Exertion is the
physical
Physical may refer to:
*Physical examination
In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally cons ...
or perceived use of
energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of h ...
.
[Newton's Third Law, Elert, Glenn. “Forces.” ''Viscosity – The Physics Hypertextbook'', physics.info/newton-first/.] Exertion traditionally connotes a strenuous or costly ''effort'', resulting in generation of force, initiation of motion,
or in the performance of
work
Work may refer to:
* Work (human activity), intentional activity people perform to support themselves, others, or the community
** Manual labour, physical work done by humans
** House work, housework, or homemaking
** Working animal, an animal tr ...
.
It often relates to
muscular
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...
activity and can be quantified, empirically and by measurable metabolic response.
Physical
In
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which re ...
, ''exertion'' is the expenditure of
energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of h ...
against, or inductive of,
inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...
as described by
Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher"), widely recognised as one of the great ...
's
third law of motion. In physics, force exerted equivocates work done.
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.
Exertion often results in force generated, a contributing dynamic of general motion.
In
mechanics
Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objects r ...
it describes the use of
force
In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...
against a
body in the direction of its
motion
In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and ...
(see
vector
Vector most often refers to:
*Euclidean vector, a quantity with a magnitude and a direction
*Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism
Vector may also refer to:
Mathematic ...
).
Physiological
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.
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
The human musculoskeletal system (also known as the human locomotor system, and previously the activity system) is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system provi ...
strength, as well as metabolic capability.
This often correlates to an output of force followed by a
refractory period of recovery. Exertion is limited by cumulative load and repetitive motions.
Muscular energy reserves, or stores for
biomechanical exertion, stem from metabolic, immediate production of
ATP and increased oxygen consumption.
Muscular exertion generated depends on the muscle length and the velocity at which it is able to shorten, or contract.
Perceived exertion can be explained as subjective, perceived experience that mediates response to somatic sensations and mechanisms.
A
rating of perceived exertion, as measured by the ''RPE-scale'', or
Borg scale
The Borg are an alien group that appear as recurring antagonists in the ''Star Trek'' fictional universe. The Borg are cybernetic organisms (cyborgs) linked in a hive mind called "the Collective". The Borg co-opt the technology and knowledge ...
, is a quantitative measure of physical exertion.
Often in health, exertion of oneself resulting in cardiovascular stress showed reduced physiological responses, like
cortisol
Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone.
It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal gl ...
levels and mood, to stressors. Therefore, biological exertion is effective in mediating psychological exertion, responsive to environmental stress.
Overexertion causes more than 3.5 million injuries a year. 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.
Overexertion, besides causing acute injury, implies physical exertion beyond the person's capacity which leads to symptoms such as dizziness, irregular breathing and heart rate, and fatigue.
Preventative measures can be taken based on biomechanical knowledge to limit possible overexertion injuries.
Psychological
In
sport psychology
Sport psychology was defined by the European Federation of Sport in 1996, as the study of the psychological basis, processes, and effects of sport. Otherwise, sport is considered as any physical activity where the individuals engage for competi ...
, the perceived exertion of an exercise is how hard it seems to the person doing it. 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. 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 and listening to music.
See also
*
Exercise
Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness.
It is performed for various reasons, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic s ...
*
Energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of h ...
*
Cost
In production, research, retail, and accounting, a cost is the value of money that has been used up to produce something or deliver a service, and hence is not available for use anymore. In business, the cost may be one of acquisition, in whic ...
*
Inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...
*
Volition (psychology)
*
Decision theory
Decision theory (or the theory of choice; not to be confused with choice theory) is a branch of applied probability theory concerned with the theory of making decisions based on assigning probabilities to various factors and assigning numerical ...
*
Ferdinand Tönnies
Ferdinand Tönnies (; 26 July 1855 – 9 April 1936) was a German sociologist, economist, and philosopher. He was a significant contributor to sociological theory and field studies, best known for distinguishing between two types of social gr ...
s_in_will_(sociology).html" ;"title="will_(sociology).html" ;"title="s in will (sociology)">s in will (sociology)">will_(sociology).html" ;"title="s in will (sociology)">s in will (sociology)*Friedrich Nietzsche [as in strong-willed, drive and will (philosophy)]
*
Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher"), widely recognised as one of the great ...
*
Bionics
*
Machine
A machine is a physical system using power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolecule ...
*
Muscular Energy
*
Musculoskeletal Strength
*
Physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which re ...
*
Physiological stress
*
Work
Work may refer to:
* Work (human activity), intentional activity people perform to support themselves, others, or the community
** Manual labour, physical work done by humans
** House work, housework, or homemaking
** Working animal, an animal tr ...
References
External links
Measuring Physical Activity Intensity: Perceived Exertion (Borg Rating of Perceived Exertion Scale)
allowing exertion by proxy in sporting games
{{Musculoskeletal physiology
Physical exercise
Exercise physiology
Effects of external causes