Within-session acquisition of anticipatory postural adjustments during forward reaching task

Area of Science:

• Motor control
• Neuroscience
• Biomechanics

Background:

• Anticipatory postural adjustments (APAs) are crucial for maintaining stability during voluntary movements.
• Understanding APA acquisition in healthy adults provides a baseline for studying motor deficits.

Purpose of the Study:

• To investigate the learning curve of anticipatory postural adjustments (APAs) during standing forward reaching in healthy adults.
• To quantify changes in APA parameters with practice.

Main Methods:

• Ten healthy subjects performed 60 forward reaching trials to a moving target.
• Electromyography (EMG), center of pressure (COP), and kinematic data were collected.
• Repeated measures ANOVA analyzed APA changes across six blocks of trials.

Main Results:

• All subjects exhibited initial APA patterns, including posterior COP shift and tibialis anterior activation.
• Significant improvements were observed in the onset of posterior COP shift (p<0.05) and reduced tibialis anterior muscle activation (p=0.01) with practice.

Conclusions:

• The study suggests that approximately 50 practice trials are sufficient to observe APA acquisition in healthy adults.
• Further research is needed to determine optimal practice parameters for populations with movement disorders.