Gross Motor Function Measure (GMFM)

The Gross Motor Function Measure (GMFM) is a structured, observational test tool designed to evaluate changes in gross motor function in children with cerebral palsy (CP). There are two main versions: the original GMFM-88, which includes 88 test items, and the shorter GMFM-66, which consists of 66 items¹ ².

Originally developed for children with CP, the GMFM-88 has also been validated for other populations, including children with Down syndrome and acquired brain injury. The GMFM-66 is currently validated only for children with CP¹ ².

The main purpose of GMFM is to assess gross motor skills in children with CP to monitor progress over time and adjust rehabilitation interventions for optimal outcomes. It is particularly useful for documenting changes before and after therapy or training

Target Population

• Applicable to children aged 5 months to 16 years with delayed motor development compared to peers.

• GMFM-88: suitable for children with varying levels of disability; can be performed with shoes, assistive devices, or orthoses.

• GMFM-66: quicker to administer, more appropriate for larger samples, but must be performed without shoes, assistive devices, or orthoses¹ ².

Structure and Administration

GMFM evaluates gross motor skills across five dimensions:

1. Lying and rolling

2. Sitting

3. Crawling and kneeling

4. Standing

5. Walking, running, and jumping

Each item is scored on a 4-point scale:

• 0 = does not initiate the task

• 1 = initiates the task (<10% completed)

• 2 = partially completes the task

• 3 = fully and correctly completes the task¹ ³

• GMFM-88: dimension scores and a total percentage score are calculated.

• GMFM-66: requires use of the Gross Motor Ability Estimator (GMAE) software to calculate total score.

Administration:

• Conducted by physiotherapists trained in pediatric motor assessments.

• Duration: ~45–60 minutes for GMFM-88; shorter for GMFM-66, depending on the child’s ability and cooperation.

Equipment

• Physiotherapy gym space with mat, bench, toys, and basic equipment

• Access to a staircase with at least five steps

Interpretation of Results

• Typically, a healthy 5-year-old child will achieve a maximum score¹.

• GMFM-88: provides detailed assessment, especially valuable for young children or those with severe disabilities.

• GMFM-66: more efficient for larger groups, but less detailed.

Results are used to:

• Track progress over time

• Set realistic goals

• Evaluate the effectiveness of interventions

Reliability and Validity

• GMFM demonstrates very high reliability and validity in assessing motor skills in children with CP¹ ² ⁵.

• Intra- and interrater reliability: ICC values >0.98 (95% CI 0.965–0.994).

• GMFM-88: especially useful for young children or severe cases, as it provides more detailed data.

• Both versions: well-documented validity and responsiveness, making them suitable for both clinical and research use.

Clinical Relevance

The GMFM provides a comprehensive overview of gross motor skills and development in children with CP and similar conditions. Its widespread international use allows standardized documentation of rehabilitation outcomes, supporting individualized treatment planning and long-term monitoring¹ ² ⁵.

Sources:

1. Ko J, Kim M. Reliabilitet og responsivitet i GMFM-88 hos barn med cerebral parese. Physical Therapy. 2013;93(3):393–400.

2. Beckers LW, Bastiaenen CH. Bruk av GMFM-66 i nederlandsk klinisk praksis – en spørreundersøkelse. BMC Pediatrics. 2015;15(1):1–10.

3. Vaščáková T, Kudláček M, Barrett U. Halliwick-metoden og motoriske ferdigheter hos barn med alvorlige funksjonsnedsettelser. European Journal of Adapted Physical Activity. 2015;8(2).

4. Concepts F. GMFCS for Cerebral Palsy [video]. YouTube; 2013 [sitert 05.07.2025]. Tilgjengelig fra: https://www.youtube.com/watch?v=5u2sLAznhnY

5. Russell DJ, Rosenbaum P, Wright M, Avery LM. Gross Motor Function Measure (GMFM-66 & GMFM-88) – brukermanual. Mac Keith Press; 2002.