Investigation of grip strength, pain threshold, pain tolerance and function in smartphone users

Few studies have demonstrated the effects of smartphone use on grip strength and upper extremity function. The present study was purposed to compare smartphone users' grip/lateral pinch strength, pain threshold/tolerance and upper limb function.

A prospective cross-sectional study was conducted with 241 individuals. Participants were divided into three groups with the cut-off values of the Smartphone Addiction Scale (SAS). The Edinburgh Handedness Inventory (EHI) was used to determine the dominant side. Thumb pain threshold and tolerance were evaluated with the algometer. A hand dynamometer measured the grip and lateral pinch strength. Upper extremity functions were evaluated with the Shortened Disabilities of the Arm, Shoulder and Hand Questionnaire (Quick-DASH).

Handgrip strength of the dominant/non-dominant extremities and Quick-DASH scores were higher in low-level smartphone users (p < 0.05). There was no significant difference between the groups on lateral pinch strength and pain threshold/tolerance (p > 0.05). Smartphone usage significantly affected dominant and non-dominant hand grip strength (Standardized β₁ = -0.15, β₂ = -0.15, p < 0.05). In addition, the smartphone use level negatively affected dominant lateral pinch strength (Standardized β = -0.12, p = 0.05). On the other hand, smartphone use positively affected upper extremity function (Standardized β = 0.17, p < 0.05).

As smartphone addiction increases, standard handgrip strength and functionality decrease. Pain threshold/tolerance is not affected by smartphone use. Future studies should focus on fine motor skills to present a more comprehensive upper limb function evaluation.