Maximal accumulated oxygen deficit in thoroughbred horses

Area of Science:

• Equine Exercise Physiology
• Sports Science
• Animal Physiology

Background:

• Thoroughbred horses possess exceptional aerobic capacity, significantly exceeding that of elite human athletes.
• Accurate measurement of aerobic capacity in horses is established, but their anaerobic capacity remains unquantified.
• Human athletes' anaerobic capacity is assessed using maximal accumulated oxygen deficit (MAOD).

Purpose of the Study:

• To determine if maximal accumulated oxygen deficit (MAOD) can be measured in Thoroughbred horses.
• To establish MAOD as a viable estimate of anaerobic capacity in horses, analogous to its use in human athletes.

Main Methods:

• Six fit Thoroughbred horses underwent treadmill testing at a 10% incline.
• Oxygen uptake (VO2) was measured during submaximal exercise to determine maximal VO2.
• Horses performed tests at 105%, 115%, and 125% of their maximal VO2, with rapid acceleration to high speeds.
• MAOD was calculated by comparing oxygen demand to measured VO2 during high-intensity exercise.

Main Results:

• Mean MAOD values were consistent across intensities (31 ± 2, 30 ± 1, and 32 ± 2 ml O2 eq/kg at 105%, 115%, and 125% VO2max, respectively).
• Mean run times decreased with increasing intensity (165s, 98s, and 57s).
• No significant correlation was found between MAOD and maximal VO2.

Conclusions:

• Maximal accumulated oxygen deficit (MAOD) is a measurable parameter in Thoroughbred horses.
• MAOD provides a reliable estimate of anaerobic capacity in equine athletes.
• This methodology offers a new avenue for assessing anaerobic performance in horses.