Myth 1: If You Take a Long Break, Your Muscle Will Turn to Fat.

TRUTH: Muscle is created by exposing your body to things that make it say, "Unless I get stronger and plump myself up, I will get killed!" When you stop training, you change the environment for your muscles. Suddenly, the need for them to hang around and be ready for battle will cease. Why keep something you don't need? Without constant tension, your muscle mass will atrophy and you'll burn fewer calories.

Most likely however, your appetite will stay the same and you'll suddenly find yourself eating way more calories than your body needs to maintain its weight. Muscle doesn't literally turn into fat, but with a slower metabolic rate, you'll accumulate more fat as your muscle size shrinks.

Myth 2: If you aren't sore the next day, your workout wasn't hard enough​

TRUTH: Soreness is inflammation and the chemical response to inflammation. The only yardstick by which you need to measure progress is that of your goal. There are Olympic athletes who haven't felt soreness in years. Judge your workout by what happens during that workout.

If you hit a PR, and you aren't sore the next day, it doesn't mean you didn't expend enough energy, it means your energy expenditure was just right. Judging your progress by a pain threshold is incorrect—you don't have to have soreness to gain muscle size or strength.
 

Myth 3: Doing cardio before weights will help you get shredded faster
 

TRUTH: If you run on a treadmill before you hit the weights, you'll be too fatigued to train as heavy as you can. You need muscle, not miles to burn fat.



Myth 4: Caffeine has only negative effects on the body

TRUTH: The problems with caffeine occur mostly because of overconsumption. But with moderate use, caffeine has many benefits beyond that of energy for athletic performance.

Myth 5: Creatine causes massive weight gain​

TRUTH: Creatine is found naturally in your body. Creatine's primary use is as an energy source. Creatine pulls water with it into the muscle cell, which can cause the cell to volumize. Volumized cells are healthy and, in super-jacked people, can actually make muscles look bigger.

The reason for the weight-gain myth is that most people combine a Creatine supplement with carbohydrates and other bulking food. Combined with sugar, Creatine can cause subcutaneous water gain.