Machel Cedenio is a Trinidadian sprinter specialising in the 400 metres. He represented his country at two outdoor and one indoor World Championships winning a silver medal in the relay at the 2015 outdoor edition. He competed at the 2016 Summer Olympics. He qualified for the final and came fourth with a new personal best of 44.01 seconds. This is the fastest fourth place time for the 400 metres.

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.