LeBron James, Johnny Sexton and Cristiano Ronaldo all look to join the 40 club

Leinster captain Isa Nacewa retired from professional rugby last weekend with a PRO14 title to add to a fourth Champions Cup medal with Leinster.

Nacewa started in both of the province's Champions Cup and PRO14 finals but this was it for him. The end of the line.

'There won’t be a timeout. Time out to recuperate and to rehab and to get the mind and body right before coming back for another go. No. Not this time. This is it. This is goodbye' - Isa Nacewa.

The decision marked the second time in Nacewa's career that he had decided to retire from rugby and he walks away from the sport as one of the most decorated players in European history. At 35, and despite having a two-year hiatus where he worked as a mental skills coach with the Auckland Blues, Nacewa's body had endured enough. 35 is generally considered a great age to retire at in professional sport but Real Madrid forward Cristiano Ronaldo, Cleveland Cavaliers forward LeBron James and Leinster fly-half Johnny Sexton could all play until they are 40, or at the vey least, they're open to the idea. Ronaldo said in 2015 that if you look after yourself and do things right, you can reach 40. LeBron said that he would be open to playing until his 13-year-old son LeBron Jr. reaches the NBA with sources close to James telling ESPN that they can see him playing until he's 40 years old. While Sexton, who didn't really crack the Leinster first team until he was 24-years-old, has said that Leinster senior coach Stuart Lancaster has him convinced that he can play until 40, much to the annoyance of his partner Laura. What's interesting is that all three players are still performing at the peak of their powers at the respective ages of 32 and 33. This season Sexton has won a PRO14 and Champions Cup double, a Six Nations title and Grand Slam with Ireland, and he was also shortlisted for the EPCR European Player of the Year and also the Six Nations Player of the Championship. He does not turn 33 until July. LeBron James is six months older than Sexton and he's averaging 32.8 points, 9.1 rebounds and 7.8 assists per game in the play-offs at 33-years-old. He’s posted nine 40-point games in the post-season. He now has the most points in NBA play-off history and he's dragged one of the worst teams to ever head to the finals for what will be his eighth consecutive trip to the final round of the NBA season. Meanwhile Cristiano Ronaldo turned 33 in February and he has scored as many goals for Real Madrid this season as games that he's played (44 goals in 44 games played). He's also just won his third consecutive Champions League title and topped the Champions League goalscoring charts for the seventh time in his career with 15 goals in this year's competition. Maturing with age Ronaldo is the first player to top Champions League goal scoring past the age of 30 since a 30-year-old Serbian striker Milinko Pantić led the 1996-1997 Champions League with five goals for Ateltico Madrid. He scored 15 goals in the tournament at age 33, which registers as the third best individual goal scoring season the tournament has seen behind his own haul of 16 goals during the 2015-16 season and 17 goals during the 2013-14 season. He's had eight straight seasons with 40 plus goals. Lionel Messi has nine straight seasons with 40 plus goals. Former West German international Gerd Müller has scored more goals than both players and he only had six 40 plus goal campaigns in 14 seasons with Bayern Munich. Similarly, at 33, James is the oldest player in NBA history to average a triple-double in a calendar month while he's the youngest player in history to reach 6,000 playoff points and the youngest player to ever win four MVP awards. Only one other player since 1990 has won at least three MVP awards: Michael Jordan. Here's how LeBron compares with Jordan, who played until he was 40, at age 33. LeBron at 33: 27.5 points per game, 9.1 assists per game (career high), 8.6 rebounds per game (career high), .542 field goal percentage Michael Jordan at 33: 29.6 points per game, 4.3 assists per game, 5.9 rebounds per game, .486 field goal percentage. Meanwhile Sexton joins Scott Fardy, Dan Carter, George Smith and Thomas Waldrom as the only players over the age of 32 to be nominated for an EPCR Player of the Year award during the last three years, while Sexton, Paul O'Connell, Brian O'Driscoll and Sergio Parisse are the only players 32 years or older to have been nominated for a Six Nations Player of the Championship award since 2014. All three players are clearly performing at a level above what is expected of their ages but the question is do they have the desire to play until they're 40 and at what point can we expect to see decline? Ronaldo, Sexton and James have all said that they would be open to the idea of playing until they're 40 but none of the three players have definitively set the age as a target, rather they intend to play as long as possible. However, each player may be able to make a legitimate run at the 40 mark if they continue to monitor their games heading into the tailend of their careers. Last season, Goal.com issued a report prior to Madrid's match against Las Palmas detailing which Real Madrid players ran the most in La Liga. Out of 17 recorded players, Ronaldo ran the second least amount of kilometres per game with the Portuguese clocking 9.2 kilometres per game. Similarly, out of all the Madrid players that have played over 900 minutes in La Liga this season, Ronaldo has the third lowest number of touches per minute at the club (for any outfield player) with his 1.25 touches per minute trailing just Nacho (1.23) and Karim Benzema (1.13) for the players that get on the ball the least. By comparison, Isco had 5280 total touches in 1778 minutes in La Liga this season compared to Ronaldo's 2869 total touches in 2292 minutes. We're seeing something similar with James in the NBA who was actually the slowest player in the NBA Eastern Conference finals averaging a speed of 3.4 MPH during the first three games against the Boston Celtics. No other player in the series averaged a lower speed. James dismissed the stat as the 'dumbest statistic he's ever heard' but it would give credence to the fact that he's picking his spots on the floor where he has time to rest before ramping up and engaging in high intensity activity again. Meanwhile Sexton played just 19 games this past season compared to a player like Devin Toner, who is just one year younger than Sexton, but played 28 games for Ireland and Leinster. Less is seemingly more as these three great athletes enter the twilight years of their careers in peak condition. We can undoubtedly expect to see some signs of deterioration and regression over the next five years with all three but there's no reason to think that they can't extend their playing careers, saving injury, especially if they are already conscious of preserving their energy at this stage. Injury, dips in form, the breakdown of the body or simply a loss of interest could stop each player from reaching 40 during their playing careers but they're all open to the idea of trying to play close to that age. Their performances are still at an exceptionally high level, they are all taking measures to ensure they prolong their careers, and specifically with Ronaldo and James, if there were ever two athletes to follow New England Patriots quarterback Tom Brady and play competitively until the age of 40; are these two not the guys? The answer is they probably are. The question is will they get there and do they even want to play to that age even if they can?