Method and apparatus for training muscle strength through progressive resistance exercise

Abstract

An apparatus for enhancing muscle strength is designed based on a curve of relation between joint angle and producible muscle strength, and includes a resistance-varying device that provides progressive resistances to give a trainee's body area being trained the most suitable load when the joint angle at the trained area changes. The resistance-varying device is embodied through serially connected four-bar linkages, two-bar linkages, or tension cords pivotally connected to one lateral side of weights of the apparatus with pins. Strength exerted by the trainee at the trained area is transmitted via a steel cord to pull a top weight upward and sequentially stretch the linkages or tension cords open, so that subsequent weights are pulled upward one by one until the last linkage or tension cord is fully stretched. A method using the apparatus to enhance muscle strength meets the human engineering and avoids unwanted injury of trained muscles.

What is claimed is:  
     
         1 . A method for training muscle strength through progressive resistance exercise, comprising the steps of preparing a resistance transmission mechanism having a resistance-varying device adapted to change a load of said mechanism, and designing said resistance-varying device based on a curve of relation between joint angle and producible muscle strength to generate resistance variations on said resistance transmission mechanism, so that said resistance transmission mechanism provides different magnitudes of resistance relative to different magnitudes of strength producible by muscles at different joint angles.  
     
     
         2 . The method for training muscle strength through progressive resistance exercise as claimed in  claim 1 , wherein said resistance-varying device comprises a plurality of linkages that are sequentially stretched open when being subjected to a pull.  
     
     
         3 . The method for training muscle strength through progressive resistance exercise as claimed in  claim 1 , wherein said resistance-varying device comprises a plurality of tension cords that are sequentially stretched open when being subjected to a pull.  
     
     
         4 . The method for training muscle strength through progressive resistance exercise as claimed in  claim 1 , wherein said resistance transmission mechanism includes a resistance source consisting of a plurality of vertically stacked weights made of a metal material.  
     
     
         5 . The method for training muscle strength through progressive resistance exercise as claimed in  claim 4 , wherein said metal weights are in a number that can be freely selected to provide different resistance for training muscle strength.  
     
     
         6 . An apparatus for training muscle strength through progressive resistance exercise, comprising: 
 a resistance transmission mechanism including a plurality of weights that constitute a source of resistance; a steel cord that has an end connected to said weights and transmits a resistance provided by said weights to a trainee's body areas to be trained; a group of pulleys that are connected to said steel cord to change directions in which the resistance is transmitted via said steel cord; and a connecting device that is connected to another end of said steel cord and transfers the resistance transmitted via said steel cord to the trainee's body areas to be trained; and    a resistance-varying device being provided at one lateral side of said resistance source of said resistance transmission mechanism, and being designed in accordance with a curve of relation between joint angle and producible muscle strength in order to change a load of said resistance transmission mechanism according to different magnitudes of strength producible by muscles at different joint angles.    
     
     
         7 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 6 , wherein said resistance-varying device comprises a plurality of linkages that are sequentially stretched open when said resistance source is subjected to a force and moved upward.  
     
     
         8 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 6 , wherein said resistance-varying device comprises a plurality of tension cords that are sequentially stretched open when said resistance source is subjected to a force and moved upward.  
     
     
         9 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 6 , wherein said plurality of weights are vertically stacked, and are in a number that can be freely selected to provide different resistance for training muscle strength.  
     
     
         10 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 6 , wherein said steel cord is a rigid transmission member without elasticity.  
     
     
         11 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 6 , wherein said resistance transmission mechanism is provided on a main steel framework, and includes slide rails to define a path along which said weights are moved upward and downward.  
     
     
         12 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 11 , wherein said resistance transmission mechanism further includes a body supporting structure for a trainee to sit or lie thereon.  
     
     
         13 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 6 , wherein said connecting device of said resistance transmission mechanism includes a grip at where the trainee holds to exert strength, and an upper arm rest on which the trainee's upper arms are positioned.  
     
     
         14 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 7 , wherein said linkages of said resistance-varying device are four-bar linkages.  
     
     
         15 . The apparatus for training muscle strength through progressive resistance exercise as claimed in  claim 7 , wherein said linkages of said resistance-varying device are two-bar linkages.