The muscles in your body are made up of two main types of muscle fibers: fast-twitch and slow-twitch. Less intense aerobics and strength training exercises generally recruit slow-twitch fibers, while exercises that require explosive power, speed and anaerobic activity usually activate fast-twitch fibers. Using fast-twitch muscle fibers has more weight loss benefits than exercising your slow-twitch fibers.
Fast-Twitch Vs. Slow-Twitch Fibers
Slow-twitch muscles use oxygen carried by blood as their energy source. On the other hand, fast-twitch fibers are powered by glycosis, which is the process of using stored glucose for energy. This occurs because fast-twitch fibers are so fast they can't utilize oxygenated blood fast enough, so they must depend on glucose already available in the body. According to fitness expert and coach Brian Mac, the average fast-twitch to slow-twitch fiber ratio is about 3-to-2.
Fast-twitch muscle fibers burn more fat during and after your workout. Your muscles must rely on stored glucose for energy, so they tap into your fat stores. A workout that recruits mainly fast-twitch fibers is a more intense workout because it requires you to exert power and speed. As a result, it releases more fat-burning hormones during your workout and causes your body to continue burning fat for eight hours after your workout. Workouts such as aerobics and general strength-training exercises that activate slow-twitch fibers, only boost your metabolism for an hour after your workout.
Fast-Twitch and Metabolism
As you get older, more fast-twitch muscle fibers become slow-twitch muscle fibers, which causes you to lose muscle mass and your metabolism to slow. However, fast-twitch muscle training can counteract this process and help you preserve your fast-twitch muscles. This will not only help you avoid weight gain, but also keep you more active as you age. Doing exercises such as jumping and sprinting, which require explosive power and speed, power trains your muscle fibers to behave more like fast-twitch muscle fibers.
Doing explosive exercises that recruit fast-twitch fibers improves your cardiovascular health, clearing out plaque in your arteries that accumulated as a result of weight gain. It's important to lose weight not just for your physical appearance, but also to lower your risk of preventable diseases, heart attack and stroke. Working fast-twitch fibers by jumping, sprinting and doing calisthenics exercises can give you an intense anaerobic cardio workout that pushes your cardio fitness harder than a regular aerobic workout.