For enabling weightlifting athletes to rapidly and efficiently improve concentric-type muscular development, exercising apparatus having two shafts provided with motor-driven barbell-tethered cables is adapted to supplement the athlete's total physiological energy with motor-assist poundage. The motor-assists are of the unidirectional type to rapidly and efficiently improve eccentric-type muscular development. Shafts-mounted braking system protect a weary athlete from the contingency of a rapidly descending barbell.
