Efficiency of grip force adjustments for impulsive loading during imposed and actively produced collisions

Area of Science:

• Neuroscience
• Motor Control
• Human Factors

Background:

• Object manipulation relies on predictive feedforward and reactive feedback for grip force (GF) adjustment.
• Impulsive load force changes during collisions (< 20 ms) necessitate predictive GF control for grasp stabilization.

Purpose of the Study:

• To investigate the impact of practice and vision on predictive GF control efficiency during collisions.
• To compare the efficiency of predictive GF control in active versus passive collision scenarios.

Main Methods:

• A collision paradigm involving subjects actively producing or receiving imposed pendulum collisions.
• Measurement of grip force (GF) levels in response to varying load forces and collision types.
• Analysis of GF adjustments with practice and the presence or absence of visual feedback.

Main Results:

• Subjects exhibited greater GF control efficiency when actively producing collisions compared to receiving them.
• Practice significantly improved GF control efficiency in the active task, but not in the imposed collision task.
• Visual feedback reduced GF levels in the imposed collision condition, suggesting enhanced confidence and potential for more efficient grip.

Conclusions:

• Predictive GF control efficiency is influenced by the nature of motor engagement (active vs. passive).
• Sensorimotor memory development through practice enhances predictive GF control in active tasks.
• Visual feedback can improve predictive GF control in passive tasks, potentially by increasing subject confidence.