THERE is a very fine line in elite sport when it comes to how fired-up athletes should be.

Too little, and the performance will be lackluster. Too much, and mindlessness and over-eagerness can take over.

It is a line Gregor Townsend knows only too well having been on both sides of it during his time as a player, most notably when he faced England.

“I used to get too pumped up,” recalled Townsend.

“I was brought up watching 1990 (Scotland’s Grand Slam victory) and at the same time, I was playing for Scotland under-18s against England under-18s and I was far too pumped up.

“I think that carried on a little bit throughout my career. I remember going to Twickenham and being far too motivated for the game.”

And as a coach, he has presided over sides who have too got it exactly right, as well as crossing the line into the red zone.

Scotland’s Six Nations fixture against England last year had both.

England raced into a 31-0 lead against an under-performing Scotland at Twickenham before the away side were imperious in coming back to take the lead 38-31 only for England to snatch a late draw.

And while it made for thrilling viewing, Townsend does not want quite the same level of excitement from his players this weekend.

Tomorrow, England will visit Murrayfield as the Scots aim to win the Calcutta Cup for the third consecutive year. If Townsend’s men manage to complete the hat-trick, it will be the first time in almost 50 years they have achieved such a feat but to paraphrase the head coach, his side must ensure they keep the heid.

“The first action of that game (against England last year), Sam Johnson flew up wanting to make a big hit and said afterwards that he was just so pumped up to tackle someone,” said Townsend.

“But you can’t do that against top teams. You have to stay within the system, you have to transfer what you’ve worked on during the week onto the pitch.

“It’s important our players are ready for the physical battle but are in control. In control of their discipline first of all but if they have that fire inside of them and they put it into tackles then great, that’s what you want to see.”

Townsend has made just one change to the side who were defeated by Ireland a week ago, with Magnus Bradbury coming in at number eight in place of Nick Haining, who drops to the bench.

Bradbury may not be a regular number eight - he usually plays blindside flanker for Edinburgh - but he has some extremely fond memories to draw upon. Last year, at Twickenham, the 24-year-old scored one of Scotland’s trys, the first time a Scottish number eight had crossed the try line for nine years. So Townsend is confident he can handle himself tomorrow.

“Magnus has played very well for us in the World Cup and at number eight against England at Twickenham.

“He’s worked more with the two back-row colleagues in Jamie (Ritchie) and Hamish (Watson)," said the head coach.

“We trained with Magnus at number eight for about four or five days leading up to the Ireland game.”

England’s players have added some spice to the game with Lewis Ludlow’s comments that “they hate us and we hate them”, before adding “it’s going to be a war and it’s something we’re excited for and we’ll be ready for.”

Townsend was careful not to get into quite as hyperbolic language as some of the English side, but he is in no doubt as to what this fixture means for both the Scotland players and the fans.

“I think both sets of players will be motivated, we always are because it is our biggest rival,” he said.

“Whether it is population number or more success historically, we know that it is rival we have to play our best against in order to have a chance, and it is a game which means so much to our people.

“I remember back in 2000 when we had lost four games in a row in the Six Nations and we won the last game against England, you almost felt the supporters believed we had won four games in a row because the joy they get seeing their team win against England stays with team for days and weeks.”

Meanwhile, there are no further developments in the Finn Russell saga, which saw the fly-half leave the squad after breaching team protocols last month. There have been discussions between the head coach and the Racing 92 player but no sign of a return for Russell. However, Townsend remains open to him re-joining the squad during this tournament, but only on the condition he adheres to the same rules that apply to everyone else.

“I spoke to Finn on Sunday night to let him know that we wouldn’t be making any changes to our squad. I will reassess things after we get through this weekend,” said Townsend.

“Finn will be playing and there will be dialogue during that week, or the weekend after he plays and we’ll see where we are.

“Whoever comes into our squad has to be aligned to what the team stands for and the standards of that team. And I’m talking about anybody, not one person in particular. That’s going to be the deal for someone who comes in.”