A person's manner of walking becomes far more exaggerated when using a cell phone.
Researchers from the University of Delaware in the US conducted the study on 22 volunteers who were asked to dial a number on their phone while walking on treadmill for two minutes.
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 at stepping over tripping hazards.
The researchers said that people unconsciously adopt this posture as 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 their diminished vision.
"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," said Kelly Seymour from University of Delaware.
"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," said Seymour.
"Gait speed is typically reduced when individuals simultaneously perform other tasks," added Dr 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 and performing another task simultaneously than while only walking. "An increase in step width is characteristic of cautious gait, correlated with fear of falling."