Running
[4] It is hypothesized that the ancestors of humankind developed the ability to run for long distances about 2.6 million years ago, probably to hunt animals.
[11] Early humans most likely developed into endurance runners from the practice of persistence hunting of animals, the activity of following and chasing until a prey is too exhausted to flee, succumbing to "chase myopathy" (Sears 2001), and that human features such as the nuchal ligament, abundant sweat glands, the Achilles tendons, big knee joints and muscular glutei maximi, were changes caused by this type of activity (Bramble & Lieberman 2004, et al.).
[12][13][14] The theory as first proposed used comparative physiological evidence and the natural habits of animals when running, indicating the likelihood of this activity as a successful hunting method.
[14][15] According to Sears (p. 12) scientific investigation (Walker & Leakey 1993) of the Nariokotome skeleton provided further evidence for the Carrier theory.
[16] Competitive running grew out of religious festivals in various areas such as Greece, Egypt, Asia, and the East African Rift in Africa.
The Tailteann Games, an Irish sporting festival in honor of the goddess Tailtiu, dates back to 1829 BCE and is one of the earliest records of competitive running.
[17] The origins of the Olympics and Marathon running are shrouded by myth and legend, though the first recorded games took place in 776 BCE.
Absorption of forces continues as the body moves from footstrike to midstance due to vertical propulsion from the toe-off during a previous gait cycle.
Midstance is when the lower extremity limb of focus is in knee flexion directly underneath the trunk, pelvis, and hips.
Research, especially in the footstrike debate, has primarily focused on identifying and preventing injuries during the absorption phases of running.
As the hip extensors transition from inhibitory to primary muscle movers, the lower extremity moves back towards the ground, aided by the stretch reflex and gravity.
With a heel strike, this phase may be just a continuation of momentum from the stretch reflex, gravity, and light hip extension, offering little force absorption through the ankle joint.
During midstance, the knee should be slightly flexed due to elastic loading from the absorption and footstrike phases, preserving forward momentum.
[33][34][35] The ankle joint is in dorsiflexion at this point, either elastically loaded from a mid/forefoot strike or preparing for stand-alone concentric plantar flexion.
[28] The arms move most effectively (as seen in elite athletes) with the elbow joint at approximately 90 degrees or less, the hands swinging from the hips up to mid-chest level with the opposite leg, the Humerus moving from being parallel with the trunk to approximately 45 degrees shoulder extension (never passing the trunk in flexion) and with as little movement in the transverse plane as possible.
Recent research into various forms of running has focused on the differences in the potential injury risks and shock absorption capabilities between heel and mid/forefoot footstrikes.
[30] Conversely, a mid/forefoot strike has been associated with greater efficiency and lower injury risk due to the triceps surae being used as a lever system to absorb forces with the muscles eccentrically rather than through the bone.
[24] Landing with a mid/forefoot strike has also been shown to properly attenuate shock and allow the triceps surae to aid in propulsion via reflexive plantarflexion after stretching to absorb ground contact forces.
[41] There does tend however to be a greater percentage of mid/forefoot striking runners in the elite fields, particularly in the faster racers and the winning individuals or groups.
This raises the question of how heel-striking elite distance runners can keep up such high paces with a supposedly inefficient and injurious foot strike technique.
[48] Elite runners tend to exhibit some degree of knee flexion at footstrike and midstance, which first serves to eccentrically absorb impact forces in the quadriceps muscle group.
[47][49][50] Secondly it allows for the knee joint to contract concentrically and provides significant aid in propulsion during toe-off as the quadriceps group is capable of producing large amounts of force.
Additionally, it facilitates avoiding the braking effect that occurs when a runner lands their foot in front of the center of mass.
[52][53] During running, the speed at which the runner moves may be calculated by multiplying the cadence (steps per minute) by the stride length.
[59] Although an optimal amount of vigorous aerobic exercise such as running might bring benefits related to lower cardiovascular disease and life extension, an excessive dose (e.g., marathons) might have an opposite effect associated with cardiotoxicity.
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.
[63] 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".
There are a variety of home remedies that runners use to deal with chafing while running such as band-aids and using grease to reduce friction.
A survey showed that shin splints make up 12.7% of the most common injuries in running, with blisters being the top percentage at 30.9%.
[92] Human physiology dictates that a runner's near-top speed cannot be maintained for more than thirty seconds or so as lactic acid builds up, and leg muscles begin to be deprived of oxygen.
