Recreation or competitive?
For the majority of recreation lifters who's goals center around bodybuilding, the most predominate mistakes I see are...
1) to little focus on strength
2) no planned progression or lacking methods to monitor progression
3) bloated templates: perform way to many lifts that have a whole lot of, and unnecessary overlap.
4) Machine, cable exercises and "accessory" lifts are turned into the main lifts while movements such as squats, press, deads, gm's, etc. are babied or not even used.
5) training mentality... they workout, they don't train.
6) to much time and energy spent on the stupid crap: pre-, peri-, post workout meals, supplements, rest intervals, pre-fatiguing muscles, etc.
7) fail at dieting: eat to little, eat to much, or eats to much bad food. Supplementation is thought of as a cure all and not a supplement.
8) poor consistency in everything: diet, getting in the gym, programming...
This is more or less the problems you see with any beginner, but those in there teens are for the most part new. To get good, always be consistent, work hard, keep a log, take a SIMPLE and brief approach to training (brief in terms of exercise selection per session), commit to your goals and if something isn't working, find the problem don't change your goal or compromise. Read everything and keep an open mind, but don't believe everything you read and hear. Commit to your principles of training, but again keep an open mind and make changes when needed - sometimes you gotta bite the bullet.
Last edited by Pull14; 02-17-2012 at 10:22 PM.