Abstract: An arm-straightening device for selectively locking an arm in a straight position, so that a bowler, or the like, is prevented from bending the arm during delivery, but which automatically allows the arm to bend during follow-through. A pair of semicircular-shaped, arm-shells are pivotally connected together at adjacent end-portions. An elastic, elongated band is positioned on the rear surfaces of the two shells and held in a first, stable state by a series of pins projecting from the rear surfaces of the shells. The band, in its first state, tends to keep the shells in an aligned, rectilinear orientation to keep the arm to which they are secured straight. Upon the application of sufficient force by the lower arm, in order to bend it, the elongated, elastic band is caused to take a second, stable state that tends to bias the shells into a bent orientation to keep the arm in its bent position for follow-through, or the like.

Abstract: An athletic accessory, which serves to permit an athlete normally to bend a jointed limb at will, but, at a critical time, to lock the limb in a fully extended, straight position, such as a bowler's arm during delivery of the ball, comprises two rigid members, a pivot for pivotally connecting the rigid members, supports and straps for attaching the rigid members to the upper and lower limb members of a jointed limb with the pivotal connection coincident with the joint, a sleeve for locking the rigid members together in a straight line, and an internal spring for governing the operation of the locking sleeve to cause the same to lock the rigid members and thus the user's limb in a straight line at the critical time in the athletic endeavor.