Fig. 7. Mean net joint moments (A,C) and muscle stresses (B,D) from a wallaby (body mass, 6.76 kg) hopping on a level runway and a 14° incline (three trials each). Hip joint moment (A) and resulting biceps femoris (BF) muscle stress (B) increased significantly between level and incline hopping. Joint moment at the knee (C) decreased significantly during incline hopping; however, due to the action of biarticular muscles, vastus lateralis (VL) stress (D) remained similar between level and incline trials. Broken lines represent ± 1 s.e.m.