Members of the Sydney Roosters first grade squad were on hand for their first official day on Wednesday to begin their preparations ahead of the 2019 NRL Telstra Premiership season.
Their first day started with various screening and testing to give the high performance staff the relevant information they needed about the squad ahead of a grueling pre-season.
To conclude their testing, the squad were taken to a jump mat and asked to jump with both legs, then again on each individual leg.
Athletic Development Coach Rubin Ruzicka was on hand to monitor the jump and to measure the stats of the individual jumper.
"They were doing a counter movement jump on a jump mat," Ruzicka explained.
"The jump mat measures the air time or vertical height of the player, which can determine where they're at in terms of speed and power.
"There are expected results based on what we know with historical data, but the idea of screening is to go in with no idea of what you're going to expect."
Though the jump mat provides the high performance staff with important information on the player, it's just one part of a process that has many parts.
"It's just one of the many components that get stacked on top of each other, but all the layers are important to the big picture.
"We want them to play footy, but the next layer below that we want them to jump well, and below that we're bulletproofing them so they can do that over and over again.
"It depends at which way you look at it, but from our perspective we want them to be able to go out there and play footy at the best of their physical ability."
Ruzicka explained that there are many different ways of determining the performance of players when it comes to explosive power and speed, but the jump mat was the best option at the present time.
The more information the staff have about a players physical ability, the better their chances are to produce a better outcome.
"With this information we believe that each player can get better individually, which gives us a better chance of improving as a group.
A players ability to jump is important, but it may not be everyone's strong suit.
"The jump is a good indicator of a player's explosive power.
"That being said, vertical ability isn't always someone's best asset.
"You may not be an incredible jumper, but you could make up for that in other ways.
"There's other physical attributes that come into play when you're out on the field."
The first week of pre-season concludes on Friday with the Yo-Yo test.