The study material was composed of 550 half-bred stallions (Polish thoroughbred halfbred, Wielkopolski, Malopolski, and others including mainly foreign breeds stallions) trained within frames of 100-day test. Examinations during the free jumps consisted in measuring the length of five following jumps over oxer of 100 cm width with variable height ranging from 100 to 120 cm. Then, jumping indices were calculated on the basis of withers height to achieve jumping efficiency parameters of required high values from a point of view of a jump description. During the observations, pulse was also recorded by means of telemetric devices. The following heart rates were determined: mean resting heart rate, heart rate during a jump, mean exercise heart rate, and mean restitute heart rate. It was used for calculating the Exercise Reaction Index (WRW) – during a jump and mean exercise value. Such achieved low-value cardiac work parameters that define a proper level of training progress were divided into those directly and indirectly associated with an exercise. Dependencies between traits were estimated on the basis of Pearson coefficients. It was found that analyzing the mean resting heart rate of young stallions may be useful when estimating their show-jumping predispositions as well as training progress. Values of cardiac work indicators during a jump gives a better view for a horse's stress level rather than real efforts to jump an obstacle. Therefore, the mean values of restitution heart rates should be taken into account to assess the exercise. Practical use of other cardiac work indices (e.g. WRW) may appear to be little precise. Breed characteristics of Wielkopolski breed and other foreign breeds should also be taken into account during the heart rate control to estimate the jumper's predispositions. In the case of the former, the control should be very thorough, while analyzing only randomly selected cardiac work parameter seems to be sufficient for the latter.