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

Purpose/aim of the study: 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.

Materials and methods: 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).

Results: 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).

Conclusions: 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.