One of the crucial elements in David Tua's comeback is a man who, perhaps more than any other, holds the key to the boxer's mental and physical strength - trainer Lee Parore.
Long recognised as one of New Zealand's premier fitness and wellbeing experts, Parore has trained sportsmen such as Jonah Lomu, Zinzan Brooke, the Blues, Sean Fitzpatrick, America's Cup yachtsmen, has advised the Sultan of Brunei and, in a former cycle, David Tua.
Parore it was who produced a sculpted Tua for that memorable showdown with Shane Cameron in 2009 - the start of Tua's last quest for a world title. It wasn't to be - Tua then had lacklustre fights against Friday Ahunanya before drawing with Monte Barrett (many thought Tua lost that bout), an unconvincing points decision over Demetrice King and then what appeared a career-ending loss to Barrett in their rematch in 2011.
Parore is the missing link in that chain of events. He was not in Tua's corner for any of those fights after Cameron.
Many think that was a telling factor. Tua carried a shoulder injury caused in training into the first Barrett fight - where he struggled to hurt the taller boxer and was himself knocked down for the first time in his career.
Knowledgeable boxing observers believe Tua lost the second Barrett fight because he had cut the services of promoter Cedric Kushner and Parore.
Tua had become his own promoter and manager, dealing directly with Sky TV. He decided to let Parore go to cut overheads.
Instead of a taskmaster like Parore being "the boss", Tua was the boss - which was why Tua appeared for the second Barrett fight at least 5kg overweight.
"In past times, if David didn't train right, he got an earful," one boxing source said. "But because he was the boss and was calling the shots, no one argued with him; no one had the tough conversations; they all went along with him, happy just to be working with Tua. Also, when a fighter manages his own affairs, he gets drawn into the commercial side and neglects what he should be focusing on: training and sparring."
Now Parore is back and has been working with Tua for at least six months. Tua has also cast his lot back with a promoter, Duco, and is apparently in a good space.
Parore said: "We are tracking well. The most important thing is to get him to the church on time, so to speak. We had to start slowly and make sure we understood his overall health.
"All the weight he had put on was a symptom and we had to look into what was causing that; we had to get his diet together and we are still fine-tuning that. David has dropped 20kg, is training really well, twice a day on many days and doing some hard work, handling a real workload and then coming back the next day and doing it again.
"This will be a tough fight; this is a tough guy he is taking on. He will try and bully us and we have to have the tools to bully him back and you only get that by being in the best possible shape."
Power is key to Tua's game and there have been doubts he retained the power of his early years in his most recent fights. However, contrary to most thinking, weight loss does not mean power is diminished - quite the opposite, if the correct steps are taken.
Parore presided over a 25kg weight loss before Tua met Cameron and has taken a holistic approach: "We really needed to gauge his overall health, so we took full blood tests to look at him metabolically - his heart, his lungs, his liver, his hormones, thyroid, his blood glucose and so on. It wasn't just the weight; we had to gauge accurately where he was at in terms of his health so we could address how big he was and map a course back for him.
"His health has turned a big corner now - and a healthy David Tua means we can actively start to get more out of him and, for David, that means power."
Another weight has been lifted from Tua's shoulders with his signing with Duco. If anyone doubts that a boxer can drop in performance when being a promoter as well as a boxer, the story of former world heavyweight champion Larry Holmes is worth telling. He decided to run his own affairs after his contract with famed and infamous promoter Don King ran out.
Holmes promoted his next fight but found that he had earned the smallest amount of any of his title defences. In addition, he was exhausted as he had kept to his training regime but had to work through the night to do the deals and all the 'hard yards' of promotional work.