Fig. 8. To investigate the effect (mechanical energy fluctuations) of walking experience (WE) on the inverted pendulum mechanism, individual mean E_k and E_p profiles (± S.D.) were inspected. The grey bars indicate double support. In the youngest children, the E_k and E_p curves are irregular. The sinusoidal pattern becomes a lot smoother after 3 months of walking experience (28 weeks WE), but variation remains large.