## 1 Introduction
On the other hand, even if designers intend to use ergonomic methods quantitatively in layout arrangements, limited dimension references are challenging to apply in diverse and precision-demanding scenarios. Human fingers possess independent motion capabilities [14], with the thumb exhibiting unique movement characteristics [15]. However, due to inherent biomechanical constraints, the motion of individual fingers is subject to interference from adjacent digits [16], thus creating a restricted movement space. These limitations become particularly pronounced under fixed hand postures, as demonstrated in studies by [PERSON] [17] and [PERSON] [18], who investigated the workspace characteristics of the two- and three-fingered manipulation during pinch gestures. Similarly, in gripping configurations, each finger should exhibit distinct movement patterns and ranges, which significantly influence the layout of joystick buttons. Another challenge is the increasing operational complexity led by button innovation. The trends toward intelligent and multimodal product operations are shifting interaction from traditional physical buttons to complex touchscreen inputs, contactless gestures, voice inputs, and other multimodal inputs. These new interaction modes introduce fresh operation patterns. Touchscreen technology has enabled natural writing and abstract gestures as new modes. Innovations like trackballs [19] have further diversified finger operation patterns. These innovations demand increased ergonomic comfort and operational efficiency in handheld devices. Another significant innovation is the integration and multifunctionality of buttons. BMW's iDrive button design [20] integrated multiple operations, including flexion, pressing, pushing, and pulling. Researchers have developed an intelligent button [21] that combines pressing and rotating actions. As the complexity of joystick operation grows, the frequency and intensity of finger keystrokes increase, which results in greater fatigue [22]. This highlights the need for a more rational key layout. Gender differences in anthropometry are crucial gradients in ergonomic design. Given that, principles and guidance of equipment for male and female design ought to be researched respectively. In this study, we explored the dynamic data and operation characteristics of the male hand during gripping to ensure sample homogeneity and establish a baseline for future female research. Our research proposed two hypotheses before the following experiment:  
* There are different operation areas for fingers when gripping. * Finger operations in different areas have generalizable features and predictable trends. The research process unfolds as follows: Firstly, we analyze grip movements and operations, identifying three distinct operational areas for hypothesis A. Then, we devised experiments focused on button operational characteristics and loads based on two primary operation fingers, thumb and index finger, for hypothesis B. Additional operational analysis was conducted for the thumb, due to its uniqueness. Fifteen participants were recruited across three hand length percentiles (P10, P50, P90) in these experiments. Finally, the study discusses the operating range and characteristics of the different areas in the grip state.