Understanding Muscular Strength

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Muscular strength refers to the amount of force a muscle can produce with a single maximal effort. The size of your muscle fibers and the ability of nerves to activate muscle fibers are related to muscle strength. It is measured during muscular contraction. Building muscle strength helps with body alignment, makes performing everyday actions easier, and increases metabolism.

What Is Muscular Strength?

You might think that muscular strength is simply how strong you are. For example, how much you weight you can carry, how many pounds you can lift at the gym or how many pushups you can do during a workout. But a true muscular strength definition is a little bit more complicated than that.

According to the American Council on Exercise (ACE), muscular strength is the maximal force a muscle or muscle group can exert during a contraction. But there are other factors that affect how strong you are and how much strength you have to complete daily chores or exercises. ACE provides definitions for these terms that are related to muscular strength:

  • Muscular endurance: The ability of your muscles to exert force against resistance over a sustained period of time.
  • Muscular power: The combination of muscular force and the speed of movement

For example, the number of pushups you can do in one minute depends in part on your muscular strength but also on your muscular power and muscular endurance.

What happens in your body to produce the effect of strength relies on several factors. The size of the muscle and the ratio of fast twitch and slow twitch fibers in that muscle is one component. Then the neural connection is key, as the motor neurons must be coordinated in their firing in order to signal the muscle fibers to contract at the same time. Strength also relies on the muscle having good support for movement of the joint, including the health of the joint, bones, ligaments, and tendons.

Muscle-Strengthening Exercise Recommendations

The "2008 Physical Activity Guidelines for Americans" from the U.S. Department of Health and Human Services recommends:

  • Children and adolescents: Muscle-strengthening physical activity at least three days per week.
  • Adults and older adults: Muscle-strengthening activities that are moderate or high intensity, involving all major muscle groups, two or more days per week.

Measuring Muscular Strength

The one-repetition maximum test (1RM) is the standard test used to measure muscle strength. During a 1RM test, an exerciser performs one repetition of a single exercise to see how much weight he or she can lift. There is a protocol developed by Kramer and Fry to conduct this test, which is usually done with the bench press for upper body strength and the leg press for lower body strength.

How to Do the 1RM Test

In physical therapy, a therapist may measure a client's muscle strength in two ways. In manual muscle testing, the client resists pressure exerted by the therapist to push a body part (such as your arm) in a specific direction. This is graded on a five-point scale. A dynamometer device can also be used, with the client pressing on it to exert a force that is then measured in pounds or kilograms.

How Your PT Measures Your Strength

How to Improve Muscle Definition and Strength

The best way to build muscle strength is to participate in a program of resistance training. Some people call it strength training or "weightlifting." But you don't have to lift weights to improve your muscles. You can do simple bodyweight exercises at home to build muscle and build strength.

Strength training improves both the size of your muscle fibers and the ability of your nerves to communicate with the muscles. So as your muscles get bigger with resistance training (muscle hypertrophy) they also become more coordinated and better able to perform movements that require strength.

How long does it take to build muscle strength? After two to three weeks of resistance training or strength training, you'll probably notice that your muscles get stronger. In addition, you may notice greater muscle definition. That is, your muscles become "defined" and easier to see on your body.

But muscle definition also depends on your level of body fat. If your muscles get bigger but you still carry too much fat, you may not see sculpted muscles on your body. To improve both muscle definition and muscular strength you need to combine a healthy diet to lose fat with a resistance training program to build muscle.

Getting the Right Start

Before you get started with strength training, talk to your health care provider to make sure there aren't restrictions or modifications that you should follow to stay safe. If you are new to training, ask for help. A few sessions with a qualified trainer can help you to get your program off to a strong start for lasting results.

Benefits of Building Muscular Strength

When you improve muscular strength and muscular definition, you enjoy many different benefits, especially if you are trying to lose weight—and you don't have to be an expert bodybuilder to take advantage of them. Strength training provides benefits for exercisers of all levels.

When you include strength training in your exercise program you build lean muscle mass and improve your metabolism. Having stronger muscles will also help you to move through your daily activities and burn more calories with greater ease. And muscles help to improve the way that your body looks. A tighter, leaner body looks better at every size.

A Word From Verywell

Exercise of any kind is important for good health and to maintain a healthy body weight. But if you do strength or resistance training two to three times per week, you build strong muscles to stand taller, burn more calories, and improve the quality of your daily activities and movement.

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