Effect of conditioning horses with an increasing number of high intensity intermittent exercise runs.

High intensive intermittent exercise (HIIE) is used to condition horses for racing. A study was done to examine the effect of short duration HIIE on the maximal speed (Speedmax) and v4 of 6 Thoroughbred race horses (v4: speed at which under defined conditions the blood lactate concentration [LA] reaches 4mmol/l). Horses were exercised during 8 weeks with one HIIE session per week on a dirt track. A HIIE session consisted of two runs of 100m each at near maximal speed separated by 10 minutes walking. After every second week during the conditioning period (CP) the number of runs was increased by one finishing with 5 runs per HIIE session in the last two weeks of CP. Prior to the CP, horses performed a submaximal standardized exercise test (SETsubmaximal) and a maximal speed test (SETspeedmax) to determine their v4 and Speedmax respectively. SETsubmaximal was conducted every 2 weeks until the end of CP and SETspeedmax after 4 weeks and 8 weeks of CP. The v4 of horses declined during the first 4 weeks of CP (p < 0.05), but returned to initial levels thereafter. Speedmax remained equal over time. The results indicate that further studies need to be done to find optimal combinations of exercises to simultaneously increase Speedmax and v4 of horses. [ABSTRACT FROM AUTHOR]