US Patent 9586074 Portable collaborative exercise device

An exercise device that is simultaneously mutually beneficial for exercising partners with one exercising by providing a continuously changing resistance and resistance-vector while simultaneously the other exercising by providing a continuously adapting (or altering) counteracting force and counteracting force-vector to the continuously changing resistance and resistance vector. In addition, the portable collaborative exercise device in accordance with one or more embodiments enables correct application of resistance between symmetrical set of muscles with unbalanced strengths, and enables immediate ceasing of an exercise routine if the resistance is incorrectly applied.