If you want to make a muscle stronger, you have to exercise it intensely enough to damage the muscle fibers and when they heal, they will be stronger than they were. You can tell you are causing muscle damage because of the burning you will feel during exercise and the soreness in that muscle you feel four to eight hours later.
Having weak quad muscles (in the front of your upper legs) increases risk for damage to the cartilage in your knees. A study from Purdue University showed that strengthening these muscles slows down knee cartilage damage and may even improve knee function.
Training for strength improves coordination. Your brain is a master switchboard that coordinates your muscles. Lifting weights does not interfere with brain function; it improves coordination in events that require strength, such as playing sports, working as a carpenter, opening a stuck door or beating a drum.
People who exercise into later life are smarter than those who do not exercise. To prove that exercise preserves brain function, studies must show that the loss of brain function with aging is not just genetic. Identical twins have exactly the same genes, so a study on twins can yield stronger results to show which environmental factors help to prevent loss of brain function.
Your most efficient stride length is determined by what feels most comfortable to you. You cannot run faster by consciously trying to increase your stride length. When you run, your foot hits the ground with great force. The tendons in your legs absorb some of this energy and then contract forcibly after your heel hits the ground, so you regain about 60 to 75 percent of that stored energy. When you try to take a stride that is longer than your natural one, you lose a great deal of this stored energy, tire much earlier and move your legs at a slower rate.
A study in mice suggests that having low levels of vitamin D may harm athletes and exercisers by limiting how long they can exercise. Many exercisers and competitive athletes are vitamin D deficient even if they live in the sunbelt.
If you are going to exercise at a relaxed pace for a few hours, you rarely need to eat or drink unless you feel hungry or thirsty. However, if you are going to compete in sports or exercise intensely for more than 70 minutes, you should take sugar just before you start and while you exercise.