Giant axonal neuropathy (GAN) is a rare neurodegenerative disorder of childhood that affects the peripheral and central nervous system. It is caused by biallelic pathogenic variants in the GAN gene leading to dysfunctional or absent gigaxonin, resulting in intermediate filament accumulation and axonal swelling. GAN leads to early sensory deficits, muscle weakness, and gait impairments. The assessment of muscle strength and motor capacity in children with GAN is essential for clinical trials. Myometry uses a hand-held device to quantitatively measure muscle strength. Based on the individual’s weight, sex, age, and exerted force, normative percentages are calculated. The Graded Functional Test (GFT) is an assessment that measures supine to stand (STS), run 10 meters, and ascend/descend four steps. These skills are timed and scored qualitatively, with a higher score indicating better performance. This exploratory analysis aims to compare the myometry normative percentages and the graded functional test’s STS and 10-meter run qualitative scores from the baseline visit of participants with GAN, 6 years and older. The myometry assessment and graded functional test were administered at baseline to 23 participants with GAN. Of the 23 participants, 11 were male with a mean age of 8.90 ± 2.96 years. Using Spearman’s rank correlation, there was a statistically significant strong correlation between the STS and 10-meter run (ρ = 0.92, p < 0.001). We found statistically significant moderate correlations between STS and knee flexors (ρ = 0.50, p = 0.02), and between the 10-meter run and knee flexors (ρ = 0.54, p = 0.008) and hip abductors (ρ = 0.42, p = 0.04). There was a statistically significant moderate inverse correlation between STS and elbow extensors (ρ = -0.47, p = 0.02). Additional studies are needed to propose the use of myometry as a predictor of an individual’s motor capacity.