Those watching the Lions' victory over Western Force on Wednesday might have noticed bumps on the back of the tourists' jerseys. So what is that underneath Brian O'Driscoll's shirt?
Well, it is GPS tracking software which helps the team's management analyse all sorts of aspects of his and his team-mates' performance.
It is kept in place in between the shoulder blades in something called a "Bro" which works in much the same way as a female athlete's sports bra. The English rugby team have previously placed the units within a pouch in their shorts.
GPS tracking has been used in rugby for a couple of years now and it can tell the Lions coaching staff a lot more than just how far a player has run.
It can reveal what a player's average speed it, when a player's intensity starts to drop, who is performing above or below their usual level and some models even contain a heart-rate monitor sensor which can identify potential problems on the pitch.
All this information can be relayed to the coaches in real time and they can then make replacements based on the information they see on their laptop screens.
There are huge health benefits to having the players carry such trackers on the field of play as they can really help stars to avoid, limit and recover from all sorts of injuries.
Chris McLellan of Bond University, in Australia, did an extensive study using GPS data in rugby league players to measure injuries.
As an Economist article in 2011 explains McLellen "did this by correlating tackles and collisions against known indicators of skeletal muscle damage, like the hormone cortisol and the protein creatine kinase.
"Players provided blood and saliva samples before a game, and for several days afterwards. Mr McLellan found a clear correlation between concentrations of the biochemical markers and the measured impact force of each collision."
All this information can help teams tailor their training regimes to help prevent such injuries.
Interestingly, one sport that forbids the use of GPS tracking on the field of play is football, despite high profile incidents on the pitch such as Fabrice Muamba's collapse at White Hart Lane last year.
Many football clubs do use the software during training and can track much of the information after the fact using external software but it does not have the same instantaneous benefits as it does when players are wearing the trackers in the moment.
Rugby not only allows it but encourages it. In 2011, the RFU carried out a study using the technology to investigate the demands on players.
Roy Headey, the RFU’s head of sports science said at the time: "A critical piece of information relates to the external loads - visible but virtually impossible to estimate - that players experience during games.
"These include distances run at various speeds, muscular effort in accelerating, decelerating, changing direction and G-forces in collisions, and GPS is currently the best available vehicle for capturing such data."
Corin Palmer, Premiership rugby's head of academies and development added: "It will allow coaches and medical staff to design training programmes to optimise player fitness, rehabilitation and general welfare, but it will also play an important part in the creation of individual player development plans for academy athletes as part of the clubs’ ongoing desire to nurture and invest in young English talent."
The same technology can be used inside of balls too and tests have already been carried out to see if it could be used to accurately determine forward passes as an additional tool for the video referee.
And while all this information is fed to players and coaches the next step could be to transmit all this data to spectators too. Soon the old fashioned coaches who reject new technology could be getting some odd advice from more tech savvy fans who are not just following the match with their eyes but also on their mobile phones.
"Oi coach, take him off, his high-intensity sprints are starting to dip in speed."
It's a whole new ball game.
- Sports & Recreation
- GPS tracking