Here are three big reasons why the principle of optimal variation is so important to your training, along with how to best exploit this principle for more results:
Getting bigger and stronger is your body's way of coping with the "threat" imposed by your training efforts. Once it's figured out what you're up to, it doesn't allow any more adaptations in the form of strength and muscle.
"That's when it's time to add more weight to the bar, obviously!" That's completely true, of course. However, there are definitive limits to how much weight you can lift (that applies to both volume and intensity).
For muscle growth, most experts feel that gaining 40-50 pounds of new muscle tissue over a natural man's entire training career is about what most people can expect. Sure there are outliers on both ends of the spectrum, but that doesn't change my point – you can only get so big or so strong.
The longer you train, the closer you get to those limits. The closer you get to your ultimate potential, the slower the adaptations come, until you reach a point where no matter how hard you train, no further improvement occurs.
Don't fret, though. There's a silver lining to this admittedly dark cloud of reality. Increasing training load (volume and intensity) isn't the only tactic in your toolbox. Another option is to change the type of training you do:
- Change your exercises.
- Change your weekly training split.
- Change the order in which you perform your exercises.
- Train more often or less often, depending on what you're doing now
- Use different lifting tempos (slow negatives, fast concentrics, pause times etc.)
- Change your training style. Add or rotate intensification techniques such as rest-pause or eccentric overloading.
The basic intent of all of these tactics is to present your body with something it's not accustomed to dealing with. If you succeed, your body will reward you with new adaptations, at least temporarily.
I often unfurl a large paper clip into a straight piece of wire and hold it up to a client's face. I'll then take the wire with both hands and repeatedly bend it back and forth in the same place while saying "front squat, front squat, front squat" until the paper clip finally breaks.
As my client's eyebrows start to furrow, I straighten out another paper clip, and instead of bending it back and forth in the same spot, I'll repeatedly bend one end while saying "front squat" and then bend the other end while saying "back squat." It quickly becomes clear that the second paper clip will be able to withstand much more abuse before it finally breaks.
Your body's structures have a limited potential to adapt, so if you chronically use the exact same exercises, your connective tissues – which are typically poorly vascularized compared to muscle tissue – will be more prone to overuse injury.
You're likely to be taken by surprise by this overuse injury since most connective tissue has limited neural input to your brain. You won't necessarily be aware of the damage you're doing until it's too late. Better to proactively rotate your exercises periodically to avoid these problems.
You might have subconsciously noticed that working hard is often a lot more palatable when you're working hard on something new. A training buddy of mine was recently doing a phase of German Volume Training and had the goal of dumbbell pressing a pair of 100's for 10 sets of 10.
The first time he attempted this he got 6 sets of 10 and then had to drop to 90's to eke out the final 4 sets. Workout by workout, he gradually improved. After about 7 sessions he finally reached his goal. When I asked him if he was going to continue with GVT, he looked at me like I was nuts.
CrossFit figured this out right from the start. When every workout is different for weeks or months on end, you'll find that you can work harder than you could if you were doing the same workout over and over again. Of course, too much variation comes with its own baggage.
Yes, you'd prefer that I confidently tell you to change all of your exercises every 6 weeks or some similar iron-clad rule, but it'd be dishonest to do that. Instead, there are four primary factors that determine the need for making exercise changes:
- A change in status: Perhaps your recent training efforts have been directed toward bringing up a weak body part such as your pecs. After 12 weeks of specialization, your pecs have responded according to plan, and now it's time to shift your focus elsewhere – time to make a few exercise substitutions.
- A change of goals: People who set and achieve their goals continuously adopt new goals, which require a change in training tactics. New goals can mean bigger "macro" objectives (such as switching from weightlifting to bodybuilding), or they take the form of smaller "micro" goals such as deciding to build those stubborn calves. Either way, new training targets usually require new exercises.
- Pain or injury: Completely out of the blue, back squats now hurt your knees. If you're smart, you'll do what you can to find the cause of this pain, but in the meantime, you'd be even smarter to discontinue those squats and find a pain-free work-around until your knees cool off. Pain always signals the need to intelligently modify your exercises.
- Adaptive resistance: The longer you do a particular exercise, the less your body will respond to it. Eventually, no matter how hard you try, you can't make any further progress with it. If you foolishly persist, you'll likely have a new injury to add to your resume.
Many commercial exercise programs like P90X make sure you never experience adaptive resistance by prescribing maximum variety in their workouts. The problem with excessive variation is that you never do any one exercise enough to become competent with it.
A second issue is that too much exercise variation makes it all but impossible to enforce progressive overload, which is why those TV infomercial programs don't work very well for most people.
The more experienced you are with any given exercise, the faster you'll experience adaptive resistance with it, which means you'll only be able to run it for a short time – perhaps 3-5 weeks – before it grinds to a screeching halt. On the other hand, if an exercise is brand new for you, you'll be able to do it for a significantly longer time before you'll need to sub it out for another exercise.
When considering whether or not to give any given exercise a break, ask yourself:
- Am I still making progress on this exercise?
- Is this exercise still comfortable and pain-free?
- Does this exercise still directly correspond to my current training status and goals?
If you answered yes to these questions, suck it up and stay the course. But if you answered no, it's time for a change.
It's often beneficial or even necessary to change other training components:
- Rep brackets (which by extension determine the intensities you use) are the simplest to address, since they're almost entirely goal-driven. Strength training requires low-rep training. Muscle growth, for the most part, demands higher-rep sets.
- Changing your training split (whole-body, upper/lower, bro-split, etc.) is typically done to suit personal preferences and life circumstances, but making changes to your training week can also be a nice way to reduce monotony, even if everything else is going well for you.
- Adding or rotating intensity techniques can be an effective and often under-appreciated way of combating adaptive resistance without the need to change exercises or other program elements. When training for strength, the use of rest-pauses will enable you to add reps when you'd otherwise be unable to. Or, during a hypertrophy phase, the use of drop sets can achieve the same result.
When you understand the underlying principles, methods tend to take care of themselves. So invest the time up front to master these principles, because that decision will repay you over and over again.