Why Movement Feels Labored: Rotational Relationships in the Human Body

Rotational inertia, also called moment of inertia, is a measure of how resistant an object is to changes in its rotation. It depends not just on how much mass an object has, but on how that mass is distributed relative to the axis around which it rotates. Mass distributed farther from the axis, center line of balance, contributes more to rotational inertia than mass held close to it.

Torque is the rotational equivalent of linear force. It describes how effectively a force causes rotation around an axis, and it depends on two things: the magnitude of the force and the distance from the axis to the point where that force is applied, called the moment arm.

A door hinge illustrates this clearly. Pushing the door near the hinge requires much more effort than pushing near the outer edge, even though the door’s weight hasn’t changed. The force is the same; the moment arm is different. More distance from the axis means more torque produced by the same force.

Angular acceleration describes how quickly rotational speed changes over time. A merry-go-round being pushed from a standstill to a full spin is a useful example: during that spin-up phase, when rotational speed is increasing, angular acceleration is present. Once it reaches a steady spin, angular velocity, the speed of rotation, continues, and angular acceleration, the rate of change of that speed, does not.

These three quantities, rotational inertia, torque, and angular acceleration, are connected by a straightforward relationship: torque equals rotational inertia multiplied by angular acceleration (τ = Iα). What this means practically is that for a given amount of torque, muscular effort, a higher rotational inertia produces less angular acceleration.

The body has to work harder to produce the same movement.

A body organized close to its neutral axis keeps rotational inertia relatively low. A body carrying postural compensations effectively distributes mass farther from that axis, raising rotational inertia. The muscular system then has to generate more torque to produce the same movement, and does so less efficiently. That is the physics behind why a compensated body feels effortful to move.

The human body often develops inefficient movement patterns over time that structurally shorten tissue. That shortening pulls the body away from neutral, generating compensation patterns that further increase rotational inertia.

Any deviation from neutral increases the distance from the axis of rotation, the lever, and the lever directly alters the energy needed to move an object. In this case your body.

A greater distance from neutral, produced by compensation patterns, increases rotational inertia, and therefore the torque and energy needed to move.

Humans are not immune to this principle. Together, torque, angular acceleration, and the resultant rotational inertia define an aspect of how you move within gravity with ease or difficulty. For a deeper look at how fascial tension contributes to these restrictions, see our post on fascia and chronic pain.

Human gait naturally involves many rotational movements within an upright body, and these rotational movements coordinate with the elastic recoil stored in fascia and tendons, allowing energy generated in one phase of the gait cycle to propel the next. Ballet dancers exude this ability.

Unfortunately, most people carry restrictions that reduce effective rotational movement, optimal elastic recoil, and lock them into dominant rotational patterns throughout the whole body, increasing movement difficulty.

Those stuck patterns prevent movement toward neutral alignment. Therefore, over time, the inability to reach neutral or move through a balanced range of rotation produces excessive tension and wear in the tissue and joints.

When someone operates within a rotational pattern, three main pathways tend to emerge. The following will elaborate key points for how people generally go about dealing with their pattern by increasing in movement specificity and longevity of the body.

The most common pathway involves no movement out of the pattern. Instead, the person heavily compensates by recruiting other areas of the body to move forward with limited available motion.

Older individuals who have not addressed their movement patterns over time often represent the most extreme version of this pathway. Time consistently accentuates unaddressed issues, deepening postural restriction and reducing mobility progressively.

The second most common pathway involves slightly more movement out of the pattern and toward neutral.

These individuals use modalities such as yoga, pilates, lifting, or sports to open more movement opportunities. These approaches offer real benefits. However, without specific awareness of individual patterns, they can inadvertently strengthen maladaptive patterns in the process. 

For those training very specific movements, exercising, they can end up breaking at a point, having an injury, in their pattern due to overuse of their maladaptive pattern.

However, this concept also applies to everyone in daily life, where movements are repeated over years and one day an injury ‘just happens’ doing something they have done forever.

Those who benefit most from this pathway are usually operating at elite levels, or do it for years, of their chosen modality and tend to start with fewer restrictions to begin with. For more on why stretching and movement modalities often fall short of resolving deep pattern restrictions, see our post on why stretching and massage alone often fall short of resolving chronic pain.

The third and least common pathway involves actively working to move out of the pattern with specificity and intention.

These individuals understand their body’s rotational pattern and have done targeted work to un-restrict and restore glide to the areas that most strongly hold their pattern.

Their awareness operates on two levels, both conscious and subconscious, and instead of repeatedly wearing down their body in daily life or exercise, they build adaptable movement patterns that heighten the health and longevity of the body. That means, over time and as you age, you do not end up hobbling or having worn out joints that require replacements.

The Anatomy Trains Structural Integration 12 series, offered at Somatic Healing and Alignment in Lakeville and Edina, develops exactly this kind of heightened awareness.

As the tensional environment settles, the body can release its individual survival mechanisms and begin supporting the whole as a cooperating unit. To learn more about how the 12 series is structured, see our post on Anatomy Trains Structural Integration: A Path to Wellbeing.

When someone operates deep within their rotational pattern without the ability to move out of it, they expend excessive energy just to move, as they have higher rotational inertia and less effective bodywide coordinated movement. Higher rotational inertia demands more torque, energy, to overcome resistance, and that demand shows up as fatigue, compensation, and strain.

The first pathway, characterized by no available extra movement and no conscious awareness, has the highest rotational inertia and consumes the most energy.

The second pathway is less energy consuming, as those individuals can typically move toward neutral and have a wider range of movement opportunity.

Both pathways, however, require a movement to go around the restriction before the desired movement can actually occur. In other words, they must move before they can move.

The third pathway is the least energy consuming of the three.

As, over time, individuals on this path continuously reduce their rotational restrictions, and therefore rotational inertia, by consciously and subconsciously learning to move out of their pattern and through gravity more efficiently. Leading to the most opportunity for movement, range of motion, and least amount of strain.

For the other two pathways, specific improvement is more largely left to chance.

The following example does not represent any one person:

Mark, a 45 year old office worker and recreational runner, came to Somatic Healing and Alignment reporting chronic right hip pain, a persistent left shoulder tension, and a sense that his running felt increasingly effortful despite consistent training.

Upon assessment, a clear rotational pattern emerged. His pelvis tilted forward and to the right. His ribcage compensated with a counter rotation to the left, and his left shoulder blade sat higher while the right shoulder fell further forward than the left.

This full body rotational pattern increased his overall rotational inertia, meaning every stride required more energy than it should have. With every rotation there are resultant tilts, shifts, and bends among the body, however rotations are the focus here.

Mark began the Anatomy Trains Structural Integration 12 series. The first four sessions released the superficial tissues from postural stability demands.

By session six, his right hip felt noticeably painless during runs and left shoulder tension had reduced significantly. The spiral line session had already unraveled the superficial rotational compensation, allowing the deeper core work to produce more lasting change.

By the end of the series, Mark described his running as effortless compared to where he had started. His body had shifted from the first and second pathway into the third, with conscious and subconscious awareness of how to sustain that change independently. For more on how the series addresses the deep front line core, see our post on embodying the core: the importance of the deep front line.

Living without ever engaging a structural integration 12 series is entirely possible. However, it commonly leads to a cycle of chronic pain issues that follow one after another without real relief or a framework for resolution.

Structural Integration provides the opportunity for your system to stay dynamic throughout the day rather than stiffening up and cycling through familiar pain. The internal movement balancing your system that follows the 12 series produces change that carries forward for life.

Natalie and Xavier, both Board Certified Structural Integration Practitioners at Somatic Healing and Alignment, bring this work to clients throughout Lakeville, Edina, and the greater Twin Cities area.