This happens a lot with small dogs. It seems really cute to have them jump up when greeting you, jump and spin around for treats, or pogo stick bounce. Although it is pretty darn cute, it is very damaging to their spines. Dog spines are meant to be parallel to the ground, not vertical. Since they have four legs contacting the ground, they don’t need a curve in their low backs. Horizontal four legged spines don’t have gravity pounding on their spinal discs all day long like humans. Upright, vertical human spines have an extra curve in the low back to act like a spring, which dissipates loads while standing, running and jumping in an upright position. Since dogs don’t have this curve, when they go upright their spine is straight and too much force gets put through their discs. This can create damage quickly that can cause the start of degenerative disc disease and spinal degeneration. So don’t encourage your four legged friend to be a biped like you, it can be very damaging in the long run. They are built to be on all fours!