Quantitative assessment of the velocity-dependent increase in resistance to passive stretch in spastic plantarflexors

The normalized passive resistance, expressed with respect to the initial one, i.e., measured at very low velocity, seems a very effective parameter to quantify the velocity-dependent increase in resistance to passive stretch in spastic plantarflexors. However, while the simplicity of the isokinetic tests and the reduced time of data treatment seems to support the clinical use of this methodology, further investigations are required to definitely standardize the protocol.