It varies by person. A quick search of body weight percentage is about 4-5% per arm and 16-17% per leg. For a 150 lb while intact man that would be about 70ish to 80ish pounds. Baskets may be carried by multiple people or dragged though.

Apparently according to one source the basket case origin was a result of rumor telephone and loss of context. https://www.grammarphobia.com/blog/2014/08/basket-case.html