Former Leinster and Ireland prop Emmet Byrne delivered a rugby masterclass in forward play on Wednesday's OTB AM.
As we countdown to the Rugby World Cup in Japan later this year, Byrne's consideration of the Irish front-row sparked a discussion on the finer points of the scrum, and the particular duties of the opposing loose and tight-head props.
"It's an inherent built-in thing with props," he noted of the difficulties that come with trying to recreate a live scrum in a training environment, "they don't want to go backwards."
Nevertheless, it is a dynamic within rugby that requires an incredible degree of care and attention.
"Hand-position in the scrum is very relevant to advantageous leveraging within the scrum," he explained, "a tight-head prop needs to reduce the surface area of what the loose-head has to work with, but he also needs to maintain pressure downwards."
"Depending on the style of play you have, that pressure downwards involves closing the shoulder off.
"So, the right shoulder of the tight-head prop is going to be engaged with the loose-head prop and your objective is to close that shoulder.
"As soon as you open up the shoulder, you're in a very, very precarious position.
"The hips are connected, so when you open the shoulder the hips move, and that's your power. As soon as they open up, you're vulnerable to a drive."
Exploring the expectations of each, Byrne detailed the vital importance of handling in such situations, and the difference that a working knowledge of certain mixed-martial arts can have for a canny prop.
"A tight-head is doing his job if he's holding the scrum, while a loose-head is not doing his job unless he puts the tight-head under pressure.
"If a loose-head can get a very deep grip up on the back, and the hand is on the middle of his back and I can open up his elbow, the shoulder goes up and he's open.
"That's where the battle is going on. Jiu Jitsu is probably the best mixed-martial art for that.
"They focus on leverage more than absolute strength, and grips are hugely important. Anything that involves wrestling or grappling starts with grips.
"If you grab the arm of an opponent he can be pretty relaxed, but if you grab a fixed part of his body and are able to move it, you can push and pull him."
One of numerous aspects explored by Emmet Byrne throughout Wednesday's OTB AM, if you want to watch back the discussion in its entirety, click here.
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