Weightlifting competitions are supposed to be held in Tokyo International Forum.
A subway, Yurakucho Line is convenient.
Get on an inbound subway at Toyosu station, “豊洲” then get off at Yurakucho station, “有楽町”. The train stops 3 stations before arriving at Yurakucho station. It takes around 7 minutes and costs 170 Yen.
The forum is to the north of the station.
It takes about 1 minute on foot.