The sports facilities of the gymnasium were constructed around 330 BC, representing one of the oldest examples in this category. They were built upon two elongated terraces at the steep descent between Castalian Spring and the sanctuary of Athena Pronaia. At the upper long terrace, there were two parallel aisles spanning approximately 180 meters each, designed for running practice. The first aisle was covered with a portico allowing the athlete to train regardless of the weather conditions. The second aisle was open in the front for training when the weather conditions were good. On the lower terrace there was the building of the palestra. It had a rectangular shape with an inner peristyle courtyard. Around the courtyard there were multiple rooms used for the training of the athletes. On the western side of the palestra there was an outdoor bath with 12 tubs and water coming from Castalian Spring. In addition, there was a big circular pool 10 meters in diameter where the athletes could shower and swim to relax from the tension of the training and the games.