Skip to Content
eNews Join our Mailing List

Find us on facebook, like the CanChild fan page

Donate to CanChild


What is the GMFM?

The Gross Motor Function Measure (GMFM) is a clinical tool designed to evaluate change in gross motor function in children with cerebral palsy. There are two versions of the GMFM - the original 88-item measure (GMFM-88) and the more recent 66-item GMFM (GMFM-66). Items on the GMFM-88 span the spectrum from activities in lying and rolling up to walking, running and jumping skills.  The GMFM-66 is comprised of a subset of the 88 items identified (through Rasch analysis) as contributing to the measure of gross motor function in children with cerebral palsy. The GMFM-66 provides detailed information on the level of difficulty of each item thereby providing much more information to assist with realistic goal setting.

GMFM scores of a sample of over 650 Ontario children with cerebral palsy with varying GMFCS levels have been used to create five Motor Growth Curves. These curves describe the patterns of motor development of this sample of children and are similar to the growth charts that are used to follow the height and weight of children as they grow.

Who is the GMFM appropriate for?

While the original measure was designed and validated for children with cerebral palsy, there is evidence that the GMFM-88 version of the measure is also valid for use with children with Down Syndrome. The updated GMFM-66 version is ONLY valid for use with children with cerebral palsy. 

As the GMFM-88 samples motor skills that are typical of normal developmental milestones, it may be useful for children other than those with whom it has been validated; however reliability and validity should be established prior to using it with other groups of children.

The original validation sample included children 5 months to 16 years of age.  The GMFM (either version) would be appropriate for children whose motor skills were at or below those of a 5-year-old child without any motor disability.

How is the GMFM administered?

The GMFM should be administered in an environment that is comfortable for the child and is large enough to hold the necessary equipment and allow the child to move freely (e.g. one item requires the child to run 4.5 m (15 feet) and return). The floor should be a smooth, firm surface.  Because the GMFM was designed to measure change over time it is important to keep the environment and assessment conditions as consistent as possible for each assessment.

How is the GMFM scored?

There is a 4-point scoring system for each item on the GMFM. Specific descriptors for scoring items are detailed in the administration and scoring guidelines. The item scoring is the same for the GMFM-88 and GMFM-66. The GMFM-88 item scores can be summed to calculate raw and percent scores for each of the five GMFM dimensions, selected goal areas and a total GMFM-88 score.  The GMFM-66 requires a user-friendly computer programme (called the Gross Motor Ability Estimator or GMAE)  to enter individual item scores and convert them to an interval level total score.

How long does the GMFM take to administer?

Administering the GMFM-88 may take approximately 45 to 60 minutes for someone familiar with the measure, depending on the skill of the assessor, the ability level of the child and the child's level of cooperation and understanding. The GMFM-66 should take less time to administer as there are fewer items.

What qualifications are required to administer and score the GMFM?

The GMFM was designed for use by pediatric therapists who are familiar with assessing motor skills in children. Users should familiarize themselves with the GMFM guidelines and score sheet prior to assessing children. It may be helpful to practice on several children with and without motor disabilities prior to using it for clinical assessments. There is a GMFM Self-Instructional CD ROM that provides useful training tips and allows assessors to work through several examples of each GMFM item. It is recommended that users assess their reliability with the GMFM prior to using it.

What equipment is necessary?

The equipment required is described in detail in the GMFM Manual. Most of what is needed is standard equipment in a physiotherapy gym (e.g. mat, bench, toys). Access to stairs (with at least 5 steps) is also necessary.  


For more information:

Frequently Asked Questions about the GMFM-88, GMFM-66

Ordering information