TRILK, J.L.*; LINDER, A.J.; GREENE, H.M.; ALBERGHINA, D.; WICKLER, S.J.: Aerobic Improvement in horses using a lactate-guided conditioning program

Although blood lactate concentrations [LA] are widely used in horse studies to assess athletic performance, they are seldom used as a guide in endurance conditioning programs. We wished to determine the magnitude and rate at which aerobic fitness increased using [LA] as the protocol guide. The speed at which [LA] reaches 2 mmol/l (V₂) was selected due to positive endurance effects seen in earlier studies with horses conditioned at V_1.5 and V_2.5 for 45 minutes. In a different study, six-weeks of training, V₂ was determined only once. We hypothesized that to continue the positive effect on V₄, speed must be adapted more frequently. Six horses performed an initial standard exercise test (SET: 6% incline, 0.5 m/s increments for 5 min). When venous [LA] measured &gt 4 mmol/l the SET was terminated. An exponential plot of [LA] vs. speed curve was used to calculate individual V₂. Horses were then conditioned three times a week (6% incline) for 45 minutes at the calculated V₂. Every seventh workday each horse performed a SET to calculate a new V₂. The protocol was repeated, ending with SET 4. Data were analyzed using RM-ANOVA. V₄ increased 17.2% from SET 1 to SET 4 (p=0.003; 5.8 &plusmn 0.7 m/s to 6.8 &plusmn 1.0 m/s). Therefore, to produce a continuous increase in V₂, it is necessary to test horses every 2-3 weeks and adjust the speed of exercise according to development. Further research can contrast other programs based on speeds guided by different [LA] to provide protocols that are more effective at improving endurance.