What Is Muscle Tone?

What is muscle tone?

"What is low muscle tone?" is a question that parents often ask their therapist.

Many people often confuse tone with muscle strength.

Here is a simplified overview and a brief description of normal, high and low muscle tone and their effect on movement.

Stolov, 1966, defined the tone in the muscle as "the resistance of the muscle to passive elongation or stretching" (1).

In other words, it is the state of muscle tension inside a muscle or muscle group when it is at rest.

Normal Tone

Normal tone means that there is the right amount of “tension” inside the muscle at rest, and that the muscle is inherently able to contract on command.

Put simply, you can “tell” your muscle to stop and start and it does what you want, when you want, with the appropriate amount of force.

Here is an everyday example of how the tone in your muscles affects you when reaching for a cup of coffee!

Imagine you are sitting in your armchair, arms resting on your lap (your arm muscles are “at rest”). You decide to have a sip of your coffee, which is on the table next to you. With your normal muscle tone, you reach out with your arm, your hand connects with your cup of coffee, grasps it with just the right amount of pressure, and you bring it back to your mouth. No spills, no fuss!

Your muscles did exactly what you wanted them to do, at exactly the right speed, with the right amount of force, without wasting energy or effort.

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High Tone

High tone means there is too much tension in the muscle at rest. In other words, the muscle is tight and tense even though it is not doing anything.

A child with spastic cerebral palsy may have high tone, which causes the arms and legs to be tightly contorted. When the arms and legs are not regularly stretched and moved through physical therapy, then “contractures” may occur, which mean less and less range of movement is possible.

Reaching for a cup of coffee:

In the everyday example I gave above, if you had increased tone in your muscles, you would have to concentrate very hard and expend a lot of effort overcoming the tension in your biceps in order to stretch out your arm.

You may well end up moving your whole body towards the coffee to try and reach it, as the tension in your arm muscles is too high to be overcome with ease. Your movements are also likely to be jerky and uncontrolled, resulting in spilled coffee.

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Low Tone

Low tone means there is not enough tension in the muscle when it is at rest.

The muscle may have a slightly mushy or floppy feel to it, and there is a lack of graded control of the muscle when it is being used (graded control means that just the right amount of movement and effort is used as appropriate to the task at hand).

Reaching for a cup of coffee:

To use the coffee example again, when you decide you want to have a sip of coffee, there is not enough tension in your muscles at rest. So you use a bit extra momentum, maybe by flinging your arm out!

You bump the cup a bit, get your fingers around the handle and then drag it back, but the cup is heavy, and you use too much oomph at first (to overcome the lack of “tension” in your muscles) with the result that the coffee sloshes out. Your low muscle tone resulted in clumsiness and a lack of control in doing what you wanted to do.

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It is important to remember that muscle tone is on a continuum – you can have normal muscle tone that is a bit on the low side or a bit on the high side.

The Effect of Low Muscle Tone

The tone of the muscles affects postural control and 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 you during movement.

Children with low tone in their muscles may battle to sit upright for any period of time, and may slouch over like the child in this picture.

They may also lack endurance in gross and fine motor activities and they may struggle with games that require coordinated, controlled movements.

Postural stability needs to develop in 3 main areas:

  1. Neck muscles
  2. Shoulder girdle muscles
  3. Core muscles (trunk muscles) 

If your child lacks good postural stability, then gross motor, fine motor, and coordination skills may be affected.

Please contact your health professional if you have any concerns about your child's muscle tone, postural control or any other aspects of development. This webpage serves to inform, not to diagnose.


Helpful Activities

If you are looking for activities to help your child develop optimally in order to be ready for school, then you can check out these pages of my site for some easy activity ideas to strengthen your child's skills:

Core Exercises
Shoulder Exercises
Gross Motor E-Books
Gross Motor Skills in Preschool
Coordination Skills for Kids
Foundations for Good Fine Motor Skills

Thank you for visiting!

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Sources:

1) Mathiowetz and Haugen. Evaluation of Motor Behavior: Traditional and Contemporary Views. Occupational Therapy for Physical Dysfunction, Baltimore: Williams & Wilkins, 1995.


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