Assessing core strength and stability for sitting

In children with DCD, joint hypermobility, low muscle tone and autism

Children with developmental movement conditions often present with weakness in the core muscles (neck and trunk muscles) and difficulties with maintaining a stable head and trunk posture in many activities. 

Core (trunk and neck) muscle strength and postural alignment and stability are closely linked, with different body postilions and tasks requiring different degrees of muscle strength and coordination. For this reason core muscle strength needs to be assessed in standing, sitting and lying tasks to cover all aspects of core muscle strength and coordination different everyday, classroom, PE and sporting activities.

Assessing core strength and stability in sitting

In sitting the neck and back muscles work to keep the head and trunk steady for extended periods of time, and are particularly active when one or both arms are moved. 

1  Sitting erect for 1 minute

► Let your child sit erect on a stool with the hips and knees flexed to 900.  

► Instruct your child to stay sitting erect and count to 60 slowly.

Tip: count with your child, vary your tone and pull faces to keep your child interested and alert. 


Good strength and control: child maintains this position for 1-2 minutes easily. 

Poor strength and control: child finds sitting erect tiring, quickly resumes a more comfortable, slumped position.  

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2. Sitting erect with arms lifted forwards.

►  Let your child sit erect on a stool with the hips and knees flexed to 900.  

►Instruct your child to lift the arms forwards to level with the shoulders, and then to stay in this position for 30 slow counts. 



Good strength and control: child maintains position with ease, trunk and head are held steady.

Poor strength and control: child finds it difficult and tiring to maintain the position, the trunk may drift backwards, arms may move upwards or downwards.


  Another child may find it difficult to keep the spine extended for more than a short period of time and flex the trunk. Trunk flexion in sitting is usually associated with extension of the neck  as the child tries to keep the face vertical.  



3  Holding the trunk steady lifting a weight 

►  Let your child sit on a stool and hold with two hands a 2 liter  plastic bottle half filled with water, or object of a similar weight. 

►  Instruct your child to lift the bottle to shoulder height with the elbows straight, and then to turn the bottle upside down and right way up 10 times. 


Good strength and control: child does the task easily, trunk and head stay steady. 

Poor strength and control: trunk and head are not held steady, may tip backwards, difficulty holding at shoulder height

4  Lifting one arm sideways.

►  Let your child sit on a stool, holding a 500 liter plastic bottle filled with water in left hand. 

►  Instruct your child to lift the bottle sideways with the elbow straight and maintain the position for 20 slow counts.


Good strength and control: child stays sitting upright, adjusts the alignment of the head and trunk to maintain balance, 

Poor strength and control: child tips the trunk and head sideways.  


Read more 

Core muscle weakness and poor core stability: what it is and how it affects children 

Training sitting for working at a table 


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