Exercise machine for fluent agonist-antagonist muscle training

An exercise machine for agonist-antagonist muscle training, comprising:

• a frame having an upper portion and a lower portion;
• a first variable resistance mechanism coupled to said upper portion of said frame, said first variable resistance mechanism having a first line extending therefrom, said first line adapted to have a first tensile force applied thereto wherein said first line is pulled downward from said first variable resistance mechanism when said first tensile force exceeds a first resistance force of said first variable resistance mechanism, and wherein said first line retracts upwards towards said first variable resistance mechanism by a first restoring force of said first variable resistance mechanism when said first tensile force is terminated, wherein said first resistance force is greater than said first restoring force;
• a second variable resistance mechanism coupled to said lower portion of said frame, said second variable resistance mechanism having a second line extending therefrom, said second line adapted to have a second tensile force applied thereto wherein said second line is pulled upward from said second variable resistance mechanism when said second tensile force exceeds a second resistance force of said second variable resistance mechanism, and wherein said second line retracts downward towards said second variable resistance mechanism by a second restoring force of said second variable resistance mechanism when said second tensile force is terminated, wherein said second resistance force is greater than said second restoring force;
• a link coupled to said first line and said second line wherein said first line, said second line, and said link are aligned along a common vertical axis, said link adapted to be engaged by a user, wherein said link includes a linear support element having a plurality of attachment elements spaced-apart along a length of said linear support element;
• a flexible loop coupled to two of said attachment elements of said linear support element, wherein said flexible loop is adapted to be gripped by a user at diametrically-opposed locations on said flexible loop between said two of said attachment elements;
• said first variable resistance mechanism and said second variable resistance mechanism positioned relative to one another such that when the user applies said first tensile force in excess of said first resistance force to said first line via said link, said first line is pulled downward from said first variable resistance mechanism against said first resistance force while said second line retracts downward towards said second variable resistance mechanism under said second restoring force, and
• such that when the user applies said second tensile force in excess of said second resistance force to said second line via said link, said second line is pulled upward from said second variable resistance mechanism against said second resistance force while said first line retracts upward towards said first variable resistance mechanism under said first restoring force.