The quickest way to quickly pack on muscle is by using basic weightlifting movements that work the major muscle groups. Forget about doing triceps extensions and cable crossovers; building muscle quick means using reasonably heavy weights, low reps, basic movements and lots of rest.
The following routine need only be done three days per week (Monday, Wednesday, Friday for example) and shouldn't take longer than 45 minutes to an hour to complete. Forget about any kind of cardio on the days you aren't weight training, this isn't training to get six-pack abs (yet), this is telling the body it's time to grow!
1. Bench Press
The bench press has been called the "upper body squat," and for good reason. Bench presses train shoulders, triceps, pecs and many stabilizing muscles in the torso. To build mass, training with about 80 percent of the one repetition maximum for between six or fewer reps can stimulate new muscle growth, as well as significant strength gains.
According to a 2010 article on the American Council on Fitness (ACE) website, a good muscle building routine will involve completing three to six sets of six to 12 repetitions with about 30 to 90 seconds of rest between sets. This is the way to train all the following movements to get buff quickly. Visit this link to learn how to do bench presses correctly
2. Barbell Bent-Over Row
The bent over row is an exercise that involves not only the back muscles but also the forearms, biceps, shoulders and even the glutes and hamstrings (they keep the body in position during the movement). This exercise will stimulate almost every muscle in the body, and when done with enough weight to accomplish between four to six reps, should help pack on new muscle.
Check out how to do the barbell bent over row here. This is an exercise that requires some caution; carefully practicing with a lighter weight first will help prevent lower back injuries from occurring.
3. Barbell Squat
Barbell squats are an exercise that stimulates almost every lower body muscle. According to 2015 article published by ACE, the squat will work the hamstrings, glutes, quadriceps, back and core muscles. That's a lot of muscle stimulation in one basic movement!
Like the barbell bent-over row, it's a good idea to start light until mastering the correct form for this exercise. Training with a squat rack that incorporates safety features is advised. Learn how to do correct barbell squats here. Remember that three to six sets of six to 12 repetitions with about 30 to 90 seconds of rest between sets should do the trick.
The deadlift can work almost every muscle in the body. It's one of the most basic lifting movements; the weight is on the floor, the exercise is simply to lift it off the floor (in the safest possible manner).
According to this 2013 article from ACE, The basic deadlift is very effective for developing the hamstrings, glutes and the entire core (so abs aren't ignored while you're bulking up), including the muscles in the back, hips and gut. Check out this website to learn how to do a safe deadlift.
5. Barbell Clean and Jerk
This is a compound exercise that, like the deadlift, will work almost every muscle group. The idea is to lift the weight from the floor to the shoulders, then push it up overhead. Not only will it stimulate most major muscle groups, but it will even get the heart rate up and possibly provide some cardio benefit.