The muscle endurance objective is pursued when you want your muscles to be able to perform the same motions over an extended period of time or in other words when you want your muscles to be strong and not become tired rapidly. You'll want to use at least 4 sets from which at least 16 repetitions are performed. The muscle endurance objective is often used for muscles in your lower body, such as those located in your legs or your buttocks.
If you are referring to how many pushups to do in one session, the short answer is as many as you can. Aim for a number that challenges you but is still realistic. Build up from day to day to increase muscle strength. If you are referring to how long you should do pushups as a form of exercise, that is up to you. Pushups are a good part of a long-term or permanent exercise regimen. Remember that if you stop doing them, your muscles will weaken.
Pro Tip: Zane also suggests that directed concentration is exceptionally important to getting the most from your training and is much easier with lower weight. If you can concentrate on the muscle through its whole movement, you will notice that the intensity will be just as strong, without the risk. We teach you this in our “Mind Muscle Connection” Bonus Guide that we include in our Old School Muscle 8-Week Program.
Synthesis primarily takes place in the kidney and liver, with creatine then being transported to the muscles via the blood. The majority of the human body's total creatine and phosphocreatine stores is located in skeletal muscle, while the remainder is distributed in the blood, brain, and other tissues. Typically, creatine is produced endogenously at an estimated rate of about 8.3 mmol or 1 gram per day in young adults. Creatine is also obtained through the diet at a rate of about 1 gram per day from an omnivorous diet. Some small studies suggest that total muscle creatine is significantly lower in vegetarians than non-vegetarians, as expected since foods of animal origin are the primary source of creatine. However, subjects happened to show the same levels after using supplements.