Real Madrid players have been seen training in unusual blue masks that resemble oxygen equipment designed to replicate high altitude training.
The equipment is understood to be worn during stress tests, with Pintus telling Real Madrid TV that they are 'designed to find out the players' aerobic and anaerobic thresholds and their current power.'
Named Cosmed K5 masks, they allow staff to measure exact VO2 max levels, which is the maximum rate the body can consume and use oxygen during high-intensity exercise.
Sports physiotherapist Ben Warbuton told BBC Sport: 'They've got hold of high-tech equipment to complete it during training. This benefits the coaches because they can test the players and train at the same time.
'If all players did a treadmill or bike test, it would be very time-consuming. They would lose a training session, and a treadmill is a harder and different surface to grass.
Essentially, it saves time for the club in terms of being able to do two jobs at the same time, rather than taking up double the time available.
There is also therefore a knock-on impact of reduced injury risk, because information is sent immediately and issues such as tight muscles can be flagged before they become worse.
It's not the first time Madrid have worn the masks, and they shared a video titled: 'The masks are back!' to their YouTube channel.
Italian company Cosmed produce the masks, and say: 'The face mask has an anatomically contoured design with resilient ribbed support structure for a leak-free, comfortable fit and integrated chin cup for stability.'
According to The Athletic, each kit costs £26,000 and some are loaned by the club.
Pintus, who is the man behind the idea, first joined Madrid in 2016 and has been using them since the 1990s, when he was at Monaco.
They were also used at Madrid under both Carlo Ancelotti and Zinedine Zidane, and, on occasion, when Xabi Alonso was in charge.