Rep out pushups and pullups according to your abilities to build muscle.
Performing high repetitions of pushups and pullups can absolutely help you build muscle in your upper body. However, to do so efficiently and effectively, you must perform the exercises within certain parameters at an appropriate difficulty level. Your level of fitness will determine which variations of these movements will be right for you in order to execute the necessary amount of repetitions to build muscle.
You can build muscle with high repetitions of pushups and pullups if you choose the right amount of difficulty.
Consider Your Reps
Generally, hypertrophy - or muscle growth - is best achieved when performing six to 12 repetitions using 67-85% of the maximum resistance you are able to perform one repetition of the exercise with. Another name for this resistance is a "one-rep-max." This does not mean you cannot build muscle with lower repetitions using a heavier weight or higher repetitions using a lighter weight. However, those rep ranges focus more on strength and muscular endurance respectively.
Reps for Pullups and Pushups
The same principles apply to pushups and pullups. If you weigh 150 pounds and are only able to perform one bodyweight pullup, 150 pounds would be your one-rep-max. In order to build muscle more efficiently, you would need to decrease the amount of resistance in that movement in order to be able to do six to 12 repetitions. Conversely, if you are able to do 100 pushups without breaking a sweat, you may build some minimal muscle but are training more for muscular endurance. Therefore, you would need to increase the amount of resistance in order to limit yourself to six to 12 moderately difficult repetitions for a greater hypertrophy focus.
Manupulate Resistance in Pullups
Pullups mainly target your lats in addition to your biceps and muscles in your upper back, such as your rhomboids, traps and posterior deltoids. To add resistance, simply attach weighted plates or dumbbells to a dip belt when performing the exercise. For the very advanced, attempt the movement using only one arm to pull yourself up. To decrease resistance, place your feet on the floor or box and support yourself just enough with your feet to render the repetitions doable but challenging. Additionally, assisted pullup machines allow you to choose the amount of resistance you would like to remove from the movement.
Adjust Your Pushups
Pushups stimulate your pectorals, triceps and anterior deltoids. For more resistance, place your feet on an elevated platform, such as a bench or a wall. The greater the elevation, the greater the amount of resistance you will feel. To make the exercise easier, have your hands at an elevation, such as on a bench or railing. This time, a higher elevation will yield less resistance. Another method to make the movement easier is to have your hands flat on the ground as you normally would, but keep your knees bent and touching the ground throughout the exercise.
Warm Up First
Stretch and warm up with light cardio or exercises with lighter weights before moving on to the working sets of your main weight-training routine. Only attempt to increase resistance if it is far too easy to perform 12 repetitions at the current difficulty level of the exercise. Additionally, in order to stimulate the targeted muscles to the fullest and prevent injury, perform each movement with proper technique. Seek the guidance of a trainer to assure that you are using the appropriate form on all of your exercises.