Please read my post on Field Work (in the slider bar) in relation to today’s workout.
Pick up a heavy, obscure object (sandbag, weight plate, kettlebell(s), weight vest, dumbbell, another person) and hike around the back loop (1.2km).
The object that you choose should be too heavy/awkward to run with and it should be a hard slog to get around the course (think 20-30 minutes).
You may do this in pairs or as an individual. If done correctly, you should want to quit at some point (which of course you will overcome) and it is not for time. It is simply an experience that with the right attitude, you will get a lot out of.