During the 80th minute of an intense Manchester derby at Old Trafford, Manchester United defender Harry Maguire was visibly fuming, unleashing a torrent of abuse towards Enzo Fernandez. The Argentine midfielder for Manchester City barely glanced at his opponent, instead lowering his gaze to his left wrist, where he calmly fiddled with a thin black strip of fabric.
The match finished with a narrow 1-0 victory for the Cityzens, marking their first derby since Pep Guardiola's departure. Enzo Maresca's side had to fight valiantly for over an hour with ten men after Phil Foden was sent off in the 23rd minute for a reckless kick at Bruno Fernandes. The Red Devils rattled the woodwork through Marcus Rashford and Kobbie Mainoo, but they couldn't find the back of the net past Gianluigi Donnarumma.
Fernandez found himself at the heart of the action, hitting the post, battling fiercely in midfield, and contributing to Erling Haaland’s goal in the 60th minute. Initially ruled out for offside, the goal was later given after VAR intervention—a decision later deemed a serious error by the Pro Referee Committee, as Fernandez had impacted the play while offside. As the match drew to a close, Fernandez went down in the opposition box appealing for a penalty, only to be hoisted to his feet by an irate Maguire, earning a yellow card in the process before making way for Nico O'Reilly.
The mysterious accessory on Fernandez's left wrist is a Whoop smart bracelet. This ultra-thin fitness tracker, which has no screen, is worn continuously by professional athletes, even during official matches.
The device wraps snugly around the wrist with an elastic fabric strap and employs built-in optical sensors to continuously track vital biometric parameters: heart rate, heart rate variability (HRV), breathing rate, skin temperature, and micro-movement patterns.
Based on the collected data, the system calculates two key daily metrics:
- Strain: objectively assesses the total volume of stress and physical work the body has undergone over the day;
- Recovery: computes the body’s current physiological readiness for intense exertion based on nightly heart rate variability, resting heart rate, and sleep phase architecture.
Footballers and club medical teams use Whoop technology for precise management of training loads, determining players' need for rest, and closely monitoring muscle recovery speed after tough matches. Thanks to this, Manchester City maintained their lead at the top of the table, leaving Manchester United languishing in 13th place.
