A flexible and self retracting crossbar, which is formed of multiple different separated pieces with an elastic device in between, and has a self retracting pulley device.

A training aid stimulator for providing fast perceptive feedback is disclosed. The training aid stimulator includes a first skin electrode and a second skin electrode both for making electrical contact to the body of a user, a charging module, a discharge module connected to one or more of the skin electrodes for a feedback discharging, and a processor for controlling the charging of a capacitor equivalent to a predetermined first voltage level, wherein the processor further being connected to the discharge module for controlling a feedback discharge of the capacitor equivalent. The stimulator comprises a voltage measurement module for measuring the level of charge of the capacitor equivalent, and the processor is configured for keeping the stimulator ready to discharge by repeatedly measuring the level of charge and by providing a maintenance charging when the voltage over said capacitance equivalent is at or below a predetermined second voltage level.

Systems, methods, and other embodiments associated with instruction production are described. In one example, a system can comprise a difference component that makes an identification of a difference between an actual action of a user and a standard action for the user. The system also can comprise an instruction component that produces an instruction to instruct the user to change from the action of the user to the standard action for the user, where production of the instruction is based, at least in part, on the difference. The system further can comprise a non-transitory computer-readable medium configured to retain the instruction. Additionally, the system can comprise an output component configured to cause disclosure of the instruction.

A training aid stimulator for providing fast perceptive feedback, the training aid stimulator comprising a first skin electrode for making electrical contact to the body of a user, and a second skin electrode for making electrical contact to the body of a user, a body capacitance charging module connected to the first skin electrode, a discharge module connected to the second skin electrode for a feedback discharging of a body capacitance, and a processor connected to the body capacitance charging module for controlling the charging of a body capacitance, C.sub.BODY, to a predetermined first voltage level, wherein the processor further being connected to the discharge module for controlling a feedback discharge of said body capacitance, C.sub.BODY, and wherein the stimulator further comprises a measurement module for measuring the level of charge of said body capacitance, C.sub.BODY.

A training aid stimulator for providing fast perceptive feedback is disclosed. The training aid stimulator includes a first skin electrode and a second skin electrode both for making electrical contact to the body of a user, a charging module, a discharge module connected to one or more of the skin electrodes for a feedback discharging, and a processor for controlling the charging of a capacitor equivalent to a predetermined first voltage level, wherein the processor further being connected to the discharge module for controlling a feedback discharge of the capacitor equivalent. The stimulator comprises a voltage measurement module for measuring the level of charge of the capacitor equivalent, and the processor is configured for keeping the stimulator ready to discharge by repeatedly measuring the level of charge and by providing a maintenance charging when the voltage over said capacitance equivalent is at or below a predetermined second voltage level.

A vertical jump system is described herein. The system includes a first member and a second member each having a member base that sits under a flooring, a flexible cord that extends between the first member and the second member at a desired height, fixtures coupled to the flexible cord along the first member and the second member. The flexible cord remains at the desired height when contacted. The fixtures are slidable along the first member and the second member and adjust the height of the flexible cord. This configuration allows a user to easily adjust the height of the vertical jump for training, athletics, and competition, without the cord or system components dislodging and causing injury to the user.

Systems, methods, and other embodiments associated with instruction production are described. In one example, a system can comprise a difference component that makes an identification of a difference between an actual action of a user and a standard action for the user. The system also can comprise an instruction component that produces an instruction to instruct the user to change from the action of the user to the standard action for the user, where production of the instruction is based, at least in part, on the difference. The system further can comprise a non-transitory computer-readable medium configured to retain the instruction. Additionally, the system can comprise an output component configured to cause disclosure of the instruction.

A training system for a jumper on a jump path over a crossbar predicts the jumper's flight path and cues the jumper if the flight path is too close to the crossbar or to take action if the jumper is predicted to strike the crossbar. The system includes a sensor viewing the jumper from a direction paralleling the crossbar and producing data points representative of the lowest edge of the jumper in the vicinity of the crossbar. A computer receiving the data points is programmed to determine therefrom the jumper's flight path, the jumper's forward speed, the location of a jumper's lower legs relative to the crossbar, an expected impact time of the lower legs with the crossbar, and a cuing time. A cuing device, such as a horn, cues the jumper to raise the lower legs so as to not impact the crossbar.

A training system for a jumper on a jump path over a crossbar predicts the jumper's flight path and cues the jumper if the flight path is too close to the crossbar or to take action if the jumper is predicted to strike the crossbar. The system includes a sensor viewing the jumper from a direction paralleling the crossbar and producing data points representative of the lowest edge of the jumper in the vicinity of the crossbar. A computer receiving the data points is programmed to determine therefrom the jumper's flight path, the jumper's forward speed, the location of a jumper's lower legs relative to the crossbar, an expected impact time of the lower legs with the crossbar, and a cuing time. A cuing device, such as a horn, cues the jumper to raise the lower legs so as to not impact the crossbar.

An adjustable height plyometric apparatus is disclosed having a platform component, a set of base leg components, a base component to which the set of base leg components are fixedly secured, and one or more optional sets of upper leg components for attachment to the base leg components or another upper leg component. The platform component is configured to be simultaneously raised or lowered relative to the base leg components in an unlocked state and to be selectively secured thereon at any one of a selection of vertical heights in a locked state. The upper leg components are attachable to the base or other upper leg components for increasing the selection of vertical heights. Each of the upper leg components may be inserted within a respective leg receiving opening in a top surface of the platform component for attachment with a respective base or other upper leg component disposed therein.