MUSCLE TONE IN BABIES
It is helpful to understand how the length of time a baby is carried in the womb prior to delivery may influence the level of tone in her muscles. The term “muscle tone” can be defined as the balanced level of tension in the muscles. By “balanced” we mean that the muscles are capable of a range of tension levels, from very contracted which brings the limbs close to the center of the body to very stretched which straightens the limbs out away from the body. A baby carried to full term usually has balanced muscle tone. This is evident in the newborn as she is lying on the floor. Observe that her limbs are bent and rather close to her torso until she learns how to move them on her own. One she begins to move them through learning the motor skill of kicking, her muscles go through the full range of motion from being flexed and close to her torso to being extended and stretched out. In babies born premature, muscles usually have lower muscle tone. This means that baby’s limbs are more stretched out, more relaxed in appearance. Sometimes the term “hypotonic” is used to describe the muscle tone in premature babies, usually those with very relaxed muscles. This means the relaxed range of muscle tone is very familiar and the contracted range is a bit difficult to achieve.
MOTOR SKILL DEVELOPMENT IN PREMATURE BABIES
Motor skill development is more challenging for babies born with low muscle tone, because their muscles have to work harder to develop a fuller range of muscle tension. The baby carried to full term usually has the fuller range of tension already in their muscles. Premature babies benefit tremendously from a lot of motor skill games and activities. Their muscles need “extra practice” for their first year milestones.
SUPPORT FOR PREMATURE BABIES
Due to the relaxed quality of the premature baby’s muscles, it is easy for the heavy parts of her body to flop backward when you pick her up. It is very important to fully support her head and neck, as well as the limbs of her body. Keep a hand behind her head and neck when holding and moving her. Try to keep her arms and legs from dangling when you hold her by folding them in toward the midline a bit. Hold her so her spine is a bit rounded rather than straight. As she develops strength in her muscles she will be able to support her head and move her muscles through the full range of motor activity.
PROPRIOCEPTION AND PREMATURE BABIES
Parents can learn hands-on activities that guide baby to feel the range of motion in various movements, making it easier for baby to find the movements on her own. For example, a “preemie” may keep her arms fairly straight but through the use of your hands you can show her how to bend and straighten her arm. These activities improve baby’s proprioception. They are fun for baby, too. They guide her toward a clearer feeling of her body and an improved ability to bend and straighten her limbs. As she learns to feel and move her muscles, they gain strength improving the range of muscle tone. This is one of the most important developments during baby’s first year. The motor milestones teach her to use her muscles, support her own body, and to travel from one place to another.