Frontal plane margin of stability is increased during texting while walking.

Injurious falls associated with cell phone use during ambulation are increasingly common. Studies examining texting while walking suggest this task alters the attentional component of walking to the extent that safety may be compromised. Here, we quantified the extent to which frontal plane dynamic stability while walking was affected by the cognitive and physical demands of texting. Twenty experienced texters performed four, 10-min treadmill walking tasks at a self-selected velocity in random order: (1) normal walk (control), (2) walking while verbally performing mathematical calculations (cognitive demand), (3) walking while bimanually holding and looking directly at a phone (physical demand), and (4) walking while texting continuous mathematical calculations (cognitive and physical). We quantified the frontal plane minimum margin of stability (MOSmin), a measure that considers the position and normalized velocity of the center of mass with respect to the lateral border of the base of support was calculated over each 10-min walking period. Compared to the normal walking condition, the texting and phone holding conditions resulted in a small but significant (6%) increase in MOSmin (p=0.005 and 0.026, respectively). Compared to normal walking, the effect of performing mathematical calculations on MOSmin was not significant (p=0.80). These results suggest that frontal plane stability of experienced texters during controlled treadmill walking conditions can be affected by the physical, but not the cognitive demand of texting. This may represent a compensatory mechanism by the CNS to ensure stability in the event of an unexpected disturbance.