tensor fasciae latae

Etymology
Borrowed from.

Noun

 * 1)  A muscle that arises especially from the anterior part of the iliac crest and from the anterior superior iliac spine, is inserted into the iliotibial band of the fascia lata about one third of the way down the thigh, and acts to flex and abduct the thigh.

Usage notes
While the plural regularly would be, apparently Latin proficiency and exercising do not overlap for it to be actually used. Instead one postpends to pluralize. Also one obtains a plural by switching to the initialism in common parlance, i.e. .