The effects of umbrella handle shape and grip type on muscle activation and postural variability under windy conditions
研究了不同雨伞手柄形状和握持类型在风条件下对前臂和上臂肌肉激活及姿势变异性的影响，发现椭圆手柄配合五指握持能降低姿势变异性，为手柄设计提供参考。
This study investigated how different shapes of umbrella handles and grip types influence muscle activation and postural variability under windy conditions. Seventeen adult participants were enrolled in this study, and different handle shapes (cylindrical, ellipsoidal, and triangular prism-shaped), grip types (four- and five-finger grip), and wind strengths were tested. Activation of the forearm and upper arm muscles was recorded using surface electromyography. Postural variability and ratings of (1) perceived difficulty of use and (2) perceived grip-posture variability were measured. The results indicated that activation of the finger flexor muscle increased under windy conditions, whereas postural variability was not affected. Weak wind (3.2-7.5 m/s) conditions caused greater perceived postural variability and activation of the wrist extensor muscle. The ellipsoidal handle shape had lower endpoint postural variability when held with a five-finger grip and also had lower perceived postural variability and difficulty compared to that with the cylindrical shape. Our findings can be used to select appropriate umbrella handle designs based on grip type and wind conditions.