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  • Lauren McDougall

What is muscle tone?

Updated: Mar 29

It's different to 'strength'. Muscle tone is the amount of tension in our muscles (all of the time!). Muscles with 'normal' tone always have some amount of tension and stiffness, and are never fully relaxed. This allows them to 'react'.

Our muscle tone helps to keep us upright when sitting and standing, and it's the changes in our resting muscle tone that allow us to move, and contributes to the control, speed and amount of movement we can achieve.


You may have heard of 'hypotonia', or low muscle one (think 'o', 'low') which means they have decreased tone, and require more effort to get our muscles moving effectively. Muscles with low tone can often appear 'floppy' and have increased flexibility.


On the opposite end, we have 'hypertonia' or high muscle tone. This means there is too much muscle tone, which can make movements stiff and difficulty to move around. This is more common in conditions such as Cerebral Palsy, brain injury, stroke etc.

physiotherapy for children

Let's look at both more closely.


Hypotonia

Muscles with low tone have

a slightly longer resting length. This means the muscle fibers aren't overlapping at an optimal level, which means there are fewer points that the muscle fibers can attach to generate a pull on the muscle.

What does this mean? The muscle needs to work harder, which uses more energy. It also means muscles with low tone often need more stimulation to activate, which affects muscle response time, and negatively influences performance. This, paired with the extra energy required, is often whey we see faster fatigue rates in people with hypotonia.


Common themes:

▪️Poor posture and core stability. Difficulty maintaining posture when sitting and standing. They might slump in a chair, lie across the desk at school rather than sitting upright etc.

▪️Delayed gross motor development and taking longer to reach developmental milestones

▪️Difficulty with fine motor skills such as writing harder. This is because posture and core control create the physical foundation for fine motor skills.

▪️Getting tired quickly, fatiguing faster than peers because they have to put so much more effort into using their muscles.

▪️Clumsiness and falling

▪️Overall reduced strength

▪️A higher than usual amount of flexibility around joints


Low muscle tone can occur in different severities so someone with “low tone” might present with more obvious features than others.


Exercise is like gold for improving and managing low muscle tone. It can’t “fix” low muscle tone, but it still works it’s magic to improve outcomes. Specific exercise can improve overall strength and endurance (including core and postural endurance) motor control and coordination, support joint stability and increase physical endurance.


Hypertonia

Hypertonia occurs when regions of the brain or spinal cord that control the messages from the brain to tell the muscles to contract, are damaged. It can be present with or without spasticity.




Hypertonia can cause a range of symptoms:

▪️reduced ability for the muscle to stretch, which can lead to contractures, which can cause decreased range of movement and function.

▪️difficulty with movements such as walking, reaching, gripping, balance, reactions etc

▪️increased falls due to difficulty to react and regain balance

▪️rigidity of muscles and spasticity of muscles

▪️pain in affected muscles


Similar to low muscle tone, the


symptoms can vary in severity between individuals.


Stretching is an important component of an exercise use regime for muscles with hypertonia. Due to muscle contractions, limbs can become out of position and impact mobility. Stretching muscles can help to lengthen the contracted muscles and improve mobility. Another important factor to support movement with hypertonia is doing exercises to help with every day movements and activities, as these can be impacted by tight muscles and contractures limiting their independence.








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