Entrepreneur Erick Thohir loves competitive sports such as badminton but hates swimming and golf, which lack the challenge of competing directly against another person.
Armstrong had posted on his Twitter account last month that he was in swimming training but he will now have to wait to make his competitive debut in the pool.
As swimming grows in popularity and commercial opportunity, more swimmers have been able to stay competitive and make a living long after college, which has nudged up the average age.