Physiological, Performance, and Oxidative Stress Responses to High-Intensity Uphill and Downhill Interval Training

Area of Science:

• Exercise Physiology
• Sports Science
• Biochemistry

Background:

• Interval training is a popular method for improving aerobic performance.
• The effects of incline on training adaptations are not fully understood.
• Oxidative stress markers may be influenced by exercise intensity and duration.

Purpose of the Study:

• To investigate the impact of opposing running slopes on aerobic performance and redox determinants.
• To compare the effects of uphill versus downhill interval training.
• To assess changes in maximal oxygen uptake, running economy, and oxidative stress markers.

Main Methods:

• Fourteen volunteers completed 8 weeks of high-intensity interval training (HIIT) on either a +10% (uphill) or -10% (downhill) grade.
• Training involved ten 30-second runs at 90% of maximal aerobic speed (MAS) with a 1:2 work-to-rest ratio.
• Evaluated parameters included VO2max, MAS, running economy, time to exhaustion, blood lactate, and redox markers (TAC, PCs).

Main Results:

• VO2max remained unchanged in both groups.
• Maximal aerobic speed (MAS) increased in the downhill group.
• Uphill interval training led to increased blood lactate levels, suggesting enhanced tolerance, while downhill training showed improvements in running economy.

Conclusions:

• Both uphill and downhill interval training maintained VO2max levels.
• Uphill HIIT may enhance lactate tolerance, while downhill intermittent running may improve running economy.
• Divergent changes in metabolic, redox, and performance indicators were observed between the two training modalities.