Are you a sprinter or a distance runner?

You must have noticed that some people are good at sprinting and others are good at long distance running. Some lift heavy weights whereas some can only do higher repetitions of lesser weights. To sum it up, some have power whereas some have stamina. You ask me to sprint for 1 minute and I will start making faces but if you ask me to run for 1 hour, I will do it happily!

Also have you ever noticed how a chicken does a sudden outrageous ‘furrr furr furr’ with its wings, only to fatigue down in a few mins/secs, whereas a goat can climb mountains, walking for hours?

Does stamina or strength have something to do with the genetic composition of our muscles?

The answer is yes!

Any force or movement that our body produces comes from the contraction of our skeletal muscles. When we have to lift a shopping bag lying on the floor, we have to curl our bicep muscles. This curling of bicep muscles, called the contraction of bicep muscles, produce the power or the strength to lift the bag. Basically this contraction of bicep muscles converts the ATP stored in the muscles to energy.

The very basic unit of our muscles is muscle fiber called myofibrils, which are strands of proteins (actin and myosin) that can grab on to each other when the muscles contract.

Now the question is, do all of us have same type of muscle fiber? Muscles fibers are of two types: fast and slow twitch fibers. We all have studied in school that the basic unit of our blood is a cell. These cells have mitochondria, which are the powerhouses. All energy is mostly stored as ATP in the mitochondria.

The slow twitch muscle fibers contain lots of blood vessels. So slow twitch muscle fibres have a rich supply of oxygenated blood and they produce good deal of energy. They contract slowly and over a long period of time. So the energy is available for a long period. This type of slow contraction does not give an immense bust of energy. The goat from the example above has mostly slow twitch fiber.

On the other hand, the fast twitch fibres contain less blood vessels but they contract quickly and powerfully producing immense bursts of energy. They produce short periods of activity with power and strength. The chicken from the example above has mostly fast twitch fiber.

The composition of these fibers in our body is largely determined by our genes. This is the reason some people can perform unending cardio sessions but cannot lift heavy weights, and vice versa.

But the question is that for normal people like us, who do not have to train for any particular sport, which kind of muscle fiber is better to look good?

Lifting light weights, with higher repetitions, over a period of time can improve our weight lifting ability but unless we do some high intensity training with heavy weights, we cannot build muscles. And it is the muscles that give our body a good shape and metabolism.

So if you have slow twitch/fast twitch fibres in your body you will have to train yourself to increase the power and strength of your muscles so as to build muscles. For that, include high intensity workouts like HIIT, sprinting, weight lifting etc in your schedule. Include workouts which require a bust of energy. These workouts will also help in increasing your stamina.

You can run for hours on the treadmill or do aerobics for hours and can lose weight for the time being but unless you build denser, stronger muscles you body shape will not change. Neither will your metabolism improve. Do a mix of high intensities. For example, run, walk, sprint. This is a better way of building muscles and losing weight for the long-term then just walking or running.