What's the heaviest weight a person can lift?

The world was in awe when British strongman Eddie Hall deadlifted 1,102 pounds (500 kilograms) at the World Deadlift Championships in 2016. Hall was the first person to break the half-ton barrier — and then, in 2020, Icelandic strongman Hafþór Júlíus Björnsson took it up a notch by deadlifting 1,104.5 pounds (501 kg). 

Meanwhile, the record for heaviest weight ever lifted by a human belongs to Canadian strongman Gregg Ernst, who in 1993 backlifted two cars with drivers that together totalled 5,340 pounds (2,422 kg).

These mind-blowing feats of strength raise a question: What is the heaviest weight possible for a person to lift?

Experts told Live Science that it's likely athletes are still operating below their muscles' maximum capacities, and it's unclear what the limit of human strength could be. But that said, it's difficult to measure a given person's maximum muscle capacity.

Related: Which Olympic sport burns the most calories? 

Bradley Schoenfeld, a professor of exercise science at Lehman College, said that muscle strength can be measured using an electromyography (EMG) machine. EMG works by recording the electrical activity generated within a muscle, both by nerve cells and by contracting muscle fibers. Such tests can only be performed in the lab, and the EMG only monitors a localized set of muscles, so it can't assess a person's body-wide muscle capacity. 

"It's hard to define that limit," said E. Todd Schroeder, a professor of clinical physical therapy at the University of Southern California who studies how strength and muscle mass can be increased in older adults. The only way to really determine your muscle capacity is through continuous training — by establishing new personal records and then seeing if you can break them, he told Live Science.