Used to carry the bundles needed for Shabbat themselves, saying that if they would do so for Rabbi Yochanan, certainly they should do so for Shabbat: Shabbat 119a
Rabbi Yochanan was so strong that when a ladder's rung broke beneath him, he was able to hold up with one hand Rav Ami and Rav Asi who had been supporting him, and to use his free hand to climb a pillar. He only wanted the supporters in order to conserve strength for his old age: Ketuvot 62a