Much of the work has focused on hard, physical training with plenty of running drills aimed at building up the squad's stamina levels.
United were famed for their high-octane approach when David O'Leary's young guns were sweeping all before them on the way to the Champions League semi-final.
And Blackwell wants to see a similar tempo adopted when Leeds kick off the Premiership season against Newcastle in 11 days' time.
Blackwell told the Yorkshire Evening Post: "We want to get back to the things that Leeds were good at two years ago.
"That was a high tempo game and a good work rate.
"We think that's the best game to adopt to get the most out of the players that are here at the club.
"For whatever reason, the players were asked to play a slower tempo aimed at ball retention last season.
"Keeping the ball's all well and good, but I don't think that slower tempo has worked over the last 12 months or so.
"By the time we kick off the season we'll have had 22 days in which we've worked with the players," added Blackwell.
"That's long enough to make a start and get certain ideas into their heads, but you're not going to turn things round in 22 days.
"I've always thought that it takes about two years to turn a club around, so 22 days is just a drop in the ocean compared to that.
"But we've used every one of those days to the maximum and I'm pleased with the work the lads have put in. There's more to be done, but we've certainly made a start.
"For the first week the lads were back all we did was fitness work. I think it's vital to get that base so the lads have something to build on. Every player needs to be going into a game knowing that they've got the energy levels to see them through 90 minutes. They need to know that they can put as much effort into the last minute as they do in the first.
"Yesterday's session will be the last time that we really put the lads through the mixer in terms of running them hard. But they needed that and I think they'll already tell you they feel better for it.
"I've always been a firm believer in starting players' training this way. When I was first getting my coaching badges I asked the Human Performance Centre at Lilleshall how hard you should be pushing players to get them as fit as possible.
"They gave me an outline plan and, over the years, I've adapted it to suit what I think's best.
"I'd like to think it's worked in the past because if there's one thing that Neil Warnock's sides have always been noted for then it's their fitness.
"We don't want to give anything away," said Blackwell. "But we've already got our ideas about how we want certain things to work.
"There'll be a lot of set drills, working out things like corners and free-kicks, and we'll be focusing in on how each player will fit into the system we want to play."