Gross Motor Milestones In Babies With Down Syndrome/Trisomy 21

The most common statement we hear from parents of a child with a Trisomy 21 diagnosis is that their baby is lazy. We usually have to stifle a chuckle because who does not love a lazy Sunday morning or even day for that matter lying around on the couch now and then?

While we all enjoy doing nothing occasionally, laziness is not the reason your baby is not moving much. The actual reason is low muscle tone.

We always correct parents immediately. We tell them that their baby is not lazy at all. They have low muscle tone. This is usually followed by a long talk about what muscle tone actually means. That seems like the perfect place for us to start right now.

What Is Low Muscle Tone?

Muscle tone is defined as the readiness of a muscle to fire or activate. When a child has low tone, they have to work harder to activate their muscles than the rest of us do. This is true for all children with Trisomy 21.

Here is an example to help you see what we mean. Let us say the firing threshold for a muscle is 60 percent electrical activity. Normally, you or I maintain a baseline of 25 percent activity while we are resting. We only need to jump from 25 to 60 when our brains decide we actually want to move. We turn the muscle fully on with just a small jump in energy.

Now take a person with low tone. Their baseline activation might be only 10 percent. You can see how much harder it would be to activate from 10 to 60. They have to increase activation by 50 percentage points versus only 35. That is a lot of extra work for a little baby.

Movers Versus Observers

Another important concept to consider is the temperament of your baby. There are generally two types of kids out there. This applies whether they have special needs or not. You have Movers and you have Observers.

Movers will naturally be easier to motivate. They see a shiny fun toy just out of their reach and they want to get it. They will wiggle and push until they grab it. Observers are different. They see the toy and are happy to just look at it. They are content to contemplate it from afar. You can think of them as Athletes versus Philosophers.

Expected Milestones

If you combine the low tone of your baby with their temperament, it usually results in some degree of gross motor delay. This is completely normal for their diagnosis. We want you to have realistic expectations so you can celebrate every victory.

Below is a listing of the major milestones for children with a diagnosis of Trisomy 21 or Down syndrome.

• Rolling from back to stomach: 7 months
• Sitting: 11 months
• Belly crawling: 14 months
• Crawling on hands and knees: 17 months
• Cruising along furniture: 18 months
• Stands for 10 seconds unsupported: 21 months
• Walking: 26 months
• Jumping: 47 months
• Running: 52 months
• Riding a tricycle: 61 months

There is one important caveat to remember here. The list above presumes your child did not have any major setbacks at birth. This includes things like heart surgery or complications from extreme prematurity. If your child faced those challenges, their timeline might look a little different.

Meeting Your Child Where They Are

The take home message for parents is two fold.

First, you must stimulate your baby. Follow the recommendations of your physical therapist closely. Give your baby lots of tummy time. This helps them build the strength they need to overcome that low muscle tone gap we talked about earlier.

Second, do not fret. With the right stimulation, the vast majority of babies with Down syndrome reach all the same milestones as typically developing babies. They just do it in their own time.

At Eyas Landing, we believe in meeting families where they are. We know that every child is unique and follows their own path. Whether your child is a Mover or an Observer, our team is here to support you. We can help you encourage their development in a way that fits your life and their personality. Your baby is working hard, and with your patience and support, they will get moving.

What Is Physical Therapy?

Physical therapy helps children develop the skills they need for everyday movement. For babies with Down syndrome, this can mean building strength, improving balance, and learning how to sit, crawl, or walk. Physical therapists are experts in movement, but they are also skilled at making every session feel like play rather than hard work.

How Play-Based Therapy Supports Your Child

You might wonder what play has to do with therapy. The answer is, everything. Play-based therapy uses your child’s natural curiosity and interests to motivate practice and skill-building. Instead of focusing on drills or exercises that feel like chores, your child will be rolling, reaching, stacking blocks, or chasing bubbles. The best part is that your child often does not even realize how hard they are working.

Play-based approaches help children with Down syndrome stay engaged and happy during therapy. When therapy feels like play, kids are more likely to participate and keep trying new things. Each small success builds confidence and lays the groundwork for the next milestone.

If you have questions about how physical therapy or play-based strategies can help your child, the Eyas Landing team is always here to partner with you. Together, we will find the activities that spark your child’s joy and support their journey toward greater independence.