You probably have heard all about how you need to vary your exercise routine in order to continue getting results. Terms like "muscle confusion" (a made-up term with no backing) have even been thrown out to indicate that for best results, you can't always do the same things. To an extent, this is true. You can't always do the same movements at the same number of sets, at the same number of reps, at the same speed, at the same weight, and expect to improve (we'll get to this soon). The problem is that historically this advice has been interpreted as "do different exercises all the time", and thus people do different exercises every time they work out. There are a few problems with doing that, however.
1. Lack of Practice = Poor Form
If you stop thinking of your workouts as training muscle groups and start thinking of them more as practicing movement patterns, you will improve rapidly and reduce your chance of hurting yourself greatly. To get good at anything, you have to do that thing a LOT. If you constantly mix up your exercises, chances are you aren't going to improve as much in any movement because you don't practice the form enough. To get good at a movement pattern you must do it over, and over, and over until it is absolutely ingrained in you.
Squats are a great example of an exercise that requires a lot of concentration and attention to detail. It's a simple concept, but more goes into a squat than most people realize. If you only do squats every two weeks, you'll have to waste time relearning the form every time only to realize that all those fancy movements you've been trying didn't really translate into squat improvements.
The second problem is that your progress is too hard to dial in when you constantly do different movements. Especially for beginners who already aren't very in tune with their capabilities yet, it can be hard to know how much to increase the weight on a particular exercise if you haven't done it in weeks. By consistently doing a movement, however, you become very aware of your capabilities within that movement and can adjust accordingly as you get stronger. This leads to much faster progress and hugely reduces the chance of injury.
It is also much more motivating to see consistent small improvements on a weekly basis than clinging on to hope that you improved after several weeks of training. In terms of sticking to a program, especially for beginners, this is absolutely critical! You need to know that what you're doing is paying off every single week.
3. Too Much Guesswork
If you don't have a plan, it's not going to go well. Period. We've all been there, though. You show up at the gym with some vague idea of what you're going to do and hope to be inspired while you're there, so you make things up as you go along. Or, you spend tons of time concocting a sophisticated "all-encompassing" fitness routine with 60 exercises per week that you have no chance in hell of sticking to anyway. Either way, it's less than ideal.
The beauty of routinely doing the same exercises is that it takes all of this guesswork and pie-in-the-sky thoughts out of the equation. You know exactly what to do when you show up at the gym and never have to stress about that. As a beginner, even just showing up can be stressful. Don't give yourself extra things to worry about like which exercises to do for every single workout.
How to Create Variety Within an Exercise
With all of that said, you still do need to create variety in your program in order to improve. However, that variety doesn't need to come from changing the exercises you do, but rather all of the other variables that go into that exercise:
-The tempo of each rep
-The number of sets
-The number of reps
-The amount of rest you take between sets
All of these variables can be manipulated to create progress towards your goals and keep an exercise challenging. The simplest way for beginners to improve is to:
-Increase the load per set
-Increase the number of sets per exercise (It's a myth that 3 sets is best. 4-6 sets is quite common in fact)
-Keep reps in the 8-15 range
Once you get some training time under your belt, you can then start to make an exercise harder with these more advanced changes:
-Slow down the repetitions (for example: 3 sec lower / pause 1 sec / 1 sec raise)
-Reduce the rest period between sets (less than one minute is tough!)
-Increase the load significantly, to a weight that only allows 5-8 reps on your last set
By gradually incorporating all of these changes into each exercise, you can master each movement pattern while simultaneously finding ways to challenge the movements, ultimately helping you achieve your goals in the least confusing way possible.
So How Often SHOULD You Change Your Actual Exercises?
So all of this begs the question then: when SHOULD you actually change up the exercises that you do? There are a few different answers to this, but they are all pretty simple.
1. When you stop making meaningful progress within those movements over a 3 week period, also known as a "plateau". 1-2 weeks of no progress could be a fluke, 3 weeks is a sign to change things up to get a new stimulus.
2. You have changed your goal. If you are mid-training program and suddenly decide you want to run a marathon, you'll need to change the way you train. Your exercise selection should always reflect the goal you are trying to achieve.
3. YOU ARE BORED. This is the most common reason people do new exercises. It's normal to not want to do the same things all the time. That said, you need to understand what you want. If your goal is to absolutely optimize your training at all costs, then you'll have to suck it up and fight through the humdrum aspects of training the same movements all the time. However, if you are willing to sacrifice some progress for the sake of having a better time - go for it! Just make sure that you choose other movements that also help you work towards your goal!
If you're a beginner looking to improve quickly, the best thing you can do is pick 8-10 exercises that cover your entire body, and practice them over and over until it is like riding a bike. You'll make much more progress that way, you'll be able to better monitor your progress, and you'll set a better foundation for more advanced movements. You can gain variety through manipulating the number of sets/reps you do, the rep speed, and the rest period between sets. Then once you have stopped making meaningful progress (it should take several MONTHS), you can change some of your exercises up and start the whole process over again.
I hope this has been helpful and let me know if you have any questions!