How do I use groundwork to prepare a spooky horse for riding?

A spooky horse ridden before its anxiety has been addressed on the ground is a horse that puts the rider at unnecessary risk, because whatever the horse cannot manage emotionally on the ground will be amplified under saddle. Groundwork before riding on a spooky day serves two purposes: it assesses where the horse is mentally and burns off enough nervous energy that the horse can think more clearly once you mount. Begin each session by checking the horse's responses on the ground — does it yield, halt, and back with normal lightness, or is everything tight and resistant? A horse that cannot yield its hindquarters softly when asked on the ground is telling you its brain is not fully available. Work through that on the ground before getting on. Long-lining or longing at a trot and canter until the horse settles — head dropping, back swinging, rhythm becoming consistent — is a reliable way to move from anxious to thinking. The transition from high-headed, irregular, tense movement to a lower, rhythmic, relaxed trot is the visual signal that the horse has crossed into a more manageable mental state. Desensitization to specific triggers before mounting is also practical: if there is a tarp in the corner, address it from the ground first. If a flag is blowing, let the horse investigate it on a long lead. Arriving in the saddle on a horse that has already worked through its concerns about the environment saves the ride and builds the horse's trust that work solves problems rather than creating them.