Body Science: The High Intensity Effect- Calories, Weakness, and Healthy Bodies Part 1

In recent years the increasing number of high intensity exercise programs and classes has shown that moving with greater intensity (speed) can significantly improve fitness levels. The benefits span all age groups, but it can specifically work 2 major areas as we age: Muscle Activation and Weight Movement.

Muscle Activation – Every muscle in your body is made of 3 different muscle fibers (we are going to discuss only 2 here to keep it brief), type I- slow twitch and type II – fast twitch fibers. Each individual has a specific percentage of each type of muscle fibers from birth (this explains why some people are genetically faster or better at some sports or activities). When you are lifting light weights at a slow or moderate pace you only utilize slow twitch muscle fibers. When you add weight or move quickly the fast twitch fibers are recruited, in addition to the slow twitch fibers to complete the exercise or movement.

As we age and with lack of use, we gradually lose the ability to recruit fast twitch muscle fibers (if you don’t use it, you lose it). This leads to a lack of balance and the ability to react quickly to a situation (i.e. falling, etc). The reason why some elderly people drive slower is the fact that they cannot react quickly when there are changes on the road in front of them. Driving slower places more distance from the car in front and therefore, more time to react.

The ability to recruit fast twitch muscle fibers are incredibly important for some occupations (example: police, firefighter, and military, reacting to an opponent or situation). First person to react correctly wins, but we all need the ability to avoid daily hazards around us.

Lesson– Lifting light can be a great way to start an exercise program, but over time it limits your progress. Challenging your body is the only way it will change. Working out slow trains your body to move slowly. And as we get older, it feels like the world is moving faster. We must be able to keep up!

Please come back tomorrow for Part 2.

This post is to answer a physiology question that was submitted on our website. If you have a specific training or physiology question, please contact us on our website listed below.

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