In the world of pediatric physical therapy, there are a couple terms that are used so often by physicians, families, and the general public that they seem to have lost their meaning. “The Core” is a big one. I wonder if people even know what they’re talking about when they say “I need to work my core!” I’m thinking the answer is probably not. “Low Tone” is definitely another one. “My pediatrician says he has low tone” What does that even mean? The term gets thrown around a lot, yet many don’t know what to make of it. The opposite of high tone, it’s become a sort of catch-all to describe muscle weakness or developmental delays. But what is it really? Let’s first look at some quick facts before we jump into characteristics of low tone.
The technical term is hypotonia. It comes with the territory for many syndromes and disorders BUT you do not have to have a syndrome to have low tone. They are not mutually exclusive. For instance, children and adults with Down Syndrome have low tone for sure. BUT just because you have low tone, doesn’t mean you automatically have Down Syndrome. Make sense? It can be just part of who you are. The tone doesn’t change, but it doesn’t always have to be a problem.
Here are a few of the ways I like to talk about muscle tone to parents to help make sense of it. Hopefully, it will help you too!
A Continuum. At one end is very very low tone. This would be someone who has difficulty even maintaining head control and doing any kind of anti-gravity activity. Then at the other end is extremely high tone. With these kids, their muscles are extremely stiff, rigid, and difficult to move. Somewhere in the middle, the rest of us can be found. We could be on the higher or lower end of “normal” resting muscle tone. Maybe a little floppy, but still independently functioning in the world, meeting milestones, and achieving goals. For the record, on this continuum, I trend toward the low end. I can definitely relate to my low tone kiddies!
Resistance to Stretch. If you have high tone, you have a lot of resistance to movement. Your muscles may be tight, and your range of motion restricted. Low tone, on the other hand, shows very little resistance to a stretch. During movement, those joints will just keep going going going going until they can’t go any further. This brings us to…….
Super Flexible. With no tension in the muscle, the joints of someone with low tone are free to keep going until they lock in place or compress against another joint where they can rest. At this point, people with low tone such as myself, rely on the tension of ligaments to hold themselves up rather than using their muscles. (hello back, hip and knee pain!) Those with low tone can hyperextend their knees or elbows, sit in a wide straddle, have really flat feet, and are what some used to call “double jointed”.
Weakness. When your muscles are this flexible, you have to give up some strength. Muscles don’t work so well when they are over elongated and positioned at the end of their range. Plus, when we think of low muscle tone, we can think beyond just the trunk and extremities. If you have low tone, it’s present in all parts of your body. This is why we often see challenges with chewing and communication in kids with low tone….because the weakness can be in the muscles of the jaw well.
Higher Threshold. All muscles need to reach a certain threshold before they’re ready to work. Kids with high muscle tone reach that threshold fast! High tone muscles are always on, always ready to go, and basically say “let’s DO this!” at the mere thought of movement. Kids with low tone though….different story. The threshold for their muscles to work is way higher. So it takes a lot of amping up to get going. These muscles like to rest and there are certain strategies that we can use to tell these muscles “Get up! Let’s get going! Come on!” to get them primed for movement.
Path of Least Resistance. Here’s a pic of my low tone self as I sit to write this article. According to my muscles, they work smarter, not harder. If there’s a chair, I’m gonna sink and curve all the way into it. I’ll slump all the way forward, rest my arms on my knee, and head on my hands. Here, I’m even using my laptop to hold me up! And as for babies with low tone, if there’s a lap, they will take it! It can be hard to resist because little ones with low tone just melt into you and love to cuddle, taking advantage of all the postural support you provide. It is important to note that these kids are NOT lazy!! Please stop telling kids with low muscle tone that they are lazy!! I’m one of the hardest working people I know. My muscles on the other hand……..
All or Nothing. Kids with low tone love living in end ranges. Either standing fully extended, hips and knees locked out, putting a ton of strain on those poor ligaments OR completely flexed into a little ball with a massive amount of compression on the joints. There is no strength in the middle of the range…..all or nothing. This becomes a problem because it makes transitions in and out of positions difficult. These are the babies who sit when you sit them, stand at the couch when you stand them, but can’t do any of the in-between movements, so they are completely reliant on others to move in any kind of dynamic way.
Just when you thought you understood low muscle tone, let me end with this: Don’t put those of us with low tone in a box. You can have low tone but be stiff. You can have high tone but be very weak. Kids with low tone can look like a puddle on the floor, staying in the same spot you left them for way too long. Or they could be flitting around non-stop spinning themselves in circles, always the “wild child”. Low tone manifests itself in many different ways, and no two are the same. An experienced physical therapist can help you connect the dots and figure out how function relates to tone for your little one!