A gainer is the acrobatic trick of performing a backwards somersault while still moving forward. In diving, this is known as reverse rotation (as opposed to front, back, or inward). Many stunt performers and martial artists are capable of performing a similar skill on the ground, sometimes in combination with a midair inverted kick. A half gainer involves the same motion, except the ending position is with the head downward. A half gainer can also be performed starting with walking on the hands and ending with the head upwards, although this is quite difficult.