LaVar Ball is back to making eyebrow-raising claims about one of his boys ... this time, he insisted Gelo bench pressed over 400 pounds on Wednesday -- but a whole lot of people on the internet aren't buying it at all.
LaVar shared video on Instagram of he and his 24-year-old brother in the workout room this week ... showing Gelo pushing some big weight off his chest -- all while Dad proudly looked on.
Gelo's form wasn't exactly ideal -- he used plenty of his lower back to get the bar down and up -- but, nonetheless, he was able to lift it.