Many of us do not run competitively, yet take our running seriously. It is the best cardiovascular exercise that one can get, and it is also the most inexpensive, because all you need is a pair of running shoes. The hamstring and quadriceps are the strongest muscles in our body and they become even stronger due to this activity. Running in your local park or track gives immense pleasure because it helps release endorphins which stimulate pleasure in the brain.