Fitness Glossary: M
marathon: An organized 26.2-mile race for runners and walkers.
maximum heart rate: The maximum number of times your heart should beat in a minute without dangerously overexerting yourself.
meditation: A mental process involving focused attention, or calm awareness, which is also called mindfulness.
mountain bike: A fat-tire outdoors bicycle with upright handlebars that is built to withstand rough terrain.
multi-gym: A home gym contraption that looks like a bunch of health-club weight machines welded to each other.
muscular failure: In a strength training program, the point at which your last repetition with weights is so difficult that you cannot perform another repetition.