The muscular system is an organ system consisting of skeletal, smooth, and cardiac muscle. It permits movement of the body, maintains posture, and circulates blood throughout the body. The muscular systems in vertebrates are controlled through the nervous system although some muscles can be completely autonomous. Together with the skeletal system in the human, it forms the musculoskeletal system, which is responsible for the movement of the body.
Exercise is physical activity that enhances or maintains fitness and overall health. It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic skills, improve health, or simply for enjoyment. Many individuals choose to exercise outdoors where they can congregate in groups, socialize, and improve well-being as well as mental health.
Aerobic exercise, also known as cardio, is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. "Aerobic" is defined as "relating to, involving, or requiring oxygen", and refers to the use of oxygen to meet energy demands during exercise via aerobic metabolism adequately. Aerobic exercise is performed by repeating sequences of light-to-moderate intensity activities for extended periods of time. Examples of cardiovascular or aerobic exercise are medium- to long-distance running or jogging, swimming, cycling, stair climbing and walking.
Exercise physiology is the physiology of physical exercise. It is one of the allied health professions, and involves the study of the acute responses and chronic adaptations to exercise. Exercise physiologists are the highest qualified exercise professionals and utilise education, lifestyle intervention and specific forms of exercise to rehabilitate and manage acute and chronic injuries and conditions.
Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of sports, occupations, and daily activities. Physical fitness is generally achieved through proper nutrition, moderate-vigorous physical exercise, and sufficient rest along with a formal recovery plan.
Anaerobic exercise is a type of exercise that breaks down glucose in the body without using oxygen; anaerobic means "without oxygen". In practical terms, this means that anaerobic exercise is more intense, but shorter in duration than aerobic exercise. This type of exercise leads to a buildup of lactic acid.
Endurance is the ability of an organism to exert itself and remain active for a long period of time, as well as its ability to resist, withstand, recover from and have immunity to trauma, wounds, or fatigue.
Strength training, also known as weight training or resistance training, involves the performance of physical exercises that are designed to improve strength and endurance. It is often associated with the lifting of weights. It can also incorporate a variety of training techniques such as bodyweight exercises, isometrics, and plyometrics.
Altitude training is the practice by some endurance athletes of training for several weeks at high altitude, preferably over 2,400 metres (8,000 ft) above sea level, though more commonly at intermediate altitudes due to the shortage of suitable high-altitude locations. At intermediate altitudes, the air still contains approximately 20.9% oxygen, but the barometric pressure and thus the partial pressure of oxygen is reduced.
High-intensity interval training (HIIT) is a training protocol alternating short periods of intense or explosive anaerobic exercise with brief recovery periods until the point of exhaustion. HIIT involves exercises performed in repeated quick bursts at maximum or near maximal effort with periods of rest or low activity between bouts. The very high level of intensity, the interval duration, and number of bouts distinguish it from aerobic (cardiovascular) activity, because the body significantly recruits anaerobic energy systems. The method thereby relies on "the anaerobic energy releasing system almost maximally".
Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe post-exercise pain, fatigue, nausea, vomiting or other negative effects. Exercise intolerance is not a disease or syndrome in and of itself, but can result from various disorders.
Interval training is a type of training exercise that involves a series of high-intensity workouts interspersed with rest or break periods. The high-intensity periods are typically at or close to anaerobic exercise, while the recovery periods involve activity of lower intensity. Varying the intensity of effort exercises the heart muscle, providing a cardiovascular workout, improving aerobic capacity and permitting the person to exercise for longer and/or at more intense levels.
Lactate inflection point (LIP) is the exercise intensity at which the blood concentration of lactate and/or lactic acid begins to increase rapidly. It is often expressed as 85% of maximum heart rate or 75% of maximum oxygen intake. When exercising at or below the lactate threshold, any lactate produced by the muscles is removed by the body without it building up.
Long slow distance (LSD) is a form of aerobic endurance training used in sports including running, rowing, skiing and cycling. It is also known as aerobic endurance training, base training and Zone 2 training. Physiological adaptations to LSD training include improved cardiovascular function, improved thermoregulatory function, improved mitochondrial energy production, increased oxidative capacity of skeletal muscle, and increased utilization of fat for fuel. Ernst van Aaken, a German physician and coach, is generally recognized as the founder of the LSD method of endurance training.
Muscle hypertrophy or muscle building involves a hypertrophy or increase in size of skeletal muscle through a growth in size of its component cells. Two factors contribute to hypertrophy: sarcoplasmic hypertrophy, which focuses more on increased muscle glycogen storage; and myofibrillar hypertrophy, which focuses more on increased myofibril size. It is the primary focus of bodybuilding-related activities.
Second wind is a phenomenon in endurance sports, such as marathons or road running, whereby an athlete who is out of breath and too tired to continue, finds the strength to press on at top performance with less exertion. The feeling may be similar to that of a "runner's high", the most obvious difference being that the runner's high occurs after the race is over. In muscle glycogenoses, an inborn error of carbohydrate metabolism impairs either the formation or utilization of muscle glycogen. As such, those with muscle glycogenoses do not need to do prolonged exercise to experience "hitting the wall". Instead, signs of exercise intolerance, such as an inappropriate rapid heart rate response to exercise, are experienced from the beginning of an activity, and some muscle GSDs can achieve second wind within about 10 minutes from the beginning of the aerobic activity, such as walking. (See below in pathology).
Although they vary in particulars, polymyositis, dermatomyositis and inclusion body myositis are idiopathic inflammatory myopathies (IIM) primarily characterized by chronic inflammation of human skeletal muscle tissue that ultimately causes the necrosis of muscle cells. This degeneration leads to muscle tissue wasting, weakness and fatigue among other serious effects. Until recently, exercise has been avoided as a type of therapy, and even forbidden due to the risk of triggering or amplifying inflammation. However, several studies have been conducted to test this assumption and have shown that aerobic exercise as well as resistance training can maintain and even improve quality of life for IIM-affected individuals without increased inflammatory response.
Cardiovascular fitness refers to a health-related component of physical fitness that is brought about by sustained physical activity. A person's ability to deliver oxygen to the working muscles is affected by many physiological parameters, including heart rate, stroke volume, cardiac output, and maximal oxygen consumption.
Respiratory adaptation is the specific change that the respiratory system undergoes in response to the demands of physical exertion. Intense physical exertion, such as that involved in fitness training, places elevated demands on the respiratory system. Over time, this results in respiratory changes as the system adapts to these requirements. These changes ultimately result in an increased exchange of oxygen and carbon dioxide, which is accompanied by an increase in metabolism. Respiratory adaptation is a physiological determinant of peak endurance performance, and in elite athletes, the pulmonary system is often a limiting factor to exercise under certain conditions.
The physiology of marathons is typically associated with high demands on a marathon runner's cardiovascular system and their locomotor system. The marathon was conceived centuries ago and as of recent has been gaining popularity among many populations around the world. The 42.195 km distance is a physical challenge that entails distinct features of an individual's energy metabolism. Marathon runners finish at different times because of individual physiological characteristics.
