Changes in Kinematics During Repeated Jumping

Abstract

Introduction Kinematic studies allow the assessment of variations in body position during jumping. This study evaluated changes in kinematic variables in horses during a jumping test. Methods Eight horses equipped with reflective skin markers were submitted to a jumping test consisting of 70 jumps in 4 series of 10, 15, 20 and 25 times each over a 1.10?m vertical obstacle. Six jumps per series were recorded; a heart rate of ≤ 90?bpm was the criterion to begin the next series. A 25?Hz calibrated camera was placed 10?m from the fence, and 2D images were analyzed. The variables were: overtracking at jumping; take-off and landing distances; jump length; distance between lowest point of the fore and hind limb and the fence; height of head, withers and croup in relation to the ground when passing the fence; and maximum withers height at jumping. Data were analysed with an ANOVA with a post-hoc Tukey test (P<0.05). Results There was a reduction in take-off distance (1.65?m to 1.46?m, P?=?0.03), landing distance (1.99?m to 1.71?m, P?=?0.001), jump length (4.51?m to 4.11?m, P?=?0.005), left forelimb distance height above the fence (9.4?cm to 5.1?cm, P?=?0.03) and maximum withers height at jumping (2.0?m to 1.95?m, P?=?0.001) from the first to the third series. Overtracking before jumping increased from 32?cm to 48?cm (P?=?0.003) and there was a reduction of right forelimb height above the fence from 7.3?cm to 2.9?cm (P?=?0.04), and of withers and croup height above the fence from 2.0?m to 1.95?m (P?=?0.001) and 1.93?m to 1.86?m (P<0.0001) respectively from the first to fourth session. Conclusions The increase in the number of jumps resulted in a decrease of take-off and landing distances, and in the distance between forelimb and fence and the withers and croup height, all indicating decreased jumping efficiency. Ethical Animal Research The research was approved by UFRRJ Ethics Committee on Animal Research: UFRRJ/ COMEP-UFRRJ: 263/2012. Sources of funding:?CNPq, CAPES and FAPERJ. Competing interests:?none.