Are you training in the gym? Are you seeing the gains you are striving for? Chances are, if you are talking with, and listening to, the guys in the gym who pump on the steroids and HGH, then you are getting all kinds of misinformation.
Here are a few "gym myths" you should know about.

1. 10 Rep rule

When I was in high school wrestling, our coach demanded 10 reps on each exercise set; no more, no less. Since those days, however, I have found that 10 reps are not always sufficient, and in fact, is rarely the correct way to go.
High tension i.e. ‘heavy weights’ provide muscle growth in which the muscle becomes much larger, leading to the maximum gains in size and strength. But you can’t always work in 10 reps if you are lifting close to your maximum limit for an exercise.
The other side of the coin is the ‘low weight’ and ‘high rep’ side (long tension), where 10 reps would not be near enough. Utilizing longer tension time boosts the muscle size by generating the structures around the muscle fibers, improving endurance.

The standard prescription of 10 repetitions provides a balance but by just using that program all of the time, you do not generate the greater tension levels that are provided by the heavier weights and lesser reps, or the longer tension achieved with lighter weights and more repetitions.

Solution: No matter what you are doing, complete each set to muscle failure! In other words, lift until you can’t lift anymore.

2. Three Set rule

The truth is there's nothing wrong with three sets but then again there is nothing amazing about it either. The number of sets you perform should be based on your goals and not on a half-century old rule. The more repetitions you do on an exercise, the fewer sets you should do, and vice versa. This keeps the total number of repetitions done of an exercise equal.

There may also be days where you are “really feeling” a certain exercise, and you will want to maximize that. If you are working the chest, and incline bench presses are really burning good, why stop after 3 sets?

3. Three to four exercises per group

This one could go either way. On some days, I will do 4 differing exercises for a group of muscles, and on other days, maybe only one. I mean, there are only so many ways to stimulate your tricep right? But when it comes to chest, I could think of 10 different ways to build.
With this in mind, you need to focus on what is “burning” and not just getting something done. As mentioned above, if a certain exercise is hitting well on a certain day, stick with that and maximize.

5. Lift weights, draw abs

Everyone wants firm abs, and in recent years, the focus has been on the idea of constantly flexing your abs during any and all workouts. Those who push this idea also say that the abs are the only muscles used to support the spine and back.
The truth is the muscles work in groups to stabilize the spine, and the most important muscle groups change depending on the type of exercise. The transverse abdominis is not always the most important muscle group. Actually, for most exercises, the body automatically activates the muscle group that is needed most for support of the spine. So if you focus only on the transverse abdominis, it can recruit the wrong muscles and limit the right muscles. This increases the chance of injury, and reduces the weight that can be lifted. If you recruit the wrong muscles, you may take yourself on a one-way trip to sciattica!

When working out, keep in mind that the most important person to listen to is yourself. You are in the gym to make gains or lose weight, and that means only you can know what is working. Listen to your body, not a dude in the gym!