[1] The lance rest was used to stop the rearward movement of the weapon upon impact.
[1] This allowed the wielder of the lance to created an unyielding platform from which to couch the weapon so that the rider's strong armour absorbed the shock of the impact, thus delivering a more solid blow to his target while lessening the chance of injury to himself.
The lance rest achieves this by spreading the impact of a blow through the breastplate to the torso of the wearer, thus redirecting the need for the hand, wrist, elbow, and shoulder of the rider to carry the force of blow through onto the target.
[2] Similarly, a vamplate in front of the gripping point on the lance would help stop it being forced back through the hand on impact.
The lance rest is typically bolted[3] to the side of the breastplate or secured through the use of metal tabs known as staples.