Antonina Vladimirovna Krivoshapka is a Russian sprinter who specializes in the 400 metres. She competed at the 2012 Summer Olympics, where her team originally was awarded a silver medal in the 4 × 400 m relay. Krivoshapka and her teammates were later stripped of this medal after Krivoshapka tested positive for the steroid turinabol.

The 400 metres, or 400-meter dash, is a sprint event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 for men and since 1964 for women. On a standard outdoor running track, it is one lap around the track. Runners start in staggered positions and race in separate lanes for the entire course. In many countries, athletes previously competed in the 440-yard dash (402.336 m)—which is a quarter of a mile and was referred to as the "quarter-mile"—instead of the 400 m (437.445 yards), though this distance is now obsolete.