3-year-old Liam Hoekstra makes a very strong impression

But when Liam picks up two five-pound dumbbells and waves them around like stuffed animals, or does rapid-fire sit-ups, it becomes abundantly clear that he has an extraordinary gift.

"A lot of the TV stations wanted to do the 'World's Strongest Boy' type of stories," Dana Hoekstra said. "They weren't interested in the science behind his condition ... and I wasn't going to put him on some kind of freak show."

Liam's amazing strength, the result of a rare genetic condition called myostatin-related muscle hypertrophy, has made him something of a global media darling.

"Liam is everything a lot of us want to be -- all muscle, no body fat and he gets to eat whatever he wants," she said.

For Liam, the result was having 40 percent more muscle mass than other children his age. He is terrifically strong, quick as a rabbit, has the metabolism of a gerbil and almost no body fat.

Liam's strength is not evident until he participates in an activity that requires raw power, such as sit-ups or chin-ups.

"He's amazing at doing sit-ups because his abdominal muscles are so strong," said his mother, who is a physician's assistant. "When he does sit-ups you can see how he is stronger than other kids his age."

The 30-pound boy thrives in strength-related activities. But Liam struggles with his balance and is less flexible than other children his age, said Phil Bishop, the head coach at Cassell Gymnastics and Dance in Norton Shores.

Bishop pointed out the major difference between Liam and other three-year-olds in his class as the children did chin-ups. Two other children in the class struggled to pull their chins up to the bar; Liam performed the task with ease.