Kinematic and morphological traits and the probability of successful jumps of young Brazilian Sport Horses

In this study, logistic regression methodology has been used to identify and quantify the relationships between conformation and kinematic traits of young Brazilian Sport Horses on successful free jumps. The young horses (n=108) aged 22-25; 23-32 and 36-39 months old (age Classes I, II and III) recorded on five attempt jumps in each age Class over a vertical fence that was 0.60, 0.80 and 1.05 m high, respectively. Jumps were recorded by a 100 Hz camera and analyzed by the Simi Reality Motion Systems® software. Traits were selected from a previous principal components analysis and used as independent traits in a logistic regression model. The most important traits for each age Class, from 45 independent traits presented in this study were selected as follows: 17 traits were selected for Class I; 19 for Class II; and 18 traits for Class III. On the logistic regression model to the Class I only the neck angle in the stance horses was significant. The logistic regression models to the Class II and III presented kinematic related traits that were significant, such as: last stride length prior to jumping, take-off distance, forelimb height at jumping, vertical distance between humeroradial and metacarpophalangeal joint, head angle, neck angle, femorotibial angle and vertical distance between the femorotibial and metatarsophalangeal joints. In conclusion, to increase the probability of a young horse jumping successfully, it is necessary to reduce stride length prior to the fence and to increase take-off distance, thus resulting in a higher height of forelimb over the fence and also to present smaller values of head and neck angles when jumping.