Rhythmic movement of the flanks is an indicator of Thumps.
Synchronous Diaphramatic Flutter is a condition in which the horse’s flanks move in rhythm to the heart beat. This is not a dangerous condition, and resting the horse will help it subside. Thumps occurs after the horse undergoes stress. Some situations include after an event where the horse is worked hard–such a showjumping–or colic. Too much calcium in a horse’s diet can predispose it to Thumps. Prevent Thumps by keeping the horse hydrated and giving electrolytes as needed.
Keep you horse hydrated!