Muscle confusion is one of the classic marketing terms that supposedly comes from the famous P90X program that was introduced in 2004. But a similar concept, “shocking the muscle,” has been used since the golden era of bodybuilding.
The concept behind “muscle confusion” is that over time your muscles adapt to any stimulus. Therefore, we should add more variety to the exercises or constantly change the workouts, which shocks/confuses the muscles and forces them to grow.
For others, however, muscle confusion is about motivation. Acc. One study states: “Building muscle mass and strength while maintaining or increasing exercise motivation appears to be a relevant factor in improving exercise adherence. In this sense, some popular exercise programs advocate frequent rotation of exercises as a means of optimizing results and improving exercise motivation. The term 'muscle confusion' was coined to describe the effects of constantly varying exercise selection as a means of providing a novel stimulus that improves muscle adaptations.”
With that logic it makes perfect sense. But is it based on science or just pseudoscience?
One study compared the effects of a traditional training program (fixed exercises and rep ranges) with a training program in which exercises and rep ranges were randomized from session to session based on markers of muscular adaptations and intrinsic motivation in resistance-trained men.
21 men were divided into 2 groups. One group performed workouts consisting of the same six upper body exercises and the same six lower body exercises, always in the same order, four workouts per week (two upper body, two lower body), three sets per exercise. The other group followed exactly the same parameters (number of exercises, sets, reps) except that the upper and lower body exercises were randomly selected from a database of 80 exercises. So one group made no exercise changes, while the other group constantly changed their exercises and the order in ways that even the participants couldn't predict.
Now the results were quite interesting as the group that varied the exercises showed increased motivation throughout the 8 week study. However, there was no difference in strength gains or muscle growth between the groups. In fact, some results appeared to be slightly attenuated by frequent exercise rotation.
The researchers concluded: “Perhaps a trade-off is that rotation of exercises too frequently impairs muscle growth and strength somewhat. Therefore, those seeking to maximize these results may wish to limit exercise variety. A possible solution is to perform more complex free-weight exercises (e.g., squats, deadlifts, rows, etc.) in a regular rotation throughout a training cycle, varying movements that have limited degrees of freedom and therefore do not require high levels of motor learning.” (e.g. leg extensions, machine presses, arm curls, etc.).”
Some trainers have also coined a new term for varying the exercises during each workout: “training attention deficit disorder.” This is due to the overload of information on the internet, which causes people to change virtually every single aspect of their workout as soon as they step into the gym.
This aspect is fine if your goal is nothing other than general fitness and exercise to keep yourself healthy. Because then it's not about a specific goal.
However, if your goal is to build muscle and gain strength, training needs to be planned and you need to do repetitive exercises to assess progress in it. You need to test your strength through a consistent set of exercise movements and try to improve with each workout. Remember that “progressive overload” is the cornerstone of strength and hypertrophy.
Remember that your muscles have no memory of their own. They simply respond to the stress/stimulus you give them. They adapt to stress by becoming stronger and larger.
So if you do dumbbell chest presses in one workout and switch them to barbell presses in the next, your muscles won't be surprised when you use a different machine and start to grow, because they'll be shocked.
Of course, training variations are necessary, but not with every other workout. For example, if you perform 3-4 exercises that target the chest in one workout. You can certainly change an exercise or something every time you hit your chest. However, the basic core movements need to stay the same for at least 4-8 weeks or longer before you can really see progress.
For example, if you lift 15kg dumbbells while doing the chest press. Your goal should be to progress to heavier dumbbells in the same exercise to see real progress in hypertrophy and strength. The goal should be to weigh 17.5, 20, 22.5, 25 kg, etc. for the next training sessions.
There would be a time when you would reach a plateau in terms of your current training progress. Then it's time to change your exercise selection. But even then, the selection isn't completely changed or placed in a random order.
If this were true, weightlifters and powerlifters would neither get stronger nor taller on the basic exercises of squats, bench presses, and deadlifts.
Furthermore, in most cases, stagnation is not due to a training plateau, but rather to other variables such as diet adherence, lack of sleep, illness, or incorrect training intensity and quantity.
Adding further confusion to the already confusing topic of muscle confusion is the reference some people make to our hunter-gatherer ancestors. Acc. Our ancestors never conducted planned training for them. They did random movements every day and were much stronger, fitter, faster and healthier than us.
The logic seems fine, but the observation and correlation are not. Our ancestors made arbitrary movements due to the demands of their lifestyle. However, if they wanted to learn a skill or develop strength, they would use the same principle of repetitive progressive overload.
For example, if they wanted to learn to climb a tree. From a young age, they practiced this skill daily. This would slowly help them develop their overall strength and ability to climb a tree.
This applies to every person, regardless of time and age. The only difference is that our ancestors did it without being aware of this principle and we do it today, understanding it more scientifically.
Developing a new skill requires daily, repeated practice. When you first learned to ride a bike, drive a car, learn a musical instrument, master a subject, etc., you had to practice for weeks and months before you could achieve precision in it.
Then there is a third aspect of the “muscle confusion” theory. Many people equate muscle soreness with delayed onset muscle soreness (DOMS). Because if they change their training or exercise selection, they will experience more muscle soreness in the next few days.
But the fact is that muscle soreness has nothing to do with muscle growth. Even the most experienced athletes experience muscle soreness when they change their exercise choices or encounter something new while training. The same applies to people who are beginners, as they always encounter new stimuli when training, or to people who are resuming training after a long break.
If someone tells you repetition sucks, it's boring. Then that is definitely the case. But remember: success is the sum of small efforts repeated day after day.
