Diffusion tensor imaging combined with chemical shift-encoded sequence to quantify the adaptive changes of calf muscles in amateur marathoners.

PURPOSE: Calf muscles play an important role in marathon race, and the incidence of injury is high in this process. This study prospectively quantified diffusion tensor metrics, muscle fat fraction (MFF) and cross-sectional area (CSA) of calf muscles induced by endurance exercise in amateur marathoners, and the potential mechanisms underlying the changes in these parameters were analyzed. METHOD: In this prospective study, 35 marathoners (27 males, 8 females; mean age (standard deviation, SD), 38.92 (4.83) years) and 26 controls (18 males, 8 females; mean age (SD), 38.35 (6.75) years) underwent magnetic resonance imaging (MRI) from September 2022 to March 2023. The diffusion tensor eigenvalues (λ1, λ2, λ3), radial diffusivity (RD), fractional anisotropy (FA), MFF and CSA of calf muscles were compared between marathoners and controls. A binary logistic regression model with gender correction was performed analyze the relationship between marathon exercise and DTI parameters, CSA and MFF of calf muscles. RESULTS: Interobserver agreement was good (κ = 0.71). The results of binary logistic regression model with gender correction showed that the regression coefficients of FA values in anterior group of calf (AC), soleus (SOL), medial gastrocnemius (MG) and lateral gastrocnemius (LG) were negative, and the odds ratios (OR) were 0.33, 0.45, 0.35, 0.05, respectively (P < 0.05). The OR of RD in SOL and λ2 in external group of calf (EC) were relatively higher, 3.74 and 3.26, respectively (P < 0.05). CSA was greater in SOL of marathoners, with an OR value of 1.00(P < 0.05). The MFF in AC and LG was lower in marathoners and OR of two indexes were -0.69 and -0.59, respectively (P < 0.05). CONCLUSIONS: Diffusion tensor imaging (DTI) combined with chemical shift-encoded sequence can noninvasively detect and quantify the adaptive changes of calf muscle morphology, microstructure and tissue composition induced by long-term running training in amateur marathoners.

Health profile and training habits of 42k marathoners, temuco chile / Perfil de salud y hábitos de entrenamiento de maratonistas 42k, temuco chile / Perfil de saúde e hábitos de treinamento de maratonistas de 42k, temuco chile

ABSTRACT Context: participation of runners in marathons increases each year, making them an attractive population to investigate. In Chile, the characteristics of marathoners in decentralized and emerging races, such as the Temuco Araucanía International Marathon (MITA), are not yet known. Objective: to describe health profile, sociodemographic characteristics, and training habits of the 42K runners enrolled in MITA during the years 2017, 2018 and 2019. Methods: Non-probabilistic convenience sample composed of people over 18 years of age, who signed informed consent. The data were obtained through a survey prepared by the authors, and were analyzed with the statistical program Stata 16.0 to describe the group based on the variables of health profile, sociodemographic characteristics and training habits. Results: 135 adult marathoners were included (n=42-2017, n=45-2018, n=48-2019). The mean age was 39.5±9.1 years and 86.6% were men. Fifteen percent self-reported comorbidities, 96.7% were non-smokers, 80% were normal weight, 65% had a high educational level and 87% were workers. Regarding training habits, it is noteworthy that the frequency was 4.9±1 days per week, with a mean duration of 89±1 minutes per session. Finally, 71.9% of the sample reported doing high intensity training. Conclusions: the MITA 42K runners are generally healthy subjects, nonsmokers and without comorbidities; mostly men, normal weight, middle age, with a high educational level and workers. They present a high frequency of weekly training, with an average duration of 90 minutes per session, this being carried out at high intensity by almost 2/3 of the sample. Knowledge of the health profile and training habits of runners is a first step to responsibly generate guidelines that contribute to strengthening the safe practice of this sport. Level of Evidence IV; Descriptive and Cross-Sectional Study.

RESUMEN Introducción: la participación de corredores en maratones aumenta cada año, convirtiéndolos en una población atractiva de investigar. En Chile, aún no se conocen las características de maratonistas de carreras descentralizadas y emergentes, como la Maratón Internacional Temuco Araucanía (MITA). Objetivo: describir el perfil de salud, las características sociodemográficas y los hábitos de entrenamiento de los corredores de 42K, inscriptos en MITA durante los años 2017, 2018 y 2019. Métodos: Muestra no probabilística por conveniencia mayores de 18 años, que firmaron el término de consentimiento informado. Los datos fueron obtenidos a través de la aplicación de una encuesta de elaboración original, analizados con programa estadístico Stata 16.0 para describir al grupo en función de las variables perfil de salud, sociodemográficas y hábitos de entrenamiento. Resultados: Se incluyeron 135 adultos maratonistas (n=42-2017, n=45-2018, n= 48-2019) La edad promedio fue de 39,5±9,1 años y 86,6% fueron hombres. El 15% auto reportó comorbilidades, 96,7% eran no fumadores; 80% eran normopeso, con un 65% de participantes con nivel educacional alto y 87% trabajadores. En cuanto a los hábitos de entrenamiento, se destaca que la frecuencia es de 4,9±1 días por semana, con una duración media de 89±1 minutos por sesión y finalmente, el 71,9% de la muestra reporta realizar entrenamiento de alta intensidad. Conclusiones: los corredores 42K del MITA son en general sujetos sanos, no fumadores y sin comorbilidades; en su mayoría hombres, normopeso, de edad media, con un nivel educacional alto y trabajadores. Presentan una alta frecuencia de entrenamiento semanal, con una duración promedio de 1:30 minutos por sesión, siendo realizada a alta intensidad casi 2/3 de la muestra. El conocimiento del perfil de salud y hábitos de entrenamiento de los corredores, constituye un primer paso para generar, de forma responsable, lineamientos que contribuyan a fortalecer la práctica segura de este deporte. Nivel de Evidencia IV; Estudio Descriptivo y Transversal.

RESUMO Introdução: a participação de corredores em maratonas aumenta a cada ano, tornando-os uma população atrativa para investigação. No Chile, ainda não são conhecidas as características dos maratonistas em corridas descentralizadas e emergentes, como a Maratona Internacional Temuco Araucanía (MITA). Objetivo: descrever o perfil de saúde, características sociodemográficas e hábitos de treinamento dos corredores de 42K inscritos no MITA durante os anos de 2017, 2018 e 2019. Métodos: Amostra não probabilística de conveniência composta por pessoas maiores de 18 anos, que assinaram o termo de consentimento livre e esclarecido. Os dados foram obtidos por meio de um questionário elaborado pelos autores e foram analisados com o programa estatístico Stata 16.0 para descrever o grupo com base nas variáveis de perfil de saúde, características sociodemográficas e hábitos de treinamento. Resultados: foram incluídos 135 maratonistas adultos (n=42-2017, n=45-2018, n=48-2019). A média de idade foi de 39,5±9,1 anos e 86,6% eram homens. Comorbidades autorreferidas 15%, 96,7% não fumantes, 80% eutróficos, 65% com alta escolaridade e 87% trabalhadores. Em relação aos hábitos de treino, destaca-se que a frequência foi de 4,9±1 dias por semana, com duração média de 89±1 minutos por sessão. Por fim, 71,9% da amostra relatou fazer treinamento de alta intensidade. Conclusões: os corredores do MITA 42K são indivíduos geralmente saudáveis, não fumantes e sem comorbidades; em sua maioria homens, eutróficos, de meia idade, com alto nível educacional e trabalhadores. Apresentam uma elevada frequência de treino semanal, com duração média de 90 minutos por sessão, sendo este realizado em alta intensidade por quase 2/3 da amostra. O conhecimento do perfil de saúde e hábitos de treino dos corredores é um primeiro passo para gerar com responsabilidade orientações que contribuam para o fortalecimento da prática segura deste esporte. Nível de Evidência IV; Estudo Descritivo e Transversal.

Sleep in marathon and ultramarathon runners: a brief narrative review.

Introduction: Sleep is considered a fundamental biological function in humans necessary for recovery from daily physical activities. Considering the increasing popularity of long-distance running and participation in races such as marathons and ultramarathons, the aim of the present study was to review the relationship of such strenuous physical activities with sleep. Methods: A search of Scopus was performed on 24/6/2023 using the syntax [ABS (sleep) AND ABS (marathon)] to identify relevant papers, the references of which were hand-searched to find additional sources. Results: Optimal sleep has been shown to affect injury prevention and susceptibility to infection positively. In turn, participation in a marathon race may influence nocturnal autonomic modulation and disturb homeostasis. Ultramarathon races may have such a long duration that results in sleep deprivation even for several days, where sleep duration is quite below the physiological range. It seems that for ultramarathons of short duration, continuous running and sleep deprivation are beneficial for performance. In contrast, for races longer than 200 miles, it is necessary to develop sleep strategies to sustain performance. Conclusion: In summary, the longer the distance of a running race, the greater the importance of an optimal sleep for race performance as well as the impact of a race on sleep.

A Pilot Study Using Entropy for Optimizing Self-Pacing during a Marathon.

A new group of marathon participants with minimal prior experience encounters the phenomenon known as "hitting the wall," characterized by a notable decline in velocity accompanied by the heightened perception of fatigue (rate of perceived exertion, RPE). Previous research has suggested that successfully completing a marathon requires self-pacing according to RPE rather than attempting to maintain a constant speed or heart rate. However, it remains unclear how runners can self-pace their races based on the signals received from their physiological and mechanical running parameters. This study aims to investigate the relationship between the amount of information conveyed in a message or signal, RPE, and performance. It is hypothesized that a reduction in physiological or mechanical information (quantified by Shannon Entropy) affects performance. The entropy of heart rate, speed, and stride length was calculated for each kilometer of the race. The results showed that stride length had the highest entropy among the variables, and a reduction in its entropy to less than 50% of its maximum value (H = 3.3) was strongly associated with the distance (between 22 and 40) at which participants reported "hard exertion" (as indicated by an RPE of 15) and their performance (p < 0.001). These findings suggest that integrating stride length's Entropy feedback into new cardioGPS watches could improve marathon runners' performance.

Does Running Increase the Risk of Hip and Knee Arthritis? A Survey of 3804 Marathon Runners.

BACKGROUND: Long-distance running is a popular form of cardiovascular exercise with many well-described health benefits, from improving heart health to the management of obesity, diabetes, and mental illness. The impact of long-distance running on joint health in recreational runners, however, remains inconclusive. HYPOTHESIS: The prevalence of osteoarthritis in runners is not associated with an athlete's running-related history, including the number of marathons completed, cumulative years of running, average weekly mileage, and average running pace. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: A survey was distributed to all participants registered for the 2019 or 2021 Chicago marathon (n = 37,917). Surveys collected runner demographics and assessed for hip/knee pain, osteoarthritis, family history, surgical history, and running-related history. Running history included the number of marathons run, number of years running, average running pace, and average weekly mileage. The overall prevalence of osteoarthritis was identified, and a multivariable logistic regression model was used to identify variables associated with the presence of hip and/or knee osteoarthritis. RESULTS: Surveys were completed by 3804 participants (response rate of 10.0%). The mean age was 43.9 years (range, 18-83 years) and participants had completed on average 9.5 marathons (median, 5 marathons; range, 1-664 marathons). The prevalence of hip and/or knee arthritis was 7.3%. A history of hip/knee injuries or surgery, advancing age, family history, and body mass index (BMI) were risk factors for arthritis. Cumulative number of years running, number of marathons completed, weekly mileage, and mean running pace were not significant predictors for arthritis. The majority (94.2%) of runners planned to run another marathon, despite 24.2% of all participants being told by a physician to do otherwise. CONCLUSION: From this largest surveyed group of marathon runners, the most significant risk factors for developing hip or knee arthritis were age, BMI, previous injury or surgery, and family history. There was no identified association between cumulative running history and the risk for arthritis.

The association between marathon running and high-sensitivity cardiac troponin: A systematic review and meta-analysis.

BACKGROUND: Marathon running is an extreme sport with a distance of about 42 kilometers. Its relationship to high-sensitivity cardiac troponin (hs-cTn) remains controversial. OBJECTIVE: As the gold standard for detecting myocardial injury, the trends of hs-cTn before and after a marathon were investigated and analyzed. METHODS: A literature search was conducted in PubMed, EMBASE, and Cochrane Library databases by combing the keywords marathon and troponin, and studies regarding high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) concentrations before and after marathon running (not for half-marathon and ultra-marathon) were included. "Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group" were used to assess the risk of bias. Statistical analysis was performed using Review Manager, presenting data as mean values and 95% confidence intervals (CIs). Sensitivity analysis and subgroup analysis were performed if there was high heterogeneity among studies based on I2 statistic. RESULTS: A total of 13 studies involving 824 marathoners were included in this systematic review and meta-analysis. Both hs-cTnI (MD 68.79 ng/L, [95% CI 53.22, 84.37], p< 0.001) and hs-cTnT (MD 42.91 ng/L, [95% CI 30.39, 55.43], p< 0.001) were elevated after running a marathon, but the concentration of hs-cTnT returned to baseline after 72 to 96 h post-race (MD 0.11 ng/L, [95% CI -1.30, 1.52], p= 0.88). The results of subgroup analysis demonstrated that the 99th percentile upper reference limit of hs-cTnT might be the source of heterogeneity. CONCLUSION: The concentrations of hs-cTnI and hs-cTnT were increased after marathon running, but the change of hs-cTnT is usually not seen as irreversible myocardial injury.

Ultrashort echo time magnetization transfer imaging of knee cartilage and meniscus after long-distance running.

OBJECTIVE: To assess the detection of changes in knee cartilage and meniscus of amateur marathon runners before and after long-distance running using a 3D ultrashort echo time MRI sequence with magnetization transfer preparation (UTE-MT). METHODS: We recruited 23 amateur marathon runners (46 knees) in this prospective cohort study. MRI scans using UTE-MT and UTE-T2* sequences were performed pre-race, 2 days post-race, and 4 weeks post-race. UTE-MT ratio (UTE-MTR) and UTE-T2* were measured for knee cartilage (eight subregions) and meniscus (four subregions). The sequence reproducibility and inter-rater reliability were also investigated. RESULTS: Both the UTE-MTR and UTE-T2* measurements showed good reproducibility and inter-rater reliability. For most subregions of cartilage and meniscus, the UTE-MTR values decreased 2 days post-race and increased after 4 weeks of rest. Conversely, the UTE-T2* values increased 2 days post-race and decreased after 4 weeks. The UTE-MTR values in lateral tibial plateau, central medial femoral condyle, and medial tibial plateau showed a significant decrease at 2 days post-race compared to the other two time points (p < 0.05). By comparison, no significant UTE-T2* changes were found for any cartilage subregions. For meniscus, the UTE-MTR values in medial posterior horn and lateral posterior horn regions at 2 days post-race were significantly lower than those at pre-race and 4 weeks post-race (p < 0.05). By comparison, only the UTE-T2* values in medial posterior horn showed a significant difference. CONCLUSIONS: UTE-MTR is a promising method for the detection of dynamic changes in knee cartilage and meniscus after long-distance running. KEY POINTS: • Long-distance running causes changes in the knee cartilage and meniscus. • UTE-MT monitors dynamic changes of knee cartilage and meniscal non-invasively. • UTE-MT is superior to UTE-T2* in monitoring dynamic changes in knee cartilage and meniscus.

Effect of balance training on the physical fitness of marathon runners / Efeito do treinamento de equilíbrio sobre a aptidão física dos maratonistas / Efecto del entrenamiento del equilibrio en la aptitud física de corredores de maratón

ABSTRACT Introduction: As a comprehensive sport, Marathon presents high demands concerning the athletes' comprehensive capacity. Objective: This paper explores to what extent balance skill training can effectively contribute to improving physical fitness for marathon runners. Methods: 120 marathon runners were selected for the pilot experiment. The experimental group received balance training, while the control group underwent no intervention. Results: In the experimental group, the time with eyes closed and feet apart increased from 33.559 ± 15.8570 to 37.203 ± 15.5865s, the time spent in the T-shaped run from 10.144 ± 0.5063s to 9.908 ± 0.5225s, the time spent in the standing long jump from 2.831 ± 0.2648m to 3.058 ± 0.3183m, and the time spent in the T-shaped run from 55.544 ± 2.2581 to 60.845 ± 2.4367 times/min. The total FMS score changed from 14.618 ± 0.9392 to 18.481 ± 1.3909. Shoulder flexibility increased from 2.777 ± 0.4756 to 2.917 ± 0.2994, and active straight knee raise changed from 2.306 ± 0.4692 to 2.803 ± 0.403. Conclusion: Daily balance training can be added to usual marathon training to improve the fitness of its athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: A maratona, enquanto esporte integral, apresenta altas exigências relativas à capacidade plena dos atletas. Objetivo: Este artigo tenta explorar em que medida o treinamento da habilidade de equilíbrio pode efetivamente contribuir para o aprimoramento da aptidão física aos praticantes do esporte de corrida de maratona. Métodos: 120 corredores de maratona foram selecionados para o experimento piloto. O grupo experimental recebeu treinamento de equilíbrio, enquanto o grupo de controle não sofreu qualquer intervenção. Resultados: No grupo experimental, o tempo com olhos fechados e pés separados aumentou de 33,559 ± 15,8570 para 37,203 ± 15,5865s, o tempo gasto na corrida em forma de T de 10,144 ± 0,5063s para 9,908 ± 0,5225s, o tempo gasto no salto em pé em distância de 2,831 ± 0,2648m para 3,058 ± 0,3183m, e o tempo gasto na corrida em forma de T de 55,544 ± 2,2581 para 60,845 ± 2,4367 vezes/min. A pontuação total de FMS mudou de 14,618 ± 0,9392 para 18,481 ± 1,3909. A flexibilidade do ombro aumentou de 2,777 ± 0,4756 para 2,917 ± 0,2994, e o levantamento reto do joelho ativo mudou de 2,306 ± 0,4692 para 2,803 ± 0,403. Conclusão: O treinamento de equilíbrio diário pode ser adicionado ao treino de maratona habitual para melhorar a aptidão física de seus atletas. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: El maratón, como deporte integral, presenta grandes exigencias en cuanto a la capacidad integral de los atletas. Objetivo: Este trabajo pretende explorar hasta qué punto el entrenamiento de las habilidades de equilibrio puede contribuir eficazmente a la mejora de la condición física de los corredores de maratón. Métodos: Se seleccionaron 120 corredores de maratón para el experimento piloto. El grupo experimental recibió entrenamiento de equilibrio, mientras que el grupo de control no se sometió a ninguna intervención. Resultados: En el grupo experimental, el tiempo con los ojos cerrados y los pies separados aumentó de 33,559 ± 15,8570 a 37,203 ± 15,5865s, el tiempo empleado en la carrera en forma de T de 10,144 ± 0,5063s a 9,908 ± 0,5225s, el tiempo empleado en el salto de longitud de pie de 2,831 ± 0,2648m a 3,058 ± 0,3183m, y el tiempo empleado en la carrera en forma de T de 55,544 ± 2,2581 a 60,845 ± 2,4367 veces/min. La puntuación total de FMS pasó de 14,618 ± 0,9392 a 18,481 ± 1,3909. La flexibilidad de los hombros aumentó de 2,777 ± 0,4756 a 2,917 ± 0,2994, y la elevación activa de la rodilla pasó de 2,306 ± 0,4692 a 2,803 ± 0,403. Conclusión: El entrenamiento diario del equilibrio puede añadirse al entrenamiento habitual de maratón para mejorar la forma física de sus atletas. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Relief of sports fatigue after marathon races by pnf stretching / Alívio da fadiga esportiva após corridas de maratona por alongamento pnf / Alivio de la fatiga deportiva tras carreras de maratón mediante estiramientos pnf

ABSTRACT Introduction: Marathon running requires stretching practices to relieve fatigue after exercise. The Proprioceptive Neuromuscular Facilitation (PNF) technique is an advanced stretching technique that allows segmenting of a specific muscle group for simultaneous stretching and strengthening. Objective: This paper explores the effect of PNF stretching exercise on relieving sports fatigue after marathon races. Methods: In this paper, 160 marathon runners were selected for the experiment, and randomly divided into experimental and control groups. The experimental group performed the PNF stretching exercise, while the control group remained with traditional stretching without any new intervention. Fatigue was assessed according to the heart rate, collected before, during, and after the experiment. Results: After nine weeks of PNF stretching training, the heart rate in the experimental group changed from 65.35 to 62.46 in the morning; during training, the group's heart rate changed from 180.79 to 173.04; after recovery, the first group's heart rate changed from 82.88 to 81.88. In the control group, the heart rate of the group also showed changes from 65.29 to 68.86 in the morning; during training, it changed from 180.7 to 175.49; and after recovery, from 86.23 to 88.4. Conclusion: PNF stretching exercise has a positive effect on relieving sports fatigue after marathon races. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: A corrida de maratona requer práticas de alongamento para aliviar a fadiga após o exercício. A técnica de Facilitação Neuromuscular Proprioceptiva (PNF) é uma técnica avançada de alongamento que permite segmentar um grupo muscular específico, para alongamento e fortalecimento simultâneos. Objetivo: Este artigo tenta explorar o efeito do exercício de alongamento PNF no alívio da fadiga esportiva após corridas de maratona. Métodos: Neste artigo, 160 corredores de maratona foram selecionados para o experimento, divididos aleatoriamente em grupos experimental e controle. O grupo experimental fez o exercício de alongamento PNF, enquanto o grupo de controle permaneceu com o alongamento tradicional, sem qualquer nova intervenção. A fadiga foi avaliada segundo a frequência cardíaca, coletada antes, durante e após o experimento. Resultados: Após nove semanas de treinamento de alongamento PNF, a frequência cardíaca no grupo experimental alterou-se de 65,35 para 62,46 pela manhã; durante o treinamento, a frequência cardíaca do grupo alterou-se de 180,79 para 173,04; após a recuperação, a frequência cardíaca do primeiro grupo alterou-se de 82,88 para 81,88. No grupo de controle, a frequência cardíaca do grupo também exibiu alterações de 65,29 para 68,86 pela manhã; Durante o treinamento, mudou de 180,7 para 175,49; e após a recuperação, de 86,23 para 88,4. Conclusão: O exercício de alongamento PNF tem um efeito positivo no alívio da fadiga esportiva após corridas de maratona. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: Las carreras de maratón requieren prácticas de estiramiento para aliviar la fatiga tras el ejercicio. La técnica de Facilitación Neuromuscular Propioceptiva (PNF) es una técnica avanzada de estiramiento que permite segmentar un grupo muscular específico, para estirar y fortalecer simultáneamente. Objetivo: Este trabajo pretende explorar el efecto del ejercicio de estiramiento PNF en el alivio de la fatiga deportiva tras carreras de maratón. Métodos: En este trabajo, se seleccionaron 160 corredores de maratón para el experimento, divididos aleatoriamente en grupos experimental y de control. El grupo experimental realizó el ejercicio de estiramiento PNF, mientras que el grupo de control permaneció con el estiramiento tradicional, sin ninguna nueva intervención. La fatiga se evaluó en función de la frecuencia cardiaca, recogida antes, durante y después del experimento. Resultados: Tras nueve semanas de entrenamiento de estiramientos PNF, la frecuencia cardiaca del grupo experimental pasó de 65,35 a 62,46 por la mañana; durante el entrenamiento, la frecuencia cardiaca del grupo pasó de 180,79 a 173,04; tras la recuperación, la frecuencia cardiaca del primer grupo pasó de 82,88 a 81,88. En el grupo de control, la frecuencia cardiaca del grupo también mostró cambios de 65,29 a 68,86 por la mañana; durante el entrenamiento, cambió de 180,7 a 175,49; y tras la recuperación, de 86,23 a 88,4. Conclusión: El ejercicio de estiramiento PNF tiene un efecto positivo en el alivio de la fatiga deportiva después de correr un maratón. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Effects of resistance training on exercise tolerance in marathon runners / Efeitos do treinamento de resistência sobre a tolerância ao exercício em corredores de maratona / Efectos del entrenamiento de resistencia sobre la tolerancia al ejercicio en corredores de maratón

ABSTRACT Introduction: A high index of exercise tolerance is fundamental for marathon runners, indicating a good capacity to perform the exercises considering their maximum duration and workload. Objective: Evaluate the effects of resistance training with different loads on exercise tolerance of marathon runners. Methods: 120 professional long-distance runners were selected as volunteers for the experiment. Divided into experimental groups A, B and Control, the intervention had a 9-week period. The experimental groups A and B received resistance training with different loads, while the Control group did not undergo training intervention. Results: Upper limb muscle mass increased from 3.38 ± 0.18 to 3.75 ± 0.37 in group A; from 3.40 ± 0.15 to 3.66 ± 0.31 in group B; peak biceps brachii moment increased from 53.60 ± 6.27 to 62.97 ± 8.87 in group A; from 53.67 ± 5.68 to 58.48 ± 6.16 in group B; from 5. 37 ± 2.16 to 5.73 ± 2.67 in group A; from 7.21 ± 2.62 to 6.76 ± 4.36 in group B; and from 154.86 ± 19.69 to 108.30 ± 31.75 in group A; group B presented a reduction from 156.97 ± 46.13 to 116.45 ± 39.09, and the data from the control group did not change significantly. Conclusion: Resistance training with different loads in daily training can effectively improve the endurance of long-distance runners. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: Um índice elevado de tolerância ao exercício é fundamental para corredores de maratona, sinalizando uma boa capacidade para a realização dos exercícios considerando sua duração máxima e carga de trabalho. Objetivo: Avaliar os efeitos do treinamento de resistência com distintas cargas sobre a tolerância ao exercício dos corredores de maratona. Métodos: Foram selecionados 120 corredores profissionais de longa distância como voluntários para o experimento. Divididos em grupo experimental A, B e Controle, a intervenção teve um período de 9 semanas. Os grupos experimentais A e B receberam treinamento de resistência com cargas diferentes, enquanto o grupo Controle não sofreu intervenção de treinamento. Resultados: A massa muscular dos membros superiores elevou-se de 3,38 ± 0,18 para 3,75 ± 0,37 no grupo A; de 3,40 ± 0,15 para 3,66 ± 0,31 no grupo B; o momento de pico do bíceps braquial aumentou de 53,60 ± 6,27 para 62,97 ± 8,87 no grupo A; de 53,67 ± 5,68 para 58,48 ± 6,16 no grupo B; de 5. 37 ± 2,16 para 5,73 ± 2,67 no grupo A; de 7,21 ± 2,62 para 6,76 ± 4,36 no grupo B; e de 154,86 ± 19,69 para 108,30 ± 31,75 no grupo A; o grupo B apresentou redução de 156,97 ± 46,13 para 116,45 ± 39,09, e os dados do grupo de controle não sofreram alterações significativas. Conclusão: O treinamento de resistência com diferentes cargas no treinamento diário pode efetivamente melhorar a resistência dos corredores de longa distância. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: Un alto índice de tolerancia al ejercicio es fundamental para los corredores de maratón, indicando una buena capacidad para realizar los ejercicios, considerando su máxima duración y carga de trabajo. Objetivo: Evaluar los efectos del entrenamiento de resistencia con diferentes cargas sobre la tolerancia al ejercicio de corredores de maratón. Métodos: 120 corredores profesionales de larga distancia fueron seleccionados como voluntarios para el experimento. Divididos en los grupos experimentales A, B y Control, la intervención tuvo una duración de 9 semanas. Los grupos experimentales A y B recibieron entrenamiento de resistencia con diferentes cargas, mientras que el grupo Control no se sometió a intervención de entrenamiento. Resultados: La masa muscular del miembro superior aumentó de 3,38 ± 0,18 a 3,75 ± 0,37 en el grupo A; de 3,40 ± 0,15 a 3,66 ± 0,31 en el grupo B; el momento máximo del bíceps braquial aumentó de 53,60 ± 6,27 a 62,97 ± 8,87 en el grupo A; de 53,67 ± 5,68 a 58,48 ± 6,16 en el grupo B; de 5. 37 ± 2,16 a 5,73 ± 2,67 en el grupo A; de 7,21 ± 2,62 a 6,76 ± 4,36 en el grupo B; y de 154,86 ± 19,69 a 108,30 ± 31,75 en el grupo A; el grupo B presentó una reducción de 156,97 ± 46,13 a 116,45 ± 39,09, y los datos del grupo control no sufrieron cambios significativos. Conclusión: El entrenamiento de resistencia con diferentes cargas en el entrenamiento diario puede mejorar eficazmente la resistencia de los corredores de fondo. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Impacts of core training on athletes' performance in long-distance running / Impactos do treino do core no desempenho de atletas na corrida de longa distância / Efectos del entrenamiento del core en el rendimiento de atletas en carreras de larga distancia

ABSTRACT Introduction: Long-distance runners cannot achieve training effects by relying only on speed endurance training. Core training exercises significantly improve stability, allowing learning of techniques with superior movement efficiency. Several factors that affect the development of athletes' special skills are considered, highlighting their main strengths and working on intermediate characteristics. Objective: Verify the impacts of core training on athletes' performance in long-distance running. Methods: This paper had 18 middle-distance runners as volunteers for the research. The athletes' physical conditioning and athletic performance before and after training were examined. Statistical analyses on the indicators of the experimental and control groups were analyzed based on the T-test. Results: There were significant differences in endurance, core muscle elasticity, core strength, explosive power, and stability (P<0.05); the results showed that the differences in core stability between the left and right legs of the experimental group were significant (P<0.05). Conclusion: Core strength exercise is more conducive to exercising a myocardial group in medium and long-distance exercise than conventional strength exercise. Core strength exercises can compensate for a lack of regular strength. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: Corredores de longa distância não podem alcançar efeitos de treinamento apenas contando com os treinos de resistência de velocidade. Os exercícios de treino do core melhoram significativamente a estabilidade que permite um aprendizado da técnica com eficiência superior do movimento. Para isso, são considerados vários fatores que afetam o desenvolvimento das habilidades especiais dos atletas, destacando seus principais pontos fortes e trabalhando nas características intermediárias. Objetivo: Verificar os impactos do treino do core no desempenho de atletas na corrida de longa distância. Métodos: Este artigo teve a participação de 18 corredores de média distância como voluntários para a pesquisa. Foi examinado o condicionamento físico dos atletas e o desempenho atlético antes e depois dos treinos. As análises estatísticas nos indicadores dos grupos experimentais e de controle foram analisadas com base no teste-T. Resultados: Houve diferenças significativas na resistência, elasticidade muscular essencial, força do core, potência explosiva e estabilidade (P<0,05); os resultados mostraram que as diferenças na estabilidade do núcleo entre as pernas esquerda e direita do grupo experimental foram significativas (P<0,05). Conclusão: O exercício de força do core é mais propício ao exercício de um grupo miocárdio em exercícios de média e longa distância do que o exercício de força convencional. Exercícios de força do core podem compensar a falta de força regular. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: Los corredores de larga distancia no pueden conseguir los efectos del entrenamiento basándose únicamente en el entrenamiento de la velocidad y la resistencia. Los ejercicios de entrenamiento del core mejoran significativamente la estabilidad que permite un aprendizaje de la técnica con una eficiencia de movimiento superior. Para ello, se tienen en cuenta varios factores que afectan al desarrollo de las capacidades especiales de los deportistas, destacando sus principales puntos fuertes y trabajando sobre las características intermedias. Objetivo: Verificar los impactos del entrenamiento del core en el rendimiento de los atletas en carreras de larga distancia. Métodos: Este artículo contó con la participación de 18 corredores de media distancia como voluntarios para la investigación. Se examinó la condición física y el rendimiento deportivo de los atletas antes y después del entrenamiento. Los análisis estadísticos en los indicadores de los grupos experimental y de control se analizaron a partir de la prueba T. Resultados: Hubo diferencias significativas en la resistencia, la elasticidad de los músculos centrales, la fuerza central, la potencia explosiva y la estabilidad (P<0,05); los resultados mostraron que las diferencias en la estabilidad central entre las piernas izquierda y derecha del grupo experimental eran significativas (P<0,05). Conclusión: El ejercicio de fuerza del núcleo favorece más el ejercicio del grupo miocárdico en el ejercicio de media y larga distancia que el ejercicio de fuerza convencional. Los ejercicios de fuerza del core pueden compensar la falta de fuerza habitual. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Effects of physical training on speed and strength in long-distance runners / Efeitos do treinamento físico sobre a velocidade e a força de corredores de longa distância / Efectos del entrenamiento físico en la velocidad y la fuerza de los corredores de fondo

ABSTRACT Introduction Long-distance running is characterized by high speed and long-term endurance. It belongs to the group of long-duration high-speed sports dominated by long-term continuous muscular activity. Objective Explore the effect of physical training in long-distance running on improving speed and strength in athletes. Methods A total of 40 student-athletes at a university in a particular city were selected as research subjects. The experimental grouping was performed by lottery, with 20 in the control group and 20 in the experimental group. Results After the independent sample t-test, the results exhibited P=0.023, less than 0.05, showing that long-distance running physical training is very effective in improving speed and strength; the baseline performance of the experimental group was slightly lower than that of the control group, after training, the mean score of the students in the experimental group elevated compared with the control group. Conclusion Long-distance running physical training can significantly improve speed and strength. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução A corrida de longa distância é caracterizada por um alto grau de combinação de velocidade e resistência a longo prazo. Ela pertence ao grupo de esportes de alta velocidade de longa duração, dominado pela atividade muscular contínua de longo prazo. Objetivo Explorar o efeito do treinamento físico em corrida de longa distância sobre a melhoria da velocidade e da força em seus atletas. Métodos Um total de 40 estudantes de atletismo em uma universidade de uma determinada cidade foram selecionados como objetos de pesquisa, e o agrupamento experimental foi realizado por sorteio, com 20 no grupo de controle e 20 no grupo experimental. Resultados Após o teste t de amostra independente, os resultados exibiram P=0,023, menos de 0,05, mostrando que o treinamento físico de corrida de longa distância é muito eficaz para melhorar a velocidade e a força; o desempenho basal do grupo experimental foi ligeiramente inferior ao do grupo controle, após o treinamento, a pontuação média dos alunos do grupo experimental elevou-se em relação ao grupo controle. Conclusão O treinamento físico de corrida de longa distância pode melhorar significativamente a velocidade e a força. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción Las carreras de larga distancia se caracterizan por un alto grado de combinación de velocidad y resistencia a largo plazo. Pertenece al grupo de deportes de alta velocidad de larga duración en los que predomina la actividad muscular continua de larga duración. Objetivo Explorar el efecto del entrenamiento físico en carreras de fondo sobre la mejora de la velocidad y la fuerza en sus atletas. Métodos Se seleccionó como objeto de investigación a un total de 40 estudiantes de atletismo de una universidad de una ciudad determinada, y el agrupamiento experimental se realizó por sorteo, con 20 en el grupo de control y 20 en el grupo experimental. Resultados Tras la prueba t de muestras independientes, los resultados arrojaron un P=0,023, inferior a 0,05, lo que demuestra que el entrenamiento físico de carrera de larga distancia es muy eficaz para mejorar la velocidad y la fuerza; el rendimiento de partida del grupo experimental fue ligeramente inferior al del grupo de control; tras el entrenamiento, la puntuación media de los alumnos del grupo experimental se elevó en comparación con la del grupo de control. Conclusión El entrenamiento físico de carreras de larga distancia puede mejorar significativamente la velocidad y la fuerza. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Recommendations for marathon runners: on the application of recommender systems and machine learning to support recreational marathon runners.

Every year millions of people, from all walks of life, spend months training to run a traditional marathon. For some it is about becoming fit enough to complete the gruelling 26.2 mile (42.2 km) distance. For others, it is about improving their fitness, to achieve a new personal-best finish-time. In this paper, we argue that the complexities of training for a marathon, combined with the availability of real-time activity data, provide a unique and worthwhile opportunity for machine learning and for recommender systems techniques to support runners as they train, race, and recover. We present a number of case studies-a mix of original research plus some recent results-to highlight what can be achieved using the type of activity data that is routinely collected by the current generation of mobile fitness apps, smart watches, and wearable sensors.

Exercise-Induced Atrial Remodeling in Female Amateur Marathon Runners Assessed by Three-Dimensional and Speckle Tracking Echocardiography.

Endurance athletes have an increased risk of atrial remodeling and atrial arrhythmias. However, data regarding atrial adaptation to physical exercise in non-elite athletes are limited. Even less is known about atrial performance in women. We aimed to elucidate exercise-induced changes in atrial morphology and function in female amateur marathon runners using three-dimensional (3D) echocardiography and two-dimensional (2D) speckle tracking echocardiography (STE). The study group consisted of 27 female (40 ± 7 years) amateur athletes. Right (RA) and left atrial (LA) measures were assessed three times: 2-3 weeks before the marathon (stage 1), immediately after the run (stage 2), and 2 weeks after the competition (stage 3). Directly after the marathon, a remarkable RA dilatation, as assessed by RA maximal volume (RAVmax, 31.3 ± 6.8 vs. 35.0 ± 7.0 ml/m2; p = 0.008), with concomitant increase in RA contractile function [RA active emptying fraction (RA active EF), 27.7 ± 8.6 vs. 35.0 ± 12.1%; p = 0.014; RA peak atrial contraction strain (RA PACS) 13.8 ± 1.8 vs. 15.6 ± 2.5%; p = 0.016] was noticed. There were no significant changes in LA volumes between stages, while LA active EF (34.3 ± 6.4 vs. 39.4 ± 8.6%; p = 0.020), along with LA PACS (12.8 ± 2.1 vs. 14.9 ± 2.7%; p = 0.002), increased post race. After the race, an increase in right ventricular (RV) dimensions (RV end-diastolic volume index, 48.8 ± 11.0 vs. 60.0 ± 11.1 ml/m2; p = 0.001) and a decrease in RV function (RV ejection fraction, 54.9 ± 6.3 vs. 49.1 ± 6.3%; p = 0.006) were observed. The magnitude of post-race RV dilatation was correlated with peak RA longitudinal strain deterioration (r = -0.56, p = 0.032). The measured parameters did not differ between stages 1 and 3. In female amateur athletes, apart from RV enlargement and dysfunction, marathon running promotes transient biatrial remodeling, with more pronounced changes in the RA. Post-race RA dilatation and increment of the active contraction force of both atria are observed. However, RA reservoir function diminishes in those with post-race RV dilation.

Myocardial Bridging Leading to Cardiac Collapse in a Marathon Runner.

Myocardial bridging (MB) is a congenital coronary anomaly, which is defined as cardiac muscle overlying a portion of a coronary artery. Although traditionally considered benign in nature, increasing attention is being given to specific subsets of MB. Sports medicine recognizes MB as a cause of sudden death among young athletes. We present a case of a 30-year-old man who suddenly collapsed during a marathon running. Diagnostic workup with coronary computed tomography angiography revealed the presence of three simultaneous myocardial bridges in this patient, possibly explaining the exercise-induced syncope. The other diagnostic tests excluded seizures, cranioencephalic lesions, ionic or metabolic disturbances, acute coronary syndromes, cardiomyopathies, myocarditis, or conduction disturbances. Exertional syncope is a high-risk complaint in the marathon runner. In the context of intense physical activity, the increased sympathetic tone leading to tachycardia and increased myocardial contractility facilitates MB ischemia. In this illustrative case, the patient's syncope might probably be associated with an ischemia-induced arrhythmia secondary to MB and potentiated by dehydration in the context of prolonged stress (marathon running). In conclusion, this case highlights that MB may be associated with dangerous complications (myocardial ischemia and life-threatening ventricular arrhythmias), particularly during intense physical activity and in the presence of a long myocardial bridge.

Marathon Performance and Pacing in the Doha 2019 Women's IAAF World Championships: Extreme Heat, Suboptimal Pacing, and High Failure Rates.

PURPOSE: The Doha 2019 women's World Championship marathon took place in extreme hot (32 °C), humid conditions (74% relative humidity) culminating in unprecedented (41%) failure rates. We explored whether extreme heat or suboptimal pacing was responsible for diminished performance against a temperate "control" (London 2017: 19 °C, 59% relative humidity) and whether physical characteristics (eg, body surface area, estimated maximal oxygen uptake, habitual heat exposure) explained performance. METHOD: Five-kilometer-pace (km·h-1) data underwent repeated-measures analyses of hot (Doha, n = 40) versus temperate pacing and performance (London, n = 78) within and between marathon pacing (finisher quartiles normalized against personal best; n = 10 per group) and within hot marathon finishers versus nonfinishers (up to 10 km; normalized data). Possible predictors (multiple regression) of hot marathon pacing were explored. Tests to .05 alpha level, partial eta squared (ηp2) indicates effect size. RESULTS: Mean (SD) of Doha (14.82 [0.96] km·h-1) pace was slower (London: 15.74 [0.96] km·h-1; P = .00; ηp2=.500). In hot conditions, athletes finishing in positions 1 to 10 (group 1) started more conservatively (93.7% [2.1%] of personal best) than slower runners (groups 3 and 4; 96.6% [2.8%] of personal best; P < .05, ηp2=.303). Groups were not different at 15 km and then slowed immediately (groups 3 and 4) or after 20 km (group 2). Finishers and nonfinishers adopted similar pace up to 10 km (P > .05, ηp2 =.003). World ranking predicted (P = .00; r2 = .248) average pace in Doha. CONCLUSION: Extreme hot conditions reduced performance. Top 10 athletes adopted a conservative initial pace, whereas lower-placing athletes adopted a faster, aggressive start. Pacing alone does not explain high failure rates in nonfinishers. Athletes competing in the heat should initially pace conservatively to optimize performance.

Xanthine oxidoreductase activity in marathon runners: potential implications for marathon-induced acute kidney injury.

Excess activation of circulating xanthine oxidoreductase (XOR) may contribute to the pathogenesis of widespread remote organ injury, including kidney injury. The purpose of this study was to determine the acute impact of marathon running on plasma XOR activity and to examine whether plasma XOR activity is associated with marathon-induced elevations in biomarkers of acute kidney injury (AKI). Twenty-three young men (aged 20-25 yr) who participated in the 38th Tsukuba Marathon were included. Blood and urine samples were collected before, immediately, 2 h (only blood sample), and 24 h after a full marathon run. Plasma XOR activity was evaluated using a highly sensitive assay utilizing a combination of [13C2,15N2] xanthine and liquid chromatography-triple quadrupole mass spectrometry. The levels of several AKI biomarkers, such as serum creatinine and urinary liver-type fatty acid-binding protein (L-FABP) were measured in each participant. Marathon running caused a transient elevation in plasma XOR activity and levels of purine degradation products (hypoxanthine, xanthine, and uric acid) as well as serum creatinine, urinary albumin, and urinary L-FABP levels. Immediately after the marathon, individual relative changes in plasma XOR activity were independently correlated with corresponding changes in serum creatinine and urinary L-FABP levels. In addition, the magnitude of marathon-induced elevation in plasma XOR activity and levels of purine degradation products were higher in individuals who developed AKI. These findings collectively suggest that marathon running substantially influences the purine metabolism pathway including XOR activity. Moreover, activated circulating XOR can be partly associated with elevated biomarkers of AKI after marathon running.NEW & NOTEWORTHY This study is the first to show marathon running transiently increases plasma XOR activity and levels of purine degradation products (hypoxanthine, xanthine, and uric acid), and further to demonstrate that activated plasma XOR may contribute to marathon-induced elevations in biomarkers of AKI. These findings significantly extend our prior knowledge of the purine metabolic pathway and several AKI biomarkers under strenuous exercise conditions.

Analysis of Medical Interventions at the Start-Finish Medical Post of an International Running Event in Rural Thailand.

INTRODUCTION: Increasing numbers of marathon running events are taking place around the world. The difficulty encountered in the management of mass gatherings, especially running in marathons, is how emergency services can deliver treatment in a timely manner. Therefore, for this kind of situation, preparation is the key to success in terms of patient management. STUDY OBJECTIVE: The aim of this study was to describe the presentation of cases at a start-finish medical post in an international marathon race set in a rural area. METHODS: All medical record forms were collected from the start-finish medical post of the Khon Kaen International Marathon (KKIM) 2020. The race took place on January 26, 2020. The data were coded by two authors, and in the case of different codes, the final codes were determined by discussion. RESULTS: The total number of participants in this event was 16,489. Participants who used the start-finish medical post numbered 74 (44.8 people per 10,000). More than one-half of patients were male (41; 56.9%), while 31 (34.0%) were female. The age range of the casualties was from 17 to 88 years old. The rate of incidence for those who used this post was 44.8 per 10,000 participants. The greatest density of users was at 3.40 hours after the marathon had started. The common symptoms which were found consisted of 17 soft tissue injuries (23.0%), 15 instances of cramps (20.3%), and 11 musculoskeletal (MSK) injuries (14.9%). Almost all patients were discharged, and only two of the cases were actually admitted to the hospital. No statistical significance between males and females was found (OR = 0.81; 95% CI, 0.51-1.3). However, marathon and half-marathon runners had a higher risk of being casualties (OR = 3.49; 95% CI, 1.71-7.15 and OR = 3.51; 95% CI, 1.79-6.88). CONCLUSION: The injuries of most of the patients who used the medical post at a start-finish point were mild. Distances which are longer than 20km increase the risk for getting injured. However, a prospective study and multi-session interpretation is recommended.

Estimating the cost of training disruptions on marathon performance.

Completing a marathon usually requires at least 12-16 weeks of consistent training, but busy lifestyles, illness or injury, and motivational issues can all conspire to disrupt training. This study aims to investigate the frequency and performance cost of training disruptions, especially among recreational runners. Using more than 15 million activities, from 300,000 recreational runners who completed marathons during 2014-2017, we identified periods of varying durations up to 16 weeks before the marathon where runners experienced a complete cessation of training (so-called training disruptions). We identified runners who had completed multiple marathons including: (i) at least one disrupted marathon with a long training disruption of ≥ 7 days; and (ii) at least one undisrupted marathon with no training disruptions. Next, we calculated the performance cost of long training disruptions as the percentage difference between these disrupted and undisrupted marathon times, comparing the frequency and cost of training disruptions according to the sex, age, and ability of runner, and whether the disruptions occurred early or late in training. Over 50% of runners experienced short training disruptions up to and including 6 days, but longer disruptions were found to be increasingly less frequent among those who made it to race-day. Runners who experience longer training disruptions ( ≥ 7 days) suffer a finish-time cost of 5-8% compared to when the same runners experienced only short training disruptions (<7 days). While we found little difference (<5%) in the likelihood of disruptions-when comparing runners based on sex, age, ability, and the timing of a disruption-we did find significant differences in the the cost of disruptions (10-15%) among these groups. Two sample t -tests indicate that long training disruptions lead to a greater finish-time cost for males (5%) than females (3.5%). Faster runners also experience a greater finish-time cost (5.4%) than slower runners (2.6%). And, when disruptions occur late in training (close to race-day), they are associated with a greater finish-time cost (5.2%) than similar disruptions occurring earlier in training (4.4%). By parameterising and quantifying the cost of training disruptions, this work can help runners and coaches to better understand the relationship between training consistency and marathon performance. This has the potential to help them to better evaluate disruption risk during training and to plan for race-day more appropriately when disruptions do occur.

Marathon race performance increases the amount of particulate matter deposited in the respiratory system of runners: an incentive for "clean air marathon runs".

BACKGROUND: In the last decades, marathon running has become a popular form of physical activity among people around the world. It should be noticed that the main marathon races are performed in large cities, where air quality varies considerably. It is well established that breathing polluted air results in a number of harmful effects to the human body. However, there have been no studies to show the impact of marathon run performance on the amount of the deposition of varied fractions of airborne particulate matter (PM) in the respiratory tract of runners. This is why the present study sought to determine the impact of marathon run performance in the air of varying quality on the deposition of the PM1, PM2.5, PM10 in the respiratory tract in humans. METHODS: The PM1, PM2.5 and PM10 deposition was determined in an "average runner" (with marathon performance time 4 h: 30 min) and in an "elite marathon runner" (with marathon performance time 2 h: 00 min) at rest, and during a marathon race, based on own measurements of the PM content in the air and the size-resolved DF(d) profile concept. RESULTS: We have shown that breathing air containing 50 µg m-3 PM10 (a borderline value according to the 2006 WHO standard - still valid) at minute ventilation (VE) equal to 8 L min-1 when at rest, resulted in PM10deposition rate of approximately 9 µg h-1, but a marathon run of an average marathon runner with the VE = 62 L min-1 increased the deposition rate up to 45 µg h-1. In the elite runner, marathon run with the VE= 115 L min-1 increased PM10 deposition rate to 83 µg h-1. Interestingly, breathing the air containing 50 µg m-3of PM10 at the VE = 115 L min-1by the elite marathon runner during the race resulted in the same PM10deposition rate as the breathing highly polluted air containing as much as 466 µg m-3 of PM10 when at rest. Furthermore, the total PM10 deposition in the respiratory tract during a marathon race in average runners is about 22% greater (203 / 166 = 1.22) than in elite runners. According to our calculations, the concentration of PM10in the air during a marathon race that would allow one not to exceed the PM10 deposition rate of 9 µg h-1should be lower than 10 µg m-3 in the case of an average runner, and it should be lower than 5.5 µg m-3 in the case of an elite runner. CONCLUSIONS: We conclude that a marathon run drastically increases the rate of deposition of the airborne PM in the respiratory tract of the runners, as a consequence of the huge VE generated during the race. A decrease of the PM content in the air attenuates this rate. Based on our calculations, we postulate that the PM10 content in the air during a "clean air marathon run", involving elite marathon runners, should be below 5.5 µg m-3.