don't concentrate on only upper body, you'll look gay. no offense to gay people. and the key to getting good looking muscles is , gettina all your muscles in good shape, and balance, because they all are connected and make each other stand out. and light weigh high rep is a good theory, but it's not an excuse to be a pussy. high reps means at least 15, and you should barely be able to get the last rep up on each set. and do at leas 3 sets. Here are some basics if you are only going for cosmetic effects, like you said, i just want my upper body bigger.
arms. the key to good arms, is tricep tricep tricep. it's 2/3 of your arm. french press(hammer skull crushers), tricep pull down, tricep push ups, close grip bench all in the same workout.
biceps, every bi work out, include hammer dumbell curls, where you are holding the weight like a hammer thumbs up., 21's with barbell (look em up, easy) switch your grips up, hard to go wrong with biceps, just do lots of sets and get the blood in there.
Chest= flys, dumbell press, dumbell incline press. (use dumbells over bar bench to make your chest even , plus more range of motion.) push ups, dips.
Back- most important muscle in the body, and most underdeveloped in most people. Pull ups, seated rows, tbar rows, and pull downs.
Why should you work your lower body?? they are the biggest muscles, if you get those inshape (weight strenght, not running) you will relase more chemicals that help you life, ie testosterone, hgh, creatine, calcium, etc.
so if you are trying to grow in one area, do a big muscle group first. Like do two sets of squats on a medium weight to get your blood flowing, then do biceps or chest if you want to grow.
The basic principal to training muscles is getting blood flow, so lift hard, and over time you will feel the "pump' when you muscle are trained. Even if you are trying to "cut up" lift hard. Trust me, you won't get too big. It's a challange to get big , you need to eat a clean 4000 plus calories of balanced protien/carbs/fat. If anyone else has questions feel free.
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