Martti Sakari Vainio (born December 30 1950 at Vehkalahti) is a Finnish former long distance runner. His achievements in major athletic championships include gold in the 10,000 metres race 1978 European Championships in Athletics in Prague and bronze in the same distance at the 1982 European Championships in Athletics in Athens. At the 1983 World Championships in Athletics he dropped to fourth by a very short margin in the 10,000 metres race, and insenced by that caught the bronze in the 5000 metres, which was also a closely contested fixture, Vainio only assuring his medal by a palpable lunge over the finish line.
At the 1984 Los Angeles Olympics Vainio finished second in the 10,000m, but was caught using steroids and stripped of the silver medal. He had already given a positive sample in Finnish Sports Association internal tests conducted at the Rotterdam Marathon on 14 April 1984, but this was covered up. The story released to the public after the Olympics alleged that Vainios neighbour, the janitor Alpo Nyrönen had given Vainio a doping-injection by accident, instead of the intended Vitamin B infusion. Later Vainio has claimed that he thought he had been using the male hormone testosterone, rather than anabolic steroids.
Initially Vainio received a life-long ban from competitive athletics, but after the domestic sports association made a plea for a reprieve, it was shortened to 18 months. After the ban, Vainio returned to the track and raced in the World Athletics Championships in Rome 1987 in the 10,000 metres race, but this comeback race can be best described as a damp squib. Not only was his speed nothing to write home about, but the officials of the race bungled and told Vainio that he had completed the race, when he in fact still had one circuit to go; as a consequence, Vainios race was recorded as a forfeit.
On the senior circuit Vainio claimed the Over 40s World Record on the 3000 metres (8.05,08 minutes) and the 10,000 metres as well (28.38,58 minutes).
The winning time he recorded 1978 in Prague - 27.30,99 - is still the domestic Finnish record and European Championship record. On the 3 km, his personal best was 7.44,42 (1984) and on the 5000 metres 13.20,07 (1983). Vainio achieved five domestic Finnish Golds on the 5 km (1978, 1980, 1981, 1982 and 1987). On the 10,000 metres he ran nine Gold Medals in domestic championships (1977, 1978, 1980-1983 and 1986-1988). The Finnish Championship for cross country running saw him on the top podium 1981, 1983, 1986 and 1987.
After his sports career, Martti Vainio has worked in the travel industry.