Fig. 6

Results from the Linear Mixed Models for the ankle-foot, knee, and hip positive work on both the ipsilateral and contralateral side. Each open circle is a participant’s data point. The blue line represents the equation at no load, and the red line represents the equation for the 30% additional load condition. a Ipsilateral hip positive work (W_{IPS _ HIP}) per stride was predicted by the interaction of stiffness (k) and load (l) as well as stiffness squared (k²) and load W_{IPS _ HIP} = 0.293 + 0.026 ∙ kl − 0.128 ∙ k²l (b) Ipsilateral knee positive work (W_{IPS _ KNEE}) per stride was predicted by the load, the interaction of stiffness and load and the interaction of stiffness squared and load W_{IPS _ KNEE} = 0.219 − 0.007 ∙ l + 0.144 ∙ kl − 0.584 ∙ k²l (c) Prosthetic ankle-foot positive work (W_{PRO _ ANK _ FT}) was predicted by stiffness and load W_{PRO _ ANK _ FT} = 0.244 + 0.002 ∙ l − 0.661 ∙ k (d) Contralateral hip work (W_{CON _ HIP}) was predicted by the interaction of stiffness and load as well as the interaction of stiffness squared and load W_{CON _ HIP} = 0.319 + 0.038 ∙ kl − 0.208 ∙ k²l (e) Contralateral knee work (W_{CON _ KNEE}) was predicted by stiffness squared and load. W_{CON _ KNEE} = 0.223 + 0.001 ∙ l − 1.293 ∙ k² (f) Contralateral ankle foot positive work (W_{CON _ ANK _ FT}) was predicted by the interaction of stiffness and load and the interaction of stiffness squared and load W_{CON _ ANK _ FT} = 0.208 + 0.016 ∙ kl − 0.057 ∙ k²l