For teenagers, the first few times at the gym is not the greatest experience. Little to no knowledge of how to train properly results in workouts in which nothing is accomplished.
You walk around, trying all the different machines. Probably using poor form trying to lift weight that is much too heavy. Try and mimic the more experienced bodybuilders, but to no avail.
Until you learn the ins and outs of proper training, you will make minimal progress towards accomplishing your goals. How long that will take depends on your willingness to learn, and deal with the fact that you are not going to transform into Ronnie Coleman overnight. Baby steps are the paths to success.
Developing A Routine
The first key to success is developing a routine.
Body Weight Routine:
As a beginner, you want to start with the basics, which means incorporating Body Weight Exercises such as Pull-Ups, Chin-Ups, Push Ups, Dips, and Hyperextensions. You need to be able to work with your own bodyweight before getting into more advanced routines.
Here is a Full Body Workout to be performed 3x a week:
Shoulders & Chest:
The 5 groups of exercises are to be done as supersets. A superset includes jumping from one exercise to the next with no rest in between. I would recommend only doing 2 or 3 sets per exercise, the last thing you need is to burn out your muscles within the first few weeks. Try and push for 12 to 15 repetitions per set, using lighter weights and utilizing precise form.
Barbell squats, barbell deadlifts, and Barbell Bench Presses should NOT be done at all during this stage. They are no doubt the best exercises for building muscle mass. However, as a beginner you are very unlikely to exhibit proper form on your lifts. Poor form on these exercises is likely to result in injuries. You will eventually perform the "Big 3" frequently.
The single most important bit of information I could give a beginner is to use pinpoint form on each and every one of your repetitions. Establishing good form from the beginning is necessary for future gains with heavier weights. Do not pay any attention to the big guys at the gym that use their entire body to jerk down the entire stack of weights during wide-grip lat pulldowns. Believe me, it DOES NOT produce results.
When you feel you have made a good amount of progress, you can now split up your routine. It will vary based on the number of days throughout the week you are able to get into the gym. As a teenager still with minimal experience, a 3 or 4-Day Split is perfect. Remember, you do not want to overtrain.
Legs & Shoulders:
Back & Biceps:
Chest & Triceps:
Back & Biceps:
Chest & Triceps:
These routines are simple, safe, and produce results You will be using Smith Machines on the more compound exercises to make sure you exhibit perfect form. The last thing you need is muscle strains or injuries from using improper form or trying to lift too much weight.
Do not go below 8 repetitions in a set. If you do, that means the weight is too heavy and you are jerking up the last couple repetitions. Stay below 3 sets per exercise, you do not want to over train and wind up losing muscle.
For abdominal work, alternate between your upper and lower abs every day. Don't slack off on your abs, either. A strong core is just as important as a strong chest. And who doesn't want a six pack?
I am a strong believer in cardiovascular work. As a teenager, I'm sure you are involved in an athletic activity. It feels great to play basketball with your buddies and watch them tire out while you still got plenty of energy left in the tank.
I personally enjoy swimming after my workouts. When you swim, you use your entire body, not just your legs. Ever seen Michael Phelps? Never lifted a weight in his life and he's extremely lean and ripped. Cardio should be your best friend.
It all sounds simple, but in reality it's not. Hard work, determination, and perseverance will help you make progress and reach your goals. Remember, proper form on every repetition. An exercise done incorrectly is an exercise not done at all. Just take it one step at a time, you will see the difference!