Mistborn is a fantasy book about people with magical abilities called allomancers.
Allomancers "burn" (metabolize metals in the body for magical powers) ingested metals, thereby enhancing various physical and mental capacities.
An pewter allomancer is referred to as a thug. Allomancer burning Pewter is able to greatly enhance their physical capabilities. While burning pewter, an Allomancer can fight or perform physical labor longer than any normal person, and is also many times stronger than his or her normal self; this applies not only to their muscle strength, but to the strength of their bones, skin, etc. This enhanced strength also allows an Allomancer to shrug off wounds that would kill or incapacitate a normal person. Pewter-burning also provides an Allomancer with an increased sense of balance and vastly increased speed and dexterity. An Allomancer performing a "pewter drag" can run for many hours at speeds up to approximately that of a galloping horse. This is extremely draining on the Allomancer's body and will require the Allomancer to burn pewter after completing the pewter drag itself, just to keep the person's body from collapsing in near-death exhaustion.