NAKIA Cockatoo has one aim for the pre-season; to make his troublesome right hamstring "bulletproof" after a season wrecked by repeated strains. 

After three bouts of rehabilitation in 2017, the 21-year-old believes he's learned some valuable lessons about how his body – and mainly his hamstrings – operate. 

And, with a strong focus on core and hip flexor strengthening exercises while maintaining a careful balance between hard training and not overdoing it, the speedster believes he's in a good position for a breakout 2018.

"I've been keeping up with the gym sessions and the hammies are feeling really good at the moment," Cockatoo told AFL.com.au. 

"I'm trying to tick those things over to try and get them bulletproof for the season.

"I've been feeling good running, I haven't had any problems throughout the two weeks we've been back.

"We've tested it out, I've been getting up to 90 per cent speed and I've been pretty happy with how things have been going so far."

The first of Cockatoo's three injuries happened in round nine against the Western Bulldogs and cost him one game, before a second in round 13 against West Coast. 

In the Eagles' game, he didn't make it to quarter-time before he suffered the injury. 

After that, he took five weeks off before facing Carlton in round 19, but came off in the fourth quarter with after another strain; this time, sustained as he kicked a goal.  

From there, he knew things had to change in his approach to rehabilitation. 

"I think that's how I got to the last game [the preliminary final against Adelaide]; you've got to stay on top of things, so I guess I did learn a fair bit about myself with being resilient and consistent with what I do," he said. 

"It was more knowing when things are sore or tighter, or what I need to work on whether it be treatment or more time in the gym, and a couple of the exercises as well helped it heal better.

"The main one was probably the different treatment I had, it was more not just around the hamstring, but around the whole of the hips; the hip flexors and all that."

It's well known Hawthorn star Cyril Rioli had to reinvent his running style to combat a spate of hamstring issues back in 2011. 

But, it's not as simple for the equally as explosive Cockatoo. There's nothing technically wrong with the way he runs; instead, it's about a disconnect between how much power he can generate with his speed and how the rest of his body copes with it.  

"My legs were a lot stronger than my upper body," he said. 

"Things didn't really jell like the way I wanted them to, and it turned into hamstring injuries in the one spot.

"I think I just wasn't used to my body yet."

Hamstrings aside, it hasn't been a clear run for the No.10 draft pick from 2014.

He played 11 AFL games in his debut season with an adductor injury causing issues mid-year, before a knee complaint (and a two-game suspension) kept him to 10 in 2016. 

Then, his third season hit a speed bump in round one this year when he hurt his thumb and needed surgery; an injury that cost him three games. 

All the injuries have eerily been on his right side, which he regards as an amusing fact, and none of them serious but more "silly, annoying things". 

Since he joined the club, he's put on eight kilos of size, and most notably, nearly three kilos of "lean muscle" this pre-season alone. 

He's desperate to make sure he doesn't have another injury-affected season after signing a two-year contract extension this year. 

"I want to really show what I've got, because I don't feel like I've been really been able to show my skills out on the field because I've been injured so much," he said. 

"It would amazing if I could just knuckle down and get a full pre-season and then a full season, it's one of the goals I'm aiming for.

"I've just got to make sure I can get the