Malcolm Harkness: How Chelsea psychologically coded matches
Harkness (right) worked for Chelsea from 2016 to 2020
Written by Training Ground Guru — August 14, 2022
FORMER Chelsea sport scientist Malcolm Harkness has revealed that the club ‘psychologically coded’ players during Maurizio Sarri’s season in charge in 2018/19.
Most of us are familiar with coding, which categorises ‘event’ actions like corners, crosses or final-third passes during a match in video and data. However, Harkness - who worked for Chelsea from 2016 to 2020 before joining Turkish side Trabzonspor for a short period - revealed that Chelsea had also been coding ‘confidence actions.’
This was done manually, with players awarded points when they displayed ‘confidence, motivation or focus’. This might be a midfielder's shot from outside the area that hit the target or an attacking run by a full back.
Harkness carried out the project in conjunction with his father Tim, who has been Chelsea’s Head of Sport Science and Psychology for 13 years, while Petr Cech, the former Technical and Performance Advisor, was also heavily involved.
Speaking to The Mind Room, Harkness said: “For the last few decades, you’ve had loads of statistics, measuring possession, number of passes and number of shots, but I don’t think anyone’s really looked too much into the number of psychological actions.
“When you code between 10 and 20 games, you start to see a lot of patterns emerging and get some really interesting insights into the players. Like the GPS data, in the future I think there might be a lot of value in a player - who’s interested in it - looking through the (psychological coding) data and maybe seeing where he’s not getting as many actions as another player in the same position or he’s getting a lot more.
"Petr Cech was very involved in the project and I think he found a lot of value in the data we gave. Before he left, (Eden) Hazard broke the charts every time. In every game he played, he made everyone else look like they’d done nothing for the whole game.
“There would always be little things that you weren’t expecting, like a player who, just by watching the game, you think didn’t play so well, but made a lot of confident actions.
“Callum (Hudson-Odoi) would come off the bench and be very effective. He would come in with a lot of confidence, drive the intensity of the game and give confidence to the other players.
“With N’Golo Kante, we would see a lot of focus actions, such as anticipating and intercepting a pass. It looked as though he was just in the right place at the right time, but he was concentrating so hard.
“Christian (Pulisic) would record a lot of motivated actions through pressing. He’s a very fit guy and he would use that to put pressure on the defence and drive the whole press of the team. He would go to the right back, then the centre back, then the goalkeeper and end up on the other side of the pitch.
“That shows motivation because he doesn’t have to do that. The reason we’re giving him the point (for a motivated action) is because he doesn’t have to do it, but he does.”
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