That June, South Africa's government massacred over 350 anti-apartheid protestors during the infamous Soweto riots. The boycott's message was clear: it wasn't enough to just exclude South Africa from the Olympics (the country was barred from playing starting in 1964, and outright expelled from the International Olympic Committee in 1970). The boycotters considered it unacceptable for any country or any international sporting organization to legitimize the South African government in any way, as New Zealand's rugby team had done, and, they believed, as the IOC was doing by refusing to exclude New Zealand from the games.

The boycott had a major impact on the 1976 Olympics, which are best remembered for the U.S.'s near-sweep in boxing and Romanian Nadia Comenici's perfect 10s in gymnastics. One million Canadian dollars in seat and hotel reservations had to be refunded, according to the BBC, during the first two days of the games alone, as a result of the boycott. A number of events were marred as well; the track meet was badly diminished by the absence of perennial powerhouses like Tanzania and Kenya.

The boycott's legacy expanded beyond the games, as sports historian Courtney Mason explained in an essay in Onward to the Olympics: Historical Perspectives on the Olympic Games. "The 1976 boycott not only generated international consciousness for the anti-apartheid movement, but also indirectly induced social and political change," she wrote.

The threat of an African boycott had already kept South Africa out of the 1968 and 1972 Olympics. As she notes, the African states' threat to skip Montreal failed to bar New Zealand from the games or to compel the country to cancel the All Blacks' tour of South Africa. But despite "being regarded as a costly tactical misjudgment," Mason identified two ways in which it was still a signal moment in the larger and eventually-successful effort to bring down South Africa's apartheid government:

First ... the boycott generated considerable international interest in the South African apartheid policy, and contributed to the evolving campaigns of opposition to it. Second, the African-led boycott may have had a more direct implication on the anti-apartheid campaign in South Africa. The united stand of black Africa was seen throughout the world. The perception of black Africa's willingness to sacrifice for the anti-apartheid cause in South Africa significantly raised the morale of the black youth protestors.

And it might have had an impact within New Zealand as well, setting the stage forfor one of the next decade's most emblematic collisions of politics and sports. The South African rugby team's 1981 tour of New Zealand was met with widespread protests and civil disobedience from New Zealanders. Stadium-occupying anti-apartheid activists even succeeded in canceling a scheduled test-match. New Zealand joined the world's athletic boycott of South Africa shortly afterwards -- a global effort that Desmond Tutu called "the sanction that hurt the supporters of apartheid the most."