Men in their 50s should be able to do 15 to 19 consecutive pushups, according to ABC News. Ten Years Younger points out that this pushup total places a man in the 80th percentile of males in their 50s.
The 50th percentile pushup count for men in their 50s is only 10 consecutive pushups, according to Ten Years Younger. This assumes pushups are done consecutively, with toes and arms on the floor and with a 90-degree bend in the arms on each pushup.
ABC News points out that men in their 50s should also be able to do 20 to 24 sit-ups. Women in their 50s should be able to perform seven to 10 pushups and 15 to 19 sit-ups.