My child has been diagnosed with low muscle tone. What does this mean?

Who gets a diagnosis of low muscle tone?

An infant or child will get a diagnosis of low muscle tone when:

  • The muscles appear to be less firm than usual
  • The child appears to be floppy and to have loose joints
  • The child appears to be less alert and have poor posture and attention

For a more technical discussion please see webmanual.skillsforaction.com/low-muscle-tone



FAQ'w.jpgThe difficulties experienced by children that lead to diagnosis of low muscle tone 

  • May be late learning to sit and walk - but not always
  • Have trouble sitting erect and working at a table - tend to sit with back rounded, may lean on one hand when drawing and writing
  • Have difficulty sitting still, tend to fidget, not complete school tasks
  • Have difficulties with handwriting and drawing 
  • May tire very quickly, not like walking far, have trouble going up stairs
  • May be good at games that involve short bursts of running, but have difficulty with posture in sitting, drawing and handwriting - these tasks require sustained activity in the postural muscles
  • Sit between legs on floor (w-sitting), do not like cross legged sitting
  • Appear to have poor attention span or concentration, give up easily
  • Cannot hang on the monkey bars, do not like climbing on the jungle gym, are fearful


    It is important to note that all these difficulties are in fact related to a mixture of coordination problems, muscle tightness, weakness and poor endurance, generalised joint hypermobility, attention difficulties, a very cautious nature and avoidance of tasks that require effort and persistence.  

A careful assessment of all these issues will highlight which are contributing to the child's difficulties so that they can be addressed. 


What causes these difficulties? 

The most common cause of these difficulties is joint hypermobility  associated with a cautious temperament.

In individuals with hypermobile joints (loose or lax joints) the connective tissue structures 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 keep a good posture and move. 

Joint hypermobility is probably the main  (and often unrecognized)  reason a child get a a diagnosis of low muscle tone. 

Children with a cautious temperament  are often quite anxious  which leads to avoidance of tasks that require effort and a tendency to give up very quickly. This in turn leads to low levels of activity, weakness and poor endurance. 

Read more here about the link between joint hypermobility and low tone 

Recognizing joint hypermobility

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Fingers that bend back to 90 degrees

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Wrist can be bent so that thumb touches the forearm 

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Knees and elbows  bend backwards 

Hypermobile joints and tight muscles as a cause of movement difficulties

Sometimes joint hypermobility is missed because the child appears to have tight muscles. It is important to understand tight muscles is a common feature of joint hypermobility, especially in the muscles crossing the back and sides of the hips.  It is also important to understand that this muscle tightness if often an important underlying cause of some of the difficulties experienced by children with a diagnosis of low muscle tone. 

ben longsitting slumped.jpg w sitting.jpg sitting slumped hips abducted.jpg
Tight back and hip muscles affect sitting posture in children with joint hypermobility

What exactly is muscle tone?

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

  1. The inherent stiffness of a muscle - its resistance to being stretched and firmness when palpated (squeezed).
  2. A muscle's (or groups of muscles') readiness for action - the muscle's responsiveness to signals from the brain and to sensory feedback.

    The term low muscle tone is used when the muscles' stiffness is less than usual (ie it is low) and the readiness for action is also low (muscles respond slowly).

​How is a muscle's firmness (tone) tested?

The clinician makes a judgment about a muscles firmness and inherent stiffness by:

  • Squeezing the muscle to feel the resistance to compression
  • Lifting up and moving the limbs and feeling the resistance to this movement 

What determines a muscle's firmness? 

The firmness of a muscle is determined by its inherent stiffness and this in turn depends on the stiffness in the connective tissue sheaths that encase each muscle fiber, hold the bundles of muscle fibers together and connects the muscle to the tendons.

In children with hypermobile joints  the connective tissue is less stiff than usual. (It has more give and is more easily stretched).

This tendency for less stiff connective tissue which results in hypermobile (lax)  muscles and joints is genetically determined. About 10-15% of people are hypermobile.

The other very important structure that that determines a muscle's firmness and resistance to being stretched is the giant molecule titin. 

Titin is a very large elastic molecule found within the muscle cell.  The size and strength of the titin molecules is determined by the  amount of work a muscle is made to do on a regular basis. Strong muscles have larger and stiffer titin molecules - and this makes the muscle firmer and stiffer.  The muscle has better tone.

Generally speaking, strong muscles are firmer and have better tone.


Muscle tone, alertness and readiness for action

The term muscle tone is also used to describe the a muscle's readiness for actionThis is set by the child's alertness,  general level of arousal and readiness for action.  

The brain primes the muscles for action by sending signals to the muscles’ sensory receptors.  In effect the sensory receptors become more alert and provide more effective sensory feedback and respond more quickly. This allows for the rapid adjustments needed for maintaining balance and postural stability.

  • When a child is alert and engaged,  the muscles are primed for action.  The muscle tone is good and the posture is erect.
  • When a child is over-aroused, the muscles may become twitchy and overactive.  This makes the child less able to focus attention on a task.
  • If a child is anxious, finds a task difficult and is having trouble focusing his attention, the normal alertness for action signals do not reach the muscles. They become less responsive and provide less sensory feedback.  Muscle tone is lowered and the child's posture becomes less erect and alert..

  


Can low muscle tone (muscle laxity) be cured? The short answer is no.

The general stiffness of a child's muscles - which is what provides the muscles' tone, depends on two factors:

The stiffness in the connective tissue - this is genetically determines (it is in the DNA) and cannot be changed.  (See  Joint Hypermobility Syndrome)

The size of the titin molecules in the muscle cells. Stronger muscles have larger titin molecules. Stronger muscles have better tone.

Muscle and joint laxity cannot be "cured".  But, and this is important,  the movement difficulties  associated with muscle and joint laxity can be improved by  training

Task specific training has been shown to be the most effective approach to increase muscle strength, flexibility, endurance, coordination and attention.  

Task specific training means that you work on the aspects of posture and motor control that need improving.

This is because motor learning and fitness training are task specific: if you want to learn to ride a bicycle you need to get on a bicycle. And if you want to win a bicycle race you have to train on a bicycle. Swimming and running are simply no good.  

Find out more about helping your child improve motor skills using a task specific approach


To help the child: understand and address the causes DG webspace.jpg

Joint hypermobility syndrome – The connective tissue is more compliant than usual, leading to joint and muscle laxity and weak muscles

  • Intervention:  Exercises to improve strength and endurance and train posture and coordination. 

A cautious nature – The child avoids  tasks and activities that are difficult or require physical effort, which affects engagement and readiness for action.

  • Intervention: providing the child with tasks that challenge them in such a way that they become less avoidant and learn courage

Muscle weakness – as a result of lack adequate opportunities for engagement in activities that load the muscles in a way that leads to increased muscle strength

  • Intervention:   an exercise training programme that provides the child with appropriate challenges to learn new skills and engage in challenging tasks that load the muscles in a way that increases muscle strength.

Developmental coordination disorder where a child has difficulty learning new skills through experience and exploring ways to perform new and challenging tasks, leading to avoidance and lack of experience.

  • Intervention: a movement training program that provides the child with opportunities for learning new skills in a structured way and encourages participation in sporting and playground activities. 

Autism - is often associated with both joint hypermobility and DCD, along with anxiety and avoidance of challenging tasks.

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  • Intervention: task based intervention that provides opportunities for learning new skills and participation in playground and sporting activities

Down syndrome where joint hypermobility and muscle laxity is a defining feature.

  • Intervention: Strengthen, strengthen, strengthen and improve endurance and active participation 

 

Help your child: starting today

More about babies with joint hypermobility and associated low muscle tone

The TAMSKA 20-minutes-a-day challenge 

 

Comments

Low muscle tone in tummy muscle

Hi, both my two younger children have low muscle tone/hypotonia, my question is about my daughter who is thirteen in a couple of weeks. Her tummy muscles have always been lax, but now as she is coming into her teens she worries more about her shape, she is not overweight at all and is actually quite slim, but as her tummy muscles don't work properly her tummy protrudes, and other children have started calling her fat. Is there anything I can buy that can help give her some shape, as I worry about her getting bbullied but also because she would like to wear nice fitted tops etc. thank you.

weak muscles

I have just been told my 2 year old wee boy left leg muscle is thinner than the other leg. what causes this.

Ask your health practitioner for more information

Hello

There a several possible reasons why one leg may be thinner than the other. If the difference is really noticeable your best bet is to ask your child's family doctor or paediatrician to take a look.  The  only way to determine the cause is to examine the child carefully.  

Pam 

Thank you

This is so well written & clear. I feel like it has clarified many things for me about hyper mobility & low muscle tone.

Thank you for the feedback

Hello and thank you for your feedback

Our knowledge of development and the factors that impact on a child's abilities is growing at a very rapid rate. I try to keep up with the scientific and evidence based literature.  The SfA website reflects my interest in translating this new knowledge and best practice guidelines  into language and practical advice that can be understood and used by parents. 

Much of the information and advice that you find on the web is based on assumptions and recommendations from the 60' and 70's of the last century when new approaches to intervention were being developed, such as Bobath  (NDT)  sensory integration therapy.  Recent research has shown that many of these ideas need to be updated or abandoned altogether. 

What is more worrying is the proliferation of brain based therapies which are based on some commonly espoused neuromyths.  One that I find particularly annoying is the "integration of primitive reflexes"  neuro-nonsense.  Watch out for therapies that promise to fix all manner of problems with a few exercises that help to integrate the primitive reflexes and in so doing allow the "higher level brain areas" to work properly! 

Snake oil in a new form.

Pam  

 

Hypotonia

Hello there, we've been told that my son who is 9 months old has hypotonia ,his gross motor and fine motor is very weak.since then we have work out some exercise for him and he can sit and can stand with a support but we are still trying to work on his fingers which he can hold but not for long .please can you tell me if he will be a normal person like us once the proper treatment start. Tia

Encourge your boy to be as active as possible

Hi Tia 

No matter what the underlying reasons are for your infant's poor movement skills and developmental delay,  he will benefit from being encouraged to be as active as possible and do as much as he can. 

Hands get stronger when they are used for picking up things, pulling, pushing, banging and rattling - all the things that young babies do when they are 9 months old. So you need to find ways to get your infant to play more. 

About whether your baby will get stronger - obviously I cannot say anything about that. The term low tone is very vague - low tone is not a developmental disorder - it says nothing about what is causing your infant's developmental delay. So you need to ask the doctor for more information. 

Pam 

 

Is Jumping Good

Hi Pam

I have a 2 yr old boy with mild hypotonia. He is crawling and can stand with support but not yet walking. I am thinking of buying him a child trampoline to help his development. Please advise if this is recommended or not.
Thanks

Jumping is good

Hello and apologies for not responding sooner. 

Jumping on a trampoline is good for getting kids active and strengthening the muscles and increasing endurance. This in turn leads to stronger connective tissue structures and increases the resistance to deforming forces. If you think the body as a set of struts held in place for tensioned wires - increasing connective tissue strength and stiffness makes the whole system more stable. 

My hypermobile late walking (18 months) grandson started jumping on our new trampoline at the age of  15 months and quickly got the hang of  bouncing from  sitting up to standing. At 2 1/2 he is an ace jumper and moves around on solid ground at speed, running interspersed with jumping and galloping. He is certainly a very "toned"  little fellow these days. 

I need to add that I was not able to find any research to back up the assumptions that are made about the value of jumping on a trampoline. So this is a very personal opinion and an observation of one child.  If your boy enjoys playing on the trampoline and it gets him moving lots, well then it is probably doing some good.  However, you still need to give your boy opportunities for running and jumping on solid ground, with different surfaces, slopes and unevenness to develop his coordination and balance. 
 
Just one word of caution - choose a well designed trampoline with adequate padding and a secure surround net. And supervise your boy on the trampoline at all time.

Pam 

7 years old and lmt..

My daughter is 7 now, she had low muscle tone. We are still trying to find a cause for hers. It was once said she had Ehlers-danlos syndrome. My daughter might have type 7 (arthrochalsia), but there is a "classical" form that is just muscle weakness. Check out their website by googling ehlers danlos national foundation. My email is [email protected]

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