Sam Underhill has modified his tackle technique as he hopes his new brain-over-brawn approach will help extend his career.

Underhill is set to start as England’s openside in the NatWest 6 Nations clash with Italy on Sunday week after missing almost two months because of the concussion he sustained against Australia last autumn.

It was his second episode of head trauma this season, resulting in an extended period of enforced rest during which he analysed his defensive technique, knowing that on both occasions he had been knocked out while making a tackle.

Stopping power and speed returning to his feet are the 21-year-old’s greatest assets, but now he must be more judicious in his use of force.

“You can’t let it play on your mind when you’re on the pitch, instead the biggest consideration for me has been how I prepare for contact,” said Underhill, speaking to promote Bath’s clash with Leicester at Twickenham on April 7.

“It’s a game of numbers. If you have a lot more contacts where your head is in a vulnerable position and they’re bigger contacts, then you’re more likely at some point to get it wrong.

“The biggest thing is to look at your tackle technique to make sure you’re in as comfortable a position as you can.

“You have to tackle efficiently because there’s no point trying to smash big guys all the time – it’s not the most efficient way to do it.

“Being a big hitter, just because you’re good at one type of tackle doesn’t mean you’re a good defender. Having better situational awareness will mean I’m more effective.

“You still want add an element of physicality to it, but it’s about being more comfortable with other forms of tackle. Not every tackle has to be a big hit.”

Underhill, an economics and politics student at Bath University who is two matches into his comeback, looks to club team-mate and veteran South Africa flanker Francois Louw for inspiration.

“It’s been a hard adjustment for me to make, but it’s a more sustainable approach,” Underhill said.

“If you watch Francois Louw for example, he can put in big hits but is also a very smart defender. His consistency shows that having variety in your arsenal is more sustainable.

“It’s an intelligent thing whereas a big hit is more of an emotional thing, which is hard to sustain over a season.

“It’s hard to always be the most aggressive player out there. But you can be a smart player consistently.”

* See Bath Rugby take on Leicester Tigers at Twickenham for The Clash, on Saturday 7th April. Tickets start from £5 for juniors, £15 for adults, available at www.bathrugby.com/theclash