Long before the NRL became awash with the wrestle, former Brisbane Broncos back-rower Peter Ryan was among the best defensive players in rugby league.
After running up three premierships with the Broncos, Ryan then switched back to rugby, the code he had played as a schoolboy with distinction, and promptly won a Super 12 title with the Brumbies, earning himself a unique piece of sporting history by becoming the first man to win the cross-code double.
The sight of Ryan chopping a ball-carrier, driving through contact with his shoulder and legs, and then finishing up in the dominant position on top of his opponent, was common place. Later, again with the Brumbies and then the Reds, he began a career as a tackle coach, just as the focus on concussion in sport really started to take off.
So there are few better placed to comment on the ongoing tackle debate in rugby, as governing body World Rugby encourages Unions around the world to employ a further drop in tackle height to "below the sternum" at its lower levels.
World Rugby chief executive Alan Gilpin has also suggested it is inevitable that the elite level of the game will also one day follow suit.
"I'm all for it," Ryan told ESPN when asked about the lowering of tackle height, first at the community level of rugby.
"Nobody's perfect, we all know that. But if my players aren't making centre-of-gravity tackles, which is well below sternum height, the bottom third of the ball is what I want my players to aim for because that is roughly your belly button; if they do that there is no jeopardy for the player carrying the ball and there is no jeopardy for the player making the tackle.
"So I thoroughly agree with their idea, I just think the delivery of it hasn't been good."
The delivery of the proposed reduction in tackle height certainly has not been handled well around the globe.
The Rugby Football Union, which governs all levels of the game in England, employed almost a dictatorship approach in its plan to move to a "below-the-waist" limit in community rugby, having sought no consultation with key stakeholders. The uproar was immediate as a result.
While the RFU backtracked slightly to say it would consult with clubs, coaches and community administrators before making a final decision, the damage had already been done. And people soon began to ponder what that meant for the professional levels of the game, a question that Gilpin seemingly answered a few days later.
Ryan, as he says, agrees with the intention if not its delivery. While he is not actively coaching at the moment, he still keeps a close eye on rugby and rugby league, and is adamant the correct technique for both codes needs to be continually reinforced.
"To be honest rugby union has gone to a better level of tackle technique, simply through decent coaching over the last 10 years or so," Ryan told ESPN. "They always knew that [previously] rugby guys weren't really oriented to individual tackle, so in the last 10-15 years they have really upper their game in individual tackle technique.
"When I was employed at the Brumbies and then the Reds as a defence coach, I would spend large amounts of time educating players about how to defend. And when I say defend, I want really heavy contact but I also want the safest possible way to deliver any tackle technique.
"We're always after centre of gravity, which is roughly at the belly button. We all know that the softest part of the body is in the middle and if you hit that part with momentum you can then dominate the tackle area. So with that being the case, we want foot speed entering the tackle... and then off the back of that; have I got my eyes up looking at the target; do I know where that target is, and then being able to hit that target consistently."
World Rugby has made no secret of its desire to get players tackling lower since the last World Cup, instigating a head-contact framework that sets out how such incidents are to be officiated by referees.
Given the weekend's Six Nations clash between Ireland and England, which saw Freddie Steward red-carded for a hit on Hugo Keenan, many believe it remains an imperfect process that fails to account for different types of collisions, or "rugby incidents", or at least that the process still needs refining.
What there is no discussion about however is the fact that head-on-head, or arm/shoulder on head contact needs to be removed from the game as much as is possible, and encouraging the tackler to drop their bodyheight and target the midriff is the best way to do exactly that.
Regardless of the level, World Rugby research has revealed that ball carriers suffer 30% of all concussions while tacklers, who by design must put their heads in harm's way, experience 70%. Head to head collisions, meanwhile, are the most dangerous.
"I was coaching both Arnold twins, Rory and Richie, they're 210cms and both of those guys hit really well just 'under ball'," Ryan said of suggestions taller players, in particular, struggled to drop their tackle height.
"Regardless of how high the ball is, or whoever is carrying the ball, it is the target. So if you aim at the target and you have foot speed to get to the target, and you maintain eye contact with the target, you will hit it every time.
"The guys who aren't doing that, and this probably pertains more to rugby league more than rugby union, the guys are being taught how to wrestle, to go in with a catching motion, and the catching motion is being upright so then you can manipulate the ball-carrier.
"Whereas in rugby at the moment I think there is more top-of-shoulder contact and the guy going forward at the point of contact - because in rugby if you have the ball when you go to ground you must release it in one direction or another and if you don't it's a penalty - so what we're trying to do is to get the guy to ground as quickly as possible and then that reduces the time that support players have to do a cleanout, secure the next phase, or pick-and-go."
One argument against a further lowering of tackle heights is that while it may lead to a drop in shoulder/head-on-head contact and resulting concussions, it may increase the rate of the tackler suffering a concussion from a head on knee/hip contact.
But Ryan said there was a time and a place for legs tackles, and reinforced his belief that, for the most part, the tackler should be targeting the ball-carrier's belly button.
"There is a given time to make legs tackles," Ryan told ESPN. "So if I've got a guy running at me from directly in front, I am not going to go for his legs. But what happens a lot of time is that guys do do that, they go lower than the centre-of-gravity point, which is roughly the belly button; we aim there because it's the softest part of the body.
"But if you have some sort of fear of making a tackle in a dominant way, then quite often, especially with smaller guys more so than other guys, is that they will tend to drop lower and not be looking at the target, which then produces head contact with the hip or knee. It's not the guy who's running the ball, it's the guy who's put his head down and the person who is carrying the ball has only moved 10cms either way, which then makes head contact and then the tackler is unconscious."
Ryan is no fan of the recent red-card replacement law trials, which have been used mainly in various Super Rugby competitions and the Rugby Championship, as he says it is doing little to encourage teams to get their players tackling with the correct technique.
He would instead like to see players who are repeat offenders rubbed out for the same time period those on the receiving end of their transgressions are forced to sit on the sidelines.
As for players he thinks are among the most efficient and dominant tackles in Australian rugby, there are a handful who have caught the eye.
"I think the guy who hits the hardest is Lachie Swinton, I really rate that guy," Ryan said. "He still hits a little bit high; he is a bit tall, but I don't think that is an excuse. I still think he can hit really hard with below-ball, or around-ball contact.
"I said to the Arnold brothers that they can hit on-ball, but they said 'no, we want to hit below-ball' and I said that's awesome. I know he's had the odd card or two, but I do really rate him [Swinton].
"And Lenny Ikitau, he hits as hard as freight train that kid, and I reckon his technique is pretty good, too."
Rugby league, too, is aware that it must work harder to limit incidents of concussion. The NRL just last week extended the stand-down protocol from contact training or playing for any individual who had suffered a concussion to 11 days.
The NRL also outlawed the dangerous shoulder charge back in 2013, yet still players continue to get it wrong, as evidenced already this season by the lengthy bans handed to the Sharks' Wade Graham and Knights' Daniel Saifiti.
Those tackles were both one out, yet it has been the onset of the wrestle, which began in the early 2000s as a means of slowing the play-the-ball down, that has seen the game move to what is generally a higher bodyheight from the tackler, while the ball-carrier is now often met by three or even four defenders.
There are also clear differences between the collisions in rugby and rugby league given the different rules, most notably the 13-player game's 10-metre rule which creates far greater force through contract as opposed to rugby's offside line, which is the last foot of any breakdown.
Ryan says he has no problem with use of wrestling techniques in rugby league, but that they need to be intertwined with good body position and the right points of contact.
"I like the wrestle, but I want it to be in conjunction with good contact," he said. "Quite often [in the past] if you got good contact, under-ball contact - and this probably comes back to the NRL head honchos a bit - but if you made a decent tackle with good contact, referees more likely than not would give you more time to [slow down the play-the-ball] because it was a good tackle.
"Whereas now they've gone away from that, and now you've got three guys milling around the guys who's got the ball, they've stopped him through upper body contact, and that's where the head knocks happen. I saw Kalyn Ponga get knocked out on the weekend because he was too high trying to make a tackle, and I'm like 'my god, I could fix the guy in 10 minutes'.
"So rugby league needs to integrate the contact first and then into wrestle. They think they're doing that, but they're not."