This is known as a hypnic jerk – but what exactly is it and why does it happen? Also known as hypnagogic jerks or sleep ...

Vaginismus is currently defined as an involuntary vaginal muscle spasm interfering with sexual intercourse that is relatively easy to diagnose and treat. As a result, there has been a lack of ...

Biofeedback therapy is a nondrug treatment in which people learn to control bodily processes that are usually involuntary, such as muscle tension, blood pressure, or heart rate. Biofeedback may ...

Charley horse is another name for a muscle spasm or muscle cramp. It’s marked by involuntary, uncomfortable, and sometimes painful muscle contractions that may last a few minutes. A charley ...

Muscle is a soft tissue composed of elongated cells (muscle fibres) that produce force and motion through contraction. Involuntary cardiac and smooth muscles are responsible for contraction of the ...