A story to help you understand how exercise works best.

Imagine that you're a contestant on a game show. In this simple game, you have a certain amount of time to collect as many rocks as you can and place them in a bucket. 

For each rock that you collect you will be given a certain amount of money.  Some rocks are worth more than others but they are all valuable! 

How would you move while you were collecting those rocks? Would you be working as hard and as fast as you can, getting tired, sweaty, and out of breath, while you collected rocks as fast as you could for that short amount of time? Or wWould you move slowly and complain about what it was how it was going along the way?

I bet you would move as fast as you could to get as much as you could as a prize.  

When it comes to exercise, the rocks that you were trying to pick up are repetitions of exercises in the gym. The set amount of time that you have is the length of the workout. Your goal is to get as much done in the workout as possible because you are the one that gets paid for each rock (rep) that you collect.

Now, remember that in our game show, some rocks are worth more than others. The rocks that are worth more are the repetitions that you do with perfect technique. I called these “gemstones”. It would be good for you to work as hard and as fast as you could to pick up rocks but it's even better to pick up the gemstones first. 

Move with perfect technique and you will be getting as large a prize as you possibly can from the effort you are putting in.