The 4 important qualities to touch on are: leadership, altruism, dedication and teamwork.
Club sport definitely works for teamwork and dedication. If you helped organise anything for club sport, you might be able to add leadership.
Your grades also demonstrate dedication, this is also important to highlight. But this would fall under the achievement category, not ECs.
If you have done any volunteering, that could fall under the altruism category.
Good luck