MUSCLE

A pop-science overview of muscles from the author of Bones: Inside and Out.

Meals, a professor of orthopedic surgery at UCLA, begins with a quick history that reveals how thinkers from all cultures taught mostly nonsense about human anatomy until the European Renaissance, when artists and researchers became obsessed with getting it right, so they began dissecting bodies. By the 19th century, scientists were able to show how muscles create movement. This is a subject less straightforward than anatomy, and the author’s admirable effort to explain it, heavy with analogies and diagrams, is generally accessible but may cause a few struggles for readers unfamiliar with biochemistry. Science buffs will perk up when he delivers the basics. Humans have 650 muscles, more or less (some are born missing a few, usually without a problem; others have extras), and there are three types. Most familiar are skeletal muscles, which make up about 40% of our weight and are under conscious control. Smooth muscles work automatically to control our digestive tract, urinary tract, blood vessels, and other housekeeping systems. Uniquely, cardiac muscle cells contract regularly without any neurological stimulus—and can do so for more than 100 years if properly cared for. In the chapter on muscle issues, Meals largely focuses on fatigue, strains, injuries, and aging, and he offers an amusing account of physical training programs throughout history. The author wisely devotes several chapters to exercise and sports, paying special attention to conditioning, nutrition, and muscle-building supplements, including a mildly skeptical review of performance enhancers and an entertaining review of cheating. Readers who suspect that many animals have muscles that produce bizarre phenomena will find plenty to engage in the chapter titled “Zoological Survey.” For example, even though the octopus has “a large brain for its body size, roughly two-thirds of tentacle control comes from nerve centers in the tentacles themselves.”

An easy-to-digest science lesson tailored for general readers.