Texting and walking: strategies for postural control and implications for safety

Abstract

There are concerns about the safety of texting while walking. Although evidence of negative effects of mobile phone use on gait is scarce, cognitive distraction, altered mechanical demands, and the reduced visual field associated with texting are likely to have an impact. In 26 healthy individuals we examined the effect of mobile phone use on gait. Individuals walked at a comfortable pace in a straight line over a distance of ∼8.5 m while; 1) walking without the use of a phone, 2) reading text on a mobile phone, or 3) typing text on a mobile phone. Gait performance was evaluated using a three-dimensional movement analysis system. In comparison with normal waking, when participants read or wrote text messages they walked with: greater absolute lateral foot position from one stride to the next; slower speed; greater rotation range of motion (ROM) of the head with respect to global space; the head held in a flexed position; more in-phase motion of the thorax and head in all planes, less motion between thorax and head (neck ROM); and more tightly organized coordination in lateral flexion and rotation directions. While writing text, participants walked slower, deviated more from a straight line and used less neck ROM than reading text. Although the arms and head moved with the thorax to reduce relative motion of the phone and facilitate reading and texting, movement of the head in global space increased and this could negatively impact the balance system. Texting, and to a lesser extent reading, modify gait performance. Texting or reading on a mobile phone may pose an additional risk to safety for pedestrians navigating obstacles or crossing the road.

Figure 1. Definition of segmental movements.

Figure 2. Lateral deviations while walking.

The left hand side depicts the absolute medial-lateral deviations from the straight line. The right hand side depicts the absolute change in lateral foot position from one stride to the next of the right foot. The absolute change in lateral foot position per stride was greater during reading and texting than walking, but did not differ between the two phone tasks.

Figure 3. Example of rotation motion of pelvis, thorax and head, and the relative rotation motion between thorax and head (neck) and pelvis and thorax (trunk) and phase angle between thorax-head and pelvis-thorax rotations when a participant walked without a phone (Control), read on a mobile phone (Reading) and texted on a mobile phone (Texting).

Note the increase in range of head rotation in relation to the global reference frame during reading and texting with reduction of phase angle and phase variability between thorax and head. The dashed vertical grey lines denote right heel strikes.