Thanks Sam!
I agree with you,poles helps to keep balance and also to work the upper body,but as the uphill sprints are mainly to work the lower part, perhaps it would be better to work witwithout poles. In my experience I also find that it is easier for my legs to complete this kind of workouts with poles,and practically they become Z4 intervals rather than ME uphill sprints.I mean that then, my heart puts the limit and not the legs.
Thank you again!
Jaume