Before we start reviewing any of these products, I want to tell you why these products work. If you want to know the secret to improving your fitness you need to have a good understanding of the body's energy system. The energy system is responsible for a huge variety of functions in your body. When we perform a physical activity we use up an energy source called ATP. ATP is the chemical that powers our muscles. When we use up ATP, our muscles stop moving and we die from exhaustion. If you perform physical activities for a long time and don't replace your ATP supply you will slowly deteriorate. You will experience muscle weakness, muscle spasms, pain and eventually muscle weakness. In order to help you know what types of supplements work best for you I will outline them in this article.
A good supplement is one that provides a high level of energy, strength, flexibility and endurance. These can be used during all kinds of physical activities like running, cycling, swimming, tennis, weight lifting, martial arts, weight training, gymnastics, swimming, running, jogging, etc. You can read more about these in my article. A good supplement that helps to increase endurance and strength is known as anaerobic training.