The aim of this study was to determine the relationship between ankle dorsiflexor strength and performances on several walking tests and to determine the effect of ankle-foot orthosis (AFO) use on walking tests. The following tests were used: 10-metre walking test (with and,without three stairs). a complex walking task (6-minute walk with cognitive loading) and a subjective evaluation (SIP68 mobility scale and questionnaire). Isometric strength of the ankle dorsiflexors was measured. All walking tests were performed with and without AFO in random order. When relating torque values to walking performances, the highest correlation was found with the "10 metre" and "10 metre with stairs" test (r = -0.51, i.e. an inverse relationship). No threshold in the degree of paresis was found below which walking disability suddenly increased. No significant improvement could be demonstrated from AFO use on the 10-metre tests. Improvement on the 6-minute test was nearly significant (p = 0.06), the questionnaire revealed a positive opinion on AFO use related to overall walking function and effort. Thus, we have to conclude that these walking tests do not aid the clinician in estimating the severity of (progression of) the paresis nor to detect differences in degree of paresis between subjects.