Do you mean the starting gate? It is like a loading stall. The groom leads the horse in, with the jockey mounted, then the groom closes the gate. There the horse waits for the starting gate to swing open. Things trainers hate are when a horse leans on the back or front gate. This can set the jockey of balance.
The starting gate.
4th
the boss
The horses are called from the paddock to the starting gate
wood helps
From the get-go or when both burst out of the starting gate, absolutely!!
The horse race starting gate (first used in Canada)
When a horse is scratched, the horses in the race do not physically shift towards the rail. The remaining horses maintain their positions in the starting gate and continue to run the race as usual.
My horse sprained her ankle, coming out of the gate.
Iron Horse
Horses, by their nature, are social animals. A racetrack with crowd noise, other horses, etc, can make a horse nervous. The other horse (known as an outrider pony or simply a pony) serves to keep the horse calm as he or she heads toward the gate.