Minimizing command timing variability is a key factor in skilled actions.

Area of Science:

• Motor control
• Biomechanics
• Computational neuroscience

Background:

• Athletes' performance variability is traditionally attributed to neural sensory and motor output fluctuations.
• Existing models explain only a fraction of observed movement inconsistencies.

Purpose of the Study:

• To propose and validate a new theory explaining movement variability.
• To investigate the role of motor command timing in movement inconsistencies.
• To explore the relationship between handedness and motor command timing variability.

Main Methods:

• Computational modeling of movement variability.
• Analysis of position and force data during discrete and periodic movements.
• Comparison of muscle timing variability between dominant and non-dominant arms.

Main Results:

• The proposed theory, emphasizing imprecisely timed motor commands, effectively explained observed position and force variability.
• Timing variability was significantly larger in the non-dominant arm's muscles compared to the dominant arm.
• This suggests a link between handedness and motor command timing variability.

Conclusions:

• Imprecisely timed motor commands represent a major source of movement variability in athletes.
• The theory offers a unifying computational framework for understanding motor control and performance inconsistencies.
• Findings highlight the importance of precise motor command timing for optimal athletic execution.