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X-seam
A person's X-seam is a measurement related to the person's height. It is measured from a sitting position with legs outstretched, and is the distance from the lower back to the soles of the feet. X-seam measurements are used for sizing recumbent bicycles and ultralight aircraft. External links X-Seam Illustration Anthropometry {{Measurement-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recumbent Bicycle
A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Most recumbent riders choose this type of design for ergonomic reasons: the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the Tuberosity of the ischium, sitting bones, the feet, and the hands. Most recumbent models also have an aerodynamics, aerodynamic advantage; the reclined, legs-forward position of the rider's body presents a smaller frontal profile. A recumbent holds the world speed record for a bicycle, and they were banned from racing under the Union Cycliste Internationale (UCI) in 1934, and now race under the banner of the World Human Powered Vehicle Association (WHPVA) and International Human Powered Vehicle Association (IHPVA). Recumbents are available in a wide range of configurations, including: long to short wheelbase; large, small, or a mix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sole (foot)
The sole is the bottom of the foot. In humans the sole of the foot is anatomically referred to as the plantar aspect. Structure The glabrous skin on the sole of the foot lacks the hair and pigmentation found elsewhere on the body, and it has a high concentration of sweat pores. The sole contains the thickest layers of skin on the body due to the weight that is continually placed on it. It is crossed by a set of creases that form during the early stages of embryonic development. Like those of the palm, the sweat pores of the sole lack sebaceous glands. The sole is a sensory organ by which we can perceive the ground while standing and walking. The subcutaneous tissue in the sole has adapted to deal with the high local compressive forces on the heel and the ball (between the toes and the arch) by developing a system of "pressure chambers." Each chamber is composed of internal fibrofatty tissue covered by external collagen connective tissue. The septa (internal walls) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultralight Aircraft
Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with ailerons, elevator and rudder, calling the former "microlight" and the latter "ultralight". During the late 1970s and early 1980s, mostly stimulated by the hang gliding movement, many people sought affordable powered flight. As a result, many aviation authorities set up definitions of lightweight, slow-flying aeroplanes that could be subject to minimum regulations. The resulting aeroplanes are commonly called "ultralight aircraft" or "microlights", although the weight and speed limits differ from country to country. In Europe, the sporting (FAI) definition limits the maximum stalling speed to and the maximum take-off weight to , or if a ballistic parachute is installed. The definition means that the aircraft has a slow landing speed and short ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
