US Patent 9314659 Dual balance exercise apparatus

A resistance exercise machine having cable and pulley linkage assemblies attached to a single weight stack or other resistance means. Each cable and pulley linkage assembly, which is independent of the other(s), can be used by one arm or leg during bilateral exercise training (that is, training in which both limbs of a pair are used to simultaneously to lift a weight or work against various resistance means). A biofeedback assembly measures and displays in real-time how much each limb of a pair is contributing to such effort.