Photo Credit mikanaka/iStock/Getty Images. Women over 40 should include progressive strength training in their fitness routine. Strength training builds muscle tone and slows the muscle loss that starts to occur in the 40s and speeds up sharply after 50.Muscle loss combined with bone-density loss increases the chances of injury from falls in older women.ee your doctor and discuss the type of training you are looking to start. This step is important for women over 50 and women who have heart disease, arthritis, diabetes or high blood pressure.