In addition, since isometric exercises are done in a static position, they won't help improve speed or athletic performance. They can be useful, however, in enhancing stabilization â maintaining the position of the affected area â since muscles often contract isometrically to aid in stabilization.
Etiology. Most (85-95%) substernal thyroid masses represent benign goiter. Historically, goiters have generally occurred because of iodine deficiency, although this is now observed primarily in developing nations.
Enlargement of the Thyroid. The term non-toxic goiter refers to enlargement of the thyroid that is not associated with overproduction of thyroid hormone or malignancy. The thyroid can become very large so that it can easily be seen as a mass in the neck.