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.
Thus, when a muscle spindle is stretched and the stretch reflex is activated, the opposing muscle group must be inhibited to prevent it from working against the resulting contraction of the homonymous muscle (Figure 2.2). This inhibition is accomplished by an inhibitory interneuron in the spinal cord.hus, when a muscle spindle is stretched and the stretch reflex is activated, the opposing muscle group must be inhibited to prevent it from working against the resulting contraction of the homonymous muscle (Figure 2.2). This inhibition is accomplished by an inhibitory interneuron in the spinal cord.