Imagine the physical and mental challenge of a beep test, but with a demanding, high intensity from the start.

Well that’s what Sydney Swans players had to endure this week as they continue to put the finishing touches on the endurance side of pre-season with a gruelling ‘yo-yo’ test.

The shuttles are still 20 metres apart and there’s a break after each run, but the speed and agility required in the yo-yo test means it’s the ultimate challenge on the eve of practice matches.

Midfielder Kieren Jack was one of the outstanding performers in Monday’s test, setting a personal best.

Speaking to SwansTV, Jack said the test is designed to replicate the movement players experience during a match, even if it is a little skewed towards the midfielders.

“It’s certainly a bit of a dreaded test, along with the 3k-er, but it was quite rewarding,” Jack said.

“I suppose it advantages the smaller people, who are a bit lower to the ground. It’s a lot of stop-start, repeat efforts, which is pretty similar to how AFL footy is played at the moment. You’ve got to be able to get up and change direction quickly and repeat high intensity efforts over a long period of time.

“I set a PB myself, as did Ben McGlynn and few others, so it’s looking promising. We’re all fit and just ready to get into games.”

The news that Jack is putting in solid performances on the track at this stage of pre-season will be welcomed by all Swans fans after the 24-year old experienced a frustrating 2011 season hampered by an ankle injury.

After missing six games last season, Jack said he benefitted from getting away from the club aand returning with an increased vigour. Now he’s just waiting to put all his hard work on show when competitive matches begin, with next Friday’s intra-club match first on the agenda.  

“I needed a break,” he said. “I needed to rest the body up, it was a little bit battered at the end of last year.”

“I’ve really attacked this pre-season and came back in November with goals of completing each session and really trying to get back into my normal fitness - which I think I’ve been able to do. 

“I’m feeling good and the ankle’s feeling 100 per cent. I’m looking forward to getting into some games and getting some form on the board.”