Author(s): DE WAAL, S., JACOBS, S., LAMBERTS, R., Institution: UNIVERSITY OF GLOUCESTERSHIRE, Country: UNITED KINGDOM, Abstract-ID: 249

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.