Lunging is a very useful way of working a horse. It enables you to see how the horse is working and can also be useful in the event of the horse being unable to be ridden due to an injury, or if it needs to let off a bit of steam before it's sat on.
The trainer will stand holding a lunge line that is attached to a cavesson under the horses bridle. The horse works around the trainer on roughly a 20 meter circle. A series of clear voice commands will let the horse know what is required, upward transitions should be said with the voice going higher and downward transitions should be said with the voice going lower helping the horse to understand.
Transitions can include walk, trot and canter. A lunging session should last for 20 minutes due to the fact that lunging on a circle is quite strenuous for the horse. The trainer should wear a hard hat, gloves and sensible footwear and during lunging will carry a lunge whip which can be used to encourage the horse forwards if required. The side reins can be attached after the horse is warmed up and the length adjusted as necessary and care must be taken to work the horse evenly on both reins.
When changing the rein unclip the side reins and fasten to the D rings, walk the horse around to change the rein then re-clip the side reins on from the outside rein first then the inside rein. At the end of the session unclip the side reins and attach to the D rings, loosen the girth off one hole on both sides.