The word ‘flat-footed’ originates from a disease called Pes planus or fallen arch, which flattens the arch of the foot and causes an imbalance of forces important to the biomechanics of motion and balance of weight on the human foot during motion. This term is also widely used in sports.
In football, when a player is caught flat-footed, s/he is unable to stretch out to reach for the freely moving ball or when dribbled by an opponent. In the flatfoot position, a player is not ready to tackle an opponent or receive a pass. It may be due to loss of concentration, poor posture or deliberate plot by the opponent to challenge one. At all times, a player is expected to be on toes and move about to avoid being caught in this position hard to recover from in time to make a save or dispossess an opponent of the ball. Enough of football.