In the first book, Oliver Wood lifts a crate containing a Quaffle, two Bludgers and a Snitch with only 1 arm.
I calculated here that a Bludger weighs 67.4 kg.
For a Quaffle, it's a leather-wrapped ball, and there is no official weight. In "Muggle Quidditch" (the real world adaptation of the fictional sport), they use a volleyball as a "Quaffle". Volleyballs weigh 0.28 kg.
In "Muggle Quidditch", they use tennis balls for Golden Snitches. Tennis balls weigh 0.0594 kilograms.
We still haven't taken the weight of the crate into account, but never mind.
0.28+67.4*2+0.0594 = 135.1394 kilograms, Athletic Human
Consistent, since after Wood graduated he became an athlete.
This is still a low-ball, for we didn't take the weight of the crate into account, and Wood did it with one arm.