Sechenov School
Home › Physiology › Motor Skill

Motor Skill

For medical students2 min readUpdated 2026-10-10

Motor skill is the result of sequential training in which the motor control system achieves maximum optimization. With practice, chaotic muscle activity is replaced by high coordination, resulting in movement economy and postural stability.

Act StructureAny complex movement requires postural stabilization, tool fixation, action execution, and outcome evaluation.
StabilogramReflects foot displacement and oscillations of the total center of gravity along the X and Y axes.
Mastered SkillCharacterized by minimal displacement of the center of gravity and energy conservation.

Structure of a Complex Motor Act

Using the example of shooting a weapon, the process of performing a goal-directed movement can be divided into four distinct stages, each serving a specific physiological purpose:

  1. Postural stabilization. Creating a stable base of support. The body fixes the position of the torso and feet, providing a foundation for subsequent actions.
  2. Tool stabilization. Precise muscle work of the upper limbs to rigidly fix the working instrument (e.g., a weapon) in space.
  3. Motor action. Direct execution of the task — for example, pulling the trigger via the isolated contraction of the index finger.
  4. Outcome evaluation. Utilizing feedback mechanisms. The individual assesses the success of the action (the location of the bullet hole on the target) to adjust subsequent attempts.

Instrumental Assessment: Stabilogram and Hodogram

To objectively assess how well a motor skill is formed, graphical methods are used. These graphs analyze the X and Y axes, which reflect foot displacement and, consequently, oscillations of the body's total center of gravity.

Learning Dynamics: From Novice to Professional

A comparative analysis of parameters clearly demonstrates the physiological difference between the start of training and a formed skill.

Beginning of Training (Novice):

Experienced Individual (Formed Skill):

Mnemonic

To remember the 4 stages of a motor act, use the abbreviation P-T-A-E: Posture — Tool — Action — Evaluation.

Frequently asked questions

Which CNS structures are involved in the formation and automation of a motor skill?

Various parts of the central nervous system interact to ensure the precision and smoothness of voluntary movements.

Key structures include:

  • Cerebral cortex — includes associative, sensory, and motor areas.
  • Basal ganglia — the striatum (Striatum, comprising the caudate nucleus and putamen), globus pallidus (Globus pallidus), and substantia nigra (Substantia nigra).
  • Diencephalic and brainstem structures — the thalamus (acts as a relay between the basal ganglia and cortex), reticular formation, and red nucleus.
  • Cerebellum — the coordination center, including hemispheres, vermis, and deep nuclei.

The key coordination mechanism is the feedback loop sequentially linking the cerebral cortex, pontine nuclei, cerebellum, and thalamus.

What does a novice's hodogram look like compared to an expert's?

In a novice, the hodogram covers a large area and consists of chaotic lines. In an expert, it is compact and concentrated in the center with a small dispersion area.

What is the primary physiological significance of a formed skill?

High efficiency of postural muscle function and overall movement economy, which minimizes redundant body oscillations.

Go deeper

More topics in Physiology

Integrative Theory of EmotionsTypes of LeukocytesPhysiology of Stress and AdaptationLipid and Protein HydrolysisFrontal and Parietal Lobes of the Cerebral CortexMicrocirculationMolecular Theory of MemoryRole of the Temporal Cortex in MemoryDeficits in Parietal Cortex LesionsPlateletsMyocardial Contraction FeaturesEndocrine Functions of the Kidneys, Heart, and Other OrgansPhysiology →