Being Tired  
When you’re tired, you don’t have enough energy to do what you need to do. You might not even know how much energy you have left until you run out. When you’re tired, you’ll make mistakes and get distracted easily. If you’re tired, you won’t be able to concentrate on your training.  

Not Having Enough Sleep 
Sleep deprivation makes you feel groggy and unfocused. Your brain doesn’t work well when you’re tired, so you won’t learn anything new. Sleep deprivation also causes you to lose muscle mass, making you weaker than usual.  

Hunger 
You might think hunger would help you train harder. But if you’re hungry, you’ll eat junk food instead of nutritious foods. Junk food isn’t good for you. It’s full of calories and bad fats, but it doesn’t provide any nutritional value. So when you’re hungry, you end up eating something unhealthy.

Stress 
Stress affects your body in many ways. It can cause headaches, upset stomach, and fatigue. It can also affect your memory and concentration.  

Losing Focus 
If you’re stressed, you might start thinking about things that aren’t related to your training. That means you won’t pay attention to the task at hand.  

Getting Injured 
Being hurt while training hurts your performance. It slows down your progress and increases your chances of getting injured.

Having No Motivation 
Motivation helps you push yourself to achieve your goals. Without it, you’ll never reach them.