There's plenty of bad advice floating around gyms. Everyone has their own theory on how to lose weight and build muscle. You may find yourself gravitating towards the guy bench pressing over three hundred pounds or the girl that does over three hundred crunches. Everyone has their own definition of fit. I can not count how many times I've been asked how much I can bench. The amount of pounds you can bench press does not equate to how strong or fit you are. You can build muscle and strength by lifting heavy weights, you can also do the same with your own body weight.
You may see some gym goers packing on the plates as they bicep curl. They may consider adding weight to their max a progression. In one aspect it is, the weight increased. On the flip side, their mobility may have decreased. This same person may attempt to do pull ups and can not do a single one. This is an exercise that is more functional and requires a great deal of upper body strength. It recruits more muscle groups than isolated weight training and is more impressive, quite frankly.
The difficulty of this exercise tends to discourage some people from trying it. The problem with isolated weight training is that it does not work muscular coordination. When you isolate your muscle groups, the muscles develop individually. Think of climbing a ladder, your legs are working with your arms to move up and down the ladder. If you tried to climb with only your arms or legs, it would be more of a challenge. A pull up engages muscles to work together, rather than isolated. This requires development of more muscles to execute the move.
No matter what your goals are, whether you are male or female, pull ups will build your arms the way you want them to look. If you can not do a single pull up, you can start by getting to a bar. Grab the bar with your palms facing away from you and propel yourself up. You can use a step to reach the bar or jump from the floor. Get to the position where your neck is lined up with the bar. You do not have to pull yourself up. Jump or climb to get there and hold for about five seconds. After the isometric hold, slowly lower your body until your arms are fully extended. Try doing this five times. The next time do it for two sets, then three sets. Try pulling yourself up every time. You'll soon notch your first pull up. This is a vertical pulling exercise. It is beneficial to work it in tandem with a vertical pushing exercise. A dip is a vertical pushing exercise. To build the strength for a dip, find a set of parallel bars and start with your arms extended and your back straight. Let your feet hang and lower your body so your elbows make a ninety degree angle. At that point, hold for five seconds and try to push your self back up. If you can not, reach your feet for the floor. Follow the same sets and reps as the pull ups. You may excel at one faster than the other, which is completely normal. Do more work on your weaker exercise to compensate.
Once you start doing pull ups and dips, they will be building building exercises. When you reach the point that you can complete about ten repetitions of each, it transitions to an endurance exercise. If you want to keep building on your strength, use a weighted belt to increase the load. If you want to tighten up your arms or if you want to build your arms, work on your vertical pushes and pulls. If you can bang out ten reps of each, you will have some solid upper body strength. A side effect may be flab free arms.