Two days after New Zealand heavyweight Joseph Parker fights American Jason Bergman here in Apia on Saturday, trainer Kevin Barry will undergo surgery on two hernias, and on the evidence of today's open training session with his man it's easy to see why.
Parker is in the tapering phase of his preparation which meant he trained with Barry inside the ring at the Faleata sports complex gymnasium where the bout will be held about at about 50 per cent of the power he hopes to use against 31-year-old Bergman.
But still, the speed, precision and impact that his gloves made on Barry's pads and especially the body protector his trainer wore around his midriff made those gathered on the ring apron at this open session wince with every blow. He will wear harder and lighter gloves for the fight.
The 24-year-old Parker, who is looking increasingly muscular around the shoulders, has been working on his portfolio of body shots recently, and in particular the liver punch, which Barry believes southpaw Berger could be vulnerable to. To that end, Parker worked on his left hook to Barry's right side.
After every round the 50 or so watching, some of whom will be fighting on the undercard, broke into applause.
Barry later revealed that Parker has broken three body protectors, made by the well-regarded "Winning" brand. The devices, which cost about $700 each, are constructed of padding over fibreglass, a hard substance not able to stand up to Parker's power.
"Winning make the No1 body protector in the world and I used it for years training [David] Tua and other fighters," Barry said. "Tua broke a few and Joe has broken about three of them on me. Body punching is a big part of our game and he's been knocking me around on my body a lot over the last couple of years.
"He throws a very, very menacing body punch now and that's something that makes me happy as a coach because I think that's going to be the difference when we fight the elite fighters. Not too many of them go to the body and in a 12-round fight you have to.
"I have very strong abs and have done for many years [but] I feel all the shots. Sometimes I will get home at night and I have cramps and soreness, especially when he throws the liver shot... because it's just brutal when he hits you in that area."
The battering is taking its toll but Barry isn't complaining - he knows he could be taking Parker to a world title shot in about 12 months.
Parker said: "I don't want to hurt him or anything, but Kev reinforces how important it is to practice what you're going to do in the ring. I feel sorry for his stomach and I don't know if I'm the cause of his hernias - I blame [training partner] Izu [Ugonoh] for part of it as well."
Parker also displayed an uncanny ability to throw a jab which stopped millimetres short of Barry's chin, something which the south Aucklander later said he had practised on his sister, Elizabeth, who is a year older, when they were growing up.
"It's something that you work on - just like skill and technique and power," Parker said. "I would ask [Elizabeth] to stand still and keeping punching like this (throws punches with both hands). She had this full trust in me and we would go, 'mum, dad, look at this' and I would punch really close to her chin."
Barry was less trusting at first but now recognises Parker's ability to find his range.
"I could never have trusted him to have the ability to do that but now he knows where his punches are going. He can measure the distance."