Temporal congruence between motor imagery and motor performancewas evaluated in 30 elementary school
children (7 and 8-year-olds) and 61 middle school children (11 and 12-year-olds), using the “Harre's Chase”
obstacle-course [Harre, D. (1976). Trainingslehre. Berlin: Sportverlag]. It is made of successive elementary
actions including running, rolling forward, changing direction, jumping and crawling. The children were
requested to perform the obstacle-course both actually and mentally. Results showed that motor imagery
durationwas closer to that of actual execution in the middle school children group, as compared to elementary
school children. We also found a gender difference, boys being more able than girls to reach the temporal
congruency between imagined and physical times. Developmental factors, as well as gender differences in
socio-cognitive traits, are discussed as the main factors explaining the development of the isochrony between
actual and imagined movements.