Voluntary may refer to:
* Voluntary (music)
* Voluntary or volunteer, person participating via
volunteering
Volunteering is a voluntary act of an individual or group freely giving time and labor for community service. Many volunteers are specifically trained in the areas they work, such as medicine, education, or emergency rescue. Others serv ...
/volunteerism
* Voluntary
muscle contraction
Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such a ...