St Kilda champion Nick Riewoldt says he found writing some chapters of his autobiography extremely tough to put into words, but therapeutic at the same time when recounting his late sister's tragic battle with aplastic anaemia. 

The six-time Trevor Barker Award winner retired at the end of this season after 17 decorated seasons and 335 games in red, white and black.

Maddie Riewoldt’s Vision launched Maddie’s Match in 2015 and it has now featured two games between the Saints and Richmond, which have raised more than $300,000 towards finding a cure for bone marrow failure.

While Riewoldt admits it was difficult to relive some of Maddie's battle, the process also helped him remember some of the better times he enjoyed with his sister.

“It was really difficult (to write about). Writing the book was quite helpful, with respects to that though,” Riewoldt told Melbourne radio station 3AW this week.

“It was painful at times reliving a lot of what we went through, particularly the last seven months in intensive care, which were just so horrible. Driving into the hospital the morning Maddie passed away and knowing we were driving in to face that.

“Even just reflecting on as human beings how we are able to function through those periods; it’s quite incredible what human beings are able to do when faced with that sort of adversity.

“Reflecting on a lot of the good times has been a real positive to come out of it as well.

“Only once I sat down with Peter Hanlon, my ghostwriter, and he prised a lot of those emotions out of me, I was able to reflect on the great memories I have of my little sister.”

Riewoldt, 35, launched his book ‘The things that make us’ earlier this week and said he didn’t want it to be another run of the mill football memoir, preferring to provide a relatable insight into the moments in time that has formed the person he has become.

“When I was first approached about going down the path of writing a book I really wanted to avoid writing another cookie-cutter football book,” he said.

“I felt like that had been done a lot of times before and to be honest, my story wasn’t all that compelling; there were players who have had won more premierships, had more success on the field and maybe more interesting football careers.

“If I did do it, I wanted to do something that was relatable and that people found interesting. The way I was able to do that was to show some vulnerability but to also open up and talk about the rest of my life and some of the events, relationships and circumstances that have conspired to make me who I am.”