We lose lean muscle mass beginning around age 50. By age 80, we have lost 50 percent of our lean muscle mass. People who are sedentary lose 15 percent of their muscle mass each decade between ages 50 and 70, and 30 percent per decade after age 70.
Functions of Muscles
Muscles keep your body moving by contracting and relaxing. In some cases, this movement is voluntary. You use your skeletal muscles to bend your arms or legs when you want. Smooth muscles, however, are part of the involuntary movement within your body. These muscles surround organs of the digestive tract as well as the arteries. You don't have to be aware of the process -- your brain controls the function! One of the most vital muscles is the cardiac muscle, or heart. Understanding the functions of muscles can help you keep them healthy or treat injury as needed.
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Dr. Gerald M. Silverman , Chiropractic Medicine, answeredMuscles have the ability to adapt to external forces, and when placed under high demand, they generate great strength and power and maintain durability. To accomplish this feat, muscles can change their shape, size, and consistency. You can see these muscular changes in the sculpted physiques of athletes and bodybuilders. As they place greater demand on the muscles, the size and shape of the muscle changes in response to the demand load. And although muscle changes aren't outwardly noticeable in most people, your muscles are constantly altering their size, shape, and consistency in response to your daily activities too. Movement helps muscles maintain their elasticity, and the lack of movement causes muscles to develop some rigidity. From their very smallest component to their largest bulky mass, muscles work in unison to expand and contract. As muscle fibers change their size and shape, they glide over the surrounding fibers. The result is a living woven fabric capable of changing its size, shape, and strength depending on the demands of the moment. -
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National Academy of Sports Medicine answeredThis common question is not easily answered. Many muscles contribute to a vertical leap, including your entire lower body, core, and some of your upper body musculature. For example, although the calves are commonly given credit for leaping ability, if you only had your calf muscles and not your thigh and hip muscles, you probably wouldn't be able to jump very high. Also, your upper body is important in helping to generate momentum for the vertical jump, making it vitally important as well. In summary, the most important muscle for for improving your vertical is all of them! However, when choosing only one muscle to focus on, a strong gluteus maximus is crucial to good vertical. This is due to its force production capabilities since it is the largest muscle in the body, and if this muscle is weak, it can disrupt lower-extremity mechanics which can lead to decreased overall force production and poor jumping performance. -
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Dr. Mehmet Oz, MD , Cardiology (Cardiovascular Disease), answeredSee All 2 AnswersMuscle cars, muscle shirts, and muscle heads - they all connote the same image. Big, bad, strong, powerful. And for good reason: Muscle is what provides your body's power. It also gives you the ability to change your body in a couple of different ways. Of course, on the outside, a lean and toned look can imply a message of health and strength more so than a lumpy, fluffy, or fatty body. More importantly, we all need muscle for the metabolic machine that it is. Simply, muscle helps your body combat fat. Adding some lean muscle mass to your body will help your body burn more calories, especially compared to fat, which contributes to you storing more fat because it takes very little energy to maintain.
Your body burns 50 to 100 calories per pound of muscle every day, compared to less than one handful of calories per pound of fat. So the result is that you burn fat by adding muscle. -
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Discovery Health answeredEvery muscle cell has some amount of ATP. Adenosine triphosphate (ATP) is the way your body uses biochemicals to store and use energy. There is enough ATP in the cell that the muscle can use immediately, but only enough to last for about three seconds. The muscle must replenish the ATP levels quickly, using a high-energy phosphate compound called creatine phosphate.
An enzyme called creatine kinase removes the phosphate group from creatine phosphate and transfers it to ADP to form ATP. The cell then turns ATP into ADP, and then the phosphagen turns the ADP back into ATP. The muscle continues to work, and the creatine phosphate levels begin to decrease. The ATP levels and creatine phosphate levels working together are called the phosphagen system. This phosphagen system supplies the energy needs of working muscle, but only for 8 to 10 seconds.
Energy is also produced by the Clycogen-Lactic Acid System and aerobic respiration.
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Discovery Health answered
In spite of what you might have heard or read in an e-mail, science doesn't have a definitive number. People's smiles vary; some people have more facial muscles than others, giving them a wider range of expression.
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Discovery Health answered
Science doesn't have a definitive number, in spite of what you might have heard or read in an e-mail. People's frowns vary; some folks have more facial muscles than others, giving them the ability to be more expressive.
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Reston Hospital Center answeredMuscle weakness is a medical term that means your voluntary muscles cannot contract normally even when you exert a full effort. Muscle contraction requires that the spinal cord and the nerves receive a signal from the brain. If the nervous system, the muscles, or the area between the two are diseased or damaged, you can have muscle weakness. Muscle weakness is not just feeling tired or weak, it is a neuromuscular disorder.
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National Academy of Sports Medicine answeredThe rhomboids are key muscles in the mid/upper back that squeeze the shoulder blades together and provide stability for the shoulder complex. They are very important postural muscles that tend to become weak due to the prolonged amount of time people spend in seated positions.
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Dr. Gerald M. Silverman , Chiropractic Medicine, answeredAn important group of structures within the muscle are the sensory and motor nerves. These nerves are responsible for positioning, movement, tone, and pain. They regulate everything from fine muscle movement that allows you to blink an eye to gross positioning of your trunk and limbs.
There are different types of nerves, and their interaction results in either a pain-free or painful neck and back.