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.
Toxic Multinodular Goiter (Plummer's disease) One or more nodules or lumps in the thyroid becomes overactive. Subacute Thyroiditis Hyperthyroid phase of subacute thyroiditis, caused by viral infection or postpartum inflammatory process. Due to thyroid inflammation, excess hormone is released into the blood circulation.