Within the framework of desire we apply in erotic shibari, we manage behavior through various techniques, including anatomical restriction.
Biomechanical Restriction
More accurately, we should refer to biomechanical restriction, as it involves how the body’s own structures—bones, joints, muscles, and ligaments—limit the range and direction of possible movements.
Types of Movement
Linear:
- Forward and backward movement (X-axis)
- Side-to-side movement (Y-axis)
- Up-and-down movement (Z-axis)
Angular:
- Rotation around the X-axis (tilt)
- Rotation around the Y-axis (yaw)
- Rotation around the Z-axis (pitch)
These six movements allow the human body, considered a rigid yet mobile block, to adopt any position and orientation in space.
However, in the real human body, joints and tissues restrict these movements, so each joint has fewer degrees of freedom depending on its structure (for example, the knee only allows flexion and extension, while the shoulder permits three angular movements).
Application in Restriction
Biomechanically, restriction is achieved by blocking the body’s kinetic chains.
For instance, by acting on the forearm, the mobility of all joints in the same movement chain, such as the elbow and shoulder, is limited.
It’s crucial to highlight a clear distinction between erotic play and martial arts or self-defense.
In erotic play, the goal is not to cause injury or incapacitate but to restrict the movements or behavior of the play partner.
In contrast, martial arts and self-defense aim to incapacitate an opponent, with many restriction techniques designed to project (throw) the opponent away. Particularly dangerous are those based on joint dislocation (Nikyo, Sankyo, etc.).
Joint dislocation refers to the complete separation of the bones forming a joint, where the bone ends, normally in contact, lose their alignment and shift from their usual position, disrupting their function and structure.
Some risks of dislocations include ligament tears, joint deformation, loss of mobility, vagal syncope, and long-term consequences like joint instability, early osteoarthritis, and loss of function.
Risk factors include incorrect technique execution, excessive resistance from the recipient, or physical fatigue.
To prevent these risks and situations, we use restriction through muscle activation, meaning we limit the movement of a joint or kinetic chain by manipulating the muscles themselves, rather than forcing a joint dislocation.
This technique relies on a functional understanding of anatomy and biomechanics.
It does not aim to cause pain or push the joint to the edge of its range but prevents the involved muscles from generating sufficient force due to their biomechanical position, often leveraging the agonist-antagonist function of the muscles.
As a result, the risk of injury is significantly reduced.