Abstract: A selectorized dumbbell has a plurality of nested weights that provide a stack of left weight plates and a stack of right weight plates. A handle is dropped between the stacks and a selector is inserted into one of a plurality of vertically spaced positions on the handle to couple a selected number of the weights to the handle. The selector has a continuous periphery enclosing an open interior. A user who is exercising with the dumbbell will be alerted to unintended dislodgement of the selector since a portion of the selector's periphery will contact a portion of the user's grip hand, wrist or forearm during such dislodgement. This prevents complete dislodgement and prompts the user to restore the selector to a fully installed position. Side walls of the selector may become curved when the selector is installed to provide an additional frictional force resisting dislodgement of the selector.

Abstract: An adjustable weight kettlebell includes a weight lifting member that rests on top of a vertical stack of weights. A weight selector is rotatable into and out of underlying engagement of the weight plates to secure a desired amount of mass to the weight lifting member.

Abstract: A textured surface for improving grip on plectra and other hand-held implements. A series of parallel ridges serve to frictionally engage thumb and forefinger surfaces and “lock” the grip in place.

Abstract: Disclosed is a dumbbell of the type commonly found in a fitness center to be used as a weight training device during a weight training or exercise program. The dumbbell includes a gripping handle and a pair of collars fixedly connected to opposites ends of the handle. A series of weight plates having correspondingly different weights are adapted to be detachably connected to each other and to each one of the collars so as to enable a user to selectively and incrementally adjust the gross weight of the dumbbell to conform to his weight training program. Each weight plate carries a lock cartridge having an engagement pin moving therethrough between retracted and extended positions in response to a manual pushing force. In the extended position, the engagement pin of an additional weight plate is received within an engagement pin extension channel of an existing weight plate being carried by the dumbbell, whereby to prevent a disconnection of the additional weight plate from the existing weight plate.