Master Thesis Proposal Defense: Xin Jin
Time: 10:00-11:00am, Tuesday, March 15th, 2011
Location: 049 Townsend Hall
Title: The effect of instruction and hand dominance on grip force coordination in manipulation
tasks
Advisor: Slobodan Jaric, PhD
Committee: Nancy Getchell, PhD; Susan J. Hall, PhD
Abstract: The ability of our hands to grasp and hold an object is the most frequent action
performed in our daily motor activities and essential for living an independent life. According to
a simple prehension model, the force applied upon a vertically oriented hand-held object could
be decomposed into two distinctive but highly coordinated components: the grip force (GF, force
component that is perpendicular to the hand-object contact area to provide friction) and the load
force (LF, force component that is parallel to the hand-object contact area that can either move
the object vertically or provides externals support of the body).The GF-LF coordination could be
affected by a number of factors that still remain underexplored. The aim of this study is to
specifically explore the possible effect of instructions and hand dominance. Fifteen right-handed
subjects will be tested on a custom designed instrumented device that records the grasping forces
applied against the device's handles. Subjects will perform bimanual manipulation tasks under
different instructions and mechanical conditions. The exerted GF and LF will be recorded and
analyzed. Indices of GF scaling, GF-LG coupling and GF modulation will be calculated
separately for the dominant and non-dominant hand. We hypothesize that the instruction "to
pull" will reveal higher indices of GF-LF coordination than the instruction "to hold", as well as
that the effect of hand dominance will be different under different instructions.