Disclosed herein are embodiments of impact absorption blocks and vehicle seatbacks and seats comprising impact absorption blocks. One embodiment of a vehicle seatback assembly comprises a seatback frame, a seat pad and an impact absorption block. The seatback frame comprises a first side member having an upper end and a lower end, a second side member spaced apart from and substantially parallel to the first side member and having an upper end and a lower end and a cross-member extending between the first and second side members. The seat pad overlies the seatback frame to define a forward surface. The impact absorption block is positioned between the seat pad and the cross member.