(Cover) - EN Showbiz - Matthew McConaughey works out using rocks rather than weights.

The American star prides himself on his toned physique, and does everything he can to lead a healthy lifestyle. He is often seen surfing and going for long walks, and prefers exercising outside to spending hours cooped up in a gym. For that reason he rarely uses classic weights as part of his workout, instead grabbing any heavy boulders he happens to see while out and about.

It's not as simple as it seems, he explained to the April edition of Mens Fitness, after revealing he uses heavy rocks to stay toned. You shift the weight from high above your head, in your right arm, then your left, then rest it on your shoulders, adding more weight to your back, then your legs.

You get a full-body workout just by finding out how many positions you can manage without having to set the weight on the ground. You also discover the stronger and weaker spots in your physique.

Matthew has kids Levi and Vida with his partner Camila Alves, and they are a very active family. Matthew and Camila often go hiking together, which has become a cause of some amusement between them.

We went up to 3,000 feet and I had on hiking shoes and I was all set up and ready to go," he explained. "[Camila] was wearing Havaianas sandals and a white skirt. I came down to the bottom of that hill afterward and had blood on me, [all] muddy... and that girl didn't have a speck of dust on her." (C) Cover Media