Kinoshita H, Kawai S, Ikuta K
Faculty of Health and Sport Sciences, University of Osaka, Japan.
Ergonomics. 1995 Jun;38(6):1212-30. doi: 10.1080/00140139508925183.
The contributions and co-ordination of external finger grip forces were examined during a lifting task with a precision grip using multiple fingers. The subjects (n = 10) lifted a force transducer-equipped grip apparatus. Grip force from each of the five fingers was continuously measured under different object weight (200 g, 400 g and 800 g) and surface structure (plastic and sandpaper) conditions. The effect of five-, four-, and three-finger grip modes was also examined. It was found that variation of object weight or surface friction resulted in change of the total grip force magnitude; the largest change in finger force, was that for the index finger, followed by the middle, ring, and little fingers. Percentage contribution of static grip force to the total grip force for the index, middle, ring, and little fingers was 42.0%, 27.4%, 17.6% and 12.9%, respectively. These values were fairly constant for all object weight conditions, as well as for all surface friction conditions, suggesting that all individual finger force adjustments for light loads less than 800 g are controlled comprehensively simply by using a single common scaling value. A higher surface friction provided faster lifting initiation and required lesser grip force exertion, indicating advantageous effect of a non-slippery surface over a slippery surface. The results indicate that nearly 40% force reduction can be obtained when a non-slippery surface is used. Variation in grip mode changed the total grip force, i.e., the fewer the number of fingers, the greater the total grip force. The percent value of static grip force for the index, middle, and ring fingers in the four-finger grip mode was 42.7%, 32.5%, and 24.7%, respectively, and that for the index and middle fingers in the three-finger grip mode was 43.0% and 56.9%, respectively. Therefore, the grip mode was found to influence the force contributions of the middle and ring fingers, but not of the index finger.
在一项使用多根手指进行精确抓握的举重任务中，研究了外部手指握力的贡献和协调情况。受试者（n = 10）举起一个配备力传感器的抓握装置。在不同物体重量（200克、400克和800克）和表面结构（塑料和砂纸）条件下，连续测量五根手指各自的握力。还研究了五指、四指和三指抓握模式的影响。研究发现，物体重量或表面摩擦力的变化会导致总握力大小的改变；手指力变化最大的是食指，其次是中指、无名指和小指。食指、中指、无名指和小指的静态握力占总握力的百分比分别为42.0%、27.4%、17.6%和12.9%。这些值在所有物体重量条件以及所有表面摩擦力条件下都相当恒定，这表明对于小于800克的轻负载，所有单个手指力的调整只需通过使用一个单一的通用缩放值就能全面控制。较高的表面摩擦力能使举重启动更快，且所需施加的握力较小，这表明防滑表面比光滑表面具有优势。结果表明，使用防滑表面时可使力减少近40%。抓握模式的变化会改变总握力，即手指数量越少，总握力越大。在四指抓握模式下，食指、中指和无名指的静态握力百分比分别为42.7%、32.5%和24.7%，在三指抓握模式下，食指和中指的静态握力百分比分别为43.0%和56.9%。因此，发现抓握模式会影响中指和无名指的力贡献，但不影响食指的力贡献。
