Isometric exercise presents unique physiological demands. Hettenger and Muller first popularized it in the 1950s, describing it as muscle contraction against an immovable subject.
An isometric exercise can be done by:
*Pushing against an immovable object or
*Holding a weight in a position with the muscles contracted
More specifically, active muscle contraction occurs with an absence of any limb movement or change in muscle length. Isometric muscle actions occur during normal human activity.
Research has shown that isometric exercise can significantly increase the tension of the muscle. Thus, a person can achieve maximum muscle contractions by performing isometric exercises, in contrast to regular isotonic weight training. Significant cardiovascular effects can occur with isometric exercise, including marked elevation of both systolic and diastolic blood pressure.
Other normal cardiovascular response includes increase in heart rate and sympathetic neural activity. There also can be greatly elevated stress to the left ventricular wall.
Isometric exercise
