Visit any major urban centre today and you are likely to be confronted with hundreds of people walking with their heads down as they fiddle with their mobile phones.

But the phenomenon is not just irritating, it is changing the way people walk, according to scientists, who found that one's gait becomes far more exaggerated when using a phone.

Researchers at the University of Delaware in the United States asked 22 volunteers to dial a number on their mobile phone while walking on a treadmill for periods of two minutes.

The walkers wore 62 markers on the arms, trunk, pelvis and legs which were picked up by motion cameras to measure knee flexion, hip movement and leg swing.


The experiment showed that when distracted by dialling, the volunteers began to walk with strange, exaggerated strides, their knees bending to peak position on each step, and their ankles fully flexed, to give themselves as much chance as possible at stepping over tripping hazards.

The researchers say that people unconsciously adopt the posture because their body senses that they are at greater risk of falling over.

The large, exaggerated movements potentially help them to negotiate crowds and compensate for diminished vision.

Author Kelly Seymour, of the department of Mechanical Engineering at the University of Delaware, said: "Our results suggest that when dialling a phone while walking, healthy adults adopt a more cautious gait pattern, which may limit the risk of falling.

"Dual tasking resulted in increased stride width in our participants. This may represent compensation for a feeling of instability during dual task walking by increasing the base of support."

A recent study by the University of Bath found that texters had developed a protective shuffle that prevents them bumping into obstacles, or tripping over hazards. They discovered that it took those texting 26 per cent longer to complete a walking task.

"Gait speed is typically reduced when individuals simultaneously perform other tasks," added Seymour.

"However, in today's fast-paced world, individuals are often rushed and do not choose to slow their gait speed, and even if they do, they remain more likely to fall while walking."

The problem of text-walkers has become such a problem that last year Antwerp in Belgium brought in "text walking lanes".