Author(s): WIEWELHOVE, T., AMEY, I., EDEL, A., HOBEIN, E., Institution: IST UNIVERSITY OF APPLIED SCIENCES, Country: GERMANY, Abstract-ID: 1661

INTRODUCTION:
HYROX is a fitness competition that combines 8 km of running with eight endurance- or strength-endurance-based workout stations, each completed after 1 km of running. In recent years, HYROX has gained substantial popularity within the global sport and fitness community. The aim of this study was to analyse the metabolic profile of a HYROX Pro race.
METHODS:
Three male (38.0 ± 4.4 years, 183 ± 5 cm, 82.0 ± 7.3 kg) and three female (30.3 ± 4.2 years, 163 ± 7 cm, 59.2 ± 7.1 kg) international-level athletes participated in a simulated HYROX Pro race. Energetic costs, as well as the contributions of phosphagen (PCr), anaerobic glycolytic (GLY), and oxidative metabolism (OX), were calculated using the three-component model of energy system contribution (PCr–La–O₂). This approach was based on indirect calorimetry, incorporating oxygen consumption during exercise and post-exercise recovery, as well as net blood lactate concentrations (BLa). In addition, heart rate (HR), ratings of perceived exertion (RPE), and completion times for each running segment and workout station were recorded.
RESULTS:
The total completion time of the HYROX Pro race was 73 ± 3 min, with running accounting for 35 ± 1 min and workout stations for 31 ± 3 min. Additionally, total transition time between exercises amounted to 8 ± 1 min across all 15 transitions. The three-component model indicated an energy cost of 56 ± 5 kJ·kg⁻¹. The relative contributions of the metabolic pathways were 78.9 ± 0.4% from OX, 14.8 ± 1.5% from GLY, and 6.3 ± 1.2% from PCr metabolism. Mean BLa, HR, and RPE across the eight 1-km running segments were 7.8 ± 2.5 mmol·L⁻¹, 173 ± 7 beats·min⁻¹, and 17.4 ± 2.2 (6–20 Borg scale), respectively, while corresponding values during the eight workout stations were 8.7 ± 2.0 mmol·L⁻¹, 170 ± 7 beats·min⁻¹, and 17.2 ± 1.5. The lowest mean values during running were observed in the first running segment (2.86 ± 0.6 mmol·L⁻¹, 162 ± 10 beats·min⁻¹, and 13.0 ± 1.3), whereas the lowest values during the workout stations occurred during the ski ergometer (6.59 ± 1.5 mmol·L⁻¹, 167 ± 13 beats·min⁻¹, and 16.0 ± 1.4). The highest mean values were recorded during the fifth running segment (8.7 ± 1.9 mmol·L⁻¹, 176 ± 5 beats·min⁻¹, and 18.7 ± 1.0) and during the wall ball exercise (10.0 ± 2.3 mmol·L⁻¹, 173 ± 8 beats·min⁻¹, and 19.8 ± 0.4).
CONCLUSION:
Overall, the HYROX Pro race was performed at a high-intensity level with respect to metabolic, cardiovascular, and perceptual demands. Energy provision was predominantly derived from OX, followed by GLY and PCr metabolism. Considering the total duration of the event and the sustained exercise intensity, these findings suggest that successful performance in a HYROX Pro race requires both a high aerobic capacity (i.e., aerobic energy turnover rate influenced by maximal oxygen uptake) and a high anaerobic glycolytic capacity, reflecting resistance to metabolically induced fatigue, including an enhanced buffering capacity against hydrogen ion accumulation.