An infant or child will get a diagnosis of low muscle tone when:
For a more technical discussion please see Rethinking Low Muscle Tone
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.
Help your child overcome these difficulties - implement a training program to improve strength, flexibility, stamina and coordination and courage.
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
Fingers that bend back to 90 degrees
Wrist can be bent so that thumb touches the forearm
Knees and elbows bend backwards
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.
|Tight back and hip muscles affect sitting posture in children with joint hypermobility|
The term muscle tone refers to two aspects of muscles structure and function.
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:
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.
The term muscle tone is also used to describe the a muscle's readiness for action. This 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.
The behaviors associated with a diagnosis of low muscle tone can be improved with a training program that addresses the underlying difficulties
Weak muscles can be strengthened to improve posture, sitting posture and endurance, jumping,running and other outdoor activities.
Tight muscles can be stretched to improve sitting posture.
General fitness and stamina can be improved with training.
Sitting posture and endurance can be improved with a combination of exercises for strength, flexibility and coordination.
Poor coordination can be improved with task based training.
Task avoidance can be improved by addressing anxiety issues, training courage and improving confidence.
Start by identifying the things that your child cannot do and then implement a training routine to address the things that are causing the difficulties. Read more
How low muscle tone affects an infant's development and what you can do to help your infant. Read more