Introduction of the stirrup

[Peroni]

I'd imagine it would be similar for cavalry using spears against the enemy. Have the bracing power would do a lot keeping them mounted and they wouldn't have to use so much leg power.

The Roman light cavalry, I'm sure would not have attacked in a straight-on lancer type attack. They would more than likely be using the spears as a stabbing weapon. Therefore no leaning back and bracing yourself is required.

Heavy cavalry using a longer and sturdier lancea may have used the shock tactic of a full on charge but you would;

a. have no protection from your shield side

b. more likely lose the life of your mount!

It would make a lot more sense to attack with your shield side facing the enemy and use your spear accross the horses body to make stabbing attacks at the enemy. But you have to keep your shield side to the enemy.

A colleague of mine is an ex Royal Household Cavalryman, and he agrees.
The Household Cavalry are still trained in lance and sword.

Regards,