ingilizce bilen varsa yabancılar şöyle açıklamış:
[FONT=verdana, helvetica, sans serif][SIZE=-1]This system is elaborate because you do a series of half reps in the lower range of motion, a series of half reps in the upper range of motion, and then a series of full reps. You can use any number of reps for this type of set. You can do 10-10-10, or 8,8,8 or any combination as long as you do the same number for each of your half reps and full reps. Traditionally, many bodybuilders have used seven reps -hence the name "21's": 3 x 7. The extra stress generated by this kind of training comes about because you have to stop the movement right in the middle, and this forces the muscles to exert themselves in ways they are not used to. Making the muscles do things that they are not used to will help spur them on to new growth. This type of exercise is typically done on the biceps or you can even experiment with this on the squat rack with a lower weight than you would normally use.[/SIZE][/FONT]