ECSS Paris 2023: OP-AP34
INTRODUCTION: Regular physical activity is known to benefit health, yet the physiological impact of extreme endurance exercise remains incompletely understood. This study examined the acute and short term effects of a prolonged ultratrail race on several biological systems by monitoring biomarkers related to cardiac stress, inflammation, renal function, and muscle damage, together with a targeted lipidomic analysis. The aim was to characterize the magnitude, time course, and reversibility of the body’s response to an exceptionally demanding endurance challenge. METHODS: Eighteen athletes competing in the Ultra Tour des Quatre Massifs (Grenoble, France), a 160 km ultratrail with major elevation gain (9500m D+), were enrolled. Blood samples were collected at four time points: pre race baseline (T1), immediately after finishing (T2), 48 hours post race (T3), and one week later (T4). The biomarker panel included high sensitivity Troponin T, NT proBNP, high sensitivity C reactive protein, creatine kinase MB, interleukin 6, myeloperoxidase, soluble ST2, nucleosomes, and catecholamines, providing insights into myocardial strain, systemic inflammation, skeletal muscle injury, and adrenergic activation. In parallel, a UPLC MS/MS method was developed to quantify selected lipid species, particularly ceramides, to assess their potential relevance as indicators of physiological strain or performance related stress. RESULTS: The extreme effort induced marked disturbances across multiple physiological domains. At race completion, substantial increases were observed in biomarkers reflecting myocardial load, muscle damage, inflammation, and renal stress, highlighting the acute multisystem burden of prolonged endurance exercise. Most biomarkers progressively returned toward baseline within one week, indicating that these alterations were largely transient and reversible in highly trained athletes. Regarding lipid metabolism, quantified ceramides did not provide meaningful added value for monitoring acute physiological stress or performance. However, their integration into a cardiovascular risk oriented score such as the CERT score may be useful for pre participation assessment or long term athlete monitoring. CONCLUSION: This study offers an integrated view of the acute multisystem responses triggered by an extreme ultratrail event and underscores the value of combining conventional biomarkers with targeted lipidomics to improve our understanding of endurance related physiological stress.
Read CV Caroline Le GoffECSS Paris 2023: OP-AP34
INTRODUCTION: Previous research in ultra-trail running found little to no relationship between exercise economy (EE) and ultramarathon performance, despite ultra-trail marathon performance taking place in the moderate intensity domain. However, much of this research used level treadmill protocols to determine EE which is not representative of competitive demands. As such, this study investigated the relationship between uphill running economy (RE) and 100 km trail running performance compared to relationships from a trail-specific V̇O2MAX test. METHODS: Twelve recreational to moderately trained male ultramarathon trail runners completed one submaximal and maximal laboratory treadmill test 13-19 days after finishing Ultra Trail Cape Town 100 km (UT100). Mean oxygen uptake (V̇O2), heart rate (HR), and RE were calculated during the submaximal test. V̇O2MAX and velocity at V̇O2MAX (vV̇O2MAX) were determined within maximal test. The submaximal test consisted of 25min continuous running at the following speeds and gradients; 5min warm-up (8km/h, 1%), 4min (7.7km/h, 5%), 4min (6.0km/h, 10%), 4min (7.2km/h, 10%), 4min (3.4km/h, 25%), 4min (4.0km/h, 25%). The maximal exercise test started at 10km/h (0.5%) after a 3min warm-up (8km/h, 0.5%) and increased continuously by 0.5km/h and 1% gradient every minute until volitional exhaustion. Relationships between UT100 finishing time (UT100time) and submaximal/maximal markers were assessed with Pearson correlations. Significance was accepted at P <.05. RESULTS: Moderate-to-strong correlations were observed between UT100 time and HR/%HRMAX (r = .59-.78) during all uphill gradients except when walking. Moderate-to-strong correlations were found between UT100time and V̇O2/%V̇O2MAX (r = .63-.84), and RE (r = .75-.81) during all uphill gradients. A moderate, non-significant, relationship was found between UT100time and V̇O2MAX while a strong correlation was found with vV̇O2MAX (r = -.85). CONCLUSION: Both uphill RE and vV̇O2MAX explained approximately 70% of variation in UT100 performance time. Improved representativeness of the submaximal uphill treadmill test might explain the stronger relationship with overall ultra-trail marathon performance than previously reported. Relative EE (%VO2MAX, %HRMAX) were more strongly associated with performance than absolute EE (VO2 ml/kg/min and ml/kg/km) demonstrating that early season maximal testing combined with regular uphill EE monitoring might represent a feasible model for season-long performance and fatigue monitoring. Preliminary findings suggested that uphill walking might present limited utility for prediction and monitoring purposes.
Read CV Simon de WaalECSS Paris 2023: OP-AP34
INTRODUCTION: Endurance performance is classically explained by V̇O2max, fractional utilization, and running economy. Durability, the resistance to fatigue-induced drifts, has emerged as a fourth dimension. While durability research has focused on physiological responses, RE is also strongly influenced by biomechanics. Prolonged running alters spatiotemporal variables (e.g., ground contact time, duty factor), potentially affecting performance. Trail running involves prolonged subthreshold running interspersed with high-intensity uphill efforts, yet the integrated physiological and biomechanical durability under controlled intensity and nutrition remains unclear. This study examined durability in trained trail runners during prolonged subthreshold running with repeated uphill time trials. METHODS: Twenty-three trained trail runners completed: (i) a graded test to determine lactate threshold (LT); (ii) a 12-min uphill time trial (CON); and (iii) a 180-min treadmill run at 85% of LT+0.5 mmol·L⁻¹ with three 12-min uphill time trials every 60 min. Gas exchange, heart rate, blood lactate, RPE, substrate oxidation, and gait variables (cadence, stride length, ground contact time [GCT], duty factor [DF], vertical oscillation, leg stiffness) were recorded. Carbohydrate intake was standardized (90 g·h⁻¹). Repeated-measures ANOVA assessed changes over time. RESULTS: During the 180-min run, V̇O2, RER, blood lactate and energy cost remained stable, while heart rate and RPE increased (p<0.001). Carbohydrate oxidation decreased and fat oxidation increased (p<0.001). GCT and DF increased early and then stabilized (p<0.05), cadence and stride length remained stable, vertical oscillation decreased slightly, and leg stiffness was unchanged. Uphill time-trial performance declined (~7%, p<0.001), with shorter stride length and higher GCT and DF, while V̇O2 and energy cost were preserved. CONCLUSION: Trained trail runners preserved metabolic cost during prolonged subthreshold running despite rising cardiovascular and perceptual strain, indicating physiological durability. Concurrent small shifts toward a more terrestrial gait (higher GCT and DF) suggest adaptive mechanical reorganization that supports energetic stability rather than biomechanical deterioration. Performance decrements in uphill time trials reflect accumulated fatigue with preserved metabolic efficiency. Durability in trail running is multidimensional, integrating physiological resilience with compensatory biomechanical adaptations.
Read CV Diego Jaen-CarrilloECSS Paris 2023: OP-AP34