Muscle strength refers to the ability of a muscle or group of muscles to exert force against resistance. It is an important aspect of physical fitness and is often measured by the maximum amount of weight a person can lift in a single effort, known as one-repetition maximum (1RM). Strength training exercises, such as weightlifting, can help improve muscle strength. Factors that influence muscle strength include muscle size, the type of muscle fibers, and the nervous system's ability to activate muscles. Regular exercise, proper nutrition, and adequate rest are essential for building and maintaining muscle strength over time.