Mechanical Advantage Extended sets were first introduced to me many years ago by my mentor Charles Poliquin. Extended Sets, much like drop sets, are a challenging, and extremely effective way to increase time under tension for a given set or body part.
To understand this concept we first need to examine what mechanical advantage is. Let’s take a look at pressing exercise to build and develop the chest. The pectoralis major is divided up into two sections, based on where it’s fibers are located: the sternal portion (lower), and the clavicular portion (upper).
In terms of pressing, for the chest, we have decline, flat, and incline presses, of varying specific degrees. As you can see in the picture above, the clavicular portions of the pec major are much smaller than the sternal fibers. If you’ve spent much time in the gym, you know that incline presses are much more challenging than a flat press. The angle you choose for your press, dictates which portion of the pec you will train. We can’t fully isolate one from the other, but the angle preferentially recruits one portion more than the other. As the angle of your incline gets steeper (closer to 90 degrees), the more the clavicular portion is called upon to do the majority of the work.
As you can see on the left picture of an incline barbell press, the clavicular portion of the pec is recruited and used more than the sternal portions. On the right, you can see on the flat press that sternal portions on the lower pecs are used the most.
By progressively lowering the height, or angle of your bench throughout your set, you can extend the length of your set by doing more reps. Since you are generally stronger on a flatter angle, you’ll be able to squeeze out an extra 5 or 6 reps changing the angle. Here’s how you put this method into practice.
Choose a weight that is challenging to complete 6-8 reps with at a 3010 tempo on a 45 degree incline bench. Complete that set of repetitions to technical failure. Rest 10-15 seconds (just long enough to decrease the angle on the bench) by one notch. Now, do as many reps as possible, maintaining perfect technique and tempo. Once you have failed at that angle, rest another 10-15 seconds, and decrease the bench angle down to a flat position. From this position, do as many repetitions as possible, again, maintaining proper technique and tempo. By incorporating this method into your training, you can take a 6-8RM weight and successfully complete 10-25% more repetitions per set. Any intensity zone (rep range) works with this method, however, experience has taught me that the 6-8 and 8-10 rep ranges will allow for the greatest improvements in performance.
(Image Courtesy of Devalier, Frederic (2010). Strength Training Anatomy.)