You can think of them as tough guy. They are at the bottom of the response curve and have a low tolerance for endurance training.
They repair muscle damage much more slowly. This is mainly because they Genotype ACTN3 (ACTN3 XX) and their levels of anabolic hormones (testosterone, estrogen, growth hormone, IGF-1, insulin) were lower than their catabolic hormones (cortisol, adrenaline, glucagon).
If anything, these people need more days off of the week for their bodies to recover. They also need higher calories and protein relative to body weight than more genetically gifted individuals.
Very few people can effectively exercise seven days a week, at least not for long. People who take steroids and are “anabolic-gifted” can do it in a short amount of time. But even for them, it requires a greatly reduced workout time to recover and re-stimulate their muscles.
That is the problem. Your muscles become resistant to a training stimulus if that stimulus occurs too often and lasts too long. Specifically, the activation of mTOR in response to exercise – the main cause of the increase in protein synthesis post-exercise – decreases significantly as you exercise more. This makes you less and less responsive to your workouts.
Fortunately, you can get back to your initial response after a week or two if you reduce the volume and intensity of your exercise. Hence it is necessary to periodically.
By working out every day, you are more likely to speed up desensitization and stop increasing faster. And for a tough guy, it’s even a problem. They tend to be of the ACTN3 XX genotype. One feature of that pattern is a lower mTOR response to initiation training. So the last thing they want to do is reduce that response even more with daily lifting.