马立定不动，先不用刀，然后用刀练习。

Exercises without arms; exercises with arms, at a halt.

youdao

骑兵在马上立定，先不用刀，然后用刀，用和步下同样的口令，使骑兵进行如同步下所学的各种防卫动作。

The troopers being mounted, without arms, and then with arms, in any suitable extended formation at a halt, cause them to take the various guards they have learned dismounted, using the same commands.

youdao