In adults, motoneurone pools of synergistic muscles which act around a common joint share a common pre-synaptic drive. Common drive can be revealed by both time domain and frequency domain analysis of EMG signals. Analysis in the frequency domain reveals significant coherence in the range 1-45 Hz with maximal coherence in low (1-12 Hz) and high (16-32 Hz) ranges. The high frequency range depends on cortical drive to motoneurones and is coherent with cortical oscillations at ~20 Hz frequencies. It is of interest to know whether oscillatory drive to human motoneurone pools changes with development. In the present study we have examined age-related changes in coherence between rectified surface EMG signals recorded from the short and long thumb abductor muscles during steady isometric contraction obtained while subjects abducted the thumb against a manipulandum. We have analyzed EMG data from 36 subjects aged between 4 and 14 years and 11 adult subjects aged between 22 and 59 years. Using the techniques of pooled coherence analysis and the Chi2 difference of coherence test we demonstrate that between the ages of 7-9 years and 12-14 years there are marked increases in the prevalence and magnitude of coherence at frequencies between 11 and 45 Hz. The data from subjects aged 12-14 years was similar to that obtained from adult controls. The most significant differences between younger children and the older age groups were detected at frequencies close to 20 Hz. The results demonstrate for the first time significant late maturational changes in the ~20 Hz common oscillatory drive to human motoneurone pools.