Having spent many years doing many different workouts involving weights, cardiovascular machines, and calisthenics, I determined that the best way to build mass and boost metabolism is by doing pushups. Lots of pushups! After less than three months training, I was able to complete a one-thousand pushup routine in exactly 80 minutes. I gained 15 lbs of solid muscle mass, lost a considerable amount of body fat and consistently ate 5000-6000 calories daily.
Calisthenics, like pull-ups and pushups, are commonly avoided because they can be extremely painful. Because strength training exercises are typically anaerobic, with few exceptions, the body produces a high amount of lactic acid, thus causing a burning sensation in the muscles. Coupled with physical and mental exhaustion, an abundance of lactic acid can persuade even the hardest of athletes to give it a rest. Remember that your body will prevail, as long as you maintain your mental strength.
To begin, I would recommend a routine consisting of no more than 100-200 pushups, spread out over an entire day. Break them down into even sets, of say 20 pushups per set. Whenever you feel confident in yourself, drop to the floor and pound out a quick set. If 20 pushups are too many when you begin, then do more sets consisting of fewer repetitions per set. Do not concern yourself with the amount of time it takes to complete the first few workouts, just make sure you drink a lot of water and eat a lot of high protein food throughout the day. The day following your first pushup workout, your chest, stomach, shoulders and legs will be sore. It will become apparent just how many muscle groups are worked when doing pushups. Take 2-3 days rest.
The secret to building the endurance strength necessary to do extremely large numbers of repetitions is to strategize with your own body. The workouts need to be strategically spaced apart and sometimes stacked together to maximize results.
The second workout should be the same as the first, however do not take a 2-3 day rest after the workout. Instead of taking a long break, work out every other day, until you no longer get sore the day after. It may take a few weeks in order to be comfortable doing 200 pushups every other day. Do not lose sight of your goal. Remember that pain is a result of muscle wear and recovery, and should mentally represent progress, not a limitation. It will never go away, but it will greatly diminish over time as your body adjusts.
The third stage requires that you compress your workout into a set time interval. For the sake of example, let's say one hour. Find a comfortable number of repetitions that you feel that you will be able to repeat until you have reached your daily goal of 200 pushups. In this example, we'll do 10 repetitions. This workout will consist of 20 sets of 10 repetitions. 20 sets, evenly divided across 60 minutes means that you will need to do one set of 10 pushups every three minutes. Make sure that whatever goal you choose is achievable, and also poses a challenge. Repeat this routine every other day, until it becomes comfortable.
Because your muscles will quickly become fatigued doing calisthenics, it is very difficult to continually add more reps or sets to your workout. The easiest and most successful method [in my opinion] for building endurance is stacking workouts. By stacking, I mean completing the same workout more than one time in less than a 24 hour period. During the fourth stage, complete a 200 pushup routine in the morning and in the evening, followed by a day of rest. Once again, just like the previous stages, do this routine until your body becomes comfortable- this should only take a couple of weeks. At which point, you will complete the workout stacking, by coupling the two sessions into one two-hour session, consisting of 40 sets of 10 pushups, totaling 400 pushups. My buildup workouts include two sessions of 300-500 pushups apiece, followed by a day of rest. Note that you should not work the same muscle group two days in a row without rest. This method gave my body time to rest and refuel between sessions without going completely into recovery mode.
If your body responds quickly and you start to build considerable muscle mass in a short period of time, which I'm sure you will, the next thing to do is increase the number of repetitions per set and decrease the amount of time between sets. I would recommend a goal of 25-30 reps per set, beginning one set every 2 minutes. If done gradually, the workout compression can be very smooth and your 400-pushup routine can be completed in 32 minutes. It sounds very difficult, but it is achievable.
Now that you have the tools; timing your sets, timing your workouts and adding reps, you can pull the strings and make the workout work for you. If you have any difficulty in any particular aspect that prevents further gains, use the other techniques to manipulate your body into cooperating. For example, if you cannot add more reps to your sets, do more sets, or if you cannot do more sets, do two larger workouts spaced apart from one another.
Two important things to remember when doing mass building exercises such as pushups are; drink lots of water and eat lots of high protein food throughout the day. When doing my one-thousand pushup routine, I drink at least one full gallon of water daily to avoid dehydration and joint fatigue. Good luck!