What to look for in a prenatal vitamin. Prenatal vitamins are available by both over-the-counter and by prescription. Although formulations can vary from brand to brand, these are the most important vitamins and minerals to look for:
Muscle pairs. Antagonistic pairs of muscles create movement when one (the prime mover) contracts and the other (the antagonist) relaxes. Examples of antagonistic pairs working are: 1  the quadriceps and hamstrings in the leg.2  the biceps and triceps in the arm.uscle pairs. Antagonistic pairs of muscles create movement when one (the prime mover) contracts and the other (the antagonist) relaxes. Examples of antagonistic pairs working are: 1  the quadriceps and hamstrings in the leg.
Muscle spindles and the GTOs are two important proprioceptors involved in flexibility, stretching and working together reflexively to regulate muscle stiffness. When the GTO is excited or activated, it causes the muscle to relax (which is opposite of a muscle spindle causing it to contract).he muscle spindleâs reflex contraction of its associated muscle simultaneously causes the antagonist muscle group to relax, which is called reciprocal inhibition. The muscle spindle serves as an alert to the muscles; they are located in the muscle belly and sense muscle stretch.