Exertion is the physical or perceived use of energy. [1] Exertion traditionally connotes a strenuous or costly effort, resulting in generation of force, initiation of motion, [1] or in the performance of work. [2] It often relates to muscular activity and can be quantified, empirically and by measurable metabolic response.
In physics, exertion is the expenditure of energy against, or inductive of, inertia as described by Isaac Newton's third law of motion. In physics, force exerted equivocates work done. [3] The ability to do work can be either positive or negative depending on the direction of exertion relative to gravity. For example, a force exerted upwards, like lifting an object, creates positive work done on that object. [2]
Exertion often results in force generated, a contributing dynamic of general motion. [1] In mechanics it describes the use of force against a body in the direction of its motion (see vector).[ citation needed ]
Exertion, physiologically, can be described by the initiation of exercise, or, intensive and exhaustive physical activity that causes cardiovascular stress or a sympathetic nervous response. This can be continuous or intermittent exertion. [2]
Exertion requires, of the body, modified oxygen uptake, increased heart rate, and autonomic monitoring of blood lactate concentrations. Mediators of physical exertion include cardio-respiratory and musculoskeletal strength, as well as metabolic capability. [4] This often correlates to an output of force followed by a refractory period of recovery. Exertion is limited by cumulative load and repetitive motions. [2]
Muscular energy reserves, or stores for biomechanical exertion, stem from metabolic, immediate production of ATP and increased oxygen consumption. [4] Muscular exertion generated depends on the muscle length and the velocity at which it is able to shorten, or contract.[ citation needed ]
Perceived exertion can be explained as subjective, perceived experience that mediates response to somatic sensations and mechanisms. [3] A rating of perceived exertion, as measured by the RPE-scale, or Borg scale, is a quantitative measure of physical exertion. [5]
Often in health, exertion of oneself resulting in cardiovascular stress showed reduced physiological responses, like cortisol levels and mood, to stressors. Therefore, biological exertion is effective in mediating psychological exertion, responsive to environmental stress. [6]
Overexertion causes more than 3.5 million injuries a year.[ clarification needed ] An overexertion injury can include sprains or strains, the stretching and tear of ligaments, tendons, or muscles caused by a load that exceeds the human ability to perform the work. [7]
In sport psychology, the perceived exertion of an exercise is how hard it seems to the person doing it. [8] Perceived exertion is often rated on the Borg scale of 6 to 20, where 6 is complete rest and 20 is the maximum effort that an individual can sustain for any period of time. Although this is a psychological measure of effort, it tends to correspond fairly well to the actual physical exertion of an exercise as well. [9] Additionally, because a high perceived exertion can limit an athlete's ability to perform, some people try to decrease this number through strategies like breathing exercises [10] and listening to music. [11]
Psychophysiology is the branch of psychology that is concerned with the physiological bases of psychological processes. While psychophysiology was a general broad field of research in the 1960s and 1970s, it has now become quite specialized, based on methods, topic of studies and scientific traditions. Methods vary as combinations of electrophysiological methods, neuroimaging, and neurochemistry. Topics have branched into subspecializations such as social, sport, cognitive, cardiovascular, clinical and other branches of psychophysiology.
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal or abnormal.
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.
Weakness is a symptom of a number of different conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in neuromuscular junction disorders, such as myasthenia gravis.
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.
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.
Exercise intensity refers to how much energy is expended when exercising. Perceived intensity varies with each person. It has been found that intensity has an effect on what fuel the body uses and what kind of adaptations the body makes after exercise. Intensity is the amount of physical power that the body uses when performing an activity. For example, exercise intensity defines how hard the body has to work to walk a mile in 20 minutes.
An elliptical trainer or cross-trainer is a stationary exercise machine used to stair climb, walk, or run without causing excessive pressure to the joints, hence decreasing the risk of impact injuries. For this reason, people with some injuries can use an elliptical to stay fit, as the low impact affects them little. Elliptical trainers offer a non-impact cardiovascular workout that can vary from light to high intensity based on the speed of the exercise and the resistance preference set by the user.
The metabolic equivalent of task (MET) is the objective measure of the ratio of the rate at which a person expends energy, relative to the mass of that person, while performing some specific physical activity compared to a reference, currently set by convention at an absolute 3.5 mL of oxygen per kg per minute, which is the energy expended when sitting quietly by a reference individual, chosen to be roughly representative of the general population, and thereby suited to epidemiological surveys. A Compendium of Physical Activities is available online, which provides MET values for hundreds of activities.
Muscle weakness is a lack of muscle strength. Its causes are many and can be divided into conditions that have either true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, including muscular dystrophy and inflammatory myopathy. It occurs in neuromuscular junction disorders, such as myasthenia gravis. Muscle weakness can also be caused by low levels of potassium and other electrolytes within muscle cells. It can be temporary or long-lasting. The term myasthenia is from my- from Greek μυο meaning "muscle" + -asthenia ἀσθένεια meaning "weakness".
Allostatic load is "the wear and tear on the body" which accumulates as an individual is exposed to repeated or chronic stress. The term was coined by Bruce McEwen and Eliot Stellar in 1993. It represents the physiological consequences of chronic exposure to fluctuating or heightened neural or neuroendocrine response which results from repeated or prolonged chronic stress.
In sports, health and particularly exercise testing, the rating of perceived exertion (RPE), as measured by the Borg rating of perceived exertion scale, is a frequently used quantitative measure of perceived exertion during physical activity. In medicine this is used to document the patient's exertion during a test for the severity of diseases, and sports coaches use the scale to assess the intensity of training and competition as well as endurance. The original scale introduced by Gunnar Borg rated exertion on a scale of 6-20. Borg then constructed a newer category (C) ratio (R) scale, the Borg CR10 scale, rated on a scale from 1-10. This is especially used in clinical diagnosis and severity assessment of breathlessness and dyspnea, chest pain, angina and musculo-skeletal pain. The CR-10 scale is best suited when there is an overriding sensation arising either from a specific area of the body rather than overall exertion, for example, muscle pain, ache or fatigue in the quadriceps or from pulmonary responses during exertion.
Musculoskeletal injury refers to damage of muscular or skeletal systems, which is usually due to a strenuous activity and includes damage to skeletal muscles, bones, tendons, joints, ligaments, and other affected soft tissues. In one study, roughly 25% of approximately 6300 adults received a musculoskeletal injury of some sort within 12 months—of which 83% were activity-related. Musculoskeletal injury spans into a large variety of medical specialties including orthopedic surgery, sports medicine, emergency medicine and rheumatology.
The central governor is a proposed process in the brain that regulates exercise in regard to a neurally calculated safe exertion by the body. In particular, physical activity is controlled so that its intensity cannot threaten the body’s homeostasis by causing anoxic damage to the heart muscle. The central governor limits exercise by reducing the neural recruitment of muscle fibers. This reduced recruitment causes the sensation of fatigue. The existence of a central governor was suggested to explain fatigue after prolonged strenuous exercise in long-distance running and other endurance sports, but its ideas could also apply to other causes of exertion-induced fatigue.
Eccentric training is a type of strength training that involves using the target muscles to control weight as it moves in a downward motion. This type of training can help build muscle, improve athletic performance, and reduce the risk of injury. An eccentric contraction is the motion of an active muscle while it is lengthening under load. Eccentric training is repetitively doing eccentric muscle contractions. For example, in a biceps curl the action of lowering the dumbbell back down from the lift is the eccentric phase of that exercise – as long as the dumbbell is lowered slowly rather than letting it drop.
Cardiovascular fitness refers 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.
Fitness instructors rely heavily on the use of music during their class as a way of motivating their clients. In addition to making physical activity and exercise more enjoyable, athletes have used music as an ergogenic aid. Most of the studies that have explored the effects of music on performance was aerobic performance. Aerobic performance is assessed by measuring specific parameters of, such as maximal oxygen consumption (VO2 max), heart rate (HR), rate of perceived exertion (RPE), and blood lactate (mmol/ L), power output (W). There is conflicting data regarding the effects of music on aerobic performance. On one hand, studies have suggested that music does increase aerobic exercise performance by influencing certain parameters, such as rate of perceived exertion and time to exhaustion. However, there are studies that rebuke this notion, stating that music had no effect on aerobic performance. The reason for this disparity among data is the construction of the tests themselves. There are several factors that need to be taken into account when exploring the effects of music on exercise. Those include: exercise intensity, the subject experience in performing exercise, and type of music.
In kinesiology, the ventilatory threshold (VT1) refers to the point during exercise at which ventilation starts to increase at a faster rate than VO2 (V – volume, O2 – oxygen). One's threshold is said to reflect levels of anaerobiosis and lactate accumulation. As the intensity level of the activity being performed increases, breathing becomes faster; more steadily first and then more rapid as the intensity increases. When breathing surpasses normal ventilation rate, one has reached ventilatory threshold. For most people this threshold lies at exercise intensities between 50% and 75% of VO2 max. A major factor affecting one's ventilatory threshold is their maximal ventilation (amount of air entering and exiting lungs). This is dependent on their personal experience with the activity and how physically fit the person is. Comparison studies of more athletic people have shown that your ventilatory threshold occurs at a higher intensity if you are more active or have been training for that exercise; although, in some cases shorter continuous tests can be used because of rapid alterations in ventilation.
Ergonomic hazards are physical conditions that may pose a risk of injury to the musculoskeletal system due to poor ergonomics. These hazards include awkward or static postures, high forces, repetitive motion, or short intervals between activities. The risk of injury is often magnified when multiple factors are present.
