Phone use 'changes how people walk'
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 actually changing the way people walk, according to scientists, who found gait becomes far more exaggerated when using a phone.
Researchers at the University of Delaware 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 reflective 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 numbers, the volunteers began to walk with strange exaggerated strides, their knees bending to peak position on each step, and their ankles fully flexed, as if to give themselves as much chance as possible of stepping over tripping hazards.
The researchers say people unconsciously adopt the posture because their body senses they are at greater risk of falling over. The large, exaggerated movements potentially help them to negotiate crowds and compensate for their diminished vision.
First author Kelly Seymour, of the department of mechanical engineering at the university, 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."
The researchers found there were few mistakes in number dialling during the experiment, which suggests that participants were prioritising dialling over walking.
The research was published in the journal Motor Behaviour.