Some babies and children may feel a little floppy when you hold their arms and legs. The term “low muscle tone” or hypotonia, is used to describe such muscles with less tension.
A baby with low muscle tone may fail to reach his milestones on time. Janell Lee, a paediatric physiotherapist, says that if your infant has their arms and legs flat on the bed most of the time, even when awake; or if they do not move their limbs much, they probably have low muscle tone.
A toddler with low muscle tone may be late learning to walk, or trip and fall more often than their peers. “An older child with low muscle tone may lack endurance for gross- and fine-motor activities, and may struggle with games that require coordinated, controlled movements,” adds Lee. Plus, they may tire easily, have difficulty maintaining good posture, and tend to lean against a support.
“Low muscle tone is not caused by a lack of nutrients…it is also not something that can be permanently changed through exercise…”
Lee points out that muscle tone is on a spectrum — it’s possible to have muscle tone that is slightly on the low side, or slightly on the higher side, and still be able to function normally.
What causes low muscle tone?
It is not caused by a lack of nutrients, Lee says. Conditions that affect the brain, central nervous system (brain or spinal cord), or muscles can produce low muscle tone. “For instance, low tone is common in premature infants and children with conditions like Down Syndome, or in the early stages of cerebral palsy,” explains Lee.
However, there are cases where low muscle tone is not related to a separate condition (benign congenital hypotonia). These children may have minor developmental delays or learning disabilities. In most of these cases, this doesn’t signal a more serious developmental disorder, and the child may catch up on the developmental delays on his own, although he will still have low muscle tone throughout his life.
It also seems to be slightly more prevalent in Asian populations, though we are unsure why.
Muscle tone differs from muscle strength
Muscle strength refers to the amount of tension you generate when you actively contract your muscles to be able to pull, push, lift or move something; however, muscle tone is controlled by the brain at an unconscious level, that is, “when testing for tone, you should not be trying to consciously move your limb at the same time”, says Lee.
This means that muscle tone is not something that can be changed permanently through exercise – and this should not be your goal during physiotherapy, notes Lee. However, increasing the strength of your child’s muscles lets the child's body compensate for the low tone, and that is what physiotherapy sessions aim to achieve.
Muscle tone is not something that can be changed permanently through exercise... However, increasing the strength of your child’s muscles lets the child's body compensate for the low tone, and that is what physiotherapy sessions aim to achieve.
Physiotherapy and occupational therapy sessions can help a child with low muscle tone.
Lee says, paediatric physiotherapists will look at correcting the posture, strengthening the muscles, coordination and balance of the child. Occupational therapists will look at the activities of daily living, sensory perception and fine-motor tasks like handwriting.
Lee also adds that regular aerobic exercises like swimming and hiking will be helpful in strengthening muscles to support their tone.
So keep your child active — it’s so good for them!
To raise awareness of children with special needs in Singapore, Janell Lee has written a series of children books about various conditions. They can be found here.
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