A Mechatronic Spotting System that mimics Human Weight-training Assistance Behavior

A leading cause of serious weight-training injuries and death among bodybuilders and weight-lifters is training with heavy barbells without the assistance of a human 'spotter ' or gym partner. A spotter can identify lack of progress or nearness of muscle failure and provide additional force to assist with the lift, so that the lift can progress slowly prior to complete muscle failure, allowing the maximum benefit to be gained from the exercise. This paper briefly describes the modeling, design and performance of a computer-controlled mechatronic system that automates the 'spotting ' process for horizontal barbell exercises, which includes exercises such as squats, bench press, overhead shoulder press, barbell triceps extensions and bicep curls. The system employs a unique pulley system attached to a strong structural frame, a solenoid-activated locking brake, optical position sensors and a low-cost embedded microcontroller system that drives a display screen, control panel, a geared electrical winch (motor) and cables attached to a standard barbell. Known as the ‘Smart Gym’, the basic system design, its different modes of operation and important safety features are described. This system also has the potential to save the lives of many people each year by preventing barbell suffocation (asphyxiation due to neck compression) and fatal injuries caused by heavy, free-falling barbells. Several fitness equipment manufacturers have already shown interest in using concepts described in this paper for implementation in current and future gym equipment. Key words: Gym, spotter, spotting, bench press, microcontroller, mechatronic 1