Rest Days for Muscle Growth - Let's Look at Science
The idea of rest days being important to building muscle must seem strange if you are new to fitness. You would think if you want to get really good at bench press, you should do it every day, right? When you say it out loud, it sounds like it makes sense, which means… it does, right?
Well, if you understand a little bit about how hypertrophy works, then you can easily understand the importance of rest, and rest days, which are TOTALLY different things, but we will talk more about that in a minute.
You see, when you lift weights, you’re actually creating micro tears in your muscles, which sounds like a bad thing, but don’t worry, it’s not. After these microtears occur, your body does everything it can to heal itself. Once it’s done enough times, “muscle mass” appears. So, in order to build muscle, you must first break it down. This is, more or less, what people mean when they say the fancy word, “hypertrophy.”
I think now you may be piecing together why rest is important. If you are continuously breaking down muscle fibers, and never allowing them time to recover, you will never achieve hypertrophy. Just as important as rest is nutrition, hydration, sleep, and supplementation. If you want to achieve top-notch results, you MUST be doing all of these things in addition to your strength training program.
Okay, so you realize rest is important now, but that in it of itself can be extremely confusing. I mean, you see the same in-shape people at the gym 5-7 days per week, right? So what gives?
Well, basically there are two ways we need to rest. A rest day is when you let your entire body take a break. Most bodybuilders only have one or two of these per week. BUT what is just as important, if not more important, is resting the individual muscles in between workouts.
How much rest is subjective, and depends on what type of workout split you are doing. I’m going to go into more detail about this, but the MAIN takeaway is that how much rest a muscle needs depends solely on how much volume, in other words muscle damage, a muscle is given on a day in the gym.
A workout split is how someone divides their workouts, such as doing upper body on one day, lower body on another.
If a person is doing the classic “bro split,” which means Chest on Monday, Back on Tuesday, Legs on Wednesday, Shoulders on Thursday, Arms on Friday, that means each individual muscle is sustaining HIGH amounts of muscle damage, which is why they only do the workout once per week.
So your chest is only worked out once per week, meaning it has a full 7 days of rest. However, this split also takes secondary muscles into account. So, the secondary muscles worked during a chest workout will typically be triceps and shoulders, but in much lower amounts of volume, which means they will receive smaller amounts of muscle damage. The shoulders won’t be worked again until Thursday, giving it 2 days of rest, and the triceps won’t be worked again until Friday, giving it 3 days of rest.
The same rule follows for the upper back. Biceps, the secondary muscle group worked during an upper back workout, are given two full days of rest until they are worked again on Friday, and the upper back is given 7 days of rest.
However, a person following an upper/lower split will have much less volume per workout, which means they need less rest in between sets. This split is basically upper body on Monday, Thursday, and Saturday, and lower body on Tuesday, Friday, and Sunday with a full rest day on Wednesday. Each workout group has 48-72 hours of rest versus 7 full days of rest. Since the overall volume for each muscle group is considerably lower, the amount of rest required for recovery is less.
Did you notice what these two splits have in common? They both have at least one FULL day for your body to recover! Even if your muscles are getting appropriate amounts of rest, always remember that your entire body needs a break too.
Whatever workout split you’re doing, I hope you now understand the importance of rest and allowing your body to recover so you can get bigger, bulging muscles faster!