power production focused on steady swimming and the aerobic muscle fibre types (e.g. van Leeuwen et al.1990; Rome et al.1993; Jayne and Lauder 1995b; van Leeuwen1995;Wardle et al.1995; Coughlin and Rome 1996a; Hammond et al.1998; Coughlin 2000; Ellerby et al.2000,2001a; Rome et al.2000; Swank and Rome 2000, 2001; Rome and Swank 2001). These studies are the basis of this review. More recently, substantial success in detailing longitudinal patterns of power production by white muscle during fast, unsteady swimming behaviours has been achieved (e.g.Ellerby and Altringham 2001; Ellerby et al. 2001b to name two very recent efforts).