The players were put through their paces during an array of events that measured upper-body and lower-body strength, as well as endurance -- all while being watched and graded by strength and conditioning coaches, scouts and general managers from each of the NHL's 30 teams.
It can be an intimidating experience, but the players said they did their best to stay focused on the grueling task at hand.
"I just blocked out the people," Barrie Colts center Alexander Burmistrov told NHL.com. "I don't care. I just want do my work. It was really hard."
"It was (weird) at first," added Calgary Hitmen defenseman Matt MacKenzie, who had the honor of being the first player to enter the testing circuit. "Once you kind of block everyone out, you get through the first couple (of stations) and then you just focus on the workout."
Medicine Hat Tigers forward Emerson Etem said all the watchful eyes actually pushed him to work harder.
"It definitely pushed my limits a lot more," he said. "It was great to have that. It definitely pushed me, gave me a lot more energy, made me want to strive to go longer. And it did exactly that."
After taking basic body measurements of height, weight, wing span and body fat at the start of the circuit, the players had their grip strength and push/pull strength measured. Then there were push-ups and sit-ups done to a pace measured by a metronome, followed by a 150-pound bench press. After that was the sit-and-reach test to measure flexibility, followed by a standing long jump, a four-kilogram seated ball toss, a jump-time mat and a vertical leap. The players then tried to stay on a balance board for one minute, and then went through a hexagonal jump pad test to measure quick feet and overall agility.
After that came the two most famously tortuous parts of the Combine fitness testing -- the Wingate Cycle Ergometer, which measures a player's power output during a 30-second burst, and the VO2 Max test, which measures a player's endurance.
"It was a little hard to sleep last night, getting geared up for this," said Plymouth Whalers center Tyler Seguin, NHL Central Scouting's No. 1-rated North American skater for this year's draft.
"Probably the hardest thing I've ever done in my life," added Prince George Cougars forward Brett Connolly, No. 3 on Central Scouting's list. "They kind of ease you into the bikes. The bikes were the toughest part. Once you hit the bikes it was game over. It was definitely hard and I'm happy it's over, for sure."
The Wingate test is geared to measure how much energy a player uses during an average NHL shift.
"If you've got somebody who is killing a penalty or someone who is trying to score a goal and you've got them on the ice for 30 seconds, what this tells us is what they have left at the end of 30 seconds," Dr. Norm Gledhill, Director of Human Performance Lab at York University, who supervises the fitness testing, told NHL.com.
"The Wingate is by far the hardest thing I've ever done," said Nobles School forward Kevin Hayes. "It's 30 seconds, and some people say it's 'only 30 seconds, it shouldn't be that bad,' but it's pretty bad."
"The Wingate is by far the hardest thing I've ever done. It's 30 seconds, and some people say it's 'only 30 seconds, it shouldn't be that bad,' but it's pretty bad."
-- Nobles School forward Kevin Haye
"If the anaerobic (Wingate) is a shift, the VO2 max is a game," said Gledhill. "If they go into overtime, what do they have left? The higher the aerobic fitness, the better fitness over the duration of the game."
The bike tests leave the players drenched in sweat and gasping for air; some even become physically ill.
"I did (the bike tests) for fun last summer," said Seguin, "and that was the last time I threw up. This was the most recent time. It was very exhausting."
Seguin wasn't the only player to have that happen, so he shouldn't feel too bad. At least he can take comfort in the fact that he went through it and survived. A number of players going on the second day poked their head into the testing room to watch the proceedings. Anyone who didn't it certain to hear about it from friends who went on Friday.
"I'm going to my hotel room and tell my roommate (Curtis Hamilton) the horror stories," MacKenzie said. "Get him scared for tomorrow."
Contact Adam Kimelman at email@example.com