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.
The actions of these two muscles are antagonistic: one muscle must relax while the other contracts to execute horizontal eye movements. Four other extraocular muscles working together control vertical eye movements and eye rotation around the mid-orbital axis (Figure 8.1, right).he actions of these two muscles are antagonistic: one muscle must relax while the other contracts to execute horizontal eye movements. Four other extraocular muscles working together control vertical eye movements and eye rotation around the mid-orbital axis (Figure 8.1, right).