Manchester United's Matteo Darmian believes a greater emphasis on attack has changed the role of the fullback, meaning the modern defender needs lung-busting endurance and intense focus as well as great technique.
Darmian has shown his own technical skill by alternating between right and left back at Old Trafford, an ability he honed as a youngster and continues to work on every week.
The Italian was converted from a central midfielder to right back at the AC Milan academy, where he was mentored by his idol Paolo Maldini, the master technician, and Brazilian Cafu, known for his pace and energy down the flanks.
The 27-year-old clearly applies a great deal of thought to his position and believes the role of fullback has changed since he started playing.
"Now a great full-back isn't just one who stops every attack, but also gets forward wherever possible because the attacking demands have increased," he told the club website (www.manutd.com)
"We need to help our strikers and wingers more than before, but we have to be focused also behind, because defending is still the most important thing. Those duties mean it is important that you are smart and focused all the time.
"Good technique helps and, of course, more and more it is important that you are a strong runner because you have to get up and down the pitch.
"If you look around at the best full-backs in the world today, they all have those attributes."
Darmian believes the best fullbacks around are Real Madrid's Marcelo, Dani Alves of Juventus and Bayern Munich's David Alaba as well as his own United team mate Antonio Valencia, a former winger.
With Valencia almost a fixture on the right flank for United, Darmian has had to fight for the left back position with Daley Blind and Luke Shaw, who limped off during United's League Cup quarter-final win over West Ham United last week.
"For me it is quite easy to change sides from right to left," said Darmian, who has started six of United's last eight games.
"When I was younger I did work hard on my left foot to make it stronger and, even now, I think it is important to do that during the week because it is my weaker side and I know that I have to keep improving it."
Sixth-placed United host fifth-placed Tottenham Hotspur on Sunday.
(Reporting by Debanjan Bose in Bengaluru, editing by Nick Mulvenney)