The present invention provides a muscle training, development, stretching and warming device for sports swings. The device comprises a handle connected with an adjustable mounting device via a tensioning element of variable resistance. The tension element of a higher resistance may be substituted for a lower resistance tension element to increase the force required to swing. Further, the handle allows for adjusting the length of the resistance arm to further manipulate the force required to be provided by the user. The mounting device may be moved vertically to adjust the angle of the resistance relative to the swing plane of the user.