Let's talk a little bit about High Intensity Interval Training (HIIT). Do you know what it is?

Let's take a look at a bunch of sources below (some of which are peer-reviewed scholarly articles, and some of which are not!) and do an evaluation of these different types of sources. For each of the sources below, let's consider: 

• Is it a peer-reviewed?
• Is it an original research article (also known as primary literature)?
• What's your assessment of the credibility/reliability of the source, and what factors would you use to make that evaluation?