If you've ever watched marathon runners or other endurance athletes compete in events, it can be an incredible testament to the physical abilities of the human body. Muscular endurance is the product of special muscle fiber types and dedicated training to improve and increase them. Some people are genetically wired to be incredible distance athletes, while others have to train a little harder -- but there are universal facts about muscular endurance that can benefit any athlete. Always talk with your doctor before making any changes to your exercise routine.
Endurance vs. Strength
Muscular endurance refers to the body's ability to exert repeated force over a period of time. This is different from muscular strength, which is the body's ability to exert a single, maximal effort. For example, the ability to run for 30 minutes without stopping requires muscular endurance, while the ability to bench press your body weight for one repetition requires muscular strength.
Your muscles are made up of fast- and slow-twitch fibers. Fast-twitch fibers are used for explosive, muscular strength, while slow-twitch fibers provide the force for muscular endurance. Slow-twitch fibers are sometimes referred to as "red" fibers because their rich supply of blood vessels make them red in appearance. The large amount of blood vessels in slow-twitch fibers are used to convert oxygen to energy for muscle contraction. Blood vessels supply oxygen-rich blood to those muscle fibers for contraction. You can increase the number of slow-twitch muscle fibers in your body by performing endurance exercises, such as running and biking, for at least 30 to 45 minutes at a time. Also, resistance training with low weight and repetitions in the 12 to 20 range will train these fibers.
How Muscular Endurance is Measured
Muscular endurance often is measured using a percentage of an individual's body weight while performing calisthenic exercises, such curl-ups and push-ups. These tests are often performed to failure. For example, during the push-up test, an individual may perform push-ups until they no longer can complete a rep. The performance ranges of what's considered excellent for these tests will vary according to gender and age. For example, an excellent number of push-ups for a 30 year-old would be greater than 37 for women, and 41 for men. Muscular endurance tests can be administered as a standard measure of fitness or as a tool to measure training progress. A variety of exercises can be used to test the muscular endurance of specific body parts, such as the lat pull-down, leg extension and bench press.
Benefits and Tips
Increased muscular endurance has benefits ranging from improved athletic performance for activities like running and cycling, to assisting in day-to-day activities such as walking through the grocery store or carrying a baby in your arms. You can improve your muscular endurance using the basic principles of fitness, which include exercise frequency, intensity, time and type. Be sure to slowly increase exercise frequency, intensity and duration to avoid overuse injuries. Vary the types of activities you do to challenge your muscles and avoid training plateaus.