You might want to keep quiet about this at a bodybuilding competition - but having bigger muscles does not necessarily make you any stronger.
Scientists at the University of Mississippi, reviewing existing studies, suggest larger muscles do not reflect how much someone can lift.
The proof comes in research which shows people who abandon the gym can hang onto the strength they have built up for months, even as their muscles shrink.
The experts also say that lifting both lighter and heavier weights create the same size of muscles.
The findings challenge many of the assumptions upon which traditional exercise programmes have been based.
Many bodybuilders try to bulk up using "hypertrophic" exercises, which means overloading their muscles, to build up biceps by lifting larger weights at a greater intensity.
The US paper states that this training, also known as resistance training, does indeed work. But, whether done with a light or a heavy weight, a similar muscle size is achieved.
The academics said: "The aforementioned evidence suggests that our understanding of muscle hypertrophy may be incomplete and perhaps misplaced regarding its influence on muscle strength."
They added: "Our paper highlights many potential issues with how we think about changes in strength following exercise."