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09:36
Measurement of Spatial Stability in Precision Grip
Published on: June 4, 2020
Effect of object width on precision grip force and finger posture
M Domalain1, L Vigouroux, F Danion
1Institute of Movement Science UMR 6233, University of the Mediterranean, CNRS, Marseille, France.
Ergonomics
|September 20, 2008
Summary
Object width significantly affects how people grasp objects. Grip force increases with object width, suggesting a strategy to maintain a consistent grip force relative to maximum capacity for better object manipulation.
Area of Science:
- Biomechanics
- Human Factors
- Motor Control
Background:
- Understanding spontaneous grasp is crucial for designing tools and assistive devices.
- Previous research has explored mass and size effects, but object width's specific impact on grip force and posture requires further definition.
Purpose of the Study:
- To investigate the influence of object width on the spontaneous grasp.
- To analyze changes in grip force, maximal grip force, and finger postures in relation to varying object widths.
Main Methods:
- Participants grasped objects of diverse masses (0.75–2.25 kg) and widths (3.5–9.5 cm).
- Grip force and maximal grip force were measured using embedded force sensors.
- Finger postures were recorded using an optoelectronic system.
Main Results:
- Index finger joint postures adapted to object width, while thumb posture remained consistent.
- Grip force escalated with increasing object width for a constant object mass.
- Maximal grip force also increased with object width, indicating a potential constant ratio strategy.
Conclusions:
- Grasp adjustments are width-dependent, with the index finger playing a key role in accommodation.
- A constant ratio between grip force and maximal grip force may be employed.
- Optimal object width for manipulation differs from that required for maximal force exertion.
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