The conversation turns to life as a professional tennis player in the 1990s and Mike Bryan brings up Andre Agassi.

Agassi was world No 1 by April 1995 and had won five of his eventual eight grand slam titles by the turn of the century. But unlike the rigorous fitness regimes players of today dedicate their lives to, Agassi took a more relaxed approach to life on the Tour.

'You would go to the court, have a burger before matches and if you had an injury maybe just slap some ice on it,' Bryan tells Sportsmail.

Mike and Bob Bryan spoke to Sportsmail about how bio-hacking has kept them strong at 41

'You would pop a couple of anti-inflammatories and you would play a match before hopping in the car without cooling down, or doing foam rolls, or going in an ice bath.

'Everyone is now ticking all of the boxes and they have really smart guys around them. Back in the day it was just a different mentality.

'I don't think Andre Agassi stretched a day in his life!'

A fast-food lifestyle no longer cuts it for those wanting to stay at the top of the sport of tennis. You only need to look at the two recent Wimbledon men's and women's singles finals to see how a shift in mentality off the court is allowing the veterans to continue setting the pace.

Thirty-seven-year-old pair Roger Federer and Serena Williams were there, slugging it out with their bodies in peak physical condition. Still.

For Mike and Bob Bryan changes off the court have them feeling 'stronger than ever' at the age of 41. Retirement plans continue to be shelved with hopes of adding to their hundreds of career titles.

Both players were forced into changing their mentality at different stages in their careers. Mike at the age of 25. Bob, more recently, as he was wheeled into an operating theatre following a nasty injury in Madrid.

The American twins have long been troubled with issues in their hips and Mike Bryan revealed that news of arthritis symptoms at the age of 25 caught him totally off guard.

They are the most successful doubles team ever and are still at the top of their game now

Serena Williams (L) and Roger Federer (R) - both 37 - are other stars rolling back the years

His plan was then to play for at least one more year. Reaching 30 seemed like an unrealistic target. He 'went down the rabbit hole' for research, trying to find ways to prolong his body and that is when he came across the work of biology pioneer Dave Asprey.

Known in science circles as a 'lifestyle guru', Asprey launched the 'Bulletproof' diet with all its varied supplements in a bit to 'hack' an individual's health and improve energy and mobility - two words unsurprisingly that catch the attention of high-level athletes.

'I stumbled on to Dave Asprey's Bulletproof diet and four years ago I tried it out and I felt better right away,' Mike Bryan explains. 'I felt better cognitively and I feel all the inflammations were leaving my body so I did more and more research.

'He has about 600 podcasts on the web and I have listened to all of them! I think he is a pioneer and a genius when it comes to optimising biology and getting the most out of your body and mind and I think that has helped me on court concentrate better, helped me recover and I feel he has been a huge help in letting me compete at a high level.

'I still feel like I am actually playing pretty well and some days I feel like I am improving! I had no intention when I was 25 - I was just hoping to just get another year out of my career, maybe play until I am 30. But it was inconceivable to play until I am 41, still have fun doing it and not be in pain after matches.

The American twins highlight Bulletproof and bio-hacking as the reason they are still strong

'It has been fun to see how the diet and some of the supplements and biohacking upgraded my life.'

The brothers are now ambassadors for Bulletproof as they have put their career longevity down to Asprey and his biohacking. But for Bob Bryan, the realisation came later, too late in one sense, as his approach was forced upon him as he prepared for a hip resurfacing operation.

No tennis player had had the surgery and made a return to the top level.

The brothers have been one of the most formidable pairings in doubles history, but when Bob Bryan went down following a serve in the Madrid Open final back in 2018, disappointment washed over him, he thought his career was finished.

'When I went into surgery, I was afraid that I would never play again, the doctors thought I had a 50-50 shot,' Bob says.

'Its uncharted territory. I took the rehab protocol seriously. No tennis player had ever come back from hip resurfacing surgery before, but it was important for me to do whatever it took to come back and finish my career together with Mike on our own terms.'

Recalling the horrifying moment in Spain more than a year ago, Mike Bryan insists he, as a twin, felt pain in his hip when Bob went down. He added: 'When he went down it was super painful. As a twin you can feel your brother's pain. I could see him go down and I have never seen him like that. He couldn't put any weight on it and I knew he had a ticking time bomb in his hips.'

But Bob Bryan made a recovery, back on court he came, alongside Mike and a new path had been laid for players in the future. This injury would not have to be the end of a career. Fast forward to the 2019 Australian Open and Andy Murray was about to find out all about it. Tears flowed as the former British No 1 accepted he could no longer go on in the pain he was in.

Bob Bryan had the same hip surgery as Andy Murray and has kept in regular contact with him

He needed his quality of life back and so he sought out Bob Bryan for advice. He, after all, was living proof the surgery works. 'Andy and I are in constant communication with one another,' he says.

'He's updating me on how his post-surgery is coming along. What he was able to do at Wimbledon was amazing. I remember after my surgery I was watching TV in bed for a few days but he was already getting after it. Day one he was already in the pool, sending me videos of all the crazy stuff he was doing in rehab.'

Murray lifted the Queen's Club title alongside Feliciano Lopez in his first tournament back before having mixed success at Eastbourne and then Wimbledon. But the signs are positive and there remains real hope that Murray can make a return to the top of the game as a singles player.

'There is no one that works harder than Andy Murray and he is the best, that's what makes him a champion,' Mike Bryan goes on to add. 'He is taking his body super seriously and he has a good team around him. He is at the courts before anyone gets there, doing everything he can, all the stretches and a proper warm-up and he is moving really well.

'It has only been a few months and he is already one of the top doubles players in the world it looked like. He was moving great and looked good serving and so doing all the things you need to do to be top at doubles.

'He has said he has no pain and he has his motion. Only time will tell if he can go back out there and compete with a (Roger) Federer or a (Novak) Djokovic for four or five hours and what that will do to a metal hip.

'He says all the muscles around the hip are strong and it has healed up in there, so I don't doubt he can come and be top 10 in the world again. The guy is so talented and he is one of the best ball strikers in the world, no-one has the type of mind he has and no-one wants it more than him so I don't doubt it.'

Murray has practiced with the brothers and is continuing to improve as a doubles player

Murray joined forces with his brother Jamie to compete in Washington last week and he would be wise to seek further advice from the Bryan Brothers on how to keep the on-court and off-court relationship equally strong.

Another slam is the motivating factor for the Bryan Brothers but while bio-hacking is giving them a chance to keep competing, it remains difficult for fans to pinpoint how the pair, at least publicly, have managed to keep a positive relationship intact given the highs and lows that comes with top-level competition.

Defeat in the last-16 of Wimbledon recently to Edouard Roger-Vasselin and Nicolas Mahut brought disappointment, strain and some choice words. 'The best thing about it is that we love each other and there is no stronger bond than a twin relationship,' Mike Bryan says.

'When things are going well it feels like we are one entity and we are bouncing around a positive force. That is unstoppable. When we have good moments we can share them together and talk about these memories for a lifetime.

'But the sibling rivalry can seep in at moments and we can be on different pages. You would say something to your brother that you would never say to an average partner. It can get personal and some of our lower moments are way lower than a regular team.

'When we lose matches there is bitterness that seeps in and it can turn sour quick but the good thing about us is we have had a million of those fights. They always happen every day in practise and we can drop it right away.

Disappointment is tough for the Bryan brothers and they reflected on losing at Wimbledon

'We had a tough loss at Wimbledon and there were some things said that we wished we didn't say and wished we could have taken back. But we hashed it out, cleared the air and we go again. When it is going well there is nothing better but you just have to be careful and sometimes keep your mouth shut!'

The Bryan Brothers know time is ticking on their esteemed careers. That may yet prove to be their final Wimbledon.

They can laugh at suggestions they can keep going until they are 51. But bio-hacking has given them a chance to keep fighting with the best new talent and Murray would be wise to learn all he can.

While they just fell short Washington, the Bryan Brothers could find some serious sibling competition in the run up to this year's US Open if the Murrays unite again.