Leg

A leg is a weight bearing and locomotive structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element capable of changing length and rotating about an omnidirectional "hip" joint.

As an anatomical animal structure it is used for locomotion. The distal end is often modified to distribute force (such as a foot). Most animals have an even number of legs.

As a component of furniture it is used for the economy of materials needed to provide the support for the useful surface, the table top or chair seat.

Terminology

Many taxa are characterized by the number of legs:

Tai chi

Often shortened to t'ai chi, taiji or tai chi in English usage, t'ai chi ch'uan or tàijíquán is an internal Chinese martial art practiced for both its defense training and its health benefits. Though originally conceived as a martial art, it is also typically practiced for a variety of other personal reasons: competitive wrestling in the format of pushing hands (tui shou), demonstration competitions, and achieving greater longevity. As a result, a multitude of training forms exist, both traditional and modern, which correspond to those aims with differing emphasis. Some training forms of t'ai chi ch'uan are especially known for being practiced with relatively slow movements.

Today, t'ai chi ch'uan has spread worldwide. Most modern styles of t'ai chi ch'uan trace their development to at least one of the five traditional schools: Chen, Yang, Wu, Wu (Hao), and Sun. All of the former, in turn, trace their historical origins to Chen Village.

Overview

The term "t'ai chi ch'uan" translates as "supreme ultimate fist", "grand supreme fist", "boundless fist", "supreme ultimate boxing" or "great extremes boxing". The chi in this instance is the Wade–Giles transliteration of the Pinyin jí, and is distinct from qì (ch'i, "life energy"). The concept of the taiji ("supreme ultimate"), in contrast with wuji ("without ultimate"), appears in both Taoist and Confucian Chinese philosophy, where it represents the fusion or mother of yin and yang into a single ultimate, represented by the taijitu symbol . T'ai chi ch'uan theory and practice evolved in agreement with many Chinese philosophical principles, including those of Taoism and Confucianism.

Physical exercise

Physical exercise is any bodily activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons, including strengthening muscles and the cardiovascular system, honing athletic skills, weight loss or maintenance, and merely enjoyment. Frequent and regular physical exercise boosts the immune system and helps prevent the "diseases of affluence" such as heart disease, cardiovascular disease, Type 2 diabetes, and obesity. It may also help prevent stress and depression, help to promote or maintain positive self-esteem, improve mental health generally, and can augment an individual's sex appeal or body image, which has been found to be linked with higher levels of self-esteem.Childhood obesity is a growing global concern, and physical exercise may help decrease some of the effects of childhood and adult obesity. Some care providers call exercise the "miracle" or "wonder" drug—alluding to the wide variety of benefits that it can provide for many individuals.

Human leg

The human leg, in the general sense, is the entire lower extremity or limb of the human body, including the foot, thigh and even the hip or gluteal region; however, the definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle (called crus in Latin; the posterior of the crus is the sura).

Legs are used for standing, walking, jumping, running, kicking, and dancing and similar activities, and constitute a significant portion of a person's mass. Female legs generally have greater hip anteversion and tibiofemoral angles, but shorter femur and tibial lengths than those in males.

Structure

In human anatomical terms, the leg is the part of the lower extremity that lies between the knee and the ankle, the thigh is between the hip and knee and the term "lower extremity" is used to describe the colloquial leg. This article generally follows the common usage.

The leg from the knee to the ankle is called the cnemis /ˈniːmɪs/ or crus. The calf is the back portion and the shin is the front. The tibia and fibula are the two bones of the crus.