Alma 56:51

for Antipus had fallen by the sword, and many of his leaders, because of their weariness, which was occasioned by the speed of their march; therefore the men of Antipus being confused, because of the fall of their leaders, began to give way before the Lamanites.

Antipus had been killed. Many of his leaders died too because they were tired from marching so fast. The men of Antipus got confused when their leaders died. They started to lose.

“Antipus had been killed, along with many of his officers. Their exhaustion from the hard march had cost them. When Antipus and his leaders fell, his men became disoriented and started falling back before the Lamanites.”