Thumb motor performance is greater for two-handed grip compared to single-handed grip on a mobile phone

Abstract

The aim of this study was to determine if thumb motor performance varied between singlehanded and two-handed grip for thumb tapping tasks on a mobile phone. A secondary aim was to determine if differences in phone movement variation and thumb flexion could account for variations in motor performance across the two grip configurations. Ten right-handed participants (5 males, 5 females) completed reciprocal thumb tapping tasks on an Apple iPhone 3® in a single-handed and a two-handed grip configuration while an active-marker motion capture system measured 3D kinematics of the thumb and phone. The results show that thumb motor performance was significantly greater for the two-handed grip configuration due to less phone movement variation compared to the single-handed grip configuration. Thumb flexion did not significantly vary across configurations. These data suggest that increasing support for the phone such as by using a two-handed grip could lead to increases in tapping performance. For example, increased performance would be expected when using phones that include a landscape mode and are wide enough to allow a stable two-handed grip.