A gait is a manner of limb movements made during locomotion. Human gaits are the various ways in which humans can move, either naturally or as a result of specialized training. Human gait is defined as bipedal forward propulsion of the center of gravity of the human body, in which there are sinuous movements of different segments of the body with little energy spent. Various gaits are characterized by differences in limb movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in contact with the ground.
Classification Human gaits are classified in various ways. Each gait can be generally categorized as either natural (one that humans use instinctively) or trained (a non-instinctive gait learned via training). Examples of the latter include hand walking and specialized gaits used in martial arts. Gaits can also be categorized according to whether the person remains in continuous contact with the ground.
Foot strike One variable in gait is foot strike – which part of the foot connects with the ground first.
forefoot strike – toe-heel: ball of foot lands first mid-foot strike – heel and ball land simultaneously heel strike – heel-toe: heel of foot lands, then plantar flexes to ball Sprinting typically features a forefoot strike, but the heel does not usually contact the ground. Some researchers classify foot strike by the initial center of pressure; this is mostly applicable to shod running (running while wearing shoes). In this classification:
a forefoot strike has the initial center of pressure in the front one-third of shoe length; a mid-foot strike is in the middle third; a rear-foot strike (heel strike) is in the rear third. Foot strike varies between types of strides. It changes significantly and notably between walking and running, and between wearing shoes (shod) and not wearing shoes (barefoot). Typically, barefoot walking features heel or mid-foot strikes, while barefoot running features mid-foot or forefoot strikes. Barefoot running rarely features heel strikes because the impact can be painful, the human heel pad not absorbing much of the force of impact. By contrast, 75% of runners wearing modern running shoes use heel strikes; running shoes are characterized by a padded sole, stiff soles and arch support, and slope down from a more-padded heel to a less-padded forefoot. The cause of this change in gait in shoe running is unknown, but Lieberman noted that there is correlation between the foot-landing style and exposure to shoes. In some individuals the gait pattern is largely unchanged (the leg and foot positions are identical in barefoot and shoes), but the wedge shape of the padding moves the point of impact back from the forefoot to the mid-foot. In other cases it is believed that the padding of the heel softens the impact. This results in runners modifying their gait to move the point of contact further back in the foot. A 2012 study involving Harvard University runners found that those who "habitually rear-foot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike." This was the first study to investigate the link between foot strike and injury rates. However, earlier studies have shown that smaller collision forces were generated when running forefoot strike compared to rear-foot strike. This may protect the ankle joints and lower limbs from some of the impact-related injuries experienced by rear-foot strikers. In a 2017 article called "Foot Strike Pattern in Children During Shod-Unshod Running", over 700 children aged 6 to 16 were observed using multiple video recording devices in order to study their foot strike patterns and neutral support. Rear foot strike was most common, in both shod and unshod running, and in both boys and girls. There was a significant reduction in rear foot strike from shod to unshod: boys shod - 83.95% RFS, boys unshod - 62.65% RFS; girls shod - 87.85% RFS, girls unshod - 62.70% RFS.
As of 2021, there was a very low level of evidence to suggest a relationship between foot strike pattern and runner injury. Studies used retrospective designs, low sample size and potentially inaccurate self-reporting.
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