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Principles of Growth (Part 1)

Long before they were backed by science, the Weider Principles were helping to build stronger, leaner bodies.

Life is fleeting. Legacy is forever. 

Very few return to the dust having inexorably changed the way things are done here among the living. Fewer still can lay claim to the conception, development and growth of an entire industry — the visionary machinations that will impact generations to come. The late Joe Weider, who passed away at the age of 93 in March, wrote the New Testament of health and fitness, shaping the training methodologies of tens of millions in the process. 

From rest-pause to pre-exhaust, many of the “hardcore” get-lean or mass-gain tactics that are employed today were first articulated by Weider. This list, which we will cover over the course of several issues, serves as a blueprint for more efficient physique building. What’s more is that the techniques Weider laid out so long ago have only been affirmed by modern-day research, not to mention a growing legion of hard-bodied gym rats.

See AlsoThe Principles of Growth Part 2

The Weider Principles are the authoritative dictates of advanced training. Those looking to transform their bodies can, should and likely are using these techniques in the gym. And for good reason. They work.

Joe Weider’s legacy isn’t quite cemented — it’s being written with every trip you take to the gym.


So much of your progress in the gym is predicated on failure. Voluntary muscular failure — taking your muscles to the point at which they can no longer perform an exercise or activity correctly, then asking them to do more. Weider embraced this concept because he knew that breaking muscle down is the best way to build it back up. That’s why so many of the Weider Principles revolve around failure.

orced reps, perhaps the most ubiquitous and widely used of the Weider Principles, calls for lifters to work to a point at which they can no longer safely do reps on their own, then enlist a training partner to gently spot them through a few more and into a whole new dimension of growth capability. Fie on those who would terminate a set before the muscles have been truly challenged!

And in case you’re not sold, research has shown that forced reps are indeed better than simply training to failure and calling it a set. A study published in the International Journal of Sports Medicine showed that subjects using forced reps had three times greater rise in growth hormone than a group just training to failure. Growth hormone is crucial not only for gains in size and strength but also for fat burning.


But like most hardcore techniques, forced reps should be used sparingly. Researchers at the Australian Institute of Sport in Canberra found that those taking multiple sets of the bench press to failure gained less strength than those who took only one set to failure. Also, training to failure too often can speed you on your way to an overtrained state.

JOE SAYS: Going beyond failure is the best way to create a stronger, bigger, leaner physique. The Forced Reps Principle is the most basic tool that you can use in this category. To get the most out of forced reps, on the last set of every exercise, rep to failure, then have a partner help you through two to three more. You can do this yourself when training unilaterally or with machines that offer self-spot mechanisms.



Bully your arms into more growth by implementing a reliable spotter and a few forced reps.


Can’t quite do 10 reps on the bench with 225? You can if you break it up into smaller segments of work. The way Weider figured it, if you kept rest periods brief enough, the body wouldn’t recognize it as actual rest — your body would still get all the benefits of doing more reps at a heavy weight. Makes sense. What the lab coats know now that Weider didn’t know then was that this method was actually far more beneficial — and genius — than he thought.

As it turns out, your body’s explosive energy stores — collectively known as phosphagen — have a shelf life of about 10 to 20 seconds. Once you burn through that, your body starts relying on other, less strength-friendly sources of fuel. But phosphagen replenishes itself in about the same amount of time once activity stops. So if you operate within this time frame — training in beast mode for 10 to 20 seconds, or about the time it takes to knock out three to six heavy reps, then resting about the same amount of time — you ensure that you are always running on your best source of energy for heavy work.

Using the bench press as an example again: The guy who can’t get 225 for 10 — maybe he can get six to seven clean reps — can try doing two segments of three and two segments of two (3+3+2+2=10), taking 10 to 20 seconds of “rest” each time he racks the bar. Now he has gotten 10 muscle-building reps and in more efficient fashion because the muscles never truly reached the point of failure. After two to three minutes of rest, the set can be repeated two to three more times. This technique adds volume to workouts because of the extra reps, so before long, a set of 10 at 225 will be this bencher’s warm-up. 

Want to really have your mind blown? The soul of rest-pause has been transplanted into other work-then-rest protocols such as high-intensity interval training and Tabata training, each backed by volumes of research of their own. 

JOE SAYS: The Rest-Pause Principle is a great way to maximize strength and size gains, but load selection is key. In each rest-pause set, you’ll still want to end up with a number of reps that promotes the gains you’re looking for (i.e., eight to 12 for size). The chest workout here is front-loaded with two big-boy rest-pause moves and followed by some isolation work to fully exhaust the whole of your pectoral mass.



Upgrade your chest-training formula with this routine, designed to take advantage of your body’s most potent pushing fuel.


Weider once hypothesized that a body constantly challenged by new exercises, rep ranges, rest periods and other variables would be more likely to respond in perpetuity. It’s worth noting that this was long before Tony Horton, Mr. P90X himself, laid claim to the concept and made a small fortune.




The idea behind muscle confusion is simple: Adaptation is inevitable. In other words, if you continue to perform the same workouts week to week, your body will eventually become reluctant to grow new muscle or shed more body fat. It reaches a point of homeostasis at which it has become fully accustomed to doing what you ask of it. Gone unchecked, muscle starts to disappear and fat starts to return. Remember, your body doesn’t want to be lean or muscular, so when it sees a window of opportunity to return to a more “natural” state, it doesn’t hesitate.

The antithesis of muscle confusion — also known as undular periodization — is linear periodization, which also has its merits. In linear periodization programs, you train a certain way for a certain number of weeks (generally six to 12), usually focusing on a particular goal such as strength, size or burning more fat. The workout variables become more intense over that time frame. Those looking to add size, for example, will add more weight on given exercises while staying within muscle-building rep ranges. 

Muscle confusion, on the other hand, thrives on forcing your body to do the unexpected and can actually produce better gains in size and strength than a strict, linear periodized program. Researchers in Brazil found this to be the case when they pitted an undular periodization group against groups on linear and non-periodized programs. After 12 weeks, those who followed a more “confused” program exhibited far greater gains in bench-press and leg-press strength than subjects in the other two groups. A similar study out of Brazil found that a group of subjects that changed rep ranges every workout increased the size of their triceps (5 percent) and biceps (10 percent) twice as much as a linear group.

JOE SAYS: While the typical model of linear periodization has you sticking within the same framework of exercises, sets and rep ranges over several weeks, the Muscle Confusion Principle advocates just the opposite. While the options are so numerous as to become, well, confusing, you can simply pick one or two variables to manipulate for your bodyparts from week to week.


Keep your shoulders guessing over the next four weeks with this varied approach.