MADISON, Wis. -- University of Wisconsin-Madison ROTC Air Force cadets are undergoing intense training this weekend, and they got a surprise Friday.

The second annual Commandant's Challenge started with a surprise landing of two Blackhawk helicopters, which flew about 20 cadets to Volk Field at Camp Douglas to set up a base camp for the other half of their class. The rest of the class was set to arrive on buses later Friday night.

"The training is meant to push ROTC Air Force cadets to the extremes," said Capt. Jose Surita, Air Force ROTC commander. "It gives us the opportunity to watch them and asses their leadership."

The events are a part of the Commandant's Challenge, which aims to push trainees and provide them with a serious physical and mental challenge.