In Finland he is recognized as the last of the great runners of the famous "V-line", the previous ones being Juha Väätäinen, Lasse Virén, and Pekka Vasala.

Martti Vainio started systematic training at the age of 20 in the autumn of 1971 with his coach Aulis Potinkara.

[2] He received his first national championships medal in 1974 when he finished third in 5000 metres after Seppo Tuominen and Rune Holmén.

The same year he was second at the Finnish Championships in Athletics in 10,000 metres after Pekka Päivärinta and was selected to his first Olympics in Montreal, Quebec, Canada.

Because of his international breakthrough, Vainio was one of the potential gold medal candidates prior to the 1980 Summer Olympics.

He won the Bislett Games in Oslo in 27:45.50 and represented Europe at the 1981 IAAF World Cup in Rome, finishing fifth running a 27:48.62.

At the Track & Field News annual world ranking he was fourth after Werner Schildhauer, Geoff Smith, and Mohamed Kedir.

In the following year 1982, Vainio succeeded again at the European Championships in Athens, where he won a bronze medal behind Alberto Cova and Werner Schildhauer in 10,000 metres running a 27:42.51.

[3] Vainio has stated that he started to use hormones in the autumn of 1982 to avoid the detrimental effects of overtraining in his preparation for the first World Championships in Helsinki, the capital of his home country, Finland.

Vainio won his bronze medal in an extraordinary way; he flung himself in the last 5 metres and fell flat on his face.

[2] After the Championships, Vainio competed in Weltklasse Zürich and finished fourth in 5000 metres with his personal best 13:20.07.

Therefore, he decided in the future to stop administering the drug earlier so it would be out of his system prior to anticipated tests.

At the Bislett Games on 28 June, he broke Lasse Virén's Finnish record in 5000 metres and finished second after Fernando Mamede[4] with a time of 13:16.02.

According to a Vainio interview in 2004, he took his next injection after the Rotterdam Marathon around 10 July, and was sure that this time period would be long enough to allow metabolism to take its effect and ensure a negative test at the Olympics.

Although Vainio's positive doping test after the Rotterdam Marathon was unofficial because of the missing B-sample, the failed drug test at the Olympics forced Finnish Athletics Association to disqualify all of Vainio's results after Rotterdam in 1984 and to discharge Antti Lanamäki from his duties.

Vainio himself did not want to provide detailed information about the incident because he, himself was still investigating the reasons for the positive test result.

Finnish mass media demanded an explanation, and one story released to the public alleged that Vainio's training partner, janitor Alpo Nyrönen, had given Vainio a hormone injection by accident, instead of the intended Vitamin B injection.

Alberto Cova later confessed the use of blood doping in his career and therefore Mike McLeod, originally third at the finish line, claims he should be awarded the gold medal.

Francesco Panetta, Salvatore Antibo and Vainio started their pursuit a little bit later and were not able to properly challenge Kipkoech.

[6] At the Track & Field News annual world ranking, Vainio was recognized as the seventh best runner in 10,000 metres.