Fig. 8. Calculated peak vertical force, normalised to total mass of the subject (including mass of horse, riding tack and rider) as a function of speed – assuming no shift in forelimb to hindlimb force distribution. Values are means + s.e.m. for forelimbs and means – s.e.m. (N=6 throughout) for hindlimbs (for clarity; indicated by different symbols) during level (0–2%) and incline (8–12%) galloping for the six horses. Peak forces were calculated from duty factor and Eqn 1 assuming no shift in forelimb to hindlimb impulse distribution from 57:43 on the level and incline. Quadratic lines of best fit (P<0.001) are shown. These were estimated for the population using mean data. Coefficients: forelimb level b₀=3.358, b₁=1.436, b₂=–0.028, r²=0.51; forelimb incline b₀=–7.271, b₂=3.355, b₂=–0.119, r²=0.70; hindlimb level b₀=–2.615, b₁=1.978, b₂=–0.063, r²=0.53; hindlimb incline b₀=–1.077, b₁=1.668, b₂=–0.052, r²=0.686.