Without getting into great detail, if you've been working out and you are not seeing the results you want, there are two things that you won't get big without.... proper diet and myofibrilar hypertrophy.
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Basically, you will need to train hard and eat right and when you are lifting remember this.... myofibrilar hypertrophy is induced at the 3-6 rep range, so make sure you put enough weight on to keep yourself from being able to do any more than 3-6 reps.