Review: Perceived Workload Using Separate (Filtering Facepiece Respirator and Face Shield) and Powered Air-Purifying Respirator and Integrated Lightweight Protective Air-Purifying Res

REview: Perceived Workload Using Separate (Filtering Facepiece Respirator and Face Shield) and Powered Air-Purifying Respirator and Integrated Lightweight Protective Air-Purifying Respirator: Protocol for an International Multisite Human Factors Randomized Crossover Feasibility Study. 

Click on the doi to read the article: doi: 10.2196/36549Links to an external site.

The purpose of these article summaries is to educate me on the study – NOT the topic. Give me facts! This is the information that I am looking for:

What is the research question?
What research method is being used?
How are the subjects chosen (explain the parameters & how many)
What are the results of the study?
What are the recommendations?
What is your opinion? 
Your references must be within the last five years, and websites are unacceptable. I am looking for scholarly research.