Technique, muscle activity and kinematic differences in young adults texting on mobile phones

Abstract

The aim of this study was to investigate whether there are differences in technique between young adults with and without musculoskeletal symptoms when using a mobile phone for texting and whether there are differences in muscle activity and kinematics between different texting techniques. A total of 56 young adults performed a standardised texting task on a mobile phone. Their texting techniques were registered using an observation protocol. The muscular activity in six muscles in the right forearm/hand and both shoulders were registered by surface electromyography and the thumb abduction/adduction and flexion/extension were registered using a biaxial electrogoniometer. Differences in texting techniques were found between the symptomatic and the asymptomatic group, with a higher proportion of sitting with back support and forearm support and with a neutral head position in the asymptomatic group. Differences in muscle activity and kinematics were also found between different texting techniques. The differences in texting technique between symptomatic and asymptomatic subjects cannot be explained by them having symptoms but may be a possible contribution to their symptoms. STATEMENT OF RELEVANCE: There has been a dramatically increased use of mobile phones for texting especially among young people during the last years. A better understanding of the physical exposure associated with the intensive use is important in order to prevent the development of musculoskeletal disorders and decreased work ability related to this use.

Frequency of De Quervain�s tenosynovitis and its association with SMS texting

“…During the past decade in Sweden only, 15-24-year-age group have 100% access to mobile phones and 93% on average utilize it for sending text messages (SMS) 13 . Use of mobile phones has increased in USA in teens for text messaging from 38% in 2008 to 54% in 2009 14 .…”

A comparison of muscle activity in using touchscreen smartphone among young people with and without chronic neck–shoulder pain

“…The higher level of muscle activation associated with unilateral texting is in agreement with previous research. In Gustafsson et al (2011), higher muscle activity in extensor digitorum was found among subjects entering text on keypad phone with one thumb and using one-handed grip compared with two-handed grip. Young et al (2013) reported that the angle of wrist radial deviation and EMG amplitude of forearm extensor/flexor muscles increased when supporting a tablet computer with a single hand, which may result in fatigue in wrist muscles and even in upper trapezius.…”

Two-handed grip on a mobile phone affords greater thumb motor performance, decreased variability, and a more extended thumb posture than a one-handed grip

“…Moreover, a single-handed grip may constrain thumb movement and require sub-optimal postures. Potentially for these reasons, Gustafsson et al (2011) found that 62% of participants held mobile phones using a two-handed grip that involved less extensor digitorum muscle activity than a singlehanded grip. However, whether the preference for a two-handed grip reflects a choice based on motor performance, posture, device stability, or other factors is unknown.…”

“…The grip that a user selects could affect motor performance and musculoskeletal strain (Gustafsson et al, 2011). Performance and strain could be related to hand size relative to the device, comfort, multitasking needs, accuracy requirements, need for support, or maintaining stability.…”