Building muscle mass without lifting weights is attainable. There are many body-weight exercises that promote muscle mass gains. According to Ideafit.com, "As you master your own weight, you will not only look better, you will also learn how to train three-dimensional movement, acquire a greater kinesthetic awareness and become empowered as you perform tasks with your body." Performing the proper body-weight exercises will help build muscle mass in all body areas.
Perform pushup variations. Pushups build muscle size and strength in the chest, shoulders and triceps. Start with regular pushups, then transition to pushups with your feet elevated. Keep your hands closer together to work the triceps and shoulder muscles. Widen your hands to work the chest.
Perform pullups to build the back, forearms and biceps muscles. Use full range of motion on this exercise to increase the amount of muscle being recruited. Start with your arms all the way down until they are fully extended, then pull up. When you have mastered the pullup for 10 total repetitions, pause at the top of the bar for three to five seconds. If you cannot perform a pullup, perform negative pullups. Military.com suggests that "All you have to do is get your chin over the bar by standing on something or having spotter push you over the bar. Then, you slowly lower yourself all the way down---let your arms hang grasping the bar fully stretched."
Perform dips. When performing the dips exercise, you must use a dip bar or two chairs. Dips are an effective compound exercise because you lift your entire body weight. When performing dips, use full extension. If you cannot perform a dip, have someone spot you by holding your legs.
Use multiple body-weight squat variations. Squat variations build the quads, glutes and hamstrings. Perform regular squats; once you are able to do 25 consecutive reps, progress to one-legged squats. Ideafit.com states, "The squat is among the most effective lower-body exercises as it incorporates most of the leg muscles working through the kinetic chain."
Do basic back extensions to strengthen your lower back. When you can do 15 consecutive repetitions, advance to the glute-ham raises. For the abdominals, start off performing basic crunches, then progress to twisting crunches. Core work with your own body weight will build muscle in your abs and lower back area.