Case C-124/21 P: Judgment of the Court (Grand Chamber) of 21 December 2023 – International Skating Union v European Commission, Mark Jan Hendrik Tuitert, Niels Kerstholt, European Elite Athletes Association (Appeal – Competition – Rules introduced by an international sports association – Skating – Private law entity vested with regulatory, control and decision-making powers, and the power to impose sanctions – Rules on the prior approval of competitions, the participation of athletes in those competitions and the arbitration rules governing conflicts – Parallel pursuit of economic activities – Organisation and marketing of competitions – Article 101(1) TFEU – Decision by an association of undertakings adversely affecting competition – Concepts of anticompetitive ‘object’ and ‘effect’ – Justification – Conditions)