ECSS Paris 2023: CP-AP18
INTRODUCTION: Marathon participation has increased markedly in recent years, with a growing proportion of novice runners. Marathon running imposes substantial physiological stress, which may differ according to training status and performance level. This study investigated marathon-induced changes in hematological and inflammatory biomarkers across performance groups and evaluated systemic and non-invasive markers of exercise-induced inflammation. METHODS: Sixty-two male and female runners participating in the Einstein Marathon 2024 (Ulm, Germany) were recruited; 52 completed post-race testing. Athletes were stratified by finish time into highly trained (G1), trained or developmental (G2), and recreationally active (G3). Blood and saliva samples were collected pre-race and post-race. Blood analyses included red blood cells, leukocytes, lactate dehydrogenase, haptoglobin, creatine kinase, interleukin-6, and kynurenine. Salivary C-reactive protein was assessed. Pre-race body composition was measured via bioimpedance. RESULTS: All groups demonstrated significant post-race increases in red blood cells, leukocytes, lactate dehydrogenase, creatine kinase, interleukin-6, and kynurenine, alongside decreased haptoglobin, indicating hemolysis, inflammation, and muscle damage. Creatine kinase differed between performance groups, with smaller increases in faster runners compared to slower groups. Other blood parameters showed no significant between-group differences. Salivary C-reactive protein did not change. Slower finishers tended to exhibit greater markers of cell damage and inflammation, though most group differences were not statistically conclusive. Age and body fat tended to be lower in faster runners, whereas marathon experience and years of training showed no clear association with performance. CONCLUSION: Marathon running elicits substantial inflammatory and muscle damage responses, largely independent of performance level. Nevertheless, observed trends toward greater physiological strain in slower runners indicate that prolonged exposure to exercise stress may influence health risk profiles. These findings highlight the importance of considering not only performance but also duration of effort when evaluating marathon related physiological load. Serum kynurenine showed potential as a responsive inflammation marker, whereas salivary C-reactive protein did not reflect exercise induced changes. Although limited by sample size, particularly in the fastest group, the study provides applied field data from a real world marathon setting. Future research incorporating larger cohorts, in-race sampling, and longitudinal recovery monitoring is warranted to further elucidate the interaction between fitness, exposure time, and systemic stress responses.
Read CV Lucas JohnECSS Paris 2023: CP-AP18
INTRODUCTION: Running performance in middle distance events results from the interaction of physiological, neuromuscular, psychological and somatic factors. From a physiological perspective, endurance performance has traditionally been evaluated using maximal oxygen uptake (VO2max) and the ability to sustain a high fraction of this capacity. In recent years, increasing attention has been given to running economy (RE), defined as the oxygen cost of running at a given submaximal speed, which represents a key determinant of endurance performance. Despite its importance, the contribution of neuromuscular factors to running economy in competitive runners remains insufficiently understood. Therefore, the aim of this study was to investigate the relationships between running economy and selected neuromuscular parameters in national-level middle-distance runners. METHODS: The research sample consisted of 11 Slovak national-level middle-distance runners (age 22.5 +/- 3.5 years; VO2max 67.9 +/- 3.8 ml kg-1 min-1). Running economy was assessed as oxygen uptake during a graded treadmill spiroergometric test combined with blood lactate measurements at running speeds of 12, 15, and 18 km/h, as well as at the maximal attained speed. Testing was performed using a Cosmed Quark CPET system (COSMED s.r.l., Albano Laziale, Italy) on an HP Cosmos Pulsar 3p treadmill (h/p/cosmos sports & medical GmbH, Nußdorf-Traunstein, Germany). Neuromuscular parameters included a drop jump test and maximal isometric ankle joint strength assessment, performed on dual force plates – ForceDecks (VALD Performance, Brisbane, Australia). RESULTS: The results demonstrated a significant negative correlation between maximal ankle joint strength and running economy across all submaximal running speeds (r = -0.62 to -0.73; p < 0.05), indicating that greater ankle strength was associated with a lower oxygen cost of running. Additionally, a significant positive relationship was observed between ground contact time and running economy (r = 0.68 to 0.82; p < 0.05), with longer contact times corresponding to poorer running economy. No significant association was found between the reactive strength index and running economy. CONCLUSION: These findings highlight the importance of maximal ankle joint strength and neuromuscular characteristics related to ground contact for running economy in competitive middle distance runners. The results support the inclusion of targeted strength training focusing on ankle plantar flexors and explosive lower-limb actions as part of endurance training programs.
Read CV Kristína ŠpitkováECSS Paris 2023: CP-AP18
INTRODUCTION: Heart rate variability (HRV) has emerged as a key metric for assessing autonomic regulation and training adaptation in endurance sports. While short-term HRV changes following acute exercise are well documented, longitudinal HRV dynamics in response to varying training loads in daily life remain underexplored. This study investigated whether nocturnal HRV reflects individual fatigue and recovery patterns in trained endurance athletes when analyzed in relation to weekly training load. METHODS: Ten healthy, trained endurance athletes (8 men: 39.4 +/- 9.4 years, 73.7 +/- 5.9 kg, 9.7 +/- 5.0 h weekly training, 47.0 +/- 3.2 bpm resting heart rate, 57.7 +/- 8.8 ml/min/kg VO2max; 2 women: 29.0 +/- 3.0 years, 71.4 +/- 7.5 kg, 7.9 +/- 5.2 h weekly training, 52.0 +/- 10.3 bpm resting heart rate, 45.9 +/- 5.9 ml/min/kg VO2max) were continuously monitored over 26 months using Garmin wearable devices. Nocturnal HRV was quantified using the natural logarithm of RMSSD (lnRMSSD), averaged over weekly intervals. Internal training load was assessed via weekly averaged Edwards TRIMP (eTRIMP) scores. To examine the association between eTRIMP and HRV, individual linear regressions were performed per participant. Additionally, a linear mixed-effects model (LMM), including random intercepts and random slopes for weekly eTRIMP, was fitted to account for repeated measures and interindividual differences in HRV responses to weekly training load at the group level. RESULTS: Significant associations between eTRIMP and lnRMSSD were observed in three of ten athletes (p < 0.05). One participant exhibited a negative association (Estimate = -0.245, p = 0.001), while two showed positive relationships (Estimate = 0.228, p = 0.046; Estimate = 0.314, p = 0.001). The remaining seven participants demonstrated no significant relationship (p > 0.05). At the group level, the LMM revealed no significant fixed effect of eTRIMP on HRV (Estimate = 0.044 per 1000 AU, 95% CI = -0.057 to 0.144, p = 0.392). However, the high conditional R2 (0.886) indicated pronounced interindividual differences in how weekly training load was associated with lnRMSSD. CONCLUSION: This 26-month longitudinal analysis revealed marked interindividual variability in nocturnal HRV responses to weekly training load in trained endurance athletes. While significant associations between eTRIMP and lnRMSSD were observed in a subset of individuals, no systematic relationship emerged at the group level. These findings suggest that weekly aggregated HRV metrics may capture general individual trends but may be insufficient to fully capture short-term autonomic responses to training stimuli. Consequently, HRV appears to be a highly individualized marker whose practical utility depends on athlete-specific interpretation and appropriate temporal resolution. Future research should focus on higher-resolution analyses and integrative approaches combining HRV with contextual and subjective measures to improve its utility for day-to-day training monitoring.
Read CV Maria OertelECSS Paris 2023: CP-AP18