PRE-SEASON training has started for Carlton and North Melbourne, with the clubs' younger players hitting the track – and the air – over the weekend.

The Blues' first- to fourth-year players returned to the club on Monday morning for the first of many training sessions in the lead up to next year's JLT Community Series.

Jacob Weitering, Harry McKay, Sam Petrevski-Seton, David Cuningham and Zac Fisher were among the Blues to start their 2018 campaign on Monday.

Meanwhile, the Kangaroos put their youngsters on a plane bound for the US on Friday.

A squad of 19 including Luke McDonald, Braydon Preuss, Trent Dumont, Jy Simpkin, Ryan Clarke, Kayne Turner and Jed Anderson have embarked on a two-week high altitude camp in Utah.

Coach Brad Scott and assistant coach Leigh Tudor have travelled with the players, along with their high performance manager Jona Segal, who was appointed by the club into his new position last week.

The young Roos can expect hikes, time trials, cross training, intervals, circuit and weights training to feature in their program, which will largely take place at the United States Ski & Snowboard Association facility in Deer Valley, Park City.

Many clubs have dabbled in high altitude training over the years, with Collingwood the biggest fans earlier this decade.

More recently, clubs have largely favoured heat over altitude and have scheduled their pre-season training camps at local destinations over summer.

But the Kangaroos are still believers in the benefits of training in the thin air found at high altitude, with a photo posted by Sam Durdin showing the chilly seven-degree conditions that have greeted the players in Deer Valley.

Look who's back!



The first group of players have arrived at the Club for day one of pre-season. #BoundByBlue pic.twitter.com/lIN4rJHmJ6 — Carlton FC (@CarltonFC) October 29, 2017

More clubs that didn't feature in the finals are expected to welcome back their younger players on Monday, November 6.

While finalists aren't due back until late November/early December, premiership Tiger Jack Riewoldt was spied running laps at Punt Road on Monday morning.

The JLT Community Series starts on Saturday, February 24.