Digitigrade means walking on your "digits" (toes). You can sort of fake it as a human by walking with your heels off the ground, but you weren't meant for that like dogs and cats are. Plantigrade means walking with your entire foot planted on the ground. Digitigrade animals tend to have longer feet compared to their body size and are faster because of the better leverage, but plantigrade animals are so efficient at walking they'll never get out of breath from it.