Over the last 6 weeks I've increased my conditioning work in preparation for the Spartan Sprint in early June. It's a shorter version of the Spartan Race (a mud run/obstacle course like Tough Mudder, Warrior Dash etc) so it's only 5k plus 13 obstacles (about half of the full race). I've been doing LISS twice/week with a few extra sessions of HIIT thrown in a few times. Now that I'm about 2 weeks out from the race I thought it might be beneficial to move toward some more intense conditioning. My thinking is that while LISS is good it's at a comfortable pace and when I do the race I'll be above the LISS heart rate range. Would it make sense to do some threshold or HISS training for the next two weeks since that will be more similar to the actual race conditions?