Running
Encyclopedia
Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait
Gait
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...

 in which at regular points during the running cycle both feet are off the ground. This is in contrast to walking
Walking
Walking is one of the main gaits of locomotion among legged animals, and is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step...

, where one foot is always in contact with the ground, the legs are kept mostly straight and the center of gravity
Center of gravity
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...

 vaults over the legs in an inverted pendulum fashion. A characteristic feature of a running body from the viewpoint of spring-mass mechanics, is that changes in kinetic and potential energy within a stride occur simultaneously, with energy storage accomplished by springy tendons and passive muscle elasticity. The term running can refer to any of a variety of speeds ranging from jogging
Jogging
Jogging is a form of trotting or running at a slow or leisurely pace. The main intention is to increase fitness with less stress on the body than from faster running.-Definition:...

 to sprinting.

The ancestors of mankind developed the ability to run for long distances about four and a half million years ago, probably in order to hunt animals. Competitive running grew out of religious festivals in various areas. Records of competitive racing date back to the Tailteann Games
Tailteann Games
The Tailteann Games were an ancient sporting event held in Ireland in honour of the goddess Tailtiu. They ran from 632 BC to 1169-1171 AD when they died out after the Norman invasion....

 in Ireland in 1829 BCE, while the first recorded Olympic Games took place in 776 BCE.

History

It is thought that human running evolved at least four and a half million years ago out of the ability of the ape-like Australopithecus
Australopithecus
Australopithecus is a genus of hominids that is now extinct. From the evidence gathered by palaeontologists and archaeologists, it appears that the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct...

, an early ancestor of humans, to walk upright on two legs. The scientists, Dennis Bramble and Daniel Lieberman, have put forward a theory that early man developed as an endurance runner in order to hunt animals, and that human features such as the nuchal ligament
Nuchal ligament
The paxwax or nuchal ligament is a fibrous membrane, which, in the neck, represents the supraspinal ligaments of the lower vertebræ...

, abundant sweat glands, the Achilles tendon
Achilles tendon
The Achilles tendon , also known as the calcaneal tendon or the tendo calcaneus, is a tendon of the posterior leg. It serves to attach the plantaris, gastrocnemius and soleus muscles to the calcaneus bone.- Anatomy :The Achilles is the tendonous extension of 3 muscles in the lower leg:...

s, big knee joints and muscular glutei maximi, were a response to that running development.

Competitive running grew out of religious festivals in various areas such as Greece, Egypt, Asia, and the Rift Valley
Rift Valley
In order of specificity, Rift Valley can refer to:*a rift valley in general*the Great Rift Valley*the Rift Valley fever*the valley of the East African Rift*Rift Valley Province, Kenya and border with Uganda...

 in Africa. The Tailteann Games
Tailteann Games
The Tailteann Games were an ancient sporting event held in Ireland in honour of the goddess Tailtiu. They ran from 632 BC to 1169-1171 AD when they died out after the Norman invasion....

, an Irish sporting festival in honour of the goddess Tailtiu
Tailtiu
Tailtiu or Tailltiu is the name of a presumed goddess from Irish mythology. Telltown in County Meath, was named for her.-In Irish mythology:...

, dates back to 1829 BCE, and is one of the earliest records of competitive running. The origins of the Olympics are shrouded in myth, though the first recorded game took place in 776 BCE.

Motion

Humans leap from one leg to the other while running. Each leap raises the center of gravity during take-off and lowers it on landing as the knee bends to absorb the shock. At mid arc, both feet are momentarily off the ground. This continual rise and fall of bodyweight expends energy opposing gravity and absorbing shock during take-off and landing. Running on a track requires more energy than walking to cover the same distance due to air resistance at higher speeds. As reported by Hall et al. males on a track running at a pace of 6.3 mph use 1.20 times as much energy to travel the same distance as walking at a pace of 3.15 mph, but on a treadmill running 6.3 mph uses just 1.01 times as much energy to travel the same distance as walking at 3.15 mph. Therefore, running is less efficient than walking in terms of calories expended per unit distance, though it is faster.

In 2004, scientists at the University of Utah
University of Utah
The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

 and Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

 hypothesized that the ability of humans to sustain long-distance endurance running may have been instrumental in the evolution of the human form.

Lower body motion

Running is executed as a sequence of strides, which alternate between the two legs. Each leg's stride can be roughly divided into three phases: support, drive, and recovery. Support and drive occur when the foot is in contact with the ground. Recovery occurs when the foot is off the ground. Since only one foot is on the ground at a time in running, one leg is always in recovery, while the other goes through support and drive. Then, briefly, as the runner leaps through the air, both legs are in recovery. These phases are described in detail below.

Support

During the support phase, the foot is in contact with the ground and supports the body against gravity. The body's centre of mass is typically somewhere in the lower abdominal area between the hips. The supporting foot touches the ground slightly ahead of the point that lies directly below the body's centre of mass. The knee joint is at its greatest extension just prior to the support phase. When contact is made with the ground, the knee joint begins to flex, and the extent it flexes varies with running style. Stiff-legged running styles reduce knee flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...

, and looser, or more dynamic, running styles increase it. As the supporting leg bends at the knee, the pelvis dips down on the opposite side. These motions absorb shock and are opposed by the coordinated action of several muscles. The pelvic dip is opposed by the tensor fasciae lataeilio-tibial band
Tensor fasciae latae
The tensor fasciae latae or tensor fasciæ latæ is a muscle of the thigh. The English name for this muscle is the muscle that stretches the band on the side...

 of the supporting leg, the hip abductor
Abduction (kinesiology)
Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...

, and the abdominals and lower back muscles. The knee flexion is opposed by the Muscle contraction eccentric contraction of the quadriceps muscle. The supporting hip continues to extend, and the body's centre of mass passes over the supporting leg. The knee then begins to extend, and the opposite hip rises from its brief dip. The support phase begins to transition into drive.

Drive

The support phase quickly transitions into the drive phase. The drive leg extends at the knee joint, and at the hips, such that the toe maintains contact with the ground as that leg trails behind the body. The foot pushes backward and also down, creating a diagonal force vector, which, in an efficient running style, is aimed squarely at the runner's centre of mass. Since the diagonal vector has a vertical component, the drive phase continues to provide some support against gravity and can be regarded as an extension of the support phase. During the drive, the foot may extend also, by a flexing of the soleus and gastrocnemius muscle in the calf. In some running styles, notably long-distance "shuffles" which keep the feet close to the ground, the ankle remains more or less rigid during drive. Because the knee joint straightens, though not completely, much of the power of the drive comes from the quadriceps muscle group, and in some running styles, additional power comes from the calves as they extend the foot for a longer drive. This motion is most exhibited in sprinting.

There has been much discussion about the exact nature of the drive phase, because it has now been shown scientifically that the quadriceps have no activity after the supporting phase; this has become known as the extensor paradox in running. Essentially, the body automatically turns off the quadriceps after the body weight moves forward of its supporting foot. This has led to a hypothesis that there is no driving phase in running, and that the runner's own body weight is providing the propulsion during this time, essentially falling through a gravitational torque created as the general centres of mass of the runner is in a forward position from the supporting foot.

Recovery

When the driving toe loses contact with the ground, the recovery phase begins. During recovery, the hip flexes, which rapidly drives the knee forward. Much of the motion of the lower leg is driven by the forces transferred from the upper leg rather than by the action of the muscles. As the knee kicks forward, it exerts torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

 against the lower leg through the knee joint, causing the leg to snap upward. The degree of leg lift can be consciously adjusted by the runner, with additional muscle power. During the last stage of recovery, the hip achieves maximal flexion, and, as the lower leg rapidly unfolds, which it does in a passive way, the knee joint also reaches its greatest, though not full, extension. During this extension of the leg and flexion of the hip, the hamstring and gluteal muscles are required to stretch rapidly. Muscles which are stretched respond by contracting by a reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...

 action. Recovery ends when the foot comes into contact with the ground, transitioning again into the support phase.

Upper body motion

The motions of the upper body are essential to maintaining balance, and a forward motion for optimal running. They compensate for the motions of the lower body, keeping the body in rotational balance. A leg's recovery is matched by a forward drive of the opposite arm, and a leg's support and drive motions are balanced by backward movement of the opposite arm. The shoulders and torso are also involved. Because the leg drive is slower than the kick of recovery, the arm thrusting backward is slower also. The forward arm drive is more forceful and rapid.

The more force exerted by the lower body, the more exaggerated the upper body motions have to be to absorb the momentum. While it is possible to run without movements of the arms, the spine and shoulders will generally still be recruited. Using the arms to absorb the forces aids in maintaining balance at higher speed. Otherwise, optimal force would be hard to attain for fear of falling over.

Most of the energy expended in running goes to the compensating motions, and so considerable gains in running speed as well as economy can be made by eliminating wasteful or incorrect motions. For instance, if the force vector in the drive phase is aimed too far away from the centre of mass of the body, it will transfer an angular momentum to the body which has to be absorbed.

The faster the running, the more energy has to be dissipated through compensating motions throughout the entire body. This is why elite sprinters have powerful upper body physiques. As the competitive distance increases, there is a rapid drop in the upper body and overall muscle mass typically exhibited by the people who compete at a high level in each respective event. Long distance runners typically have lean muscles.

Upright posture and a slight forward lean

Leaning forward places a runner's center of mass on the front part of the foot, which avoids landing on the heel and facilitates the use of the spring mechanism of the foot. It also makes it easier for the runner to avoid landing the foot in front of the center of mass and the resultant braking effect. While upright posture is essential, a runner should maintain a relaxed frame and use his/her core to keep posture upright and stable. This helps prevent injury as long as the body is neither rigid nor tense. The most common running mistakes are tilting the chin up and scrunching shoulders.

Stride rate and types

Exercise physiologists have found that the stride rates are extremely consistent across professional runners, between 185 and 200 steps per minute. The main difference between long- and short-distance runners is the length of stride rather than the rate of stride.

During running, the speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...

 at which the runner moves may be calculated by multiplying the cadence
Cadence (gait)
Cadence in sports involving running is the total number of 'revolutions per minute' , or number of full cycles taken within a minute, by the pair of feet, and is used as a measure of athletic performance. It is very similar in respect to cadence in cycling, however it is often overlooked in its...

 (steps per second) by the stride length. Running is often measured in terms of pace in minutes per mile or kilometer. Fast stride rates coincide with the rate one pumps one's arms. The faster one's arms move up and down, parallel with the body, the faster the rate of stride. Different types of stride are necessary for different types of running. When sprinting, runners stay on their toes bringing their legs up, using shorter and faster strides. Long distance runners tend to have more relaxed strides that vary.

Running injuries

Because of its high-impact
Impact force
In mechanics, an impact is a high force or shock applied over a short time period when two or more bodies collide. Such a force or acceleration usually has a greater effect than a lower force applied over a proportionally longer time period of time...

 nature, many injuries are associated with running. They include "runner's knee" (pain in the knee), shin splints
Shin splints
Shin splints or medial tibial stress syndrome refers to pain along or just behind the shins with sports that apply extreme pressure to the legs, such as gymnastics...

, pulled muscles (especially the hamstring
Hamstring
In human anatomy, the hamstring refers to any one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the posterior thigh muscles, or the tendons of the semitendinosus, the...

), twisted ankles, iliotibial band syndrome
Iliotibial band syndrome
Iliotibial band syndrome is a common injury to the thigh, generally associated with running, cycling, hiking or weight-lifting .- Definition :...

, plantar fasciitis
Plantar fasciitis
Plantar fasciitis is a painful inflammatory process of the plantar fascia, the connective tissue on the sole of the foot.Longstanding cases of plantar fasciitis often demonstrate more degenerative changes than inflammatory changes, in which case they are termed plantar fasciosis. The suffix...

, Achilles tendinitis, and stress fracture
Stress fracture
A stress fracture is one type of incomplete fracture in bones. It is caused by "unusual or repeated stress" and also heavy continuous weight on the ankle or leg...

s. Repetitive stress on the same tissues without enough time for recovery or running with improper form can lead to many of the above. Runners generally attempt to minimize these injuries by warming up
Warming up
A warm-up is usually performed before participating in technical sports or exercising. A warm-up generally consists of a gradual increase in intensity in physical activity , a joint mobility exercise, stretching and a sport related activity. For example, before running or playing an intense sport...

 before exercise, focusing on proper running form, performing strength training
Strength training
Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...

 exercises, eating a well balanced diet, allowing time for recovery, and "icing" (applying ice to sore muscles or taking an ice bath).

Foot blister
Blister
A blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing , burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid called serum or plasma...

s are also common among runners. Specialized socks greatly help to prevent blisters.

Another common, running-related injury is chafing, caused by repetitive rubbing of one piece of skin against another, or against an article of clothing. One common location for chafe to occur is the runner's upper thighs. The skin feels coarse and develops a rash-like look. A variety of deodorants and special anti-chafing creams are available to treat such problems. Chafe is also likely to occur on the nipple
Jogger's nipple
Fissure of the nipple, also known as jogger's nipple, is a condition that can be caused by friction that can result in soreness, dryness or irritation to, or bleeding of, one or both nipples during and/or following running or other physical exercise...

.
A cold bath is a popular treatment of subacute injuries or inflammation, muscular strains, and overall muscular soreness, but its efficacy is controversial. Some claim that for runners in particular, ice baths offer two distinct improvements over traditional techniques. First, immersion allows controlled, even constriction around all muscles, effectively closing microscopic damage that cannot be felt and numbing the pain that can. One may step into the tub to relieve sore calves, quads, hams, and connective tissues from hips to toes will gain the same benefits, making hydrotherapy an attractive preventive regimen. Saint Andrew's cross-country coach John O’Connell, a 2:48 masters marathoner, will hit the ice baths before the ibuprofen. "Pain relievers can disguise injury", he warns. "Ice baths treat both injury and soreness." The second advantage involves a physiological reaction provoked by the large amount of muscle submerged. Assuming one has overcome the mind's initial flight response in those first torturous minutes, the body fights back by invoking a "blood rush". This rapid transmission circulation flushes the damage-inflicting waste from the system, while the cold water on the outside preserves contraction. Like an oil change or a fluid dump, the blood rush revitalizes the very areas that demand fresh nutrients.

Some runners may experience injuries when running on concrete surfaces. The problem with running on concrete is that the body adjusts to this flat surface running and some of the muscles will become weaker, along with the added impact of running on a harder surface. Therefore it is advised to change terrain occasionally – such as trail, beach, or grass running. This is more unstable ground and allows the legs to strengthen different muscles. Runners should be wary of twisting their ankles on such terrain. Running downhill also increases knee stress and should therefore be avoided. Reducing the frequency and duration can also prevent injury.

A common acronym used to help the recovery process is RICE
RICE (medicine)
RICE is a treatment method for soft tissue injury which is an acronym for Rest, Ice, Compression and Elevation. When used appropriately, recovery duration is usually shortened and discomfort minimized....

: Rest, Ice, Compression, and Elevation.

Another injury prevention method common in the running community is stretching
Stretching
Stretching is a form of physical exercise in which a specific skeletal muscle is deliberately elongated, often by abduction from the torso, in order to improve the muscle's felt elasticity and reaffirm comfortable muscle tone. The result is a feeling of increased muscle control, flexibility and...

. Stretching is often recommended as a requirement to avoid running injuries, and it is almost uniformly performed by competitive runners of any level. Recent medical literature, however, finds mixed effects of stretching prior to running. One study found insufficient evidence to support the claim that stretching prior to running was effective in injury prevention or soreness reduction. Another, however, has demonstrated that stretching prior to running increases injuries, while stretching afterwards actually decreases them. The American College of Sports Medicine recommends that all stretching be done after exercise because this is when the muscles are most warmed up and capable of increasing flexibility. Recent studies have also shown that stretching will reduce the amount of strength the muscle can produce during that training session.

Barefoot running
Barefoot running
Barefoot running is running while barefoot—without wearing any shoes on the feet. Running in thin-soled, flexible shoes, often called minimalist running, such as moccasins is biomechanically related to running barefoot, but alters sensory feedback from the plantar mechanoreceptors...

 has been promoted as a means of reducing running related injuries though this position on barefoot running remains controversial and a majority of professionals advocate the wearing of appropriate shoes as the best method for avoiding injury.

Recent studies have shown that runners do not have more osteoarthritis than people who do not run.

Benefits of running

While there is the potential for injury in running (just as there is in any sport), there are many benefits. Some of these benefits include potential weight loss, improved cardiovascular and respiratory health (reducing the risk of cardiovascular and respiratory diseases), improved cardiovascular fitness, reduced total blood cholesterol, strengthening of bones (and potentially increased bone density), possible strengthening of the immune system and an improved self esteem and emotional state. Running, like all forms of regular exercise, can effectively slow or reverse the effects of aging.

Running can assist people in losing weight, staying in shape and improving body composition. Running increases your metabolism. Different speeds and distances are appropriate for different individual health and fitness levels. For new runners, it takes time to get into shape. The key is consistency and a slow increase in speed and distance. While running, it is best to pay attention to how one's body feels. If a runner is gasping for breath or feels exhausted while running, it may be beneficial to slow down or try a shorter distance for a few weeks. If a runner feels that the pace or distance is no longer challenging, then the runner may want to speed up or run farther.

Running can also have psychological benefits, as many participants in the sport report feeling an elated, euphoric state, often referred to as a "runner's high". Running is frequently recommended as therapy for people with clinical depression and people coping with addiction. A possible benefit may be the enjoyment of nature and scenery, which also improves psychological well-being (see Ecopsychology#Practical benefits).

In animal models, running has been shown to increase the number of newly born neurons
Neurogenesis
Neurogenesis is the process by which neurons are generated from neural stem and progenitor cells. Most active during pre-natal development, neurogenesis is responsible for populating the growing brain with neurons. Recently neurogenesis was shown to continue in several small parts of the brain of...

 within the brain. This finding could have significant implications in aging as well as learning and memory.

Running events

Running is both a competition and a type of training for sports that have running or endurance
Endurance
Endurance is the ability for a human or animal 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. In humans, it is usually used in aerobic or anaerobic exercise...

 components. As a sport, it is split into events divided by distance and sometimes includes permutations such as the obstacles in steeplechase
Steeplechase (athletics)
The steeplechase is an obstacle race in athletics, which derives its name from the steeplechase in horse racing.-Rules:The length of the race is usually 3000 m; junior events are 2000 m, as women's events formerly were. The circuit has four ordinary barriers and one water jump. Over 3000 m, each...

 and hurdles. Running races are contests to determine which of the competitors is able to run a certain distance in the shortest time. Today, competitive running events make up the core of the sport of athletics. Events are usually grouped into several classes, each requiring substantially different athletic strengths and involving different tactics, training methods, and types of competitors.

Running competitions have probably existed for most of humanity's history and were a key part of the ancient Olympic Games as well as the modern Olympics. The activity of running went through a period of widespread popularity in the United States during the running boom of the 1970's. Over the next two decades, as many as 25 million Americans were doing some form of running or jogging – accounting for roughly one tenth of the population. Today, road racing is a popular sport among non-professional athletes, who included over 7.7 million people in America alone in 2002.

Limits of speed

Footspeed
Footspeed
Footspeed, or sprint speed, is the maximum speed at which a human can run. It is affected by many factors, varies greatly throughout the population, and is important in athletics and many sports, such as Football, Rugby, and American Football....

, or sprint speed, is the maximum speed at which a human can run. It is affected by many factors, varies greatly throughout the population, and is important in athletics and many sports.

The fastest human footspeed on record is 44.72 km/h (27.79 mph), seen during a 100 meter sprint (average speed between the 60th and the 80th meter) by Usain Bolt
Usain Bolt
The Honourable Usain St. Leo Bolt, OJ, C.D. , is a Jamaican sprinter and a five-time World and three-time Olympic gold medalist. He is the world record and Olympic record holder in the 100 metres, the 200 metres and the 4×100 metres relay...

.

Running speed over increasing distance

Distance metres Men m/sec Women m/sec
100 10.44 9.53
200 10.42 9.37
400 9.26 8.44
800 7.92 7.06
1000 7.58 6.71
1500 7.28 6.51
1609 mile
Mile run
The mile run is a middle-distance foot race which is among the more popular events in track running.The history of the mile run event began in England, where it was used as a distance for gambling races...

7.22 6.36
2000 7.02 6.15
3000 6.81 6.17
5000 6.60 5.87
10000 track 6.34 5.64
10000 road 6.23 5.49
15000 road 6.02 5.38
20000 track 5.91 5.09
20000 road 6.02 5.30
21097 Half marathon
Half marathon
A half marathon is a road running event of . It is half the distance of a marathon and usually run on roads. Participation in half marathons has grown steadily recently. One of the main reasons for this is that it is a challenging distance, but does not require the same level of training that a...

6.02 5.29
21285 One hour run 5.91 5.14
25000 track 5.63 4.78
25000 road 5.80 5.22
30000 track 5.60 4.72
30000 road 5.69 5.06
42195 Marathon
Marathon
The marathon is a long-distance running event with an official distance of 42.195 kilometres , that is usually run as a road race...

5.67 5.19
90000 Comrades
Comrades Marathon
The Comrades Marathon is an ultramarathon of approximately 90 km run in the Kwazulu-Natal Province of South Africa between the cities of Durban and Pietermaritzburg. It is the world's largest and oldest ultramarathon race...

4.68 4.23
100000 4.46 4.24
273366 24-hour run 3.16 2.82

Events by type

Track running

Track running events are individual
Individual sport
-Examples:Examples of individual sports include:*Archery*Athletics*Bodybuilding*Badminton*Boomerang*Boxing*Chess*Croquet*Cycling*Darts*Equestrian*Fencing*Figure Skating*Golf*Gymnastics*Knife Throwing*Krav Maga*Judo*Lawn Bowls*Orienteering*Pilates...

 or relay
Relay race
During a relay race, members of a team take turns running, orienteering, swimming, cross-country skiing, biathlon, or ice skating parts of a circuit or performing a certain action. Relay races take the form of professional races and amateur games...

 events with athletes racing over specified distances on an oval running track. The events are categorised as sprints, middle and long-distance
Long-distance track event
Long-distance track event races require runners to balance their energy. These types of races are predominantly aerobic in nature and at the highest level, exceptional levels of aerobic endurance is required more than anything else...

, and hurdling
Hurdling
Hurdling is a type of track and field race.- Distances :There are sprint hurdle races and long hurdle races. The standard sprint hurdle race is 110 meters for men and 100 meters for women. The standard long hurdle race is 400 meters for both men and women...

.

Road running

Road running takes place on a measured course over an established road (as opposed to track and cross country running
Cross country running
Cross country running is a sport in which people run a race on open-air courses over natural terrain. The course, typically long, may include surfaces of grass and earth, pass through woodlands and open country, and include hills, flat ground and sometimes gravel road...

). These events normally range from distances of 5 kilometers to longer distances such as half marathon
Half marathon
A half marathon is a road running event of . It is half the distance of a marathon and usually run on roads. Participation in half marathons has grown steadily recently. One of the main reasons for this is that it is a challenging distance, but does not require the same level of training that a...

s and marathons, and they may involve large numbers of runners or wheelchair entrants.

Cross country running

Cross country running takes place over open or rough terrain. The courses used at these events may include grass
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...

, mud
Mud
Mud is a mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone . When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds...

, woodlands, hills, flat ground and water. It is a popular participatory sport, and is one of the events which, along with track and field, road running, and racewalking, makes up the umbrella sport of athletics.

Events by distance

Sprints

Sprints are short running events in athletics and track and field. Races over short distances are among the oldest running competitions. The first 13 editions of the Ancient Olympic Games featured only one event – the stadion race, which was a race from one end of the stadium to the other. There are three sprinting events which are currently held at the Olympics and outdoor World Championships: the 100 metres
100 metres
The 100 metres, or 100-metre dash, is a sprint race in track and field competitions. The shortest common outdoor running distance, it is one of the most popular and prestigious events in the sport of athletics. It has been contested at the Summer Olympics since 1896...

, 200 metres
200 metres
A 200 metres race is a sprint running event. On an outdoor 400 m track, the race begins on the curve and ends on the home straight, so a combination of techniques are needed to successfully run the race. A slightly shorter race, called the stadion and run on a straight track, was the first...

, and 400 metres
400 metres
The 400 metres, or 400 metre dash, is a common sprinting event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 . On a standard outdoor running track, it is exactly one lap around the track. Runners start in staggered positions and...

. These events have their roots in races of imperial measurements which were later altered to metric: the 100 m evolved from the 100 yard dash, the 200 m distances came from the furlong
Furlong
A furlong is a measure of distance in imperial units and U.S. customary units equal to one-eighth of a mile, equivalent to 220 yards, 660 feet, 40 rods, or 10 chains. The exact value of the furlong varies slightly among English-speaking countries....

 (or 1/8 of a mile), and the 400 m was the successor to the 440 yard dash or quarter-mile race.

At the professional level, sprinters begin the race by assuming a crouching position in the starting blocks
Starting blocks
Starting blocks are a device used in the sport of Track and Field, known worldwide as Athletics, by sprinters to hold their feet at the start of a race so they don't slip as they push out at the sound of the gun...

 before leaning forward and gradually moving into an upright position as the race progresses and momentum is gained. Athletes remain in the same lane on the running track throughout all sprinting events, with the sole exception of the 400 m indoors. Races up to 100 m are largely focused upon acceleration to an athlete's maximum speed. All sprints beyond this distance increasingly incorporate an element of endurance. Human physiology
Human physiology
Human physiology is the science of the mechanical, physical, bioelectrical, and biochemical functions of humans in good health, their organs, and the cells of which they are composed. Physiology focuses principally at the level of organs and systems...

 dictates that a runner's near-top speed cannot be maintained for more than thirty seconds or so as lactic acid
Lactic acid
Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3...

 builds up and leg muscles begin to be deprived of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

.

The 60 metres
60 metres
60 metres is a sprint event in track and field athletics. It is a championship event for indoor championships, normally dominated by the best outdoor 100 metres runners. At outdoor venues it is a rare distance, at least for senior athletes...

 is a common indoor event and it an indoor world championship event. Other less-common events include the 50 metres
50 metres
50 metres is a sprint event in track and field. It is a championship event for indoor championships, normally dominated by the best outdoor 100 metres runners. At outdoor athletics competitions it is a rare distance, at least for senior athletes...

, 55 metres
55 metres
55 metres is a sprint event in track and field. It is a championship event for indoor championships, normally dominated by the best outdoor 100 metres runners. At outdoor venues it is a rare distance, at least for senior athletes....

, 300 metres and 500 metres which are used in some high and collegiate
College athletics
College athletics refers primarily to sports and athletic competition organized and funded by institutions of tertiary education . In the United States, college athletics is a two-tiered system. The first tier includes the sports that are sanctioned by one of the collegiate sport governing bodies...

 competitions in the United States. The 150 metres, though rarely competed, has a star-studded history: Pietro Mennea
Pietro Mennea
Pietro Paolo Mennea is an Italian former sprinter and politician, who was the 1980 Moscow Olympic 200 meter Champion, and also held the 200 m world record for 17 years.-Biography:...

 set a world best in 1983, Olympic champions Michael Johnson
Michael Johnson (athlete)
Michael Duane Johnson is a retired American sprinter. He won four Olympic gold medals and eight world championship gold medals. Johnson currently holds the world and Olympic records in the 400 m and 4 x 400 meters relay. He formerly held the world and Olympic record in the 200 m, and the world...

 and Donovan Bailey
Donovan Bailey
Donovan Bailey is a retired Canadian sprinter, who once held the world record for the 100 metres race following his gold medal performance in the 1996 Olympic Games. He was the first Canadian to legally break the 10-second barrier in the 100 m...

 went head-to-head over the distance in 1997, and Usain Bolt
Usain Bolt
The Honourable Usain St. Leo Bolt, OJ, C.D. , is a Jamaican sprinter and a five-time World and three-time Olympic gold medalist. He is the world record and Olympic record holder in the 100 metres, the 200 metres and the 4×100 metres relay...

 improved Mennea's record in 2009.

Middle distance

Middle distance running events are track races longer than sprints up to 3000 metres. The standard middle distances are the 800 metres
800 metres
The 800 meter race is a common track running event. It is the shortest common middle distance track event. The 800 meter is run over two laps of the track and has always been an Olympic event. During indoor track season the event is usually run on a 200 meter track, therefore requiring four laps...

, 1500 metres
1500 metres
The 1,500-metre run is the premier middle distance track event.Aerobic endurance is the biggest factor contributing to success in the 1500 metres but the athlete also requires significant sprint speed.In modern times, the 1,500-metre run has been run at a pace faster than the average person could...

 and mile run
Mile run
The mile run is a middle-distance foot race which is among the more popular events in track running.The history of the mile run event began in England, where it was used as a distance for gambling races...

, although the 3000 metres
3000 metres
The 3000 metres is a popular amateur middle distance track event where 7.5 laps are completed around a 400 metre track. This event is generally classified as middle distance, but it could be classed as a long distance event in many high schools, since they do not promote races such as the 5000 and...

 may also be classified as a middle distance event. The 880 yard run, or half mile, was the forebear to the 800 m distance and it has its roots in competitions in the United Kingdom in the 1830s. The 1500 m came about as a result of running three laps of a 500 m track, which was commonplace in continental Europe in the 1900s.
  • Long distance
    Long-distance track event
    Long-distance track event races require runners to balance their energy. These types of races are predominantly aerobic in nature and at the highest level, exceptional levels of aerobic endurance is required more than anything else...

  • Marathon
    Marathon
    The marathon is a long-distance running event with an official distance of 42.195 kilometres , that is usually run as a road race...

  • Ultrarunning
  • Multiday running
    Multiday races
    Multiday races are ultramarathon running events which are typically either segmented into daily events of a specified distance or time, or staged so that runners can run as far as they want, at their own discretion, over a set course or over a set number of days...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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