Levels of movement construction

Today I read a bit about Nikolai Bernstein, a neurophysiologist who studied movement and action in the USSR. He was overshadowed by Pavlov, and the book he’s most known for (On Dexterity and its Development) wasn’t published until 20 years after his death.

For some reason I’m most interested in his Levels of Construction which breaks movement down into four levels.

• The Level of Tonus: This is muscle tone and posture, the most basic level. These movements maintain posture and muscle readiness. Think tension and stability.
• The Level of Synergies: This is the coordination of muscle groups. This level coordinates groups of muscles (synergies) that produce familiar patterns of movement and rhythms.
• The Level of Space: This is spatial and temporal movement planning. Here movement is planned in relation to the environment using higher order sensory information. It’s about timing, trajectory, spatial relationships, and movement in 3D space.
• The Level of Meaning: This is intention and semantic organization. Movement at the highest level, concerned with intention, purpose, and goal-setting. It connects movement with meaning, linking action with cognition, emotion, and symbolic thought.

If I’m reaching for a cup, at the level of tonus I’m going to shift my weight to counterbalance the arm reaching out. At the level of synergies I’m executing a preprogrammed action I’ve repeated thousands of times called reaching. At the level of space I’m adjusting my movement to slip past the water bottle standing next to the cup. And at the level of meaning I’m reaching with a bit of pomp and performance because I’m handing it over to a guest. Altogether this constructs the specific movement I perform.