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.