A clinical sign is described consisting of a brief extension of the toes after upward tapping of the plantar surface of their terminal phalanges. Electrological data support the hypothesis of a long loop reflex, which we call the "toe phasic posture reflex" (TPPR). In a preliminary study, this sign was observed in patients with central nervous system disease, especially in subcortical brain disorders regardless of etiology. In Parkinson's disease, it was seen mostly in severe and postural forms. Among 237 healthy subjects, it was observed in none of those under 70 years old (n=116), and in 10p. cent of those over 69 years and doing no sport (n=132), but in none of those doing regularly gymnastics or swimming (n=29). TPPR could thus be a sign of motor and especially postural aging.