Abstract
The average length of the shortest paths along the backbone of the incipient infinite cluster is expected to diverge near the percolation threshold pc as mod p-pc mod - nu s, with nu s different from the correlation length exponent nu . The author applies the position space renormalisation group (PSRG) technique to obtain nu s both for square and cubic lattices and for a triangular lattice in two dimensions. The results obtained ( nu s=1.49 for d=2 and 1.21 for d=3) are in very good agreement with the existing results obtained by different methods.