The ISU previously banned athletes from taking part in financially lucrative but unsanctioned events such as Icederby competitions.

Dutch speed skaters Mark Tuitert and Niels Kerstholt appealed against their inability to participate at the events.

The European Commission ruled against the ISU in December 2017, claiming the rules were a breach of EU anti-trust laws.

The EU General Court has now backed the initial decision after the ISU appealed the verdict.

It sets a precedent for other disputes which may arise in sport in future.

"The General Court, called upon to rule for the first time on a Commission decision finding that rules adopted by a sports federation do not comply with EU competition law, confirms that the classification of a restriction of competition by object established by the Commission in respect of the rules at issue is well founded, but partially annuls the contested decision as regards the corrective measures imposed on the ISU," the decision reads.

"In the first place, the General Court finds that the Commission was right to conclude that the eligibility rules have as their object the restriction of competition within the meaning of Article 101 TFEU.

"In that regard, the General Court finds, first of all, that the situation in which the ISU finds itself is capable of giving rise to a conflict of interests.

"On the one hand, the ISU carries out a regulatory function, by virtue of which it has the power to adopt rules in the disciplines for which it is responsible, and, thus, to authorise competitions organised by third parties, while, on the other hand, in the context of its commercial activity, for its own part, it organises the most important speed skating competitions in which professional skaters must participate in order to earn their living.

"In that regard, the General Court considers that the obligations binding on a sports federation in the exercise of its regulatory function under Article 101 TFEU are those consistently set out in the case law relating to the application of Articles 102 and 106 TFEU, with the result that, in those circumstances, the ISU is required to ensure, when examining applications for authorisation, that third-party organisers of speed skating competitions are not unduly deprived of access to the relevant market, to the extent that competition on that market is distorted."

The General Court found the European Commission was wrong to dispute the ISU's arbitration rules.

The court annulled an initial decision which would have required the ISU to amend its eligibility rules with respect to the Court of Arbitration for Sport arbitration system.

The protection of the integrity of the sport was also deemed a "legitimate objective", with the General Court understanding the ISU's aim "to establish rules seeking both to avoid the risks of manipulation of competitions liable to result from sports betting and to ensure that sporting competitions meet common standards".

This was welcomed by the governing body.

"The ISU notes with satisfaction that the General Court has recognised the legitimacy of the ISU's pre-authorisation system intended to ensure that any organiser of sporting competitions 'comply with common standards', seeking in particular to ensure that competitions take place fairly and the physical and ethical integrity of sportspeople is protected," an ISU statement read.

"The ISU also notes that the General Court has expressly recognised that it was legitimate for the ISU 'to establish rules seeking to prevent sports betting from creating risks of manipulation of competitions and athletes'.

"The ISU maintains that its eligibility rules have never been enforced with a view to preventing the organisation of third-party skating events and regrets that the judgment does not address the substantial evidence put forward by the ISU confirming this.

"Following the adoption of the 2017 Commission decision, the ISU amended its eligibility rules in 2018 pursuant to implementation discussions with the European Commission.

"The Court judgment relates to a version of the eligibility rules which is no longer in force and therefore has no impact on the ISU's current operations."

The ISU added that it was further evaluating the judgment and reserved the right to appeal to the European Court of Justice.

European Elite Athletes Association, also known as EU Athletes, welcomed the judgement made by the general court.

The association praised Dutch skaters Mark Tuitert and Niels Kerstholt for their decision to challenge the ISU's rules.

EU Athletes supported the two athletes since their initial complaint in 2014.

"The General Court’s decision reaffirms that the sport organizations engaging in an economic activity have to operate within the EU law," said Paulina Tomczyk, EU Athletes general secretary. 

"‘Specificity of sport’ cannot be used as an excuse not to do so. 

"It’s an important step towards making the global sport governance fairer and making sure it respects athletes’ rights and interests."

"Once again, we applaud Mark and Niels’ for their courage and commitment to pursuing this case, which has a potential to significantly improve the situation of thousands of athletes around the world," added Brendon Batson, EU Athletes President.

"It is also an important message to sport federations that they should work in partnership with the stakeholders, especially the athletes, to develop the rules and the sport itself."

The ISU softened its stance towards event organisers such as Icederby following the initial decision.

The governing body sanctioned a trial Icederby event last year, which saw speed skaters and short track skaters compete against each other on a 220 metre track.

The ISU is not the first governing body to have been referred to the European Commission in recent years.

An attempted was made by the International Swimming Federation to stop the emergence of the rival International Swimming League, before they backed down after anti-trust lawsuits were lodged.

The International Basketball Federation has also clashed with EuroLeague over the sport's calendar.

Velon filed an anti-trust complaint to the European Commission against the International Cycling Union last October.