According to a study published in the International Journal of Environmental Research and Public Health, the motor performance of children with spinal muscular atrophy (SMA) depends on muscle strength, range of motion, and deformities of the spine, chest, and pelvis.

Weaker children revealed more pronounced relationships when assessed by functional scales, either the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) or the Hammersmith Functional Motor Scale Expanded (HFMSE).

Given the results, the study authors believe that “the motor assessment of a child with SMA should, therefore, not be limited only to the use of motor scales, but also take into account postural parameters, as well as measurements of the range of motion and muscle strength.”

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In addition, Stępień et al found that the development of scoliosis compromises motor function, range of motion, and muscle strength. They described a strong relationship between muscle function and the size of the scoliosis, severity of chest deformity, and oblique position of the pelvis.

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These results support the need for preventing spine deformation and strict monitoring of the musculoskeletal system.

Moreover, Stępień et al found movement ranges to be associated with motor skills and strength values. Hence, routine measurement of ranges of motion is important and particularly valuable in weaker children diagnosed with both SMA and scoliosis.

Ultimately, “the analysis of the relationships between postural parameters, range of motion, and muscle strength brings a lot of valuable information that is useful for planning therapy.”

The study included 27 children (age range, 6 months to 15 years) with genetically confirmed SMA type 1 (n=19) or SMA type 2 (n=8).


Stępień A, Gajewska E, Rekowski W. Motor function of children with SMA1 and SMA2 depends on the neck and trunk muscle strength, deformation of the spine, and the range of motion in the limb joints. Int J Environ Res Public Health. 2021;18(17):9134. doi:10.3390/ijerph18179134