Not Warming Up Properly
If you don’t focus on increasing your core body temperature before you train (I.e Warm Up!), you are likely to severely limit your performance in the gym. So if mass matters to you, don’t just head straight for the bench or squat for a “light set or two” before starting your heavy work. Warming up properly will not only help prevent injuries but it can actually increase productivity in the gym.
Lack of sleep
Sleep is one of the most critical forms of recovery that the body will need. Remember muscles grow during rest periods, NOT whilst training. When you sleep your body releases most of its growth hormone, IGF-1, and testosterone. All of these hormones aid in the recovery and the muscle building process. Lack of sleep will result in limited opportunity for muscles to fully recover… So get some SLEEP!
Fail to incorporate Basic Compound Free Weight Exercises
Basic Compound exercises recruit the most muscle fibers and let you use maximum weight to overload the muscle. Incorporating compound lifts require effort from the target muscles and also neighboring areas, (in the case of squats and deadlifts, the whole body is forced to work systemically, thus producing a system-wide, or total-body, effect).
Some Key Lifts To Focus On:
Bench Press: Chest – Use both the incline and flat version to develop a balanced chest
Barbell Rows: Back
Pull Ups: Back
Military Press: Shoulders
Close Grip Bench/Dips: Triceps
Barbell Curls: Biceps