Many women still fear strength training because they do not want to gain a large amount of muscle mass, but for most women, this fear is unfounded as they do not have the genetic makeup to bulk up. Second, lean body mass is denser than fat mass, taking up about 22 percent less space. If a person loses an amount of fat weight and gains the exact number of pounds of lean body weight, they'll look 22 percent thinner. In general, with a good diet and an adequate exercise program, it is very difficult to gain as much lean muscle weight as one will lose in fat weight. Another benefit to women who lift weights is strength training's role in the prevention of osteoporosis.
Most people think of osteoporosis as a disease afflicting the elderly.
However, around the age of 30, bone mass has peaked and remains relatively stable until 40 to 45 years of age. After age 45, both men and women gradually lose bone mass at about one percent each year, which can result in a critically low bone density as early as age 60. It is after the age of 60 that fractures of the hip, wrist and even collapsed vertebrae because of low bone mass become problematic. It is clear that any physical activity can increase bone mass and density in young women. This will greatly reduce the chance of fractures caused by osteoporosis.