTS: The sample was composed of 435 runners. Runners whose ACWR was under 0.70 had about 10% predicted probability of sustaining RRI (9.6%; 95% credible interval [CrI] 7.5-12.4), while those whose ACWR was higher than 1.38 had about 1% predicted probability of sustaining RRI (1.3%; 95% CrI 0.7-1.7). The association between the ACWR and RRI was significant, varying from a small to a moderate association (1-10%). The higher the ACWR, the lower the RRI risk. CONCLUSIONS: The ACWR showed an inversely proportional association with RRI risk that can be represented by a smooth L-shaped, second-order, polynomial decay curve. The ACWR using hours or kilometres yielded similar results. The coupled and uncoupled methods revealed similar associations with RRIs. The uncoupled method presented the best discrimination for ACWR strata. The EWMA method yielded sparse and non-significant results.

Can we explain running-related injury preventive behavior? A path analysis.

BACKGROUND: Behavioral and social science theories/models have been gaining attention in sports injury prevention. OBJECTIVE: To investigate the potential of the Theory of Planned Behavior in explaining running-related injury preventive behavior. METHODS: Six-month prospective cohort study based on data gathered from a randomized controlled trial. From a total of 1512 invited trail runners, 232 were included in this study. Preventive behaviors and their determinants were assessed at baseline and two and six months after baseline. Five-point Likert scales were used to assess the determinants of preventive behavior. A Bayesian path analysis was conducted applying mixed models and mediation analysis. RESULTS: A 1-point increase in intention, attitude, subjective norm, and perceived behavioral control predicted an increase of 54% (95% Bayesian credible interval [BCI]: 38, 71) in the rate of performing running-related injury preventive behavior, explaining 49% (R2 0.49; 95% BCI: 0.41, 0.56) of the variance around preventive behavior. Intention and perceived behavioral control predicted running-related injury preventive behavior directly, while 40% (95% BCI: 21, 61) and 44% (95% BCI: 20, 69) of the total effect of attitude was mediated by intention and perceived behavioral control, respectively. Attitude, subjective norm, and perceived behavioral control predicted intention. CONCLUSIONS: The Theory of Planned Behavior may have the potential to explain half of the variance around running-related injury preventive behavior and intention. Therefore, such theory may be considered a relevant and useful tool in developing, investigating, and/or implementing programs aimed at preventing running-related injuries.