yo-yo club
noun [ C ] UK informal uk/ˈjəʊ.jəʊ ˌklʌb/ us/ˈjoʊ.joʊ ˌklʌb/
(also yo-yo side, yo-yo team, elevator club)悠悠俱乐部（不停升级又降级的足球俱乐部）
a football club that repeatedly moves between higher and lower divisions (= groups of teams who play each other)
West Brom were something of a yo-yo side, winning promotion one season only to be relegated the next. 西布朗队有些像个悠悠俱乐部，在一个赛季刚刚升级了，结果下一个赛季又被降级。