@Tlittle98 thanks for reaching out with your trekking pole/race question! Just a quick heads-up that even though you posted this question on the "Ask an REI Employee" board, you may also get suggestions from other members of the community. Please know that REI employees can be recognized by the roles of "REI Employee," "REI Community Moderator," and "REI Community Manager."
Trekking poles can certainly be very helpful on steep terrain, both on the uphill and downhill. If you are planning to use them in a specific race, the advice from @mathineer is great - ensure that the race allows them. Also, here is an article that provides lots of information on features of trekking poles and how to pick the right pair. You'll likely want to get an adjustable-length pole, and probably one with shock-absorption. External locks tend to be more reliable and easier to repair than internal locks. And the grip type is totally personal preference!