What is muscle tone?

The term muscle tone refers to two aspects of muscle structure and function:

• the inherent stiffness of a muscle (its resistance to being stretched)
• the firmness when it is palpated (squeezed).

The term muscle tone is also used to describe a muscle’s readiness for action.  For example, muscles in our arms will contract with more force when we lift something or push something. But our postural muscles have a continuous and subconscious partial contraction at all times. This allows for the rapid adjustments needed for maintaining balance and postural stability. Normal muscle tone means that there is the right amount of “tension” or TONE inside the muscle at rest, and that the muscle is able to contract on command. With normal muscle tone, you can “tell” your muscles to stop and start, and they will do what you want, when you want!  Your muscle tone affects your postural control and your postural stability. Postural control and postural stability give you the “background” control of your body that is necessary for helping you to stay upright and to stabilize your core while you move your limbs.

In children, postural stability needs to develop in 3 main areas:

• Head/neck muscles
• Shoulder girdle muscles
• Core muscles (trunk muscles).

Poor stability in the large postural muscles will have an impact on both the child’s fine motor and gross motor skills.

What does a child with low muscle tone look like?

• The muscles may appear to be less firm than usual.
• The child may seem to be floppy and to have loose joints.
• The child appears to have poor posture and attention.
• The child may be late learning to sit and walk – but not always.
• The child may have trouble sitting up straight and working at a table. They may sit with their back rounded, and may lean on one hand when drawing and writing.
• The child may have difficulty sitting still, tend to fidget, and not complete fine motor tasks.
• The child may tire very quickly, not like walking far, and have trouble going up stairs.
• The child may be good at games that involve short bursts of running, but have difficulty with posture in sitting, difficulty coming down stairs, or difficulty walking across a balance beam– these tasks require sustained activity in the postural muscles.
• The child may sit between legs on floor (w-sitting) when on the floor.
• The child may not be able to hang on the monkey bars, or not like climbing on the jungle gym.

What are loose joints?

Children with low muscle tone often have loose joints. In individuals with hypermobile joints (loose or lax joints) the connective tissue structures, such as the ligaments and tendons, that hold the body together have more give (are more easily stretched) than usual. This means that the muscles must work harder than usual to hold the body up and maintain good alignment of the body.

What can be done about low muscle tone?

Hypermobility(loose joints) and low muscle tone are genetically determined at birth.  Low muscle tone and joint laxity cannot be “cured”; but the movement difficulties associated with muscle and joint laxity can be improved by increasing muscle strength, flexibility, endurance, and coordination. Children with low muscle tone benefit from frequent changes in position—lying, standing, or kneeling to do work– instead of just sitting. Special seat cushions can help give these children more support while they are developing better strength and endurance.