It is generally recommended to workout 4-6 days a week and hit each muscle group twice. More than 6 days a week of training is usually deemed as counterproductive and hitting an individual muscle more than 6 days a week is seen by most as extreme to the point of harm.
This is because, after working out the muscle needs to be able to recover fully before undergoing additional training. If a muscle is not able to recover, you run the risk of injury and CNS fatigue. The muscle also will not be able to perform well which forces other smaller muscles to take over for the movement which compounds the risk for injury and degrades lifting form.
Training a muscle everyday does have some upsides but even these benefits usually are diminished if there are not at least 1-2 rest days for the muscle per week.
The main benefits of training a muscle everyday are higher volume and nucleus overload resulting in an increase in myonuclei in muscle cells.
Nucleus Overload Training
Nucleus overload training is a style of working out where you train one muscle group at a high volume everyday for a period of 2-4 weeks in order to increase the nuclei in the muscle. After these 2-4 weeks of high volume minimal-rest training, you give the muscle 4-7 days to fully recover then begin training it again, this time with more nuclei in the muscle resulting in higher amounts of hypertrophy.
This method has been researched and the results are promising for its effectiveness. This study found that following resistance training, the number of myonuclei in muscle cells were increased. This increase in muscle cell myonuclei was permanent and despite inactivity and muscle atrophy, this number of myonuclei stayed the same.
This would explain why, after training for several years, taking time off, then training again, you are able to make gains much faster the second time around than the first. Instead of only muscle memory, the quicker rate of hypertrophy could be explained by a permanently increased amount of nuclei.
The science behind nucleus overload training is that by putting a muscle under high amounts of stress everyday for multiple weeks, the muscle will be forced to increase the number of nuclei in muscle cells in order to sustain the workload. This will allow it to grow quicker once the high volume high frequency training period is over.
Another study done on myonuclei confirmed this result. It found that resistance training leads to an increase in the nuclei of muscle cells that do not degrade once the overload training stops.
This all relates to training a muscle everyday because, by training a muscle in very high amounts of volume, there may be a longterm positive effect on that muscle’s ability to grow.
There are, of course, downsides to training a muscle everyday though. These are why when doing nucleus overload, you still need to take 1-2 rest days per week.
How Long Does It Take For a Muscle To Recover?
For hypertrophy to occur, there needs to be time for the muscle to have its damage proteins repaired. This process of repair is the mechanism by which muscles increase in size and strength.
Without recovery, muscles would not grow and would likely become fatigued to the point of tearing or incapability of proper functioning. Even with nucleus overload training, it is recommended to build in rest days to avoid these problems.
The amount of recovery time a muscle needs to recover can fluctuate. Every individual requires a different amount of recovery time. There are multiple factors that influence the amount of time recovery needed. Some of these factors are wether you are in a caloric surplus or deficit, how much sleep you are getting, the amount of protein in your diet, the volume of your training, and other stress factors that can inhibit optimal muscular growth.
Taking these factors into account, for most people around 2 days of recovery are needed for a muscle to grow following training.
If you are working out the same muscle everyday, that recovery time window is never going to be fully completed and the muscle will not be performing or growing optimally. Growth and strength gains might still occur, but over time if you are training at a high intensity, the muscle will not be able to work like it needs to and will fatigue.
Pros and Cons of Working Out the Same Muscle Everyday
The primary pro to working out the same muscle everyday is that it is likely that the myonuclei of the muscle cells will increase in number which will allow the muscle to grow quicker in the future as well as from the current training. Another pro is that a lagging muscle could be able to “catch up” from the added volume and attention.
The cons of working out the same muscle everyday are that injuries are more likely, joints will be adversely affected, there is a significant chance of CNS fatigue, recovery for that muscle will not be optimal, and that muscle could fatigue entirely and not be able to endure any training at all.
Overall, you can workout the same muscle everyday but for optimal recovery and performance, you shouldn’t.
This is because if you never take rest days off from training, there is a high chance of injury, the muscle will not be able to continue lifting at the same intensity, the central nervous system could fatigue, gains will not come as quickly as they could otherwise, and overall health and strength can decline.
If you want to train a muscle everyday in order for it to catch up to the other muscles and grow more quickly, train that muscle intensely for 4-5 days a week and give it at least 1-2 days off. Do this style of training for 2 weeks to a month then return to your normal split. After this period of nucleus overload, you should see a positive increase in the size and strength of that muscle.
Make sure you are not over stressing the CNS and that your joints are not being worn down because any gains you make from high frequency high volume training will be negated by injuries and inability to train in the future.
For more on training, such as how to start lifting again after time off and the possible benefits from doing the stomach vacuum exercise, click here.