REUTERS, New York

A more lenient refereeing style that allows officials to prioritise the flow of the game over minor contact has emerged as one of the defining features of the World Cup, as the tournament heads into the knockout phase.

Referees have been encouraged to avoid whistling for trifling fouls, helping reduce stoppages and increase ball-in-play time in a tournament already marked by high-scoring matches and relentless intensity.

Experts in data science, physical preparation and refereeing say the approach has combined with the rise of stronger, faster players to produce a quicker and more physically demanding World Cup than ever before.

The changes have been widely welcomed, but specialists warn that players who are not fully fit -- particularly those returning from injuries affecting explosive movements such as sprinting and acceleration -- could struggle to cope with the demands of the tournament.

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