Sydney Swans co-captain Kieren Jack says no training session will be wasted as the build up to season 2016 intensifies.

Following a two week hiatus to celebrate Christmas and New Year holiday, pre-season recommenced for the entire playing list on Monday with a short and sharp 40-minute run at UNSW’s David Phillips Sports Field.

A majority of the squad were put through skill-based drills while a select number, including Isaac Heeney and Sam Reid, who are continuing on modified programs, ran laps of the pristinely kept sports grounds.

With the NAB Challenge less than seven weeks away, Jack highlighted the importance of not thinking too far ahead and remaining focused on squeezing everything out of the current pre-season campaign.

“You keep the year ahead in the back of your mind, but really about session on session for us,” Jack said.

“The sessions we do are in three-hour blocks so we can’t afford to waste any session – we’ve worked that out already.

“When we come here we prepare hard and we work hard at training. That’s our sole focus. If we can tick off our three main sessions, it’s a positive week and look forward from there.

“Games will be starting late February so that’s in the back of our minds but at the moment it’s building session on session.”

The 28-year-old skipper declared the group had come back “in really good nick” which was all thanks to the gruelling November-December training block.

With a strong fitness base, Jack says the workload will gradually increase over the next month all in readiness for the all-important practice matches.

“The program over the break is a freshen-up,” he added.

“There was a couple of running sessions in there but nothing strenuous as we’ve put a fair amount of stress on our bodies already.

“So we’re fit and firing and ready to ramp it up this January period.”

The Swans play Port Adelaide at Blacktown on February 20, in the first of three NAB Challenge matches in 2016.