Published online by Cambridge University Press: 23 December 2009
Summary
When transporting an object during locomotion, the inertial forces that are indirectly generated through the motion of multiple body parts must be taken into account to prevent object slippage. The grip–inertial force coupling that maintains a secure grasp on a hand-held object is preserved across a variety of locomotor tasks that include variations in velocity and precision demands (e.g. transporting a cup of water). When the locomotor pattern is altered by changing the step length or stepping over an obstacle, the grip–inertial force coupling continues to be under anticipatory control. However, the coupling is less robust and can be explained by increased attention demands. Furthermore, the fine motor grasping functions and gross motor locomotor functions are precisely coordinated across multiple limb segments to ensure successful performance right from the onset of gait initiation. These findings support the notion that grip force is based on moment-to-moment predictions of inertial forces acting on the object at gait initiation and throughout predictable variations in the gait cycle. Internal representations of the interactions between body segments through which inertia is transferred to the object–digit interface are proposed to provide the basis for this anticipatory grip force control.
Introduction
A central question in the study of systems motor control is how simultaneous tasks involving multiple body segments are coordinated. For example, during voluntary movements with a hand-held object, grip (normal) force is coupled to the object's load as well as to the motion-induced inertial (tangential) force in an anticipatory manner to prevent slippage.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.