PEAK PERFORMANCEWeeks to result

Henneman Size Principle

Recruit motor units

Problem it solves

Individuals who struggle to build and sustain consistent behaviors in peak performance, relying on willpower instead of systems that make good actions automatic.

Best for

Individuals looking to improve muscle strength and hypertrophy

Not ideal for

Those with severe muscle or nerve damage

Overview

Why this framework exists

The Henneman size principle explains how motor units are recruited to control muscle movement. It states that motor units are recruited in a specific order, from low to high threshold, to conserve energy. Understanding this principle can help individuals optimize their workout routines to improve muscle strength and hypertrophy.

Core principles

3 total
  1. Motor units are recruited in a specific order to conserve energy
  2. The recruitment of motor units is dependent on the intensity of the movement
  3. The Henneman size principle applies to all types of muscle movement, including voluntary and involuntary movements

Steps

3 steps
  1. Understand the Henneman size principle
    Learn about the Henneman size principle and how it applies to muscle movement. Understand the concept of motor units and how they are recruited to control muscle movement.
    Pro tipFocus on understanding the underlying physiology of muscle movement
    WarningIgnoring the Henneman size principle can lead to ineffective workout routines
  2. Apply the Henneman size principle to workout routines
    Use the Henneman size principle to optimize workout routines. Focus on recruiting motor units in the correct order to improve muscle strength and hypertrophy.
    Pro tipStart with low-intensity movements and progress to higher-intensity movements
    WarningOverdoing it can lead to injury or burnout
  3. Monitor progress and adjust workout routines
    Monitor progress and adjust workout routines as needed. Use the Henneman size principle to adjust the intensity and volume of workouts to continue making progress.
    Pro tipKeep a workout journal to track progress
    WarningPlateaus can occur if workout routines are not adjusted

Checklist

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Examples

2 cases
Example 1: Applying the Henneman size principle to a workout routine

An individual applies the Henneman size principle to their workout routine by starting with low-intensity movements and progressing to higher-intensity movements. They monitor their progress and adjust their workout routine as needed.

OutcomeThe individual sees significant improvements in muscle strength and hypertrophy.
Example 2: Ignoring the Henneman size principle

An individual ignores the Henneman size principle and starts with high-intensity movements. They do not monitor their progress and do not adjust their workout routine.

OutcomeThe individual sees little to no improvement in muscle strength and hypertrophy and may experience injury or burnout.

Common mistakes

3 traps
Ignoring the Henneman size principle
Ignoring the Henneman size principle can lead to ineffective workout routines and a lack of progress in improving muscle strength and hypertrophy.
Overdoing it
Overdoing it can lead to injury or burnout. It is essential to start with low-intensity movements and progress to higher-intensity movements.
Not monitoring progress
Not monitoring progress can lead to plateaus. It is essential to monitor progress and adjust workout routines as needed.

Origin story

How this framework came to be

The Henneman size principle was first proposed by Elwood Henneman in the 1950s. Since then, it has been widely accepted and applied in the fields of muscle physiology and neuroscience.

Source

Traced to primary
Source · PODCAST
Build Muscle Size, Increase Strength & Improve Recovery | Huberman Lab Essentials
Andrew Huberman · 2025
Open source →