Muscle tone refers to the amount of tension within a muscle when it is relaxed or resting. It helps us maintain posture and positioning, control movement, and is fundamental to the development of motor skills, balance and coordination. Muscle tone can be thought of as a spectrum, with some people having higher tone and others having lower tone.

Kate herself has lower muscle tone. While she has always been fit and strong, the resting state of her muscles isn’t that high. For example, she is often slouching when at rest. In contrast, other people seem to have firm and strong muscle even though they don’t do a lot of exercise. Muscle tone is neurologically determined and genetically based.

Muscle tone isn’t something that can be changed through exercise however, we can change strength. Muscle strength is the power we can exert using our muscles when we are actively contracting it. We can alter the appearance of muscle tone through doing strengthening and increasing muscle bulk. But we cannot consciously control our resting muscle state. The difference in muscle tone and strength is very important. In therapy, such as in orofacial myofunctional therapy, we are working on muscle strength and motor repatterning. This is to achieve better function rather than ‘curing’ lower muscle tone.

Low muscle tone, also known as hypotonia, refers to muscles which have less tension or resistance to movement. It is the resting state of a muscle (not the power that it can actively create against resistance, which is strength). Hypotonia occurs when the muscle is abnormally long and the muscle fibres do not overlap at an optimal level. Less tension within the muscles causes less support or stability of the joints. As a result, the muscles need to work harder to receive the same level of joint support than people who have higher tone.

A lot of people with low muscle tone also have joint hypermobility. Hypermobility is highly correlated to ligament length (ligaments are the tender parts of the body that connect muscle to bone). These people are also likely to have increased tendon length (structures that connect bone to bone).

The reason why some people have hypermobility is due to the differences in the protein collagen within ligaments, tendons and connective tissue. It is something you are born with and can’t necessarily change. When these structures stretch, they don’t bounce back. For example, after pregnancy, women often have less stability in their joints. They then need to regain stability through regaining strength via exercise but there will always be a difference to prenatal times.

For children who have hypermobility in their joints such as fingers and elbows, this can affect their fine motor skills, in particularly handwriting. We need to consider this when setting therapy goals. For example, reducing hypermobility is not a reasonable or evidence-based goal. Rather, we should look at increasing strength and consolidating motor planning to gain function. We can also look at external compensation to offer the joints more support with grips, tapes, straps etc.

As a mother of 4, Kate observes that all her children have different muscle tone profiles. Her kids with lower muscle tone fatigue more rapidly than their siblings. They can also be more emotional and exhibit different behaviours. Kate is always mindful of this and ensures she plans a weekly schedule that enables her children with lower muscle tone to not become overly fatigue as the week goes on.

As children with low muscle tone are prone to fatigue and also possibly reduced coordination, they may not participate in motor activities as much as their peers. So, there is a potential that children of this profile are associated with a delayed motor development.

Children with low muscle tone often experience difficulty maintaining posture and stability. For example, they can be more upset if they have to stand in lines during school pick up due to muscle fatigue. Low muscle tone also affects their ability to coordinate and control movement. We can see this at rest such as sitting at the table and during movement, such as on a swing or on the bicycle.

Children with low muscle tone may also experience difficulty performing fine motor tasks such as grasping a pencil and manipulating objects within the hand. Also, reduced stability in your core (proximal control) affects your limbs (distal control). That’s why sometimes we see children with low muscle tone do ‘fixing’ which is when they hold their joints in a tight rigid way to compensate for the lack of stability in their core. For example, clients attending Occupational Therapy for handwriting are likely to sit with their arm planted against their desk and their shoulders elevated with their weight bearing through their upper arm. This might look like they have increased muscle tone but really it is increased muscle tension in their shoulders and back. It is likely secondary to having low muscle tone and low core strength.

Low tone can impact speech and feeding because we have skeletal muscle in our face, lips cheeks and tongue. It also relevant to toilet training as it breathing, digestion and the movement of the diaphragm. We also know that people with lower muscle tone have reduced interoceptive senses so they may not be aware of their urge to go to the toilet.

Muscle tone affects sensory feedback. Individuals with lower muscle tone have different sensory feedback. There is no such thing as a pure motor skill. Everything we do is really sensorimotor. Even with skills like walking which we do quite automatically, we are still constantly processing sensory information to modify our performance. For example, our brain is taking in the information of the position of our feet depending on our shoe, the type of surface we’re walking on and the pace of walking. There are always micro adjustments being made, even to well consolidated motor plans. If you have reduced sensory feedback, from the muscles in your body, you may be a little bit more clumsy because you are not able to readily make the adaptations to your motor plan.

A key challenge associated with low muscle tone is rapid fatigue. You need to exert excess energy to maintain posture and produce movement, causing an increase in fatigue. Often, children with low muscle tone avoid participation in gross motor tasks and find it difficult to persist with such tasks.

However, they may benefit from gross motor tasks. For example, a 3 or 4 year old with low muscle tone may need 20 min instead of 30min swimming lessons. There performance for the final 10 mins may reduce significantly that they are no longer enjoying it and become over tired, rather than feeling invigorated and primed for an active day.

Although muscle tone itself cannot be improved, there are many ways to improve muscle strength and physical endurance. Muscle strength is the ability of muscles to produce force against some form of resistance, allowing appropriate movement to occur. As muscle strength and endurance improves, low muscle tone has the potential to become less of a barrier. Therefore, improving muscle strength is key for children with low muscle tone.

Warm up activities
Engaging in warm up activities trains the muscles to activate more quickly. Activating the muscles required to perform a specific task will assist in improving strength and extend the duration for which the activity can be participated in. Depending on the task being performed, warm up activities may include bouncing on a trampoline, doing star jumps or playing with play dough or putty – e.g. for handwriting.
 
However, we need to monitor the child’s response. Sometimes the high level of activity such as bouncing on a trampoline before a table top task can help prime and increase body awareness, and build arousal to support optimal performance. But some children’s muscle tone are extremely low and those activities can actually be very fatiguing and does not enhance the subsequent tasks. Warm up activities are definitely worth trialling but should be tailored to each child.

Gross motor activities
Engaging in gross motor activities which require use of the whole body will assist in building muscle strength and endurance. It is important to work your way up to them to avoid injury.
 
Some examples of fun activities include:

• Playground activities (such as swinging on monkey bars and climbing) – these activities are a great way to improve upper body strength and encourage positive engagement in gross motor tasks. It is important that children have a go at these activities but adults should always be there on stand by to ensure they are engaging their muscles and have activated their grip before they let go to ensure they aren’t just hanging and stretching which may cause injury
• Animal walks (such as frog jumps and bunny hops, crab walking) – this activity is a fun and simple way to encourage gross motor movement and building muscle strength. You can do them anywhere such as the living room, on a path, in the garden.
• Obstacle courses which incorporate multiple gross motor movements (such as running, jumping and climbing) – this activity promotes activation of various muscles within each element of the course, aiming to build both strength and endurance whilst being motivating for your child. It doesn’t have to be complicated and use what is available. Dirty laundry and cushions can be stepping stones. The spontaneous and dynamic creation in your home space means that the child will be activating various muscles in different elements of the course. It will also support development of their motor planning.
• Swimming – this activity engages every muscle in the body to produce movement and encourages development of postural control. It removes the impact of gravity. It is common to see children who may be clumsy on land to be a strong swimmer as it is easier for their motor plan. It is a fantastic way to build core strength and muscle strength in a motivating way rather than soccer or trampoline which they may not be motivated due to their high impact nature.
• Gymnastics, dance and martial arts – they build both muscle strength and endurance and promotes improvements in balance and postural control.

It is important to flag to instructors and teachers that your child has lower tone and hypermobility as they are at more risk of injury.

Providing regular rest breaks
Providing regular rest breaks and opportunities to recover is key for children with low muscle tone. This will prevent excessive fatigue, risk of injury, and ensure that your child remains motivated to participate in the tasks.

• Give your child feedback when they are performing activities to help them to develop awareness of tone and posture.
• Break larger tasks down into smaller tasks to ensure they are manageable. This helps them to develop proficiency and mastery in small components which can then come together into a bigger motor plan.
• Ensure activities are fun and engaging to assist in improving alertness, tone and to maintain motivation.
• Provide significant encouragement and positive reinforcement to motivate your child to continue to engage in the activity.
• It is all about striking balance in engaging long enough to build strength but not too long to create fatigue. We need to be mindful and observant of their responses.

While muscle tone isn’t something we can change, we can build your understanding and child’s understanding of their body and the things in life they find easier or harder.

To find out more, contact us at SPOT Therapy Hub on spottherapyhub@gmail.com or 02 9389 3322. Also check out our podcasts and blogs on a variety of topics at www.spottherapyhub.com.au