I once carried a log that weighed about double my body weight and carried it 100ft. My back has never been the same, I really don't recommend it unless you know what you're doing.
I concur. A lapse in training and one careless fess-up is all that's needed for a lifetime injury.
I managed to carry my bodyweight in each hand for a strength event (100kg). I guess the total distance was 20m? I was OK afterwards, and I'm no freak of strength.
The idea discussed in the article was one of progressive overload; slowly make your body adapt to an ever increasing workload. Don't go straight for the 200kg deadlift when you are new to the gym, in other words.