The answer is B.

A may or may not be incorrect. Some reports say that isometric contractions recruit more muscular units than isotonic contractions but the latest say the opposite, so this issue is controversial (I don’t know why that would be an answer as the debate is still going on.)

There was a short bit in an article I read recently:

It is at the bottom under the heading “Dynamic Exercise: A Bigger Deal for Men”

B is correct because isometric work builds strength only at the joint angle used. This is why powerlifters use isometric work to break through sticking points.

C is incorrect because the muscle is only strengthened at the joint angle used. For example, many people can hold an isometric contraction using a heavy weight in the 1/4 squat position, but they cannot do the same weight when doing a full squat, because the strength does not transfer to the full ROM movement.

D is incorrect, for the most part, because you do not gain a lot of coordination holding an isometric contraction simply because you are not moving. You might be able to balance in that position a little better, but isotonic movements generally require more coordination.

So the best answer is B. The answer choices, particularly A and D, are too ambiguous and you could probably debate them if they were on the actual test.

The answer is A.

Isometric exercise is practiced by pushing or pulling an immovable object like a wall or bar anchored to the floor. Research has shown that a muscle contraction during Isometric exercise produced more force then a contraction generated by lifting weights. Although research shows that Isometric exercise increases muscle tension significantly, it still fails to change the length of the muscles. Today, it is primarily used for rehabilitation purposes.