Research on holding behavior under the interaction of mobile phone form, user hand characteristics and grip posture

As smartphones evolve toward higher performance, multi-functionality, and diverse forms, users' grip characteristics increasingly influence heat dissipation design and operational comfort. This study investigates how hand size (across genders) and phone form affect holding behavior. A mixed experimental design was adopted, examining three phone types (regular flat-panel, small flat-panel, and left-right foldable), three grip postures (vertical, horizontal, and calling grip), and two genders. Twenty participants completed subjective holding assessments. By simulating typical usage scenarios and using an infrared thermal imager to record temperature cloud patterns at contact points, we accurately identified grip position and geometric shape. Grip posture cloud maps were generated, and differences across genders and hand sizes were analyzed. Hand coverage rate (HCR) was quantified, and the effects of phone type, grip posture, and their interaction on HCR were examined via ANOVA. Correlations between hand dimensions and coverage area were also explored. Results showed that for flat-panel phones, HCR followed: horizontal grip > vertical grip > calling grip. Grip posture had a significant main effect, and its interaction with phone type was significant. After including the foldable phone, the main effects of both phone type and grip posture remained significant, as did their interaction (p = 0.000). This research integrates human factors engineering with thermal management studies. The proposed experimental methods and analysis models provide theoretical support and data references for smartphone heat dissipation design and HCI optimization.