The 2019 IAAF World Rankings document the best performing athletes in the sport of athletics, per the International Association of Athletics Federations (IAAF) individual athlete ranking system. It was the first year that the IAAF used the system. Individual athletes are assigned a points score best on an average of their best recent competition performances. The performance scoring is primarily based on the time or mark of the athlete, plus additional points for their placing within the competition, and some minor modifications based on the conditions. The world rankings are updated each Wednesday. As of 2 October 2019, the number
Also named stair-climbing machines, they work the user's legs as he/she pumps pedals up and down, much like climbing stairs. Some climbing machines have handles to push and pull to exercise the whole body.
An exercise machine is any machine used for physical exercise. These range from simple spring-like devices to computerized electromechanical rides to recirculating-stream swimming pools. Most exercise machines incorporate an ergometer. An ergometer is an apparatus for measuring the work a person exerts while exercising as used in training or cardiac stress tests or other medical tests.
Ellipticals (elliptical machines) are a combination of stair-climbing and a treadmill. Generally it contains two tracks upon which the user stands; when he or she moves his or her legs, they describe an elliptical motion (hence the machine name). Some ellipticals have magnetic resistance controls that add difficulty to doing the motion.
Weight machines use machine.php" >gravity as the primary source of resistance, and a combination of simple machines to convey that resistance, to the person using the machine. Each of the simple machines (pulley, lever, wheel, incline) changes the mechanical advantage of the overall machine relative to the weight.