Understanding the Dynamics of Movement: “When Flexors Flex, Extensors Extend"

In human movement, muscles must coordinate effectively to maintain balance and function.

This fundamental principle was identified by Dr. Ida Rolf, the founder of Rolfing Structural Integration, encapsulated in her statement: “When flexors flex, extensors extend.”

This observation underscores the reciprocal relationship between muscle pairs, which is essential for efficient movement.

In this discussion, we will explore the implications of this principle and its importance for improving bodily structure and movement through Rolfing.

Deep Tissue Release

The Basics of Muscle Pairs and Movement

Our bodies are composed of numerous muscles that work harmoniously to allow us to move, stretch, and perform activities. Muscles typically work in pairs, known as agonists and antagonists:

  • Agonists are the muscles primarily responsible for executing a movement by contracting.
  • Antagonists are the muscles that relax and extend to accommodate the agonist’s contraction.

This relationship demonstrates balance and coordination within our musculoskeletal system, which is crucial for smooth and efficient movements. Dr. Rolf referred to this principle when she said, “When flexors flex, extensors extend.”

Flexors and Extensors: The Dance of Movement

  • Flexors: These muscles help bend joints and decrease the angle between two bones. For example, when you curl your arm, your biceps (a flexor) contract, decreasing the angle at the elbow.
  • Extensors: In contrast, extensors work to straighten joints and increase the angle between bones. Following our previous example, when you stretch your arm out, your triceps (an extensor) takes over, increasing the elbow’s angle.

This interplay is known as reciprocal inhibition, where the activation of flexors inhibits the activity of extensors and vice versa, facilitating smooth and coordinated movements.

Why Is This Important in Rolfing?

In Rolfing Structural Integration, understanding and applying the principle of “when flexors flex, extensors extend” is vital. It helps Rolfers in several ways:

  • Enhancing Body Alignment: Rolfers can help rebalance the body’s structure by recognising which muscles are overactive or underactive.
  • Improving Movement Efficiency: Teaching clients about their muscle dynamics can lead to more fluid and less strenuous movements.
  • Reducing Pain and Discomfort: Often, pain arises from imbalances in muscle activity. Correcting these can alleviate discomfort and enhance overall well-being.

Practical Applications

During Rolfing sessions, practitioners employ a variety of techniques to adjust and optimize the body’s alignment and functioning. One common focus is addressing muscle imbalances by releasing tension in tight extensors or strengthening underused flexors. Here’s a deeper look into how these interventions can enhance physical well-being:

Releasing Tension in Tight Extensors: 

Extensor muscles, which help straighten joints, can often become tight due to prolonged sitting, repetitive activities, or imbalanced exercise routines. Tight extensors can restrict movement and lead to discomfort or pain. During a session, a Rolfer uses targeted manual therapy techniques to stretch and loosen these muscles, helping to restore their elasticity and reduce stiffness. This alleviates immediate discomfort and improves the range of motion, making everyday movements more accessible and fluid.

Strengthening Underused Flexors: 

Conversely, flexors, which bend joints and are essential for movements like walking or bending, can sometimes become weak if they are not engaged regularly or adequately. This weakness can lead to an overreliance on other muscle groups, causing further imbalances and potential strain. Rolfers might incorporate specific movements and exercises to strengthen these flexors, enhancing their functionality. Doing so ensures that muscle pairs work more symmetrically, promoting better posture and more efficient movement patterns.

Supporting the Area Being Worked On: 

Focusing on specific muscle groups, such as tight extensors or weak flexors, helps to relieve localized issues. For instance, addressing tightness in the lower back extensors can significantly improve lower back pain, a common complaint among many people.

Contributing to the Body’s Overall Harmony and Functional Efficiency: 

The benefits of addressing specific muscle imbalances extend beyond the localized area. By ensuring that all parts of the body function optimally, Rolfing helps to distribute forces more evenly across the musculoskeletal system. This holistic improvement in muscle function and joint movement reduces the overall strain on the body, decreases the risk of injuries, and improves overall physical performance. Furthermore, as the body becomes more aligned and balanced, individuals often experience enhanced energy levels and a greater sense of well-being.

Through these focused interventions, Rolfing sessions aim to create a more balanced body that moves with greater ease and efficiency, supporting specific physical issues and enhancing overall health and functionality.


Dr. Ida Rolf’s exploration of the reciprocal nature of muscle action provides a framework for understanding the balance our bodies strive to maintain for optimal function.

In Rolfing, these principles are applied to address imbalances and improve movement efficiency, contributing to better health and increased vitality.

For further updates on how Rolfing can deepen your understanding of your body and improve your physical health, keep an eye on our blog.

If you’re interested in experiencing the benefits of Rolfing firsthand, consider scheduling a session.

Discover how heightened body awareness can foster significant improvements in both your physical and mental well-being.