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4.5 year old can't do a crunch?

Hi! My 4.5 year old can’t sit up without using his hands (ie do a crunch). Is this a red flag and what can I do to work with him on developing core muscles?

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Hi @Kates7208 -this alone would not be a red flag for core weakness as many kids can’t do independent sit-ups. As a PT I would look at overall function to determine core and extremity strength. How does he do with gross motor activities? Playing on the playground, swimming, running with friends, galloping, skipping…… If general function is on par with other children his age, then there’s no need to worry.

If you are noticing a difference and your son is struggling in gross motor, and possibly fine motor activities, then that paints a different picture.

To test strength, I often go to yoga poses-asking a child to hold positions like downward dog, table, plank, warrior etc. will help determine if your son has sufficient strength or uses a lot of momentum to compensate.

Also, I would have him engage in gross motor play for 10 minutes straight-play tag, climb a jungle gym or similar activities and see how easily he tires.

I hope this is helpful and I’m happy to answer any other questions you have :relaxed:


Here is a resource for core strength activities and information to help as well! All About the Core – Round Up


Thank you! This is super helpful.


Hi :wave: @Kates7208
Thanks so much for reaching out to this community of therapists. All of what has been said is perfect advice!
Here is another little test which test Abdominal strength. Have your little one lay on their back , knees bent / feet flat .
Just see if they can lift their head… nothing else
If they can do that, up the difficulty and see if they can lift their head and shoulder blades off the ground.
It is very important that they do not bring their elbows down to the floor by their side, as that could be a crutch/compensation for underlying weakness
You can place your hand on their belly while asking #1&#2 of them .you should feel some firmness in the belly area which would be the abdominals attempting to contract when they lift their head .
#3 would be reaching for a beach ball with both hands….
If they can’t do 1,2 or 3 then I would get a formal physical therspy assessment. Or tell/ show your pediatrician. No harm in a PT Eval with Home ex recommendations!

These lil tests are not quite a full sit up but do test core strength

Best to you!
Jennifer Aguillard PT PCS