Isometric exercise strengthens muscles without
a. contracting muscle fibers
b. changing muscle length
c. burning calories
d. conscious effort

Isometric exercise strengthens muscles without changing muscle length. Correct B

In this type of strength training in which the exercises work on the muscles in a static position and demand muscle tension without any actual movement. The joint angle and muscle length do not change during contraction.

b. changing muscle length

Explanation:

The isometric exercises are the strength-enhancing exercises that are done to support the contractions of the specific groups of muscles. During the isometric exercises, the muscles do not change their length and there is no visible movement at the joint. In other words, these exercises make tension over the muscles without actually moving the muscles. The three main kinds of isometric exercise are pulls, holds and presses for a considerable time duration.

answer; training;

d, i believe because of it's activity level