Pretty sure the object on the right is an intensity tracker that measures bar speed etc. on different portions of the lift and would be connected to the fit bit style trackers they all have on their wrists. The idea of the resistance bands is to make it harder at the top of the movement, generally with a deadlift (or trap bar deadlift like Slips is doing here) the hardest portion of the movement is the initial movement from the floor which is where things can go to shit for your lower back. By using bands you can make it harder at the top of the movement without adding unnecessary pressure on your spine at the start of the movement. The boys jumping in the air is a bit of a pisstake because that's pretty light for a prop.