How Input From Muscles and Joints Affects Our Balance
Just as a baby first learns how to balance by practicing and repeating certain movements, each of us adjusts to changing environments or health conditions throughout our lives to keep our balance. But how do our muscles and joints play into this?
Balance Maintained by Our Complex Sensorimotor Control Systems
Our balance is maintained by complex sensorimotor control systems all working together, and if one of these systems is upset or not working properly, we can lose balance. The three main systems of the body that provide sensory information to keep us in balance are vision, the vestibular system (inner ear) and the proprioceptive (or somatosensory) system.
It is the proprioceptive system that involves feedback to our brains from our muscles, joints and pressure sensors. This system has pressure and position sensors in the feet, trunk and spine. According to the Vestibular Disorders Association (VeDA), sensory information coming from our necks and ankles are the most important. "Proprioceptive clues from the neck indicate the neck indicate the direction in which the head is turned. Cues from the ankles indicate the body’s movement or sway relative to both the standing surface (floor or ground) and the quality of that surface (for example, hard, soft, slippery, or uneven).”
Information from muscles, joints and skin is produced from sensory receptors that react to pressure or stretching in tissues surrounding it in the body, telling our brains about our position in space.
How Does Motor Output Back to Our Muscles and Joints Affect Balance?
If we start tipping forward for example, the brain senses increased pressure in the front of the soles of our feet and our ankles bending. The brain can then send instructions to the muscles along back of our body to keep us from tipping further forward and pull us back upright if we weren’t leaning forward on purpose. The other two balance systems should help out with this reaction as well: the eyes should notice the forward sway relative to one’s surroundings and the inner ears should sense the forward tilt as well.
If one or more of these three systems is not working well, then the brain’s instructions to these antigravity muscles can be delayed or inaccurate, resulting in unsteadiness. Vestibular rehabilitation and balance training can help a person learn to compensate and improve their balance reactions by utilizing the remaining systems more effectively.
Source: LifeMark Vestibular Blog